Don't Despair, Repair! Deep Conditioning Mask

The base most products are built on. It carries the other ingredients and has no safety concern.

A fatty alcohol used to soften skin and stabilize creams. Despite the name, it does not dry the skin.

A corn-derived solvent and humectant that has largely replaced propylene glycol in "clean" formulas; CIR reviewed the alkane diol group and found use concentrations up to about 40 percent in leave-on products like deodorant sticks with no meaningful irritation signal.

A fatty alcohol derived from stearic acid that thickens creams and gives them a smooth, non-greasy glide. It is one of the fatty alcohols the CIR panel reviewed together and found safe as used, with a very low reported rate of contact sensitization.

A blend of cetyl and stearyl fatty alcohols used to thicken lotions and soften skin. It is chemically unrelated to drying alcohols like ethanol, and the CIR expert panel has found fatty alcohols safe as used in cosmetics.

A rich botanical oil from avocado fruit, used to nourish and soften the skin. It is generally well tolerated across skin types and provides conditioning benefits.

A nutrient-rich oil pressed from sweet almond kernels, used to soften and condition skin. It is generally well tolerated, though people with tree nut allergies should patch test first, as it can rarely trigger allergic reactions.

A lightweight botanical oil pressed from rosehip seeds, used to nourish and condition the skin. It is generally well tolerated, though as a botanical extract it may rarely trigger sensitivity in individuals prone to plant allergies.

A fatty-acid and tocopherol-rich plant oil used as a hair and skin emollient; CIR's review of plant-derived fatty acid oils found no evidence of irritation or sensitization and a long history of safe use in food and cosmetics.

A plant-derived water or extract used mainly as a soothing humectant filler. Evidence for dramatic skin benefits beyond mild hydration and soothing is limited, but it is well tolerated by most people.

A soothing humectant that helps skin and hair look conditioned. Very well tolerated.

A protein fragment that draws water into the hair shaft and is used to strengthen and add body. People with wheat sensitivity or protein allergies should patch-test first, as protein hydrolysates can trigger reactions in those with known sensitivities.

An energizing plant extract used in skincare preparations, known for antioxidant activity in cosmetic applications. Cosmetic safety assessments generally support its use, though like many botanical ingredients it may trigger reactions in very sensitive individuals.

Calendula extract is a traditional soothing botanical used in balms and after-sun formulas with a generally reassuring safety history. Like chamomile, it is part of the Asteraceae family, so cross-reactive contact allergy is possible for people already sensitive to ragweed or related plants.

A modified guar gum used to thicken and stabilize emulsions and gels. It is derived from guar beans and is well tolerated when applied topically. It is common in skincare formulas where a smooth texture is valued.

A lightweight hydrocarbon that gives formulas a smooth, silky feel. Used in color cosmetics and sunscreens. Well tolerated and inert.

A quaternary ammonium salt used as a conditioning and antistatic agent in hair products. It has been extensively documented as safe in cosmetics when used in typical rinse-off formulations.

A long-chain quaternary ammonium compound used in rinse-off conditioners and leave-on styling products for conditioning and static control. It is well documented in cosmetic use with a strong safety record.

Used in tiny amounts to set a product to skin-friendly pH. No concern at those levels.

A synthetic ester used to thin out heavy formulas and help other ingredients absorb faster. It is considered safe as used by CIR, but it has a reputation among acne-prone users for feeling occlusive on skin, so people who clog easily may prefer to patch test or choose lighter alternatives.

A lightweight humectant and solvent similar in role to propylene glycol, used to carry actives and give lotions a lighter feel. CIR has reviewed it and considers it safe as used in cosmetics.

A humectant that draws water into the skin. One of the best-studied, best-tolerated ingredients in personal care.

An undisclosed scent blend that can contain dozens of components. The single most common cause of cosmetic contact allergy, and the blend is not itemized, so you cannot see what is in it.

Dehydroacetic acid is a preservative regulated under the EU preservative annex with a set maximum concentration. Sensitization appears to be rare, though occasional contact dermatitis case reports exist, so people with reactive skin may want to patch test.

A common preservative and fragrance/solvent ingredient found naturally in many essential oils. It is well tolerated by most people at the levels used in cosmetics, but it is one of the 26 EU-designated fragrance allergens and can trigger reactions in people with an existing sensitivity.