Magnesium Chloride Bath Flakes: What the Sources Say and Safety
Magnesium chloride bath flakes checked: little proof that magnesium soaks through skin, one small bath study, and why swallowing magnesium salts can be dangerous.
Content last updated . This page has not been medically reviewed.
What is Magnesium Chloride Bath Flakes good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Magnesium soaking through the skin: claim check
Not enough evidenceA 2017 review concluded transdermal magnesium (sprays, flakes, salt baths) is scientifically unsupported. A 2026 pig-skin lab study found minimal magnesium passing through intact skin; passage rose by orders of magnitude when the top skin layer was stripped away.
Supplements: No good evidence that bath flakes raise magnesium levels or fix low magnesium.
Magnesium-rich salt bath for dry, atopic skin
Preliminary or mixedA 2005 study had volunteers with atopic dry skin soak one forearm for 15 minutes in a 5% solution of a magnesium chloride-rich Dead Sea salt and the other in tap water. Skin barrier function improved in those with high water loss; hydration, roughness and redness also improved.
Supplements: Applies to that product and route; not shown for plain flakes or full baths.
Magnesium cream and chloride spray: small pilot results
Preliminary or mixedA 2017 single-blind pilot (25 adults) of a magnesium cream saw a serum magnesium rise that was significant only in a subgroup. A 2023 open-label pilot of a magnesium chloride spray in 20 people with advanced kidney disease saw lower symptom scores and no significant change in serum magnesium.
Supplements: Pilots cannot show benefit and do not apply to bath flakes.
Sore muscles, sleep and stress from magnesium flakes
Not enough evidenceProper evidence not found in the sources we read for magnesium chloride bath flakes relieving sore muscles, stress or poor sleep.
Supplements: No trial found.
Detox claim for bath flakes
Not enough evidenceProper evidence not found in the sources we read that magnesium flakes remove toxins.
Supplements: No source found.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Health goals (1)
- Healthy SkinPreliminary or mixed
One small 2005 study of a magnesium chloride-rich Dead Sea salt bath in atopic dry skin saw better barrier function and hydration; one product and route.
Body systems (3)
- Kidney & UrinaryDocumented risk
High magnesium is a risk in significantly reduced kidney function (MedlinePlus).
- Integumentary SystemPreliminary or mixed
Small study of a magnesium chloride-rich salt bath in atopic dry skin.
- Skin, Hair & BeautyPreliminary or mixed
Small study of a magnesium chloride-rich salt bath in atopic dry skin.
Body parts (2)
Biomarkers (1)
- MagnesiumPreliminary or mixed
Serum magnesium rose slightly with a cream in a 25-person pilot (significant only in a subgroup) and did not change significantly with a spray in a 20-person kidney pilot; a 2017 review calls transdermal claims unsupported.
Conditions & symptoms (3)
- HypermagnesemiaDocumented risk
Swallowed magnesium salts (Epsom salt in case reports) have caused dangerous overload; kidney disease raises risk.
- Kidney DiseasesDocumented risk
People with significantly reduced kidney function are the main group at risk from high magnesium intake.
- Dermatitis, AtopicPreliminary or mixed
One small 2005 forearm-soak study of a magnesium chloride-rich Dead Sea salt saw better skin barrier and less redness; one product, small study.
Documented risks and interactions (3)
- Swallowing magnesium salts: overload cases. Case reports of Epsom salt (magnesium sulfate) swallowed as a laxative describe weakness, slow heartbeat, low blood pressure, confusion and breathing failure needing a tube and dialysis; a near-fatal case occurred with normal kidney function. The sources we read do not describe swallowed magnesium chloride flakes specifically.
- Kidney disease and high magnesium. MedlinePlus says side effects from high magnesium intake are uncommon except in people with significantly reduced kidney function, and excess most often comes from supplements or magnesium laxatives.
- Broken or irritated skin: higher passage in the lab. In a 2026 pig-skin study, magnesium passage was far higher through skin with its top layer removed than through intact skin. This is not a human safety study; the sources we read do not describe irritation from bath flakes.
Safety first: bath flakes are for the bath, not for swallowing, and the claim that they "top up" your magnesium through the skin is not supported. A 2017 review concluded that promoting transdermal magnesium is scientifically unsupported. [1] Magnesium salts that are swallowed can cause dangerous magnesium overload: case reports describe loss of consciousness, a slow heartbeat and the need for a breathing tube and dialysis after Epsom salt was swallowed. [8][9] This page separates seller claims, lab findings and human studies, and keeps skin, bath and swallowing apart.
What magnesium chloride bath flakes are
Bath flakes are sold as magnesium chloride (MgCl2), usually as clear to white irregular flakes that dissolve in water. They are also called magnesium flakes, magnesium bath flakes or "zechstein" or "Dead Sea" flakes by sellers. Magnesium chloride is a different compound from Epsom salt (magnesium sulfate); see Epsom salt. The sources we read do not describe how bath flakes are mined or purified, or whether bath-grade differs from food- or medicine-grade, so we make no claim. Do not assume a bath product is safe to eat. Magnesium as a nutrient is covered at Magnesium; this page does not repeat it.Claims and what the sources found
| Claim or use | What the best source found | Evidence label | Route, product and who was studied |
|---|---|---|---|
| Magnesium soaks through the skin and fixes low magnesium | A 2017 review of the literature concluded that transdermal magnesium (sprays, flakes, salt baths) is scientifically unsupported, noting growing marketing that claims it beats oral magnesium. [1] | No good evidence of benefit | Narrative review; mixed products |
| Skin absorption in the lab | A 2026 lab study on pig skin found minimal magnesium passed through intact skin from a magnesium sulfate solution, with no significant difference from controls. Passing through skin with the top layer stripped away rose by several orders of magnitude. [2] | Lab or animal only | Pig skin in a lab dish; magnesium sulfate, not chloride |
| A magnesium cream raises blood magnesium | A 2017 pilot of 25 adults found serum magnesium rose in the cream group, but the difference was statistically significant only in a subgroup of non-athletes; the trial was single-blind and lasted two weeks. [3] | Promising but limited | 25 adults; cream, not a bath |
| Magnesium chloride spray helps nerve symptoms | A 2023 single-arm, open-label pilot of 20 people with advanced kidney disease (14 finished) using a magnesium chloride spray found symptom scores fell, and serum magnesium did not change significantly. [4] With no comparison group, this cannot show the spray worked. | Promising but limited | 20 adults with advanced kidney disease; spray on limbs |
| Magnesium-rich salt baths help dry, atopic skin | A 2005 study had volunteers with atopic dry skin soak one forearm for 15 minutes in a 5% solution of a salt rich in magnesium chloride from the Dead Sea and the other in tap water. Skin barrier function improved in the subgroup with elevated water loss, and hydration, roughness and redness improved. [5] | Promising but limited | Small study; one forearm bath with one specific Dead Sea salt |
| Bath flakes relieve sore muscles, stress or poor sleep | Proper evidence not found in the sources we read for magnesium chloride bath flakes. | Insufficient evidence | |
| Flakes "detox" the body | Proper evidence not found in the sources we read. | No good evidence of benefit |
The limits: most studies are small, short and not blinded; they test different products and routes (cream, spray, forearm soak, pig skin), and a result for one does not carry to a full bath or to swallowing. The skin-barrier results came from a branded Dead Sea salt that sellers also market, so they may not apply to plain flakes.
Safety by group
- Swallowing and poisoning. MedlinePlus says side effects from high magnesium intake are not common except in people with significantly reduced kidney function, and that excess most often comes from too much supplement or magnesium-containing laxatives. [6] Case reports of Epsom salt (magnesium sulfate) swallowed as a laxative describe a man needing intubation and dialysis [8] and a woman with normal kidney function who lost consciousness after swallowing it and needed a breathing tube and continuous dialysis. [9] The sources we read do not describe swallowed magnesium chloride bath flakes specifically. If anyone has swallowed bath flakes and seems unwell, call Poison Help (US 1-800-222-1222, free, 24 hours) or your local emergency number, and call 911 for collapse, seizures or breathing trouble. [11] See Poisoning: urgent help.
- Kidney disease. Kidney disease is the main group named for high-magnesium risk. [6] The pilot spray study was done in advanced kidney disease and found no significant change in blood magnesium, but it was 20 people and cannot show safety. [4] Ask your kidney team first. See Kidney disease and supplements and Magnesium side effects, toxicity and kidney disease.
- Broken or irritated skin. In the lab study, magnesium passed through skin with its top layer stripped far more than through intact skin. [2] That is a pig-skin finding, not a human safety study, but it is a reason to avoid soaking on open wounds without a clinician's advice. The sources we read do not describe skin irritation from magnesium chloride flakes. Not described is not proof of none.
- Medicines. The sources we read do not list medicine interactions for bath flakes. For swallowed magnesium, ask a pharmacist; see Magnesium and medicines and Medication interactions.
- Hot baths. The sources we read do not cover heat risks for this product. People with heart or blood pressure problems should ask a clinician about hot soaks. See Bath salts and soaks: safety and patch testing.
- Pregnancy, breastfeeding, babies and children. The sources we read do not cover bath flakes for these groups, so we make no claim. Keep flakes out of reach of children. The NHS notes that supplemental magnesium over 400 mg a day taken short term can cause diarrhoea, which shows swallowed magnesium is not harmless. [7] See Pregnancy and breastfeeding and Child swallowed a supplement or natural product.
- Contamination. We did not find a source we could read on heavy metals or other impurities in magnesium chloride flakes. Quality varies, and a label cannot tell you purity.
How it is used and what to look for on a label
- Flakes are dissolved in a bath or foot soak; magnesium chloride is also used in sprays (the kidney-disease pilot above used one). [4]
- Look for a plain ingredient list ("magnesium chloride") and a statement of intended use. A "bath" product is not a supplement.
- Be wary of claims like "absorbs through the skin," "replaces supplements," "detox" or "84 minerals." The best review we read calls the absorption claim unsupported. [1] A 2026 review adds that magnesium supplements are heavily advertised for benefits that need better evidence. [10]
- No amounts of flakes are given here, because the sources we read do not give any.
- Compare with Magnesium oil sprays, lotions and Epsom salt baths: claims checked.
Related pages
Frequently asked questions
Does magnesium chloride absorb through the skin?
A 2017 review called the claim scientifically unsupported. [1] A 2026 pig-skin lab study found minimal passage through intact skin. [2] A small cream trial saw a limited rise in blood magnesium. [3]
Do magnesium flakes help sore muscles or sleep?
Proper evidence not found in the sources we read for bath flakes. [1]
Is it safe to swallow bath flakes or Epsom salt?
No source we read supports swallowing bath flakes. Swallowed magnesium salts have caused dangerous magnesium overload in case reports. [8][9] Call Poison Help at 1-800-222-1222 if someone has swallowed flakes and seems unwell. [11]
Can flakes help eczema or dry skin?
One small 2005 study found improvements after soaking forearms in a magnesium-rich Dead Sea salt solution. [5] It tested a specific product, and no study we read tested plain flakes.
Are the flakes safe for pregnancy, babies or kidney disease?
The sources we read do not cover pregnancy or babies. People with significantly reduced kidney function are the main group at risk from high magnesium intake, so ask a clinician. [6]
References
- Gröber U, Werner T, Vormann J, Kisters K. Myth or Reality: Transdermal Magnesium? Nutrients. 2017;9(8):813. Review, abstract read 2026-10-24.
- Camili V, Stürup S, Heinz A. Does magnesium permeate the skin? An ex vivo investigation of magnesium ion delivery through intact and barrier-disrupted skin. Eur J Pharm Biopharm. 2026. Abstract read 2026-10-24.
- Kass L, et al. Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: A pilot study. PLoS One. 2017. Abstract read 2026-10-24.
- Transdermal Magnesium for the Treatment of Peripheral Neuropathy in Chronic Kidney Disease: A Single-Arm, Open-Label Pilot Study. J Palliat Med. 2023. Abstract read 2026-10-24.
- Proksch E, 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. Int J Dermatol. 2005;44(2):151-157. Abstract read 2026-10-24.
- MedlinePlus (US National Library of Medicine). Magnesium in diet. Read 2026-10-24.
- NHS (UK). Vitamins and minerals: Others (magnesium, phosphorus, potassium, salt). Read 2026-10-24. Short-term supplements over 400 mg can cause diarrhoea.
- Walker P, Parnell S, Dillon RC. Epsom Salt Ingestion Leading to Severe Hypermagnesemia Necessitating Dialysis. J Emerg Med. 2020. Case report, abstract read 2026-10-24.
- Si GF, et al. Case report: Near-fatal hypermagnesemia resulting from the use of Epsom salts in a patient with normal renal function. Front Med. 2024. Abstract read 2026-10-24.
- Sankararaman S, et al. Magnesium: Hype and Health Benefits. Curr Nutr Rep. 2026. Review, abstract read 2026-10-24. Says magnesium supplements are heavily advertised for purported benefits needing better evidence, and urges caution in kidney insufficiency.
- Poison Help (America's Poison Centers). Poison Help. Read 2026-10-24.