Renewing Cucumber Peel-Off Gel Mask

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

A synthetic polymer used as a film-former and thickener that creates a protective layer on skin. It has extensive use in cosmetics and pharmaceuticals with a well-established safety profile.

A fast-evaporating solvent used to carry actives and give toners a light, "clean" feel; at the concentrations used in classic astringents it can be genuinely drying or irritating with repeated use, especially on dry or compromised skin, though it is not inherently toxic and is a normal, well-studied cosmetic ingredient.

A lightweight polyethylene glycol that draws moisture into skin and helps dissolve other ingredients. Published safety reviews support its use; concerns about absorption through skin are overstated for leave-on formulations.

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

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 rich, solid-at-room-temperature oil that deeply softens dry skin and hair. It is well tolerated overall, but its high lauric acid content is considered comedogenic by many dermatologists, so it can trigger breakouts in people who are acne-prone.

A warming root extract with anti-inflammatory and antioxidant properties. Some individuals report mild warming or tingling sensations; those with sensitive skin should start with lower concentrations or patch test first.

A mild enzymatic extract from papaya fruit that softens and hydrates skin. It is generally considered safe, though those with tree fruit allergies may wish to patch test first.

A botanical fragrance ingredient derived from Australian sandalwood. Essential oils and natural fragrance materials can trigger sensitivities in individuals with fragrance allergies or sensitized skin. Those with known fragrance sensitivities may prefer to monitor for reactions.

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

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

A soothing, skin-conditioning compound (also found in comfrey root) commonly added to calm and hydrate irritated or sensitive skin. It has a long history of safe use with very low irritation potential.

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.

An extract from cucumber fruit valued in skincare for its hydrating and soothing properties. It is well tolerated across skin types and commonly included in formulas designed to refresh and calm the skin.

Sodium PCA is a natural component of skin's own moisturizing factor and is used in cosmetics as a humectant to help skin hold onto water. It has an extensive history of safe use with no meaningful irritation or sensitization signal.

The most well-studied form of topical vitamin C, used as an antioxidant and to support collagen signaling and brighten uneven tone. It is acidic and can sting or irritate sensitive skin, and it oxidizes readily once a bottle is opened, which can reduce its effectiveness rather than create a safety issue.

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 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.

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.

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.

Butylphenyl methylpropional, widely sold under the trade name Lilial, was banned from cosmetics in the EU starting March 2022 after being classified as toxic to reproduction based on animal studies. Products made and sold in the EU after that date should no longer contain it.

A rose-scented fragrance ingredient found naturally in geranium and rose oil. It is one of the 26 fragrance allergens the EU requires to be labeled by name because a minority of people develop skin sensitization to it, though most users tolerate it without issue.

A jasmine-like fragrance compound frequently used in soaps and lotions. It is one of the 26 EU-designated fragrance allergens, though studies suggest its sensitization potency is comparatively low relative to other listed allergens.

An FDA-approved synthetic colorant used in cosmetics to impart a blue hue. Blue dye sensitivity is rare but documented in a small subset of individuals. Generally well tolerated at regulated cosmetic levels.