6% Acid Renewal Peeling Serum

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

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.

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

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

Mandelic acid is a larger-molecule alpha hydroxy acid that tends to penetrate skin more slowly than glycolic acid, which is generally associated with less stinging and redness. It carries the same general AHA cautions around sun sensitivity but is often better tolerated by reactive skin.

A cross-linked polymer used to thicken formulas and create lightweight gel textures. The large molecular weight prevents penetration into the skin and is not absorbed; well tolerated in cosmetics.

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

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

Gluconolactone is a polyhydroxy acid that exfoliates gently while also acting as a humectant and mild antioxidant, and it is generally recommended for sensitive or barrier-compromised skin over smaller AHAs. A full cosmetic panel review found it safe as used, though some users still report mild stinging or redness at higher concentrations.

A humectant naturally derived from sugar beets that helps skin draw in and hold water; it has a long history of safe use with no meaningful irritation or sensitization concerns.

A plant extract used in Korean skincare for its soothing, antioxidant reputation. It is well tolerated with a low reported irritation rate; the soothing claims rest on limited but reasonable evidence.

A liquid ester used as a texture modifier and mild emollient in cosmetics. It helps formulas spread smoothly and gives them a non-greasy feel. It is well tolerated at cosmetic use levels.

A salt form of glycyrrhizic acid, a compound from licorice root prized for soothing irritated skin. It is well tolerated at cosmetic levels and has a long history of use in skincare formulations.

A polyethylene glycol ester of hydrogenated castor oil, widely used as an emulsifier and solvent in rinse-off and leave-on cosmetics. PEG-modified ingredients are graded as safe in cosmetics by the CIR when formulated at typical use levels.

The smallest and most penetrating alpha hydroxy acid, used to loosen the bonds between dead skin cells for smoother texture and tone. It is a genuine irritant at higher concentrations or low pH, can increase sun sensitivity, and the EU restricts free acid content and requires sunscreen-use wording on labeling.

A naturally derived molecule combining glycerin and glucose that functions as both a humectant and emollient. It is graded with no known concerns in cosmetic use and draws moisture into the skin.

A larger, gentler alpha hydroxy acid than glycolic acid, used to exfoliate and to draw in moisture. It can still cause stinging or increased sun sensitivity at higher concentrations, so daytime SPF use is sensible, but it is generally better tolerated than glycolic acid.

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 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.

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

A naturally occurring alpha-hydroxy acid (AHA) from grapes, used for gentle exfoliation and pH adjustment. At exfoliating concentrations and low pH, it can irritate sensitive skin. More research exists on glycolic and lactic acids; use with caution if you react to other AHAs.

A cyclic oligosaccharide derived from corn starch that acts as a solubilizer and delivery vehicle for other ingredients. It is chemically inert, well tolerated, and has extensive use in pharmaceuticals and cosmetics.

A PEG-type emulsifier (ethoxylated cetearyl alcohol) that helps blend the water and oil parts of a cream. CIR concluded ceteareth ingredients are safe as used, with the one caveat that they are not meant for broken or damaged skin.

A plant extract long used in traditional wound care and now common in "cica" soothing products, valued for calming redness and supporting the skin barrier. It is generally well tolerated, with rare contact allergy reported.

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

A lab-made version of a lipid naturally found in the outer skin barrier. It is added to creams and cleansers to help replace lipids that washing can strip away, and it is not linked to irritation or safety concerns.

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 naturally occurring dipeptide with antioxidant properties, studied for skin health and barrier function support. It is widely used in skincare and cosmetic formulations with a strong safety history. No known contact allergens or sensitization reactions have been documented.

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 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.

Arbutin is a plant-derived brightening ingredient that is chemically related to hydroquinone and can release small amounts of it in formulation. EU regulators have set new maximum use levels for arbutin and alpha-arbutin in leave-on products because of this hydroquinone-release concern, so products sold there must stay within those caps.

Pentylene glycol is a humectant and solvent that also offers mild antimicrobial support in formulas. It is generally well tolerated, with only rare reports of irritation, mostly in already sensitive or compromised skin.

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.

Tranexamic acid is used topically at low concentrations to help even the look of dark spots and redness-related discoloration. It has an extensive systemic safety record as an oral medicine, and topical skin absorption is minimal, though a dedicated cosmetic-specific safety review has not yet been published by the main cosmetic safety panels.

A fatty alcohol emollient that softens and conditions skin. The CIR Expert Panel concluded it is safe as used in cosmetics, with this determination originally made in 1985 and reaffirmed in 2006.

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

A phospholipid emulsifier from soy or sunflower that binds water and oil and helps other ingredients absorb. It is a natural component of skin membranes, well tolerated, and reviewed as safe as used; a soy-derived grade is not a meaningful concern for a soy food allergy because the protein is largely absent.

A chemically cross-linked form of sodium hyaluronate designed to remain on the skin surface longer and provide sustained hydration. It functions as a humectant and is well tolerated, with the same safety profile as standard hyaluronic acid.

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

An extract from the root of the baical skullcap plant, used for antioxidant and skin-conditioning effects. It is generally well tolerated at cosmetic concentrations.

A plant extract rich in resveratrol, a polyphenol studied for antioxidant properties in cell and animal models. Human clinical data on topical efficacy is more limited than marketing sometimes suggests, but documented safety concerns are minimal at cosmetic concentrations.

A preservative and antioxidant that helps prevent microbial growth and oxidative degradation in formulas. Published assessments support its use at cosmetic levels.

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.

An emulsifier made from glycerin and stearic acid that stabilizes oil-in-water and water-in-oil formulations. It has a long history of safe use in cosmetics and is assessed as a low-concern ingredient in published safety reviews.

A soothing plant extract traditionally used in skincare, valued for its potential anti-inflammatory properties. Published assessments note it is generally well tolerated in cosmetic formulations, though people with sensitivities to botanicals may want to patch test.

Chamomile extract is used for its soothing and mild antioxidant reputation and is generally well tolerated. It belongs to the Asteraceae (Compositae) plant family, so people with a known ragweed or daisy-family allergy occasionally react to it and may want to patch test first.

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.

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 lower molecular weight version of hyaluronic acid designed for better skin penetration. It has been extensively studied and shown to support skin hydration and barrier function with excellent tolerability in diverse formulations and skin types.

A glycerin derivative used as a skin conditioner and preservative booster, often paired with phenoxyethanol to allow lower total preservative levels. It has a low irritation and sensitization profile in safety reviews.

A waxy sterol found naturally in skin and used in cosmetics as an emollient and emulsifier. It supports the skin barrier and is well tolerated across skin types.

A plant-derived lipid precursor found naturally in skin that supports barrier function and lipid composition. It is used in skincare formulations to strengthen the stratum corneum and is documented as well tolerated, though rare individual sensitivities may occur.

A chemically modified form of hyaluronic acid that improves stability and penetration in skincare formulations. Clinical assessments show it hydrates skin effectively and is well tolerated across sensitive and normal skin types.

Natural fat molecules present in healthy skin that help reinforce the skin barrier. They are graded with no known concerns in cosmetic assessments and are well tolerated as skin conditioning agents.

Large, water-binding polysaccharides derived from connective tissue, used to support hydration and skin firmness. They are inert polysaccharides with no known contact allergens or sensitization potential, and their size and chemistry make significant systemic absorption unlikely.

One of the three major ceramides naturally found in human skin. Ceramide AP plays a critical role in maintaining the skin barrier and is extensively studied as a safe, essential ingredient. It is derived synthetically or from plant sources.

A preservative derived from caprylic acid (coconut-sourced) with antimicrobial activity that supports formula stability. Available data support its use at cosmetic concentrations.

A quaternized derivative of hyaluronic acid that combines hydration and film-forming benefits for enhanced moisturizing effects. It is documented in cosmetic use as well tolerated, though people sensitive to quaternary ammonium compounds may want to perform a patch test.

The potassium salt of hyaluronic acid, a naturally occurring molecule found in skin that binds moisture. It is graded with no known concerns in cosmetic assessments and is well tolerated across all skin types.

A key structural lipid naturally found in healthy skin that reinforces the barrier and improves hydration. It is well established in skincare formulations and assessed as having excellent safety across all skin types, including sensitive and compromised barriers.