Restoring Scalp Serum

The active anti-dandruff ingredient in medicated shampoos, used at 1% or 2% to reduce Malassezia yeast and flaking. It is well studied and considered safe in rinse-off use; EU rules cap leave-on hair products because it is more irritating with prolonged skin contact, which is why it is formulated into shampoos meant to be rinsed out.

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

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

A light, non-comedogenic oil from safflower seeds, high in linoleic acid. It is well tolerated across skin types and valued for its ability to condition the skin without a heavy feel.

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

Green tea extract is a well-studied topical antioxidant with a long history of use in serums and moisturizers, generally well tolerated at cosmetic concentrations. Panel safety reviews of Camellia sinensis-derived ingredients have not identified meaningful topical hazard.

A form of vitamin B3 used to support a more even-looking tone and a comfortable barrier. Well tolerated at cosmetic levels.

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

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.

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.

An aromatic plant extract rich in natural antioxidants, valued in skincare formulations for its protective properties. Published cosmetic assessments indicate it is generally well tolerated, though the botanical origin means some sensitive individuals may react.

A synthetic or extracted aromatic aldehyde that mimics vanilla scent. It is a known contact allergen in people with fragrance sensitivities, and oxidation over time can increase allergenicity, making it a watch-if-sensitive ingredient in cosmetics.

A metabolite produced through fermentation of milk by Lactobacillus bacteria, valued in skincare for humectant and antioxidant properties. It is documented in cosmetic formulations as well tolerated, though people sensitive to fermentation byproducts or lactic acid may want to patch test.

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.

A synthetic polymer derived from acrylic acid and taurine amino acid that stabilizes emulsions and thickens formulas. Direct human data is limited, but no adverse effects have been reported and it is considered safe for topical use.

A strong alkali used in tiny amounts to adjust the pH of cosmetics to safe, skin-friendly levels. At the pH found in finished products, sodium hydroxide is neutralized and well tolerated.

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.

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.

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

A floral fragrance component and one of the EU-labelled fragrance allergens. Usually fine, worth watching if you react to scented products.