Glow and Radiance with Vitamin C and Citrus Essential Oil

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

A common foaming cleanser, milder than SLS. Fine for most people in a rinse-off product.

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.

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 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.

Ordinary salt, used in surfactant-based products like shampoos and body washes to adjust viscosity by interacting with the surfactant micelles. It has no meaningful toxicity concern at cosmetic use levels; the main practical downside is that too much can make a formula feel less mild.

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

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

Tea tree oil is used for its antimicrobial reputation in blemish-focused products, but it is a genuine, well-documented contact sensitizer, and its allergy potential rises sharply once the oil has oxidized from air exposure. Fresh, well-preserved, low-concentration formulations are much lower risk than old or improperly stored oil.

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 more stable, esterified form of vitamin E used as an antioxidant and skin-conditioning ingredient. It is a different substance from the vitamin E acetate implicated in vaping-related lung injury, which involved inhaling the oil, not applying it topically to skin.

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.

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.

A chelating agent that binds trace metal ions to keep formulas stable and preservatives working properly. It is not a functional skincare "active" and only a very small amount is used, with minimal skin penetration expected.

Methylchloroisothiazolinone is typically used together with methylisothiazolinone in a 3:1 mix and is a well-documented skin sensitizer at higher rates than most preservatives. EU rules now restrict this combination to rinse-off products only, at a low maximum concentration.

A preservative that caused a wave of contact allergy in the 2010s. The EU banned it from leave-on products and tightly limits it in rinse-off ones. A genuine concern, not a myth.