Pure Vitamin C12 Serum

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

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 lightweight, volatile silicone that gives serums and primers their silky slip and quick-evaporating finish. Human safety data are reassuring; the EU restriction on this ingredient in rinse-off products is about environmental persistence in waterways, not skin safety.

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

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.

Used like sodium hydroxide to adjust pH in cosmetics at very low levels. At finished-product pH, it is neutralized and well tolerated.

A silicone-based powder used to improve texture and slip in formulas. It is lightweight, absorbs excess moisture, and provides smooth application. Well studied in cosmetics with no skin safety concerns.

A silicone polymer used in hair and skin care products for conditioning and shine. It is inert and well tolerated, with no identified safety concerns at cosmetic concentrations.

A silicone that gives a smooth, soft feel and helps hold water in the skin. Inert and well studied.

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 multi-ester emollient created from pentaerythritol and ethylhexanoic acid. It provides silky texture and skin conditioning with no documented safety concerns at cosmetic concentrations.

An antioxidant that helps protect a formula and condition skin. Well tolerated.

A humectant that holds water at the skin surface for a more hydrated look. No safety concern.

A broken-down form of hyaluronic acid with smaller molecules intended to penetrate more deeply into the skin. It functions as a humectant and is well tolerated, with the same safety profile as standard hyaluronic acid.

A naturally occurring nucleoside used in anti-aging formulas, often marketed for smoothing the look of fine lines. It has a low irritation profile and no established hazard at cosmetic use levels.

A beta hydroxy acid used to smooth texture and clear pores. Safe at cosmetic levels; can be mildly irritating if overused.

Xanthan gum is a microbial-fermentation-derived polysaccharide used to thicken and stabilize textures, similarly common in food. Cosmetic panel review of this and related microbial gums found them safe as used, with no meaningful irritation signal at typical concentrations.

Caprylyl glycol is a plant-derived humectant that also has mild antimicrobial properties, so it is commonly paired with other preservatives to allow lower overall preservative levels. Available data do not point to meaningful irritation or sensitization concerns at typical use levels.

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.

A small-dose synthetic antioxidant that prevents oils and fragrance in a formula from oxidizing. Not shown to pose a toxicological risk at the levels used in cosmetics.

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.