Skin

Nutrients connected to Skin

A link means the body needs the nutrient for this, or that low intake is linked to it. It does not mean extra supplements help if your intake is already adequate; each link shows how strong the evidence is.

• Vitamin DEstablished role

  Skin makes vitamin D from sunlight. Sun exposure also carries a skin cancer risk, so it is not a free source.

• Vitamin B3 (niacin)Deficiency link

  Pellagra causes inflamed, scaly skin sores mainly on sun-exposed skin; niacin treats it.

• YarrowDocumented risk

  Allergic contact dermatitis from yarrow has been described since 1899; the plant is also traditionally applied to small wounds.

• AngelicaDocumented risk

  Furanocoumarins in angelica preparations can make skin react to UVA light. The EU herbal committee advised a UV warning.

• RueDocumented risk

  Contact with rue followed by sunlight or a tanning bed can cause blistering burns; a documented skin risk, not a benefit.

• TansyDocumented risk

  Thujone can irritate skin; daisy-family allergy is possible.

• Cayenne and chili pepperDocumented risk

  Capsaicin products can burn or blister skin and must not be used on broken skin; hot chili oil irritates skin when handled.

• Bakuchi (babchi)Documented risk

  Psoralens can cause phototoxic reactions on sun-exposed skin.

• MayappleDocumented risk

  Blistering, tissue death and scarring after skin contact; absorbed through broken skin (IPCS, CDC).

• BloodrootDocumented risk

  Black salve containing bloodroot causes burning, scarring and tissue destruction of the skin; it is not a safe treatment for skin growths.

• Jasmine Oil (Absolute)Documented risk

  Jasmine absolute caused positive patch tests in 1.8% of tested clinic patients; reactions often go with other fragrance allergies.

• Thyme OilDocumented risk

  EFSA's panel describes thyme oil as a skin and eye irritant and a skin and respiratory sensitizer for people who handle it.

• Oregano OilDocumented risk

  EFSA's panel calls the oregano oil it assessed an irritant to skin and eyes and a potential skin sensitizer.

• Sweet Marjoram OilDocumented risk

  EFSA's panel says marjoram oil is an irritant to skin and eyes and a dermal sensitizer for users.

• Lemongrass OilDocumented risk

  EFSA says to treat lemongrass oil as a skin and eye irritant and sensitizer, and 2.6% of clinic patients patch tested reacted to it. Clinic patients are not the general public.

• Citronella OilDocumented risk

  EFSA says to treat citronella oil as a skin and eye irritant and a skin sensitizer.

• Lemon OilDocumented risk

  Phototoxicity of pressed oil and allergy to oxidized limonene are the best-documented effects on skin.

• Bergamot OilDocumented risk

  Phototoxic (sun-triggered) skin reactions after bergamot oil.

• Lime OilDocumented risk

  Sun reactions, irritation and sensitization.

• Petitgrain OilDocumented risk

  EFSA says to treat petitgrain bigarade oil as a skin irritant and skin sensitizer.

• Sandalwood OilDocumented risk

  Skin is where documented reactions occur: sandalwood oil had over 2% positive patch tests in one review and 1.8% in a German clinic network.

• Patchouli OilDocumented risk

  EFSA classes it as a skin and eye irritant; a case of allergic contact dermatitis is reported.

• Cinnamon Oil (Leaf and Bark)Documented risk

  NCCIH, a mud bath case report and an occupational series document irritation and allergic dermatitis.

• Yarrow OilDocumented risk

  Yarrow is a known skin sensitizer; allergic reactions are the best-documented risk (plant and extracts; yarrow oil was not patch-tested in the sources we read).

• Cajeput OilDocumented risk

  EFSA considers cajeput oil an irritant to skin and eyes and a skin sensitizer; the basis was a safety data sheet, not a published patch-test study.

• Ravintsara OilDocumented risk

  Ravintsara was a leading cause of allergic contact dermatitis in a French clinic series; dilute and patch test.

• Bay Oil (West Indian Bay and Bay Laurel)Documented risk

  Laurel oil can cause allergic contact dermatitis; use diluted only and stop if a rash appears.

• Litsea (May Chang) OilDocumented risk

  EFSA says litsea berry oil is a skin irritant and sensitizer; citral is a listed fragrance allergen.

• Cassia OilDocumented risk

  The Tisserand Institute, NAHA and NCCIH describe high skin-reaction and sensitization risk with cassia and cinnamon bark oils.

• Cumin OilDocumented risk

  The FDA, LactMed and NAHA describe blistering, phototoxic reactions and irritation after contact with cumin oil.

• Angelica Root OilDocumented risk

  Skin is where the oil causes sun-triggered reactions (phototoxicity).

• Tagetes (Marigold) OilDocumented risk

  The SCCS set a phototoxicity limit for Tagetes oils in leave-on cosmetics; sensitization was shown in guinea pigs for marigold chemicals.

• Medical-Grade HoneyClinically supported

  The studied use is a dressing on damaged skin (burns, ulcers, surgical wounds), applied in care settings. Strongest for partial-thickness burns.

• Olive OilPreliminary or mixed

  Studies measured the skin barrier and pressure ulcers; results differ by skin type and age.

• LanolinDocumented risk

  Applied to skin; documented contact allergen in 1 to 5 percent of people patch tested in clinics.

• Vitamin AEstablished role

  Vitamin A helps maintain skin; low intake causes dry, scaly skin.

• Vitamin B2Established role

  The NHS says riboflavin helps keep skin healthy.

• Vitamin CEstablished role

  Skin contains collagen, which needs vitamin C to form. Extra supplements have not been shown to help skin when intake is adequate.

• ZincEstablished role

  Zinc supports wound healing; skin sores are a sign of deficiency.

• AstaxanthinPreliminary or mixed

  Small trials found better skin moisture and a higher UV dose needed to redden skin; results are preliminary.

• LavenderDocumented risk

  Skin products with lavender may cause allergic reactions.

• Aloe veraPreliminary or mixed

  NCCIH says clinical research suggests aloe gel on the skin may speed burn healing and reduce burn pain; evidence for other skin uses is small. Mostly small studies, so this is promising but not settled.

• GarlicDocumented risk

  NCCIH says fresh raw garlic applied to the skin may cause severe irritation and chemical burns.

• ArnicaDocumented risk

  The skin is the site of use and of possible irritation and contact allergy.

• St. John's wortDocumented risk

  Oral use in large amounts or use on the skin might cause severe skin reactions after sun exposure.

• Black seedDocumented risk

  Pure black seed oil on the skin has caused allergic reactions and contact dermatitis in reports.

• ElecampaneDocumented risk

  Contact (skin) allergy to daisy-family plants including elecampane was found in Danish patients; alantolactone, a main root compound, was among frequent triggers.

• Dong quaiDocumented risk

  Dong quai can make skin more sensitive to light.

• GuggulDocumented risk

  Hypersensitivity rash was reported in trials of guggul extracts.

• Oregon grapePreliminary or mixed

  Creams made from Oregon grape extract improved psoriasis in several small trials, but reviews say the studies are too small to be sure. It does not apply to products taken by mouth.

• Witch hazelPreliminary or mixed

  Applied to skin as a distillate in creams and ointments; benefit mainly rests on tradition.

• ShiitakeDocumented risk

  Shiitake dermatitis after raw or undercooked mushrooms, and sun sensitivity after prolonged powder use (case reports).

• BergamotDocumented risk

  Cold-pressed bergamot oil on skin plus sunlight can cause reactions; furanocoumarin-free oil is expected not to.

• Saposhnikovia (fang feng)Documented risk

  Plants of the carrot family can make skin react to sunlight through furanocoumarins; fang feng chemistry includes imperatorin, but sun sensitivity was not measured for it in people.

• Mustard seedDocumented risk

  Mustard powder used as a skin plaster has caused second-degree burns in case reports.

• Chitrak (Ceylon leadwort)Documented risk

  A root extract moderately irritated rabbit skin; reviews advise caution with topical use.

• VanillaDocumented risk

  Vanilla extract and pods have caused positive skin patch tests in some people, especially those allergic to balsam of Peru and bakery workers.

• Sausage tree (kigelia)Documented risk

  Traditionally applied to skin; raw fruit pulp can blister it. Benefits are unproven.

• LimesDocumented risk

  Contact with lime juice followed by sunlight can cause a skin reaction in some people.

• TepezcohuitePreliminary or mixed

  Used on skin wounds and ulcers; trial evidence is small and mixed.

• Mandarins & TangerinesEstablished role

  Vitamin C helps maintain skin and heal wounds.

• MangoDocumented risk

  Handling mango skin or sap can cause an itchy delayed rash in people sensitised to poison ivy (case reports); the flesh seems to carry little of the allergen.

• LovageDocumented risk

  The root contains furanocoumarins and a case report describes sun-sensitivity reactions; avoid strong sun during use per an encyclopedia.

• Costus root (mu xiang)Documented risk

  Skin allergy to costus oil is documented.

• Ancho chileDocumented risk

  Capsaicin oil can irritate skin and eyes; the EU monograph lists skin reactions for capsicum products.

• Aleppo pepperDocumented risk

  Capsaicin can irritate skin on contact, and washing does not remove it well.

• Kashmiri chiliDocumented risk

  Chili can cause contact irritation or dermatitis; capsaicin cream often causes skin irritation.

• Makrut (kaffir) lime leafDocumented risk

  Juice or peel on the skin followed by sunlight can cause blisters (phytophotodermatitis); this is not about eating the leaf.

• CeleryDocumented risk

  Celery furocoumarins plus UV light can cause blistering and dark patches on skin, mostly after repeated handling.

• Nopales (Prickly Pear Pads)Documented risk

  Spines and glochids can embed in skin and cause irritation or allergic contact dermatitis.

• Lovage seedDocumented risk

  Furanocoumarins in the plant can make skin sensitive to sunlight, described in a harvesting case report; the seed is not described.

• Poison fire coralDocumented risk

  Peeling of palms, soles and scalp was reported in several patients.

• Lavender OilDocumented risk

  Lavender is a documented skin sensitizer (clinic studies).

• Chamomile Oil (Roman and German)Documented risk

  Contact allergy to chamomile compounds is documented.

• Clary Sage OilDocumented risk

  EFSA classification as an irritant and sensitizer.

• Ylang Ylang OilDocumented risk

  Allergic contact dermatitis is documented; masseurs and cosmeticians had higher risk in one series.

• Geranium OilDocumented risk

  Allergic contact dermatitis is documented; reactions can occur on skin contact.

• Neroli OilDocumented risk

  Allergic contact dermatitis is documented.

• Palmarosa OilDocumented risk

  Allergic skin reactions are possible with essential oils; palmarosa was a weak sensitizer in a mouse test.

• Tea Tree OilPreliminary or mixed

  Topical use for acne and fungal skin infections; irritation and contact allergy documented.

• Orange Oil (Sweet and Bitter)Documented risk

  Sun sensitivity (bitter orange, pressed) and allergy to oxidized limonene.

• Frankincense OilDocumented risk

  A case report describes allergic contact dermatitis from frankincense oil; Poison Control says rashes can occur with essential oils.

• Myrrh OilDocumented risk

  EMA says allergic skin reactions have been reported with myrrh medicines; the tincture can also irritate through its alcohol.

• Cedarwood OilDocumented risk

  EFSA calls cedarwood Texas oil an irritant to skin and eyes and a skin sensitiser.

• Pine OilDocumented risk

  EFSA calls related pine products skin irritants and sensitisers.

• Rosewood OilDocumented risk

  Danish patch-test clinic: 3.1% of 6,719 patients had positive tests to linalool hydroperoxides; rosewood is mostly linalool.

• Helichrysum Oil (Immortelle)Documented risk

  Two cases in a 42-patient French allergy study were attributed to a helichrysum flower absolute; a review reports an allergic reaction to its extracts.

• Clove OilDocumented risk

  Patch-test and case-report evidence of allergic reactions to clove oil and eugenol.

• Fennel Oil (Sweet and Bitter)Documented risk

  Skin or breathing allergy to fennel is listed in the EU monograph; dilute and stop if skin reacts.

• Anise and Star Anise OilDocumented risk

  Allergy to aniseed and anethole is listed by the EU monograph; dilute and stop if skin reacts.

• Wintergreen OilDocumented risk

  Absorption, rash, and necrosis under heat or occlusion.

• Camphor Oil (Dangers)Documented risk

  Irritant and sensitiser per EFSA; absorbed through skin per Pet Poison Helpline (animals).

• Sage Oil (Dalmatian and Spanish)Documented risk

  The EU assessment calls sage oil a moderate skin irritant.

• Jojoba OilDocumented risk

  A case report links jojoba oil to contact dermatitis; we found no rate.

• Sweet Almond OilDocumented risk

  Tree nut allergy is a major allergy; whether almond oil on skin triggers reactions is not described in sources read.

• Coconut Oil and Fractionated Coconut OilPreliminary or mixed

  Trials of virgin coconut oil on skin (child and adult eczema, newborn skin, stretch marks) were mostly favorable but small and usually compared with other oils.

• Blue Tansy OilDocumented risk

  Daisy-family plants, including other Tanacetum species, can cause allergic skin reactions; blue tansy oil itself has not been patch-tested in the sources we read.

• Niaouli OilDocumented risk

  Essential oils can cause skin rashes; Poison Control says allergy is possible and to dilute. Niaouli-specific rates were not found.

• Lemon Eucalyptus Oil (and PMD)Documented risk

  Repellents are applied to skin; OLE/PMD products are not for children under 3 (CDC), and topical repellents caused mild skin reactions in 0.6% of trial participants (Cochrane, not OLE-specific).

• Inula (Elecampane) OilDocumented risk

  Same: plant-allergen patch tests show elecampane among sensitizers; oil data lacking.

• Kunzea OilDocumented risk

  Essential oils can irritate skin or cause allergic rash; no kunzea-specific study was found, but its tea tree relative has documented allergy.

• Manuka OilDocumented risk

  Essential oils can irritate skin or cause allergic rash; no manuka-specific study was found, but its tea tree relative has documented allergy.

• Yuzu OilDocumented risk

  Poison Control says many essential oils can cause skin rashes; yuzu-specific sun and allergy data are limited (NAHA lists it as non-phototoxic).

• Dill OilPreliminary or mixed

  Skin is the studied route: one trial of less itch, and EFSA's irritant and sensitizer warning.

• Coriander OilDocumented risk

  EFSA and LactMed describe skin irritation, sensitization and contact dermatitis with coriander oil.

• Frankincense Species Compared (Carterii, Sacra, Frereana, Serrata)Documented risk

  A case report describes allergic contact dermatitis from B. carterii oil; Poison Control warns of rashes from essential oils.

• Sweet Birch OilDocumented risk

  Poison Control warns of rashes from essential oils; methyl salicylate is absorbed through skin, and case reports describe poisoning and tissue damage with occlusion or heat.

• Fuller's EarthLab or animal research only

  Skin decontamination after chemical exposure shown in pigs and skin samples; no human or face-mask trial found.

• Montmorillonite ClayPreliminary or mixed

  Applied to skin as masks; a 2024 review calls for larger trials.

• Dead Sea SaltPreliminary or mixed

  Skin barrier, hydration and redness improved in atopic dry skin after soaking.

• Magnesium Chloride Bath FlakesPreliminary or mixed

  Skin is the route; absorption through intact skin was minimal in a lab study, and a small bath study saw skin barrier changes.

• Borax (Sodium Borate)Documented risk

  Irritation and, in severe poisoning, a red rash with skin loss.

• Potassium AlumClinically supported

  A styptic pencil with aluminum sulfate is allowed to claim it stops bleeding from minor shaving cuts; deodorant claims are lab-only.

• Zinc OxidePreliminary or mixed

  Applied to skin as a protectant and sunscreen ingredient.

• HoneyClinically supported

  Applies to sterilised honey dressings used under care for partial-thickness burns; jar honey is a different product and is not covered.

• Manuka HoneyPreliminary or mixed

  Used in wound dressings applied by clinicians; evidence for manuka alone is limited and jar honey is not a dressing.

• PropolisDocumented risk

  Contact allergy to propolis is well documented; trials of wound and herpes ointments also exist.

• Jojoba OilPreliminary or mixed

  Applied to the skin as a moisturizer and base; evidence limited. A contact allergy case is also reported.

• Coconut OilPreliminary or mixed

  Applied to skin, it improved hydration in a two-week dry-skin trial and was used in preterm skin-care trials.

• Shea ButterPreliminary or mixed

  Applied to skin; trials of shea-based products on babies' diapered skin and children's eczema were small and product-specific.

• Cocoa ButterPreliminary or mixed

  External use only; skin protectant label status, small hydration study, negative stretch mark trial.

• Marula OilPreliminary or mixed

  One small study found more skin moisture and reduced water loss; limited evidence.

• Tamanu OilLab or animal research only

  Applied to skin; lab and rat studies of wound healing only. Allergic contact dermatitis has been reported.

• Squalane (Olive and Sugarcane)Preliminary or mixed

  Squalane is applied to skin; its safety for cosmetic use was reviewed by CIR, but benefit trials of squalane alone were not found.

• Collagen Peptides (Hydrolyzed Collagen)Preliminary or mixed

  Studied for hydration, elasticity and wrinkles by instruments; visible change was not clearly shown.

• Bovine Collagen (Types I and III)Preliminary or mixed

  Meta-analyses of hydrolyzed collagen (all sources pooled) reported better skin hydration and elasticity than placebo; trials were small, short and had biases, and none isolated bovine collagen.

• Marine Collagen (Fish)Preliminary or mixed

  Pooled reviews of hydrolyzed collagen reported better skin hydration and elasticity than placebo, with biases; small trials of marine products point the same way but the source was not shown to matter.

• Hair, Skin and Nails FormulasPreliminary or mixed

  Collagen trials showed skin hydration and elasticity gains; authors flag bias and the need for larger trials.

• Vitamin EEstablished role

  The NHS says vitamin E helps maintain healthy skin. Supplement benefit when intake is adequate is not shown.

• Vitamin B7Deficiency link

  Biotin deficiency can cause skin rashes and dermatitis.

• Omega-6 fatty acidsDeficiency link

  Skin changes are the historical sign of linoleic acid deficiency; no sourced evidence of benefit for healthy skin.

• GlutathionePreliminary or mixed

  Oral glutathione at 500 mg/day in studies reviewed showed a possible brightening in sun-exposed skin; evidence inconclusive.

• Carotenoids: lutein, zeaxanthin and lycopenePreliminary or mixed

  Tomato and lycopene supplements reduced redness after UV light in a meta-analysis. Evidence is limited to this measure.

• Beta-caroteneDocumented risk

  Very high intake can turn skin yellow or orange; this fades when intake is reduced and is not a skin benefit.

• RosemaryDocumented risk

  Contact dermatitis is listed as a possible reaction (frequency unknown); do not apply to broken or irritated skin.

• CinnamonDocumented risk

  Topical cinnamon may cause irritation or contact dermatitis.

• FenugreekPreliminary or mixed

  EU committee accepts fenugreek seed on the skin for minor inflammation on traditional use only.

• CalendulaPreliminary or mixed

  Traditionally used on the skin for minor irritation and small wounds; human trials are limited and mixed, so benefit is not confirmed.

• FeverfewDocumented risk

  Skin contact may cause dermatitis, particularly in people sensitive to daisy-family plants.

• Gotu kolaPreliminary or mixed

  Traditionally applied to minor wounds; a systematic review of four trials found it might aid healing but more studies are needed, and the EU accepts a traditional skin use.

• Licorice rootPreliminary or mixed

  Topical licorice gels were preliminarily studied for eczema and burns; they may also irritate skin.

• CleaversLab or animal research only

  Cleavers has been used on the skin and wounds in folk medicine. Only cell and lab studies exist; no human trial was found.

• HorsetailPreliminary or mixed

  A traditional skin use for superficial wounds; one trial of a 3% ointment after episiotomy found better wound and pain scores than placebo.

• NeemDocumented risk

  Allergic contact dermatitis has been reported with neem oil on the skin. Traditional skin use has no controlled trial support in the sources read.

• Plantain herbPreliminary or mixed

  Used on the skin in wound trials with lab-made gels; evidence is limited and does not cover crushed leaf.

• Sea buckthornPreliminary or mixed

  One 55-patient trial found second-degree burns healed faster with a sea buckthorn cream than with a standard silver sulfadiazine dressing. Burns need medical care.

• MyrrhPreliminary or mixed

  Used on minor wounds and small boils under EU traditional use; a trial of sitz baths for childbirth wounds was positive but small.

• EucalyptusDocumented risk

  Undiluted oil can irritate skin and large-area use has caused poisoning in a child; contact allergy to the leaves has been reported.

• KavaDocumented risk

  Long-term heavy use can cause kava dermopathy (dry, scaly skin) and itchy or burning rashes.

• Horny goat weedDocumented risk

  One case of a vasculitic rash with horny goat weed and/or ginkgo.

• Honeysuckle (Lonicera)Preliminary or mixed

  Meta-analysis of 7 trials suggests help with rash from EGFR-inhibitor cancer drugs; certainty low to very low. The plant can also irritate skin on contact.

• AgrimonyPreliminary or mixed

  EU traditional use for minor skin inflammation and small superficial wounds; no human trial found.

• TremellaLab or animal research only

  Only laboratory and animal work; no human skin trial of eating or applying tremella was found.

• Cauliflower mushroomPreliminary or mixed

  Skin water loss was lower in one small placebo-controlled trial; wound healing is animal-only.

• Prickly pear (nopal)Documented risk

  Spines and glochids can embed in skin and cause irritation or allergic contact dermatitis.

• AjwainPreliminary or mixed

  The studied products were creams or oils applied to skin or gums; only mild local skin reactions were reported in a review that included an ajwain cream trial.

• ChrysanthemumDocumented risk

  Daisy-family herbs are an important cause of allergic skin reactions, mainly from sesquiterpene lactones; evidence for chrysanthemum tea itself was not found.

• SandalwoodDocumented risk

  Sandalwood oil can cause skin irritation or allergy in some people. Small studies also looked at warts and acne, but they are not conclusive.

• Mucuna pruriens (velvet bean)Documented risk

  Hairs on cowhage-type pods cause intense itching and dermatitis.

• Calamus (sweet flag)Documented risk

  A lab-model study found the rhizome oil to be an irritant and sensitiser; human patch testing was not done.

• Nirgundi (Chinese chaste tree)Documented risk

  One case report links nirgundi oil massage with a skin infection-type reaction; cause not proven.

• Usnea (old man's beard lichen)Documented risk

  Topical use may cause local irritation and allergic reactions.

• Heartsease (wild pansy)Preliminary or mixed

  Traditional use only (EU, based on long-standing use); no controlled human trial was found. Skin forms should not go on open wounds or large areas of damaged skin.

• Yellow brain fungusLab or animal research only

  A 2026 cell-dish study of a polysaccharide extract found raised skin-barrier and water-channel markers; no animal or human data.

• Poke root (pokeweed)Documented risk

  Skin contact with the juice can cause absorption, and the Kentucky review reports swelling, pain and edema.

• Horseradish and wasabiDocumented risk

  Skin reactions were among those reported after pure mustard oil.

• Pink peppercornDocumented risk

  The plant's sap can cause skin reactions in sensitive people, similar to poison ivy; sources do not say if the dried fruit does.

• CinnamonDocumented risk

  Irritation or contact dermatitis from oil or powder.

• ClovesDocumented risk

  Eugenol can irritate skin and cause allergic contact dermatitis.

• CuminDocumented risk

  LactMed reports occasional skin reactions to sunlight after contact with the oil.

• FenugreekPreliminary or mixed

  The EU committee accepts seed on the skin for minor inflammation on traditional use only.

• Annatto (achiote)Documented risk

  Hives and swelling are the usual skin signs in annatto allergy case reports.

• Angelica dahurica (bai zhi)Documented risk

  Possible sun-related skin reaction from furanocoumarins; not confirmed for this herb.

• Angelica pubescens (du huo)Documented risk

  Photosensitizing coumarins (xanthotoxin, bergapten, psoralen, osthole) can make skin react to sunlight.

• Black seed (nigella)Documented risk

  The oil on skin has caused contact dermatitis and, in one report, a severe reaction.

• Coriander seedDocumented risk

  Contact dermatitis and light sensitivity are reported; the essential oil is an irritant and sensitiser.

• Celery seedDocumented risk

  Celery furocoumarins can cause sun-triggered skin blistering, mainly with frequent handling or tanning-bed use.

• Ajwain (carom seed)Preliminary or mixed

  The creams in the nerve-pain trials were applied to the skin; they test a local effect, not a skin benefit. Thymol oil can burn skin when concentrated.

• Blue flagDocumented risk

  Sap and rootstock can irritate the skin. Use of blue flag for skin disease has no human trials behind it.

• HoneybushPreliminary or mixed

  One 12-week trial of a fermented honeybush extract reported improvements in wrinkles, elasticity and moisture loss; one trial only.

• Greater celandineDocumented risk

  The fresh latex can irritate skin, and one woman developed contact dermatitis after using it on warts.

• Chaparral (creosote bush)Documented risk

  A 2022 review attributes contact dermatitis to the plant; black salve contains chaparral per Memorial Sloan Kettering.

• Citrus Fruits (overview)Deficiency link

  Slow wound healing and bleeding gums are signs of vitamin C deficiency; citrus is a source.

• LemonsDocumented risk

  Citrus juice on skin followed by sunlight can cause a painful rash (phytophotodermatitis), documented mainly for lime.

• OrangesEstablished role

  The NHS says vitamin C helps maintain healthy skin; the point is meeting normal needs, not extra benefit.

• JewelweedPreliminary or mixed

  Used on skin for poison ivy rash. Small trials conflict: fresh mash helped in one study, juice and stem extract did not in two others.

• PineappleEstablished role

  NHS says vitamin C supports skin, blood vessels, bones and wound healing; pineapple supplies vitamin C but was not tested for skin outcomes.

• Iceland mossDocumented risk

  Contact allergy is possible in sensitive people; the EU lists lichen allergy as a contraindication.

• FigsDocumented risk

  Contact with fig sap or leaves followed by sunlight can cause blistering skin reactions; this concerns the tree, not the fruit.

• Amchur (dried green mango powder)Documented risk

  Raw mango peel can cause a delayed rash in people already sensitive to poison ivy; the flesh appears to carry little of the allergen.

• FigwortLab or animal research only

  Used traditionally on and for the skin; only lab and horse-wound findings exist, no human trials.

• Chipotle (smoked jalapeno)Documented risk

  Capsaicin can cause contact dermatitis when handling hot chilies; use gloves and avoid touching eyes.

• Calotropis (arka)Documented risk

  Skin application was part of the exposure in the heart-collapse case; skin injury details were not read.

• ParsnipsDocumented risk

  Wild parsnip sap plus sunlight can blister skin (case report and reviews).

• Chili PeppersEstablished role

  Vitamin C supports skin (NHS); chili is one source. Capsaicin skin products are a separate medicine.

• Zucchini (Courgette)Established role

  Vitamin C helps maintain skin and wound healing; zucchini contributes some vitamin C.

• Poison hemlockDocumented risk

  Skin contact can cause irritation.

• PumpkinEstablished role

  Vitamin A supports healthy skin; very high beta-carotene intake can turn skin yellow or orange, which is harmless and fades.

• Butternut SquashEstablished role

  MedlinePlus says vitamin A helps maintain skin and mucous membranes; squash is a carotenoid source.

• Dried fenugreek leaf (kasuri methi)Preliminary or mixed

  The EU committee accepts seed on the skin for minor inflammation on traditional use only.

• Dried citrus peelDocumented risk

  Limonene in concentrated orange peel oil can irritate skin.

• Ginkgo NutsDocumented risk

  Contact with the ginkgo tree can cause allergic contact dermatitis attributed to ginkgolic acids.

• Rose Oil (Otto and Absolute)Documented risk

  Essential oils can cause skin rash and contact allergy, especially undiluted or at high concentration; rose-specific data not found.

• Peppermint OilDocumented risk

  Skin irritation and rare allergy.

• Rosemary OilDocumented risk

  Scalp itching in the trial; contact dermatitis listed for the leaf by EMA.

• Mandarin and Tangerine OilDocumented risk

  General allergy and irritation caution for essential oils.

• Juniper Berry OilDocumented risk

  Irritation and allergic reactions have been reported.

• Vetiver OilDocumented risk

  Skin sensitization potential noted by the SCCS for the acetylated material; the FDA warns plant materials can irritate skin.

• Argan OilPreliminary or mixed

  One small trial of skin elasticity; allergy to the oil is also reported in case reports.

• Rosemary TeaDocumented risk

  Contact dermatitis is listed as a side effect; do not apply to broken or irritated skin.

• Olive Oil as a CarrierPreliminary or mixed

  Applied to skin; benefit shown for pressure injury prevention in hospital patients; rare allergic reactions.

• Black Seed Oil (Nigella)Documented risk

  Allergic contact dermatitis and severe skin reactions are reported for the oil on skin.

• Calendula TeaPreliminary or mixed

  External use on skin is the accepted traditional use; drinking is not described.

• Corn Masa & Corn TortillasDeficiency link

  Pellagra includes inflamed skin (MedlinePlus); lime-treated corn avoids the niacin shortage.

• Koji & AmazakePreliminary or mixed

  Skin barrier, hydration and elasticity measures in trials.

• Bentonite ClayPreliminary or mixed

  Applied as a mask; preliminary evidence.

• Kaolin Clay (White Clay)Clinically supported

  Listed as a skin-protectant active ingredient for labeled products.

• Diatomaceous EarthDocumented risk

  Dryness and irritation.

• Illite ClayPreliminary or mixed

  Used on the skin as a face pack or lotion ingredient; evidence from two small studies.

• Dead Sea MudDocumented risk

  Redness in trials; metals found in some products.

• Peloids and Mud TherapyDocumented risk

  Redness in trials; product variation.

• Zeolite (Clinoptilolite)Lab or animal research only

  Specialized zeolite skin formulations at lab stage.

• Sea Salt, Himalayan Salt and Dead Sea Salt: Mineral ClaimsPreliminary or mixed

  One small bath study with Dead Sea salt in atopic dry skin.

• Sulfur (Sulphur) BathsPreliminary or mixed

  Spa baths studied for psoriasis and eczema; sulfur is an allowed acne ingredient in OTC products.

• BeeswaxPreliminary or mixed

  Applied to the skin and lips as a barrier; it can also cause contact allergy in some people.

• Castor OilDocumented risk

  Rare contact dermatitis reported; generally well tolerated on skin per a 2026 review.

• Black Seed Oil (Nigella)Preliminary or mixed

  Small trials of Nigella gels and ointments; reactions to the oil on skin are reported in case reports.

• Argan OilPreliminary or mixed

  Skin elasticity improved in one small trial. Allergic skin reactions are also reported.

• Evening Primrose OilPreliminary or mixed

  Oral evening primrose oil has not been shown to help eczema, and the EU accepts it only on traditional use for dry-skin itching. Skin-product evidence was not found in the sources we read.

• Hemp Seed OilPreliminary or mixed

  Skin dryness, itch and water-loss measures changed in small studies of the oil by mouth or in a gel.

• Camellia Oil (Tsubaki)Preliminary or mixed

  Applied to skin in small trials; evidence preliminary.

• Sesame Oil on Skin and HairPreliminary or mixed

  Used on skin in small trials for radiotherapy dermatitis and phlebitis; results preliminary.

• Candelilla WaxDocumented risk

  Case reports describe allergic reactions to candelilla wax on lips and skin; these look rare.

• Carnauba WaxDocumented risk

  Rare allergic contact reactions of lips and eyelids are reported; patch tests of lipstick and blush products found no sensitization in small old studies.

• Chicken Collagen (Type II)Preliminary or mixed

  One 12-week trial in women aged 39 to 59 on a blended chicken cartilage product.

• Multi-Collagen Blends (Types I, II, III, V, X)Preliminary or mixed

  Skin measures improved in two trials of mixed products.

• Vegan Collagen and Collagen BoostersPreliminary or mixed

  Small skin trials of silica and oral hyaluronic acid; none of vegan collagen.

• B-Complex FormulasDocumented risk

  Niacin as nicotinic acid can cause flushing: warmth, redness, itching or tingling of the face, neck and upper chest.

• Mushroom Blends and Mushroom CoffeeDocumented risk

  Shiitake flagellate rash reported after mushroom coffee.

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