The Kure Strength Repair Shampoo

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

A primary cleansing surfactant similar in strength to sodium laureth sulfate, used in many "sulfate-lite" shampoos even though it is itself a sulfonate detergent. CIR concluded it is safe in rinse-off products; it can be drying or irritating for already-sensitized scalps at higher use levels, same as most anionic surfactants.

A coconut-derived amphoteric surfactant used to boost foam and mildness in cleansers and shampoos. CIR has reviewed it as safe as used, but it is one of the more established contact-allergy triggers in personal care, usually traced to manufacturing impurities such as amidoamine and dimethylaminopropylamine (DMAPA) rather than the betaine itself. People with a history of eyelid or scalp dermatitis are more likely to react.

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

A coconut-derived amphoteric surfactant used alongside primary detergents to soften foam and reduce irritation, similar in role to cocamidopropyl betaine. It has a generally good safety record, with occasional mild eye or skin irritation reported mainly in leave-on or highly concentrated rinse-off products.

A common emulsifier and texture-softener made from glycerin and stearic acid. CIR review of this class found no evidence of reproductive, carcinogenic, sensitizing, or phototoxic effects in the studies examined.

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 rich plant butter pressed from shea tree nuts, valued for softening and cushioning dry skin. It is generally well tolerated, though very rare allergic reactions have been reported and people with tree nut allergies who are cautious may want to patch test first.

Lavender essential oil naturally contains linalool, geraniol, and coumarin, several of the recognized fragrance allergen constituents, so it can trigger contact reactions in fragrance-sensitive users even though it is a "natural" ingredient. It is not a general hazard for most people, but those with a known fragrance allergy should treat it like any other essential oil.

Rosemary extract is widely used at low levels as a natural antioxidant to help stabilize oils and extend product shelf life, in addition to appearing as an active botanical in some formulas. It is generally well tolerated, with occasional mild contact reactions reported, mostly at higher leave-on concentrations.

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 gentle humectant derived from glucose. It draws water to the skin and is mild enough for sensitive skin types. Widely used in cosmetics without reported safety concerns.

A PEG-based emulsifier that blends oils and water in formulas. It is a workhorse ingredient in stable emulsions and is approved for cosmetic use. Well tolerated.

A polymer of quaternary ammonium compounds widely used as a conditioning and antistatic agent in hair products. It is well established in cosmetic formulations with a strong safety record in rinse-off applications.

A positively charged conditioning polymer used in shampoos and conditioners to reduce frizz and improve manageability. It is well tolerated and has been safely used in cosmetics for decades.

A widely used emulsifier and solubilizer that has been in cosmetics and pharmaceuticals for decades. The CIR has assessed it as safe with no known concerns at typical cosmetic concentrations. As with any surfactant, some people with very sensitive skin may experience mild irritation.

A small humectant and solvent molecule that helps other ingredients dissolve and helps skin hold water. It is one of the most studied cosmetic ingredients and is considered safe at the concentrations used in personal care products.

A gentle amino acid-based surfactant derived from coconut oil, used as a primary cleanser in many sulfate-free shampoos and body washes. It is well tolerated and designed to reduce irritation common to harsher sulfonated surfactants.

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

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.

A widely used preservative, safe at the legal limit of 1% or less. Often the "paraben-free" replacement.

A widely used, gentle preservative also common in food. It is generally well tolerated, though it can occasionally cause mild, transient irritation in people with already-compromised or very reactive skin.

The sodium salt of benzoic acid, used as a preservative in both foods and cosmetics. Decades of safety review support its use at typical cosmetic concentrations, with mild irritation the main reported issue in sensitive skin.

A naturally occurring acid used to preserve and adjust pH in cosmetic formulas. It is generally recognized as safe at cosmetic use levels, with mild irritation possible on broken or very sensitive skin at higher concentrations.

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.

A fragrance fixative and solvent found naturally in balsams and used to help scents last longer. It is one of the 26 EU-designated fragrance allergens, with documented but uncommon contact sensitization.

Hydroxycitronellal is a lily-of-the-valley scented fragrance ingredient on the EU allergen disclosure list. It has well-documented sensitizing potential in patch-test studies, so it is worth checking the label if you have known fragrance sensitivities.

A citrus-scented fragrance component. Fine for most, but it oxidizes over time into a known contact allergen, so it must be labelled in the EU.