Salts & Minerals · Bath salt
Magnesium Chloride Bath Flakes
Magnesium chloride, MgCl2 (a mineral salt, not a plant) · also called Magnesium flakes, magnesium bath flakes, magnesium chloride flakes
Magnesium chloride flakes are a mineral salt that dissolves in bath water. They are sold to soothe muscles, help sleep and top up magnesium through the skin. A 2017 review calls the skin-absorption claim scientifically unsupported, and we found no trial of a flakes bath for muscles or sleep. Safety point: never swallow them, and ask a kidney doctor before using any magnesium product if your kidneys are weak.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Magnesium Chloride Bath Flakes
Magnesium chloride flakes are a mineral salt sold for baths and foot soaks. The research is a handful of small pilots, a review that doubts skin absorption, and lab work on skin. No trial tested a flakes bath for muscles, sleep or magnesium levels. The risks on record come from swallowing magnesium salts and from kidney disease.
What it is
Magnesium chloride is a salt of the mineral magnesium. It dissolves in water and is sold as clear-white flakes for baths. It is not a plant.
It is not the same as Epsom salt (magnesium sulfate) or Dead Sea salt, which holds many minerals. Results for one do not carry over to the others. The sources we read do not say how bath flakes are sourced or how pure they are.
Traditional and current uses
Topical magnesium is described as one of the oldest therapies for skin disease, for example Dead Sea therapy and Epsom salt baths. Today flakes are marketed for tired muscles, sleep, stress and skin.
Marketing says the skin takes magnesium in better than the gut does. A 2017 review says that claim is scientifically unsupported. Tradition is not proof that a bath works or is safe.
What the research shows
Skin absorption: a 2026 pig-skin study found minimal magnesium crossing intact skin and several orders of magnitude more through stripped skin. A 2016 human-skin lab study found some passage that depended on concentration and time. Neither measured a bath or levels in a person.
People: a 25-person cream pilot saw no significant overall rise in blood magnesium (0.82 to 0.89 mmol/L, p = 0.29). A 20-person spray pilot in advanced kidney disease saw no significant change in serum magnesium. A gel trial in 35 runners found no benefit for soreness.
Skin: one small controlled study of a branded Dead Sea salt soak on a forearm saw benefits in dry, atopic skin. It does not show the same for plain flakes.
At a glance
Traditional uses history, not proof
- Topical magnesium is described as one of the oldest forms of therapy for skin disease, for example Dead Sea therapy and Epsom salt baths (Chandrasekaran 2016 abstract).
- Today flakes are sold for soaks and foot baths; the sources read give no dated history for the flakes themselves.
Studied for research
- Raising magnesium through the skin, very low certainty
- Sore muscles and recovery, evidence against (a gel trial found no effect)
- Sleep, stress and relaxation, insufficient
- Dry, atopic skin (a Dead Sea salt soak), low
- Fibromyalgia and nerve symptoms (sprays, uncontrolled), very low
- Detox, insufficient
Main compounds
- Magnesium chloride (MgCl2)
Common forms
- Flakes dissolved in a bath or foot soak
- Related but different: magnesium chloride sprays, creams and gels
Research links: Myth or Reality: Transdermal Magnesium? 2017 review (abstract) · Magnesium gel and exercise recovery, 2025 trial (abstract) · Magnesium through pig skin, 2026 lab study (abstract) · Dead Sea salt soak for atopic dry skin, 2005 (abstract) · MedlinePlus: Magnesium in diet · Poison Control · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Magnesium chloride (MgCl2) bath flakes: a mineral salt, not a plant
- Synonyms
- Magnesium flakes; Magnesium bath flakes; Magnesium chloride flakes
- Common names
- Magnesium flakes (English); Magnesium chloride flakes (English)
- Family or group
- Metal chloride salt of magnesium (magnesium dichloride, Cl2Mg, molecular weight 95.21, PubChem CID 5360315)
- Habitat
- The sources read do not say how bath flakes are mined, extracted or purified.
- What it looks like
- Sold as clear-white flakes that dissolve in bath water.
- Harvest and processing
- Not described in the sources read; processing differs by supplier.
- Look-alikes and adulterants
- Name: Epsom salt (magnesium sulfate); Note: A different magnesium salt (PubChem: magnesium sulfate, MgO4S). Lab and case results for one should not be assumed for the other.; Name: Dead Sea salt; Note: A mixed salt rich in magnesium chloride plus other minerals. The one bath study used a branded Dead Sea salt, not plain flakes.
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| Traditional spa and Dead Sea therapy | Topical magnesium is described as one of the oldest forms of therapy for skin disease, for example Dead Sea therapy and Epsom salt baths. | p27624531 |
| Recent marketing | Transdermal magnesium (sprays, flakes, salt baths) is promoted as more effective than oral magnesium; the 2017 review says this is unsupported. | p28788060 |
Traditional use shows how it was used. It does not show that it works or is safe today.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Magnesium chloride PubChem 5360315 | inorganic salt | The main ingredient; purity of products not described in the sources read. | Dissolves in water to release magnesium ions. Magnesium is an essential mineral; MedlinePlus says deficiency is rare in people eating a normal diet. 11 | Identity (database) |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Passage of magnesium through skin | None | Pig skin: minimal passage through intact skin, several orders of magnitude more through skin with its top layer removed (magnesium sulfate). Human skin samples: passage depended on concentration and time and was helped by hair follicles. 2 3 | Laboratory |
| Skin barrier and hydration (proposed) | None | The authors of the Dead Sea salt study suggest magnesium salts bind water, affect skin cell growth and help barrier repair. Not isolated from other minerals in the salt. 8 | Human observation |
| Magnesium status | None | Blood magnesium did not change significantly with a magnesium chloride spray in advanced kidney disease and rose significantly only in a subgroup with a cream. 7 1 | Human pilot |
Absorption, metabolism and elimination
- Absorption
- Uncertain. A review calls skin absorption claims unsupported; lab skin work is mixed; no bath study measured body levels.
- Distribution
- Not studied for baths.
- Elimination
- Kidneys clear extra magnesium (MedlinePlus).
- Bioavailability
- Not established through skin.
Isolated compounds versus whole extracts
Plain magnesium chloride flakes, Dead Sea salt (many minerals) and Epsom salt (magnesium sulfate) are different products. Results do not transfer between them.
Nutritional composition
Magnesium is an essential nutrient, but a bath is not a proven way to supply it. MedlinePlus says deficiency is rare with a normal diet.
1 low certainty2 very low certainty2 not enough evidence1 evidence against
What was looked at
The 6 benefits and uses checked for Magnesium Chloride Bath Flakes, each with how strong the evidence is. Tap one to open it.
- Raising magnesium levels through the skinVery low certainty
- Sore muscles, aches and recovery after exerciseEvidence against
- Sleep, stress and relaxationNot enough evidence
- Dry, atopic skin (magnesium-rich salt bath)Low certainty
- Fibromyalgia and nerve symptoms (sprays)Very low certainty
- Detox or drawing out toxinsNot enough evidence
Lab markers tracked in the studies
Serum magnesium
What is Magnesium Chloride Bath Flakes good for?
The uses people ask about and how strong the evidence is for each. None is shown for plain magnesium chloride flakes in a bath.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Raising magnesium levels through the skin
Very low certaintySellers say magnesium soaks in through the skin and beats pills. A 2017 review calls that claim scientifically unsupported. Small human pilots of a cream and a spray did not show a clear rise in blood magnesium. Lab work on skin is mixed: very little crossed intact pig skin, and more crossed damaged skin.
5 studiesCream and spray in the pilots, not bath flakes; no advice here.
Studies, doses and limits
What the trials found
One 25-person pilot of a magnesium cream and one 20-person uncontrolled pilot of a magnesium chloride spray in kidney disease. No trial of a bath of magnesium chloride flakes measuring magnesium in blood or urine was found.
Results
Cream: serum magnesium 0.82 to 0.89 mmol/L (p = 0.29 overall; p = 0.02 only in a non-athlete subgroup) versus 0.77 to 0.79 with placebo. Spray in advanced kidney disease: serum magnesium did not change significantly.
Effect sizes as reported
Cream pilot: 8.54% rise in serum magnesium versus 2.6% with placebo; not significant overall.
Why this rating
No bath study. The pilots are tiny, one has no control group, and the one overall result was not significant. A review calls the idea unsupported. Lab skin studies disagree in emphasis and are not human baths.
Form and dose studied
Cream and spray in the pilots, not bath flakes; no advice here.
Who was studied
25 adults (cream); 20 adults with advanced kidney disease (spray).
Limits
Pilots, a different product from flakes, no long-term data. The 2026 pig study used magnesium sulfate, not chloride.
Why researchers looked
Oral magnesium can upset the gut, so sellers promote skin routes as a gentler way in.
Traditional use
Topical magnesium is described as one of the oldest therapies for skin disease, for example Dead Sea therapy and Epsom salt baths (Chandrasekaran 2016 abstract).
Proposed mechanism Pharmacological theory
The outer skin layer limits how much magnesium crosses. A 2026 pig-skin study found minimal passage through intact skin and far more through skin with the top layer removed. A 2016 human-skin lab study found some passage that depended on concentration and time, helped by hair follicles. Neither measured a bath, flakes or levels in the body.
A proposed mechanism does not show that the effect happens in people.
People with kidney disease need to ask their kidney doctor before using any magnesium product (see Safety).
Sore muscles, aches and recovery after exercise
Evidence againstA soak is a popular way to ease tired muscles. A good trial of a magnesium gel on the thighs after hard running found no effect on soreness or muscle damage markers. We found no trial of magnesium chloride flakes in a bath for muscle soreness.
2 studiesGel on the thighs in the trial; not a bath, no advice here.
Studies, doses and limits
What the trials found
One randomised, double-blind trial of a magnesium gel (35 healthy adults) after downhill running. No trial of flakes in a bath.
Results
No differences between magnesium gel and placebo on any outcome. Soreness at 24 hours was 43 (SD 27) with magnesium and 41 (SD 26) with placebo.
Effect sizes as reported
No difference on soreness, strength, creatine kinase or interleukin-6.
Why this rating
The only controlled trial found for a magnesium product on skin and muscle soreness was null. It tested a gel, so it does not rule out the warmth and rest of a bath, but it gives no support to magnesium itself.
Form and dose studied
Gel on the thighs in the trial; not a bath, no advice here.
Who was studied
35 healthy active adults.
Limits
Gel not flakes; authors say the amount or application may have been too small.
Why researchers looked
Oral magnesium has been studied for muscle soreness, so people ask whether a soak does the same.
Traditional use
Warm baths for tired muscles are a long-standing home habit; the sources read give no dated history for magnesium flakes.
Proposed mechanism Pharmacological theory
The idea is that magnesium enters the body through the skin and relaxes muscle. The mechanism is not shown, because passage through skin is itself uncertain.
A proposed mechanism does not show that the effect happens in people.
Heat and long soaks can affect people with heart or blood pressure problems; no source read covers this, so ask a doctor (see Safety).
Sleep, stress and relaxation
Not enough evidenceSellers claim magnesium baths calm the mind and help sleep. We found no trial of magnesium chloride flakes for sleep, stress or mood. A warm bath may feel relaxing by itself, but that is not evidence for the magnesium.
1 studiesNot studied.
Studies, doses and limits
Results
No results to report.
Why this rating
No human study found. Seller claims are not evidence.
Form and dose studied
Not studied.
Who was studied
Not studied.
Limits
Searches of PubMed titles and abstracts were limited; a trial could exist that we did not find.
Why researchers looked
Low magnesium is linked in the literature to sleep and mood problems, so a soak is promoted as a fix.
Traditional use
Evening baths are a common wind-down habit; no source read dates a magnesium flakes tradition.
Proposed mechanism Pharmacological theory
The suggested route is magnesium entering through the skin. That is not shown (see above).
A proposed mechanism does not show that the effect happens in people.
Do not swap a soak for medical help if sleep or mood problems are serious.
Dry, atopic skin (magnesium-rich salt bath)
Low certaintyOne controlled study had people with dry, atopic skin soak a forearm in a Dead Sea salt rich in magnesium chloride. Skin barrier, hydration, roughness and redness improved compared with the tap-water arm. It tested one branded salt on one forearm. It does not show that plain flakes in a full bath do the same.
1 studiesA 5% solution of a branded Dead Sea salt for 15 minutes on one forear…
Studies, doses and limits
What the trials found
One controlled clinical trial (2005); number of people not given in the abstract.
Results
Barrier function (water loss) improved versus tap water in the subgroup with high starting water loss; hydration rose on the salt arm in each group; roughness and redness fell.
Effect sizes as reported
No numbers in the abstract.
Why this rating
A controlled design with benefits reported, but one small study, one branded Dead Sea salt, forearm soaks only, and no numbers or group sizes in the abstract. It is not a test of plain magnesium chloride flakes.
Form and dose studied
A 5% solution of a branded Dead Sea salt for 15 minutes on one forearm; not advice.
Who was studied
Adults with atopic dry skin.
Limits
Product named in the abstract and funding not stated; other minerals present; short follow-up (6 weeks).
Why researchers looked
Dead Sea salt baths are an old skin treatment, and magnesium salts are known to bind water.
Traditional use
Dead Sea therapy for skin is described as one of the oldest topical magnesium treatments (Chandrasekaran 2016 abstract).
Proposed mechanism Pharmacological theory
The authors suggest the high magnesium content helps: magnesium salts bind water, influence skin cell growth and help the skin barrier repair. This is their suggestion; the study did not isolate magnesium from the other minerals.
A proposed mechanism does not show that the effect happens in people.
Salt can sting broken or inflamed skin. Patch test and ask a doctor if you have eczema flares.
Fibromyalgia and nerve symptoms (sprays)
Very low certaintyTwo small studies with no comparison group used a magnesium chloride spray on the limbs. Fibromyalgia questionnaire scores improved in one, and nerve symptom scores fell in another in people with advanced kidney disease. These were sprays, not baths, and cannot separate the spray from placebo effect.
2 studiesMagnesium chloride sprays on the limbs in both studies; not advice.
Studies, doses and limits
What the trials found
A 2015 feasibility study of 40 women with fibromyalgia (24 finished) and a 2023 single-arm pilot of 20 people with advanced kidney disease (14 finished). Neither had a control group.
Results
Fibromyalgia: total impact score improved at weeks 2 and 4 (p = 0.001). Kidney disease: nerve symptom score fell from 6.92 to 4.04 at week 8 and 4.26 at week 12 (p < 0.05).
Effect sizes as reported
Only the kidney pilot gives numbers (scores above).
Why this rating
Uncontrolled, open, small, many dropouts, self-reported scores, and a spray rather than a bath.
Form and dose studied
Magnesium chloride sprays on the limbs in both studies; not advice.
Who was studied
40 women with fibromyalgia; 20 adults (mean age 78.9) with advanced kidney disease.
Limits
No placebo group; high dropout; not bath flakes.
Why researchers looked
Low magnesium has been linked to chronic pain, so sprays were tried as a feasibility step.
Traditional use
No tradition described in the sources read.
Proposed mechanism Pharmacological theory
Authors suggest magnesium plays a role in chronic pain. Whether the spray raised body magnesium is not shown: serum magnesium did not change in the kidney study.
A proposed mechanism does not show that the effect happens in people.
People with advanced kidney disease should only use magnesium products under a kidney doctor's advice.
Detox or drawing out toxins
Not enough evidenceSellers say a flakes bath pulls toxins out of the body. We found no human study that shows this. The US NIH centre NCCIH says a 2015 review found no compelling research that detox diets or products remove toxins.
2 studiesNot studied.
Studies, doses and limits
Results
No results to report.
Why this rating
No human study; claim is not supported by the guidance read.
Form and dose studied
Not studied.
Who was studied
Not studied.
Limits
Absence of a study is not proof of no effect, but a claim needs evidence before it is believed.
Why researchers looked
Detox is a common reason bath products are bought.
Traditional use
Not described in the sources read.
Proposed mechanism Pharmacological theory
No mechanism for removing toxins through the skin is shown in the sources read.
A proposed mechanism does not show that the effect happens in people.
Long hot soaks do not detox the body; the liver and kidneys do that work.
Connections to the rest of health
How Magnesium Chloride Bath Flakes connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Muscle Recovery | Evidence against | Sore muscles, aches and recovery after exercise: A soak is a popular way to ease tired muscles. A good trial of a magnesium gel on the thighs after hard running found no effect on soreness or muscle damage markers. We found no trial of magnesium chloride flakes in a bath for muscle soreness. | 4 6 | |
| Better Sleep | Not enough evidence | Sleep, stress and relaxation: Sellers claim magnesium baths calm the mind and help sleep. We found no trial of magnesium chloride flakes for sleep, stress or mood. A warm bath may feel relaxing by itself, but that is not evidence for the magnesium. | 6 | |
| Stress Reduction | Not enough evidence | Sleep, stress and relaxation: Sellers claim magnesium baths calm the mind and help sleep. We found no trial of magnesium chloride flakes for sleep, stress or mood. A warm bath may feel relaxing by itself, but that is not evidence for the magnesium. | 6 | |
| Healthy Skin | Demonstrated clinical effect | Low certainty | Dry, atopic skin (magnesium-rich salt bath): One controlled study had people with dry, atopic skin soak a forearm in a Dead Sea salt rich in magnesium chloride. Skin barrier, hydration, roughness and redness improved compared with the tap-water arm. It tested one branded salt on one forearm. It does not show that plain flakes in a full bath do the same. | 8 |
| Detoxification Support | Not enough evidence | Detox or drawing out toxins: Sellers say a flakes bath pulls toxins out of the body. We found no human study that shows this. The US NIH centre NCCIH says a 2015 review found no compelling research that detox diets or products remove toxins. | 12 6 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Integumentary System | Biological association | Very low certainty | Studied for: Raising magnesium levels through the skin Studied for: Dry, atopic skin (magnesium-rich salt bath) | 6 7 1 2 3 8 |
| Muscular System | Biological association | Evidence against | Studied for: Sore muscles, aches and recovery after exercise | 4 6 |
| Nervous System | Biological association | Not enough evidence | Studied for: Sleep, stress and relaxation Studied for: Fibromyalgia and nerve symptoms (sprays) | 6 5 1 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Hypermagnesemia (high magnesium) | Adverse effect or risk | Very low certainty | Two severe cases after swallowing magnesium sulfate; none found for bath flakes. Preparation or compound: Epsom salt swallowed (case reports) |
10 9 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Serum magnesium | Biological association | Very low certainty | Measured in trials: no-clear-change. A lab change is not the same as a health benefit. | 7 1 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Magnesium chloride | Biological association | Identity (database) | Dissolves in water to release magnesium ions. Magnesium is an essential mineral; MedlinePlus says deficiency is rare in people eating a normal diet. | 11 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).
Evidence at a glance: what the research found for 6 outcomes
Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.
The evidence
The research centre for Magnesium Chloride Bath Flakes. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We searched PubMed, read the abstract of each cited paper, and read the FDA cosmetics, NCCIH detox, MedlinePlus and Poison Control pages. Certainty ratings are the compiler's own reading. The NIH Office of Dietary Supplements page was blocked and not read. Regulators outside the US were not checked. No study is cited that we could not verify.
Study library: every study we checked 14
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Athavale 2023 Transdermal Magnesium for the Treatment of Peripheral Neuropathy in Chronic Kidney Disease: A Single-Arm, Open-Label Pilot Study. Journal of Palliative Medicine · PMID 37486715 · DOI |
Single arm pilot |
20 20 adults with advanced chronic kidney disease and nerve symptoms (mean age 78.9; 14 finished); Sydney |
Magnesium chloride spray on affected limbs (not bath flakes) mineral salt solution Five sprays to each affected limb daily (per abstract) 12 weeks |
Symptom score fell from 6.92 at baseline to 4.04 at week 8 and 4.26 at week 12 (p < 0.05). Serum magnesium did not change significantly. The authors say it may be beneficial. Methods, limits and fundingOutcomes: Nerve symptom score (NTSS-6); serum magnesium Limitations: No comparison group, open label, symptom scores are self-reported, 6 of 20 did not finish. Cannot separate the spray from placebo effect. People with advanced kidney disease are the group in whom extra magnesium needs a clinician. Funding and conflicts: No funding statement in the abstract. Registration: ACTRN12621000841875 Read: abstract |
| Camili 2026 Does magnesium permeate the skin? An ex vivo investigation of magnesium ion delivery through intact and barrier-disrupted skin. European Journal of Pharmaceutics and Biopharmaceutics · PMID 42372834 · DOI |
Laboratory animal-ex-vivo |
Pig skin in a diffusion cell (intact and tape-stripped) | Saturated magnesium sulfate solution (Epsom salt type), not magnesium chloride mineral salt solution Saturated solution 24 hours · vs Control samples |
Little magnesium crossed intact skin, with no significant difference from controls (8.3 +/- 3.4 versus 3.9 +/- 0.8 micrograms per square cm over 24 hours). With the top skin layer removed by tape-stripping, passage rose to about 13.0 +/- 5.3 mg per square cm, several orders of magnitude more, with big differences between samples. The authors conclude delivery from simple water solutions is unlikely under normal skin conditions but may be much higher in damaged skin. Methods, limits and fundingOutcomes: Magnesium passing through skin Limitations: Pig skin in a lab, a sulfate salt, not human and not chloride flakes. Not a safety study. Funding and conflicts: Not stated in the abstract Read: abstract |
| Chandrasekaran 2016 Permeation of topically applied Magnesium ions through human skin is facilitated by hair follicles. Magnesium Research · PMID 27624531 · DOI |
Laboratory human-ex-vivo |
Human skin samples in the lab | Topically applied magnesium solution mineral salt (not a plant) Varied exposure time |
The authors say magnesium crosses human stratum corneum in a way that depends on concentration and time of exposure, and that hair follicles make a significant contribution to the amount passing through. They also call the transport of magnesium across skin contentious. Methods, limits and fundingOutcomes: Magnesium passing through human skin and the role of hair follicles Limitations: Abstract gives no amounts. Lab skin samples, not a person in a bath, and no measure of magnesium status in the body. This result partly disagrees in emphasis with the 2026 pig-skin study; both are lab work. Funding and conflicts: Not stated in the abstract Read: abstract |
| Coates 2025 No Effect of Topical Application of a Commercial Magnesium Gel on Exercise Recovery in Active Individuals. International Journal of Sport Nutrition and Exercise Metabolism · PMID 40537122 · DOI |
Randomized controlled trial |
35 35 healthy active adults after a 40-minute downhill treadmill run |
Commercial magnesium gel on each thigh (not bath flakes) mineral salt in a gel 0.53 mg/ml gel (per abstract) Before and right after the run; follow-up to 48 hours · vs Placebo gel |
There were no differences between gel and placebo on any outcome. Soreness at 24 hours was 43 (SD 27) with magnesium and 41 (SD 26) with placebo. The authors say the amount or the way it was applied may have been too small to have an effect. Methods, limits and fundingOutcomes: Muscle soreness (0-100 scale), muscle strength, creatine kinase, interleukin-6 Limitations: Healthy runners, a gel on the thighs, one exercise bout. Not a bath. The authors suggest the dose may have been too low. Funding and conflicts: Not stated in the abstract Read: abstract |
| Engen 2015 Effects of transdermal magnesium chloride on quality of life for patients with fibromyalgia: a feasibility study. Journal of Integrative Medicine · PMID 26343101 · DOI |
Uncontrolled feasibility study |
40 40 women with fibromyalgia enrolled, 24 finished (mean age 57.2) |
Magnesium chloride spray on arms and legs (not bath flakes) mineral salt solution 4 sprays per limb twice a day (per abstract) 4 weeks |
Questionnaire scores improved at weeks 2 and 4 (total score p = 0.001). Results were similar with the completers only. The authors say it may be beneficial. Methods, limits and fundingOutcomes: Revised Fibromyalgia Impact Questionnaire; SF-36; quality of life Limitations: No control group, open design, 16 of 40 did not finish, self-reported scores. Cannot show the spray works better than placebo or time. Funding and conflicts: No funding statement in the abstract. Registration: NCT01968772 Read: abstract |
| Groeber 2017 Myth or Reality-Transdermal Magnesium? Nutrients · PMID 28788060 · DOI |
Narrative review |
Published literature on magnesium applied to the skin (sprays, flakes, salt baths) | Magnesium applied through the skin (sprays, flakes, salt baths) versus oral magnesium mineral salt (not a plant) |
The authors evaluated the literature and say that the promotion of transdermal magnesium is scientifically unsupported. They note that oral magnesium has been studied in detail for magnesium deficiency, and that marketing for sprays, flakes and salt baths claims better absorption and fewer side effects than oral use. Methods, limits and fundingOutcomes: Whether magnesium passes through the skin and works better than oral magnesium Limitations: Abstract read only; this page does not repeat the review's detailed argument. A narrative review, not a systematic one; the abstract gives no search method or numbers. Funding and conflicts: Not stated in the abstract Read: abstract |
| Kass 2017 Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: A pilot study. PLoS One · PMID 28403154 · DOI |
Randomized controlled trial |
25 25 adults (mean age 34.3), randomised to magnesium cream or placebo cream |
Magnesium cream (not bath flakes) mineral salt in a cream 56 mg magnesium a day (per abstract) 2 weeks · vs Placebo cream |
Serum magnesium went from 0.82 to 0.89 mmol/L with the cream (p = 0.29) and from 0.77 to 0.79 in the placebo group. The rise was statistically significant (p = 0.02) only in a subgroup of non-athletes. Urinary magnesium rose slightly with no significance (p = 0.48). The authors call it a pilot and say future studies should test higher amounts for longer. Methods, limits and fundingOutcomes: Serum and 24-hour urine magnesium Limitations: Small single-blind pilot. A cream, not flakes in a bath. The overall serum change was not significant. The authors note the amount was low compared with commercial products. Funding and conflicts: No funding or conflict statement in the abstract. Registration: ISRCTN15136969 Read: abstract |
| Proksch 2005 Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin. International Journal of Dermatology · PMID 15689218 · DOI |
Controlled clinical trial |
Volunteers with atopic dry skin (number not given in the abstract) | 5% solution of a branded Dead Sea salt rich in magnesium chloride (Mavena Dermaline Mg(46)) mineral salt (not a plant) One forearm soaked 15 minutes in 5% salt solution Weeks 1 to 6 follow-up · vs Other forearm soaked in tap water |
Barrier function improved versus the tap-water arm in the subgroup with high starting water loss. Hydration improved on the salt arm in each group. Roughness and redness were significantly reduced. The authors suggest the high magnesium content is the likely reason. Methods, limits and fundingOutcomes: Skin water loss (TEWL), hydration, roughness, redness Limitations: One branded salt, forearm only, number of people not given in the abstract. A Dead Sea salt holds other minerals too, so magnesium chloride alone is not shown to be the cause. Not a full-body bath of plain flakes. Funding and conflicts: The product is named in the abstract; who paid for the study is not stated in the abstract. Treat as possible manufacturer link until checked. Read: abstract |
| Si 2024 Case report: Near-fatal hypermagnesemia resulting from the use of Epsom salts in a patient with normal renal function. Frontiers in Medicine · PMID 39021819 · DOI |
Case report |
1 One 60-year-old woman with a stomach operation in the past and a history of nephrotic syndrome |
Epsom salt (magnesium sulfate) taken by mouth before an endoscopy mineral salt (not a plant) Single ingestion |
She lost consciousness 30 minutes after taking it. Her magnesium level was 8.71 mmol/L. She needed a breathing tube, calcium and continuous kidney replacement therapy; the level fell to 1.35 mmol/L and she recovered. The authors say few people survive a level above 7 mmol/L and that this can happen with normal kidney function. Methods, limits and fundingOutcomes: Magnesium level and recovery Limitations: One case; magnesium sulfate swallowed, not a bath. The abstract says normal renal function though she had a nephrotic syndrome history. Funding and conflicts: Not stated in the abstract Read: abstract |
| Walker 2020 Epsom Salt Ingestion Leading to Severe Hypermagnesemia Necessitating Dialysis. Journal of Emergency Medicine · PMID 32389435 · DOI |
Case report |
1 One 56-year-old man in an emergency department |
Epsom salt (magnesium sulfate) swallowed as a laxative mineral salt (not a plant) Single ingestion |
He had weakness, a slow heart rate and low blood pressure, then confusion and breathing failure needing a breathing tube. His magnesium level was above 3.91 mmol/L. It fell quickly with dialysis and he went home in good condition after 3 days. Methods, limits and fundingOutcomes: Magnesium level and organ effects Limitations: One case; magnesium sulfate, swallowed, not magnesium chloride and not a bath. Funding and conflicts: Not stated in the abstract Read: abstract |
| n/a MedlinePlus: Magnesium in diet n/a · Source |
Authoritative guidance n/a |
n/a | n/a |
Says side effects from high magnesium intake are not common except in people with significantly reduced kidney function, and that magnesium excess most often occurs with supplements or laxatives that contain magnesium. Methods, limits and fundingOutcomes: Safety of high magnesium intake Limitations: About dietary magnesium and swallowed products; the page is not about baths and shows no date in the text read. Read: full-text |
| n/a 2025 NCCIH: Detoxes and cleanses: what you need to know (last updated March 2025) n/a · Source |
Authoritative guidance n/a |
n/a | n/a |
Says a 2015 review concluded there was no compelling research to support the use of detox diets for eliminating toxins from the body, and that studies of detox products have been of low quality. Methods, limits and fundingOutcomes: Evidence for detox claims Limitations: About detox diets and products in general, not bath flakes. Read: full-text |
| n/a 2025 FDA: FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated (content current as of 11/18/2025) n/a · Source |
Authoritative guidance n/a |
n/a | n/a |
Says cosmetic products and ingredients do not need FDA premarket approval, except colour additives, but FDA can take enforcement action against products on the market that do not comply with the law. Methods, limits and fundingOutcomes: How the US regulates cosmetics Limitations: General cosmetics law. It does not mention bath salts or magnesium chloride. Other countries were not checked. Read: full-text |
| n/a 2026 Poison Control (National Capital Poison Center): home page, read 2026-10-25 n/a · Source |
Authoritative guidance n/a |
n/a | n/a |
Says help is free, expert and confidential online and by phone at 1-800-222-1222 (US), and to call 911 if the person collapses, has a seizure, has trouble breathing or cannot be awakened. Methods, limits and fundingOutcomes: What to do after a poisoning Limitations: Service information, not research. US numbers only. Read: full-text |
What we do not know yet
- No trial of magnesium chloride flakes in a full bath that measured magnesium in blood or urine.
- No trial of flakes for muscle soreness, sleep or stress.
- No tests for metals or impurities in bath flakes.
- No data on pregnancy, children, hot baths with heart conditions, or medicine interactions.
How new research is added
New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it changes any evidence rating or safety wording.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 1
Serum magnesium
No-clear-change in trials
The amount of magnesium in a blood sample, measured in millimoles per litre. It is a rough check of magnesium status.
Very low certaintyResults and what it means
Why it was measured
If magnesium passes through the skin, blood levels should rise.
Statistical vs. clinical meaning
No clear rise in either pilot; neither tested a bath.
Safety implication
A level that rises too high is dangerous in kidney disease, but no source read shows baths do this.
| Study | Result | People | Product |
|---|---|---|---|
| 7 | Cream: 0.82 to 0.89 mmol/L versus placebo 0.77 to 0.79 (p = 0.29); significant (p = 0.02) only in non-athletes. | 25 adults | Magnesium cream versus placebo cream, 2 weeks |
| 1 | No significant change in serum magnesium over 12 weeks of a magnesium chloride spray. | 20 adults with advanced kidney disease (14 finished) | Magnesium chloride spray, single arm |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 5
- Do not swallow it. Case reports of swallowed Epsom salt (magnesium sulfate, a close cousin) describe weakness, a slow heartbeat, low blood pressure, confusion and breathing failure needing a breathing tube and dialysis. One near-fatal case was reported in a woman the authors describe as having normal kidney function. No report on swallowed bath flakes was found, but the same mineral is involved. Bath flakes are sold for external use only. If someone has swallowed them and feels unwell, call poison control. Case report 10 9 14
- Kidney disease raises the risk. MedlinePlus says side effects from high magnesium intake are uncommon except in people with significantly reduced kidney function. Ask a kidney doctor before using any magnesium product, including soaks and sprays. Authoritative guidance 11
- Damaged skin may take up more. In a pig-skin lab study, far more magnesium passed through skin with its top layer removed than through intact skin. This is not a human safety study, but it is a reason to avoid soaking cuts, sores or raw skin and to ask a doctor first. Laboratory 2
- Most sold claims are not supported. A 2017 review calls the promotion of transdermal magnesium scientifically unsupported. Do not use flakes in place of medical care or oral treatment for low magnesium. Narrative review 6
- Skin reactions and quality are not tested for you. The FDA says cosmetics do not need FDA premarket approval, so a label tells you little about purity. We found no report on how flakes are sourced or on impurities in them; not described is not proof of none. Patch test, keep flakes out of eyes, and stop if skin stings or reddens. Authoritative guidance 13
Side effects 3
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Magnesium overload (hypermagnesemia) after swallowing a magnesium salt Epsom salt (magnesium sulfate) swallowed, not magnesium chloride and not bathing. | Not established | life-threatening Both cases recovered after intensive treatment, including dialysis | Case report 10 9 |
| Skin irritation or stinging from flakes The 2005 Dead Sea salt study said the bath was well tolerated, but no rates for plain flakes were found. | Not established | unknown Not stated | Gap |
| Higher magnesium passage through broken skin Pig skin, magnesium sulfate; a lab signal, not an injury report. | Not established | unknown Not stated | Laboratory 2 |
Liver
No report of liver injury from magnesium chloride baths was found in the sources read. LiverTox was not searched.
How often. No rate in people.
Monitoring. No monitoring advice was found.
This is a safety connection. It is not evidence that Magnesium Chloride Bath Flakes supports liver health.
Medicines and supplements 3
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Kidney conditions (reduced kidney function) condition | Kidneys clear extra magnesium; when they work poorly, magnesium can build up. | MedlinePlus names significantly reduced kidney function as the main group at risk from high magnesium intake. No bath-specific data were found. | Authoritative guidance Low certainty 11 | Ask a kidney doctor before any magnesium soak, spray or supplement. |
| Medicines that affect heart rhythm, blood pressure or muscle strength prescription | Swallowed magnesium overload slows the heart and lowers blood pressure; whether a bath could add to a medicine's effect was not described in any source read. | No interaction study of baths found. | Gap Not enough evidence 10 | Ask a pharmacist or doctor if you take such medicines and use frequent soaks. |
| Skin treatments and prescription skin creams topical | Not described in the sources read. | No study found. | Gap Not enough evidence | Ask a doctor or pharmacist before soaking while using prescription skin products. |
Who should check first 6
| Situation | Advice | Evidence |
|---|---|---|
| Kidney disease | Ask your kidney doctor before using magnesium products. Magnesium excess is mainly a problem in significantly reduced kidney function. | Authoritative guidance 11 1 |
| Open wounds, sores or raw skin | Avoid soaking. A pig-skin lab study found far more magnesium passes through skin with a damaged top layer. | Laboratory 2 |
| Pregnancy and breastfeeding | No data on bath flakes were found. Ask your midwife or doctor, especially before long or very hot soaks. | Gap |
| Babies and children | No data on bath flakes were found. Keep flakes out of reach so they are not swallowed, and ask a doctor before using them for a child. | Gap |
| Heart or blood pressure problems | No source read covers hot baths with flakes. Ask a doctor, especially if you feel faint in hot water. | Gap |
| Eczema or very sensitive skin | Patch test first. Salt can sting inflamed skin; the one study of a salt bath was in dry atopic skin on a forearm. | Controlled clinical trial 8 |
Overdose, product quality and regulators
Summary. Magnesium chloride is a mineral salt, not a plant, so there are no toxic plant parts. The main danger is swallowing a large amount, which can cause magnesium overload. The cases we found involved Epsom salt (magnesium sulfate).
Animal. Not searched for magnesium chloride.
Human doses studied. No safety studies of bath doses were found.
High dose or long term signals. Two case reports of severe overload after swallowing Epsom salt; recovery needed intensive care and dialysis or kidney replacement therapy.
Overdose response. If someone has swallowed bath flakes and feels unwell, call poison control (US 1-800-222-1222) or your local emergency number. Call 911 for collapse, seizure, trouble breathing or inability to wake.
Genotoxicity. Not read.
We found no source describing how bath flakes are sourced or graded, or what impurities they may hold. Not described is not proof of none.
Heavy metals and other impurities. No test of magnesium chloride bath flakes was found in the sources read.
Regulation. The FDA says cosmetics and their ingredients do not need FDA premarket approval, except colour additives. 13
| Body | Action | Date |
|---|---|---|
| US FDA (United States) | Cosmetic products and ingredients, except colour additives, do not need FDA premarket approval; FDA can act against non-compliant products on the market. source | 2025-11-18 |
When to get medical help
- Collapse, a seizure, trouble breathing or being impossible to wake after swallowing flakes: call 911 or your local emergency number.
- Swallowed bath flakes and feel unwell, weak, faint or confused, or a child has swallowed them: call poison control (US 1-800-222-1222).
- Spreading redness, blistering, pus or worsening pain where flakes touched skin: stop and contact a clinician.
- Kidney disease and new weakness, slow pulse or drowsiness after using magnesium products: seek urgent medical help.
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What are magnesium chloride bath flakes?
Does magnesium really absorb through the skin in a bath?
Do magnesium flakes raise magnesium levels in the blood?
Do magnesium flakes ease sore muscles?
We found no trial of flakes. A randomised trial of a magnesium gel after hard running found no difference from placebo on soreness or muscle damage markers. A warm soak may still feel good for other reasons.
Do magnesium baths help sleep or stress?
We found no trial of magnesium chloride flakes for sleep, stress or mood. Any calm from a warm bath is not shown to come from the magnesium.
Is it safe if I have kidney disease?
What happens if flakes are swallowed?
Can flakes help dry skin or eczema?
One small controlled study found that soaking a forearm in a branded magnesium-rich Dead Sea salt improved barrier function, hydration and redness. It was one product on one forearm, so it does not show the same for plain flakes. Patch test first.
Is it safe to soak with broken skin?
It is wise to avoid it. In a pig-skin lab study, far more magnesium passed through skin with its top layer removed. Ask a doctor if you have cuts, sores or an active skin flare.
Is it safe in pregnancy, while breastfeeding or for children?
No data on bath flakes were found. Ask a midwife or doctor, and keep flakes out of children's reach so they are not swallowed.
Do magnesium flakes detox the body?
No human study shows that. NCCIH reports a 2015 review that found no compelling research that detox diets remove toxins from the body.
How is it regulated?
In the US, the FDA says cosmetic products and ingredients, except colour additives, do not need premarket approval, though it can act against non-compliant products. Other countries were not checked.
Explore by health goal
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-25
- Last substantive update
- 2026-10-25
- How we research
- We searched PubMed, read the abstract of each cited paper, and read the FDA cosmetics, NCCIH detox, MedlinePlus and Poison Control pages. Certainty ratings are the compiler's own reading. The NIH Office of Dietary Supplements page was blocked and not read. Regulators outside the US were not checked. No study is cited that we could not verify.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown.
Sources 14
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Athavale A, Miles N, Pais R, et al. Transdermal Magnesium for the Treatment of Peripheral Neuropathy in Chronic Kidney Disease: A Single-Arm, Open-Label Pilot Study.. Journal of Palliative Medicine. 2023. PMID 37486715. DOI 10.1089/jpm.2023.0229. (abstract)
- Camili V, Stuerup S, Heinz A. Does magnesium permeate the skin? An ex vivo investigation of magnesium ion delivery through intact and barrier-disrupted skin.. European Journal of Pharmaceutics and Biopharmaceutics. 2026. PMID 42372834. DOI 10.1016/j.ejpb.2026.115173. (abstract)
- Chandrasekaran NC, Sanchez WY, Mohammed YH, et al. Permeation of topically applied Magnesium ions through human skin is facilitated by hair follicles.. Magnesium Research. 2016. PMID 27624531. DOI 10.1684/mrh.2016.0402. (abstract)
- Coates AM, Patel DV, Binet ER, et al. No Effect of Topical Application of a Commercial Magnesium Gel on Exercise Recovery in Active Individuals.. International Journal of Sport Nutrition and Exercise Metabolism. 2025. PMID 40537122. DOI 10.1123/ijsnem.2025-0034. (abstract)
- Engen DJ, McAllister SJ, Whipple MO, et al. Effects of transdermal magnesium chloride on quality of life for patients with fibromyalgia: a feasibility study.. Journal of Integrative Medicine. 2015. PMID 26343101. DOI 10.1016/S2095-4964(15)60195-9. (abstract)
- Groeber U, Werner T, Vormann J, et al. Myth or Reality-Transdermal Magnesium?. Nutrients. 2017. PMID 28788060. DOI 10.3390/nu9080813. (abstract)
- Kass L, Rosanoff A, Tanner A, et al. Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: A pilot study.. PLoS One. 2017. PMID 28403154. DOI 10.1371/journal.pone.0174817. (abstract)
- Proksch E, Nissen HP, Bremgartner M, et al. Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin.. International Journal of Dermatology. 2005. PMID 15689218. DOI 10.1111/j.1365-4632.2005.02079.x. (abstract)
- Si GF, Ge YX, Lv XP, et al. Case report: Near-fatal hypermagnesemia resulting from the use of Epsom salts in a patient with normal renal function.. Frontiers in Medicine. 2024. PMID 39021819. DOI 10.3389/fmed.2024.1416956. (abstract)
- Walker P, Parnell S, Dillon RC. Epsom Salt Ingestion Leading to Severe Hypermagnesemia Necessitating Dialysis.. Journal of Emergency Medicine. 2020. PMID 32389435. DOI 10.1016/j.jemermed.2020.04.023. (abstract)
- n/a. MedlinePlus: Magnesium in diet. n/a. . (full-text)
- n/a. NCCIH: Detoxes and cleanses: what you need to know (last updated March 2025). n/a. 2025. (full-text)
- n/a. FDA: FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated (content current as of 11/18/2025). n/a. 2025. (full-text)
- n/a. Poison Control (National Capital Poison Center): home page, read 2026-10-25. n/a. 2026. (full-text)
Where to buy
Check the label first. Whatever you buy, look for these:
- Whether it is iodized if you rely on salt for iodine
- The origin and purity statement
- Food grade versus bath or cosmetic grade
- Sodium amount, which matters for blood pressure
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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