A Complete List of Skin Irritants and Allergens

Skin care products can bring skin problems rather than solve them. Though it is not easy to choose the right products because each individual responds differently to each skin care product, it is wise to avoid skin irritants and allergens as much as possible. I summarized the following list for your reference. In skin care, nothing is absolute. Some of the ingredients listed here are actually double–edged swords. They benefit skin in a sense but pose risks at the same time. In any case, I hope this list is helpful. At least, when some skin care product causes problems, you know which ingredient is likely the culprit so that you can avoid it in the future.

Please note that some of these ingredients pose irritation when they reach certain percentages. For those ingredients, I have put the maximum concentration a skin care product can have. You can consider a product if the concentration of this kind of ingredient is way below the limit.

Some natural plants are used in skin care products as fragrance but they are usually listed as natural ingredients instead of fragrance. Please be aware that natural forms of fragrance can cause as much reactions as synthesized ones if not more.

Certain alcohols:

  • Avoid ethanol, denatured alcohol (aka alcohol denat. or SD alcohol followed by a number), ethyl alcohol, and methanol.
  • Benzyl alcohol and isopropyl alcohol are antibacterial but can be irritating, especially in high concentrations. If they are at the bottom of the ingredient list, they are preservatives and you can consider the product. Otherwise, avoid them.
  • Behenyl alcohol, cetearyl alcohol, cetyl alcohol, cetyl alcohol 40, stearyl alcohol, cetostearyl alcohol are emulsifiers and thickeners. They are not drying.

Balsam Peru: has high incidence of causing reactions.

Benzalkonium chloride: skin irritant at concentrations greater than 0.1%. It is, however, used in some cosmetic products at up to 5%.

Benzyl salicylate: generally used as fragrance, is more likely to cause allergy among Asian people.

Black pepper: surprised? It does appear in cosmetic products.

Borates: still being used in spite of repeated warnings by medical scientists.

Borax: has high pH.

Bromelain: found in pineapple and causes sloughing of the skin.

Camphor: causes contact dermatitis. There are reports of poisonings through skin absorption and accidental ingestion.

Cananga: used as fragrance (usually not marked as fragrance in skin care product) and may cause allergic reactions.

Caprylic acid: irritant.

Capsaicin: component of capsicum.

capsicum: a chili plant.

Capsicum oleoresin: the fatty resin derived from capsicum.

Cedar: photosensitizer used as fragrance.

Cedarwood: photosensitizer used as fragrance.

Cedrus atlantica: photosensitizer used as fragrance.

Ceteareth-20: irritant.

Chlorhexidine: May cause contact dermatitis. Strongly alkaline. Safe for use in cosmetic products at concentration of up to 0.14%.


Cinnamic alcohol

Cinnamic aldehydeor

Citrullus colocynthis: bitter apple.

Citrus aurantium(-amara): bitter orange.

Clary: fragrance.

Clove oil: strongly irritating.

Coleus barbatus: member of the mint family and may be irritating.

Comfrey: carcinogenic. Can only be used short term for medicinal purpose.

Coriander: fragrance.

Cyclamen: fragrance.

Cyclamen aldehyde: fragrance.

Elecampane: do not use or even handle it.

Ecalyptus: causes allergic reaction.

Essential oils: if the name “essential oils” is listed directly without clarifying the specific type, they are used as fragrance.

Fennel: may cause allergic reaction.

Feverfew: parthenolide contained in feverfew is sensitizing. But parthenolide-depleted extract of feverfew may be beneficial.

Fir needle oil: fragrance.

Fragrance: top one skin allergen. It is hard to find products that are completely fragrance free but try to avoid it as much as you can. There are many other ways to enjoy fragrance other than putting it directly on your skin.

Fumaric acid: may cause skin irritation.

Galbanum: fragrance.

Geranium oil: can be a skin sensitizer or irritant. Taking less than an ounce may kill an adult.

Grapefruit peel oil: one or more animal studies show skin irritation at moderate doses. No research found any irritation caused by grapefruit oil or grapefruit seed oil though.

Guaiacwood oil: fragrance.

Hyssop: fragrance.

Isopropyl myristate: irritant and very comedogenic.

Isostearyl neopentanoate: moderately irritant and comedogenic.

Jasmine: fragrance.

Jonquil extract: fragrance.

Laureth-4: irritant and very comedogenic.

Lavandin oil: Essential oil of the hybrid lavender plant Lavandula hybrida.

Lavandula angustifolia, Lavandula officinalis, Lavender extract or oil: can cause allergic reaction. Please get their antidepressive and relaxing benefits in other ways but don’t let them touch your skin.

Lemon oil: should not exceed 2%.

Lime: can cause an adverse reaction when skin is exposed to sunlight.

Lime oil: can cause an adverse reaction when skin is exposed to sunlight. Shouldn’t exceed 0.7%.

Linalool: fragrant component of lavender and coriander.

Linalyl acetate: fragrant component of lavender, is known to cause contact dermatitis.

Marjoram: can irritate the skin and may cause allergy. it is believed to penetrate the skin easily and produce systemic effects.

Menthol: gives that cool feeling to the skin. In concentrations of 3% or more it exerts an irritant action.

Menthyl lactate: used as a cooling agent and fragrance.

Methylchloroisothiazolinone: sensitizer. Shouldn’t be used in leave-on products. In Canada, it is permitted up to a maximum of 0.0015% in rinse-off products and 0.000075% in leave-on products.

Methylisothiazolinone: sensitizer. Shouldn’t be used in leave-on products. In Canada, it is permitted up to a maximum of 0.0015% in rinse-off products and 0.000075% in leave-on products.

Narcissus oil: fragrant oil that is likely to cause allergy especially when it is mixed with other fragrance.

Neroli: fragrant plant oil produced from the blossom of the bitter orange tree.

Oak bark extract: contains tannic acid and is exceedingly astringent.

Orange oil: fragrance.

PABA: see Para-aminobenzoic acid.

Papain: contained in papaya and classified as an irritant.

Papaya: papain contained in papaya is classified as an irritant.

Para-aminobenzoic acid (PABA): sunscreen rarely used any more. It can cause allergic eczema and a sensitivity to light.

Patchouli: fragrance.

PEG 16 lanolin (Solulan 16): Not all lanolins are irritating but this one is irritating and comedogenic.

Peppermint: can cause allergic reactions.

Pine oil: is an irritant in concentrated form.

PG laurate: irritant.

Quince seed: may cause allergic reaction.


Sandalwood oil: fragrance.

Santalum album: fragrance.

Silver: used as a coloring agent and can be irritating to the skin.

Sodium carbonate

Sodium hydroxide: skin irritant at high concentrations. Low concentrations are acceptable because sodium hydroxide is often used to adjust pH.

Sodium lauryl sulfate: a skin irritant but not related to cancer.

Sodium silicate: strongly alkaline.

Sodium sulfite: known to cause skin rash.

Spearmint: can cause allergic reactions.

St. John’s wort: contains several components that are toxic on the skin in the presence of sunlight.

Steareth-10: irritant and comedogenic.

Sulfur: antibacterial but strongly irritating. There are better antibacterial agents now so sulfur is not recommended for the skin any more.

Tangerine oil

Tannin: not for regular use.

Thyme: fragrance.

Tormentil: powerful astringent.

Tridectyl neopentanoate: irritant, seen in eye shadows, foundations and other products.

Wintergreen oil: strong irritant.

Witch Hazel: widely used in alcohol-free toners. It is anti-inflammatory and helps remove skin oil. Short-term use can be beneficial. Long-term use is controversial.

Xylene: aromatic liquid that is rarely seen in skin care products today. It is irritant and comedogenic.

Yarrow: may cause a sensitivity to sunlight and artificial light, in which the skin breaks out and swells.

Ylang-ylang: fragrance.

Zinc sulfate: astringent.

[1] Ruth Winter. A Consumer’s Dictionary of Cosmetic Ingredients 6 Edition, 1999.
[2] Katharine Martin, Runa Sur, Frank Liebel, Neena Tierney, Peter Lyte, Michelle Garay, Thierry Oddos, Mike Anthonavage, Stan Shapiro and Michael Southall. Parthenolide-depleted Feverfew (Tanacetum parthenium) protects skin from UV irradiation and external aggression. Archives of Dermatological Research 2007; vol. 300 num. 2: 69 – 80.
[3] James E. Fulton, Jr., Comedogenicity and irritancy of commonly used ingredients in skin care products. J. Soc. Cosmet. Chem., 40, 321-333 (November/December 1989).
[4] A. Prashar, I. C. Locke and C. S. Evans, Cytotoxicity of lavender oil and its major components to human skin cells. Cell Proliferation Volume 37 Issue 3, Pages 221 – 229.

6 Responses to “A Complete List of Skin Irritants and Allergens”

  1. […] low concentrations of comedogenic ingredients can cause acne. This is different from skin irritants and allergens, some of which do not cause problems at very low […]

  2. […] to sting the skin for a while after you apply it. Menthol is not beneficial to skin. As I said in A Complete List of Skin Irritants and Allergens, menthol exerts an irritant action to the skin in concentrations of 3% or more. Cellbone vitamin C […]

  3. […] sunscreen products, the common ingredients that cause problems are oxybenzone, alcohol, cooling agents (usually menthol), fragrance (also be aware of lavender) and sensitizing […]

  4. […] the inactive ingredients of this sunscreen include alcohol denat., which is not suitable for long-term use either. On the package of Kiehl’s Dermatologist […]

  5. Chelsea says:

    Alcohol-free toners don’t have alcohol explicitly on the ingredient list but witch hazel by itself contains alcohol. If witch hazel is not a main ingredient, the effect is minimal. Otherwise, it can be irritating especially for the sensitive skin.

  6. Jenn says:

    Just for clarity, “alcohol-free witch hazel toners” are in fact, NOT alcohol-free???

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