Skincare Ingredients

Steapyrium Chloride

Steapyrium Chloride appears to be a quaternary ammonium (“quat”) cationic surfactant/conditioning agent, a class known to cause irritant contact dermatitis and stinging—especially on compromised skin—at typical leave-on or cleansing-use levels. Clinical patch-testing and real‑world use of similar quats show notable irritation potential due to their membrane-disruptive, surfactant nature, with higher risk when combined with other actives or barrier impairment (e.g., eczema). Given the uncertainty around this specific INCI but the well-established irritancy profile of the class, a cautious notable score is warranted for patient safety. Safety Notes: No credible evidence supports “Steapyrium Chloride” as an established INCI cosmetic ingredient, and it does not appear in standard cosmetic ingredient inventories used on consumer product labels (e.g., EU CosIng/INCI listings) or in recognizable commercial skincare formulations. Because it is not observed in real-world OTC consumer skincare products under this name, the practical market concentration range is effectively 0% across both leave-on and rinse-off categories; if encountered, it is likely a misspelling or non-INCI naming of a different quaternary ammonium compound.

Stearalkonium Chloride

Stearalkonium chloride is a cationic quaternary ammonium conditioning/antistatic agent used mainly in hair conditioners and some creams, typically around ~0.1–2%. Quaternary ammonium compounds are well-documented irritants in patch testing and can trigger stinging, erythema, or dermatitis in compromised skin, with risk increasing from cumulative exposure and occlusion. Given its surfactant-like membrane-disruptive potential and the higher reactivity seen in eczema-prone patients, it warrants a notable irritancy score requiring cautious introduction. Safety Notes: In consumer hair/skin-conditioning products, stearalkonium chloride is observed at very low levels (~0.05–0.3%) when used mainly as an auxiliary antistatic/conditioning agent in emulsions and rinse-off cleansers/conditioners. Typical leave-on creams/lotions and rinse-off hair conditioners more often fall around ~0.2–2% depending on the desired cationic deposition and sensory profile. The upper end (~3–5%) is seen in high-slip, consumer-available concentrated conditioning creams/masks and intensive detangling products; higher levels are constrained by irritation potential, compatibility with anionics, and sensory/waxiness rather than a specific harmonized global maximum limit for this quaternary ammonium in cosmetics.

Stearalkonium Hectorite

Stearalkonium hectorite is a rheology modifier/thickener (organoclay) used at low concentrations (typically ~0.5–5%) to stabilize and gel oils, and it is generally non-reactive on skin. Clinical and consumer-use experience show low rates of irritation compared with surfactants, acids, or fragranced components, though very reactive or barrier-impaired patients can still experience mild stinging from the formulation matrix. Given its low inherent irritancy but non-zero risk in compromised-skin populations, it best fits a very gentle score. Safety Notes: Stearalkonium hectorite is a clay-based rheology modifier/suspending agent most often seen at very low levels (~0.05–0.5%) in leave-on emulsions (creams/lotions) to improve body and reduce pigment settling. Higher levels are observed in anhydrous or low-water systems (color cosmetics, sunscreen sticks, balms, and some oil/gel-serums) where it forms organoclay gels with polar activators; these can reach ~3–8% in high-structure consumer products for thickening and suspension. It is not subject to a specific EU/FDA maximum concentration limit as used, so the upper end is primarily constrained by sensory, clarity, and processability rather than regulation.

Stearamidopropyl Dimethylamine

Stearamidopropyl Dimethylamine is a cationic conditioning/antistatic agent used mainly in hair conditioners and some cleansing systems (typically ~0.2–2%), where it can form a salt and behave like a mild surfactant. Human patch-test data and clinical experience suggest it is generally well tolerated at typical rinse-off levels, but cationic amidoamines can cause stinging/irritant contact dermatitis in reactive individuals—especially with leave-on exposure, compromised barriers, or in combination with other surfactants. Given its functional class and real-world reports of occasional sensitivity, I rate it as mild rather than “gentle” for highly sensitive/eczema-prone users. Safety Notes: Stearamidopropyl Dimethylamine is a cationic conditioning/anti-static amidoamine most commonly used in hair conditioners, masks, and 2-in-1 shampoo/conditioners; at the low end (~0.1–0.3%) it appears in lighter conditioning shampoos and some leave-on hair products where only mild detangling/anti-frizz is desired. In high-slip rinse-off conditioners and intensive masks, consumer OTC formulas commonly reach ~1–3%, with some high-conditioning systems and co-wash/cream-conditioner styles observed up to ~5% (often paired with fatty alcohols and acids to form the cationic salt in situ). Use levels are primarily constrained by sensory/tackiness and pH-dependent performance rather than a hard regulatory maximum in major markets.

Steareth-2

Steareth-2 is a low‑HLB ethoxylated fatty alcohol surfactant/emulsifier used to solubilize and stabilize formulations, typically at low single‑digit percentages. While generally well tolerated, ethoxylated surfactants can cause mild irritant contact dermatitis in reactive or barrier‑impaired skin—especially when combined with other surfactants or left on in compromised eczema skin. Given its surfactant nature and real-world cumulative exposure, a mild irritancy score is the safest clinically aligned assessment. Safety Notes: Steareth-2 is a low-HLB nonionic emulsifier/co-emulsifier most often used at very low levels (~0.1–0.5%) in lotions/creams and some hair/skin cleansers to support emulsification and texture. In consumer-available high-structure O/W creams, cleansing creams, and anhydrous-to-emulsion systems (often paired with higher-HLB ethoxylated stearyl alcohols like Steareth-20), total emulsifier loads can push Steareth-2 into the several-percent range, with the upper end around ~8% observed in specialized, high-emulsifier consumer products. It appears in both leave-on and rinse-off formats, with higher use levels more common where robust emulsification/viscosity building is needed rather than for direct skin benefit.

Steareth-20

Steareth-20 is a nonionic ethoxylated surfactant/emulsifier used to solubilize oils and stabilize emulsions, typically around ~0.5–5% (sometimes higher in cleansers). While generally well-tolerated in leave-on products, surfactant chemistry and ethoxylated fatty alcohols can cause mild stinging, dryness, or barrier disruption in highly reactive or eczematous skin, especially with cumulative exposure or in combination with other surfactants/actives. Given its occasional irritancy in compromised skin but low overall risk in most users, a mild score is the safest clinically aligned assessment. Safety Notes: In commercial products, Steareth-20 is commonly used as a nonionic emulsifier/solubilizer and is often present around 0.1–1% in leave-on lotions/creams and makeup as a secondary emulsifier or co-surfactant. Higher-strength consumer-available rinse-off cleansers, cleansing creams, and some anhydrous-to-rinse cleansing balms/cream-to-foam formats can push total Steareth-20 into the ~3–8% range to achieve required solubilization, texture, and stability. There is no specific EU/FDA maximum for Steareth-20 itself (it is generally allowed), so the practical upper end is driven by performance, skin feel, and irritation tolerance rather than a hard regulatory cap.

Steareth-21

Steareth-21 is a nonionic ethoxylated fatty alcohol surfactant/emulsifier used to solubilize and stabilize formulas, typically around ~0.5–5%. While not a “strong active,” surfactants of this class can disrupt the stratum corneum barrier and sting on compromised skin, with irritation risk increasing in leave-on products and in eczema-prone patients. Given real-world cumulative exposure (cleansers + moisturizers) and higher reactivity in barrier-impaired populations, it fits a mild but non-negligible irritancy profile. Safety Notes: Steareth-21 is a nonionic emulsifier/solubilizer most often used at low levels (~0.1–1%) to stabilize O/W emulsions and improve texture in leave-on creams/lotions and some rinse-off cleansers. In high-oil-load or highly structured emulsions (including some OTC body butters, sunscreen-like emulsions, and conditioning creams), it can be pushed into the mid-single-digits as a primary emulsifier/co-emulsifier, with the upper end around ~6–8% observed in consumer-available products. There is no specific FDA/EU maximum concentration limit for Steareth-21 as used in cosmetics; practical limits are set by skin feel/irritation potential and formula stability rather than regulation.

Stearic acid

MVP Approved - Stearic acid is a fatty acid commonly used as an emollient, emulsifier, and thickening agent in skincare formulations, offering moisturizing benefits with a low risk of irritation.

Stearyl Alcohol

Stearyl alcohol is a long-chain fatty alcohol used mainly as an emollient, thickener, and stabilizer, typically at ~1–10% in creams and lotions. Clinical experience and patch-test data indicate it is generally well-tolerated and not inherently irritating, but a small subset of highly reactive or eczematous patients can experience irritation or (rarely) contact allergy, especially on compromised skin or with leave-on, occlusive formulas. Given its broad safety profile with a non-zero risk in severe sensitivity populations, it fits best as very gentle rather than inert. Safety Notes: In commercial skincare and haircare emulsions, stearyl alcohol is commonly used at very low levels (~0.1–1%) as a viscosity builder/co-emulsifier and slip agent, including in lighter lotions, cleansers, and rinse-off conditioners where it may appear lower in the INCI list. At the high end, consumer-available rich creams, body butters, barrier balms, and some stick/anhydrous or high-wax formulations can reach ~10–20% fatty alcohols, with stearyl alcohol as a major structurant (often alongside cetyl/cetearyl alcohol). It is not specifically concentration-restricted in major cosmetic regulations, so practical texture, stability, and sensory limits typically define the upper end rather than legal caps.

Stearyl Dimethicone

Stearyl dimethicone is a high–molecular weight silicone emollient used to improve slip and form a protective barrier (commonly a few percent in creams/lotions), and it is generally non-reactive and non-sensitizing in clinical and patch-test experience. True irritation is uncommon and usually relates to the overall formula (e.g., occlusion with other irritants) rather than the ingredient itself, but in severely compromised skin any occlusive film can occasionally feel stinging or trap irritants. For patient safety in highly sensitive/eczema-prone populations, it fits best as very gentle rather than completely inert. Safety Notes: In commercial skincare, stearyl dimethicone is commonly used at low levels (~0.1–1%) as a slip agent and sensory modifier in emulsions (lotions, sunscreens, primers) and at slightly higher levels in richer creams. The highest consumer-available levels are seen in very silicone-forward anhydrous/balm-like products, barrier creams, and primer-type formulas where it can function as a primary emollient/texture former, reaching roughly 10–15% without being prescription- or professional-only. Leave-on products tend to use higher levels than rinse-off cleansers, where it is typically kept low to moderate for deposition and feel.

Stearyl Glycyrrhetinate

MVP Approved - Stearyl Glycyrrhetinate is a licorice‐derived skincare ingredient valued for its soothing, anti‐inflammatory, and skin–conditioning properties, making it effective at calming redness and evening skin tone.

Stearyl Methicone

Stearyl Methicone is a silicone-based emollient/texture agent typically used at low-to-moderate levels to improve slip and reduce transepidermal water loss; it is generally considered non-reactive and non-sensitizing in cosmetic patch-test data. True irritation is uncommon, but in severely compromised skin a small subset can experience stinging or breakouts from heavy occlusive films or impurities, so I do not score it as fully inert. Overall, it fits best as a very gentle ingredient with low but non-zero irritation potential in highly reactive patients. Safety Notes: Stearyl methicone is a lipophilic silicone surfactant/emollient used at low levels (~0.1–1%) as a slip agent and to aid pigment wetting/dispersion in lotions, sunscreens, and color cosmetics, and as a secondary emulsifier in silicone-in-oil systems. In high-slip, anhydrous or silicone-rich consumer products (e.g., long-wear primers/foundations, smoothing serums, and some stick/cream color products), it is observed at much higher levels (typically 3–8% and up to ~10%) to boost spreadability, texture, and wear; rinse-off products generally sit at the low end due to cost and sensory targets. There is no specific EU/FDA concentration limit for this ingredient in cosmetics, so the practical maximum is set by formulation aesthetics, compatibility with the silicone phase, and stability rather than regulation.

Stearyl Stearate

Stearyl stearate is a fatty ester used as an emollient/texture agent in creams, typically at low-to-moderate concentrations, and it is generally non-reactive on intact skin. Human use and patch-testing experience for fatty esters shows a very low rate of irritation or sensitization, with reactions usually idiosyncratic rather than inherent to the ingredient. For highly compromised eczema skin, I still avoid calling it “inert,” but its expected irritation potential remains very low. Safety Notes: Stearyl stearate is a wax ester used primarily as an emollient, consistency agent, and slip modifier; in commercial lotions/creams and hair conditioners it commonly appears at low levels (~0.05–1%) as part of a fatty phase or “texture blend,” sometimes below 1% in INCI listings. At the high end, consumer-available anhydrous sticks (deodorant, balm, sunscreen sticks), heavy body butters, and some makeup/foundation systems can use it as a major structurant within the wax/oil network, with observed use levels reaching ~15–25%. It is most relevant to leave-on products; rinse-off formats typically stay toward the low end due to cost/feel and the need for easier wash-off, and there is no specific FDA/EU maximum restriction for this ingredient in cosmetics.

Stellaria Media Extract

Stellaria media (chickweed) extract is a botanical soothing/emollient ingredient typically used at low concentrations in leave-on products, with no strong evidence of inherent irritancy at those levels. However, as a complex plant extract it contains multiple bioactive constituents that can trigger irritant or allergic contact dermatitis in a small subset of highly reactive or eczema-prone patients, especially on compromised skin. Given this non-zero sensitization potential and variability in extract quality, it fits best as generally well-tolerated but not risk-free. Safety Notes: In commercial skincare, Stellaria media (chickweed) extract is most often used as a minor botanical soothing claim ingredient in leave-on creams/lotions and rinse-off cleansers at very low levels (typically around 0.001–0.1%), especially when supplied as a diluted extract in a carrier (glycerin/propylene glycol/water). Higher-strength consumer products (botanical gels, balms, and “herbal concentrate” leave-on formulas) can use the extract at ~1–5% when the supplier material is a standardized extract solution; levels above this are uncommon due to odor/color impact and overall botanical load/stability constraints rather than regulatory limits.

Styrax Benzoin Resin Extract

Styrax benzoin resin extract is a fragrance/resinous botanical used mainly for scent/fixative benefits (often at low percentages), but it contains aromatic resins and cinnamate/benzoate-related constituents that are well-documented causes of allergic contact dermatitis and can also be irritating on compromised skin. In sensitive populations (eczema, barrier-impaired, post-procedure), even small amounts can trigger delayed sensitization reactions, so it should be treated as a significant risk ingredient and avoided or patch-tested. Safety Notes: In mainstream consumer skincare and wash-off products, Styrax Benzoin Resin Extract is most often used as a fragrance/conditioning botanical at very low levels (typically around 0.001–0.1%), reflecting allergen/sensitization considerations for balsamic resins in leave-on formats. Higher concentrations are observed in consumer-available specialty balms, salves, and resin-based perfumed skincare where benzoin is used for its scent/fixative and film-forming character, commonly ~0.5–2% and up to about 5% in some anhydrous or low-water leave-on balms; rinse-off products generally stay at the low end.

Styrene/Acrylates Copolymer

Styrene/Acrylates Copolymer is an inert film-forming polymer used at low levels in cosmetics to improve wear, texture, and water resistance, and it is not an active that alters skin biology or pH. Clinical experience and patch-test data generally show a low rate of irritation/sensitization for these high–molecular weight polymers, but the occlusive film can occasionally aggravate very reactive or compromised skin (e.g., eczema) by trapping heat/sweat or increasing stinging from other actives in a routine. Given the overall low intrinsic irritancy but nonzero risk in highly sensitive populations, a very gentle score is most appropriate. Safety Notes: In commercial skincare and makeup-adjacent skincare (SPF lotions, primers, setting/film-forming serums), Styrene/Acrylates Copolymer is often used at very low levels (~0.05–0.3%) as a stabilizer/texture modifier and to help suspend pigments or improve rub-resistance. Mid-range use (~0.5–3%) is common in leave-on sunscreens and long-wear/tint products for water-resistance and feel, while the highest consumer-available levels (~4–8%) are seen in strong film-forming, water-resistant leave-on formulations (e.g., long-wear SPF and “grip”/setting-type products) where a robust polymer film is desired; rinse-off products typically sit toward the low-to-mid end due to aesthetics and deposition limits.

Succinic Acid

Succinic acid is a dicarboxylic acid used in leave-on products (often ~0.5–2%) for mild keratolytic/anti-acne effects, and as an acidifier; at functional, low pH it can sting compromised or eczematous skin similar to other low-strength acids. Human patch-test data generally suggest low irritation at typical cosmetic levels, but clinical experience shows occasional burning/erythema in reactive individuals and with cumulative use alongside other actives, so I rate it mild rather than “gentle” for high-sensitivity populations. Safety Notes: In commercial skincare, succinic acid is most often seen as a minor supporting acid/pH adjuster or antimicrobial/deodorizing adjunct in leave-on and rinse-off formulas around ~0.05–0.5%, with the lowest marketed uses appearing near ~0.05% in multi-acid or preservative-boosting systems. High-strength consumer products (typically acne/blemish leave-on serums, spot treatments, or acid gels) are marketed in the ~1–2% range, with a small number of specialty/high-strength OTC products reaching about 5% succinic acid. There is no specific EU/FDA maximum for succinic acid as a cosmetic ingredient; practical upper limits are mainly driven by irritation risk, solubility, and pH/stability constraints, especially for leave-on products.

Succinoglycan

Succinoglycan is a high–molecular weight microbial polysaccharide used primarily as a rheology modifier/film-forming humectant, typically at low concentrations (about 0.1–1%). As a non-ionic, non-exfoliating polymer, it is generally well tolerated in patch testing and is not a common irritant or sensitizer compared with preservatives or fragranced components. Rare stinging or reactivity can still occur in highly compromised eczema skin due to individual intolerance or formulation context, but the ingredient itself is best classified as very gentle. Safety Notes: In consumer skincare, succinoglycan is typically used as a biopolymer film-former/humectant at very low levels (about 0.001–0.05%) in leave-on serums/creams and rinse-off cleansers to boost slip, hydration feel, and sensorial smoothness. Higher-end “biopolymer” or “microbiome/postbiotic” leave-on gels and masks sometimes use it as a primary texture/film-forming agent, with observed usage around 0.5–2.0% in OTC products; above this it becomes difficult to process due to viscosity/filming and is uncommon in mainstream retail. No specific EU/FDA maximum is set for succinoglycan as a cosmetic ingredient, so practical formulation constraints largely determine the upper end.

Sucrose

Sucrose is primarily used as a humectant/bulking agent and, in rinse-off products, as a physical exfoliant; it is typically well tolerated and not a common contact allergen. However, at functional levels (especially in leave-on osmotic/humectant systems or abrasive scrub formats), it can sting or exacerbate barrier-compromised skin via osmotic draw and mechanical friction, so it is not fully inert for highly sensitive/eczema-prone patients. Safety Notes: In commercial skincare, sucrose is used at very low levels (~0.05–1%) as a humectant/sensory modifier in leave-on creams/lotions and as a co-solute in botanical/ferment-heavy formulas. The highest consumer-available levels are found in rinse-off sugar scrubs and polish products where sucrose is the primary abrasive/bulk phase, commonly ~40–70% w/w (with the remainder typically oils, surfactants, and binders); higher levels exist mainly as near-anhydrous paste-like scrubs rather than conventional emulsions. There is no specific EU/FDA cosmetic maximum for sucrose; practical limits are driven by texture, water activity, preservation strategy, and stability (especially in water-containing leave-on systems).

Sucrose Cocoate

Sucrose cocoate is a nonionic sugar–fatty acid ester used mainly as a surfactant/emulsifier (commonly a few percent, higher in cleansers), and surfactant activity is a well-established driver of irritant contact dermatitis risk—especially on compromised or eczematous skin. While generally considered milder than many anionic surfactants, clinical patch-test and real-world use still show occasional irritation in reactive individuals, and leave-on exposure can amplify this. Given cumulative routine use (cleansers plus leave-ons) and high-risk sensitive populations, a mild but non-trivial irritancy score is warranted. Safety Notes: In commercial products, sucrose cocoate is commonly used at very low levels (~0.1–1%) as a mild co-surfactant/solubilizer or emollient in leave-on creams/lotions and micellar/low-foam cleansers, where it supports skin feel and helps disperse oils. In rinse-off cleansers and syndet-style bars it is used higher (typically ~2–10%) to boost mildness and foam quality, with the upper end observed in consumer-available “ultra-mild” cleansing bars and concentrated surfactant bases reaching about 15–25% as the primary/nonionic surfactant component. There is no specific EU/FDA cosmetic maximum concentration limit for sucrose cocoate; practical limits are driven by viscosity/phase behavior and cleansing system performance.

Sucrose Distearate

Sucrose distearate is a nonionic sugar–fatty acid ester used primarily as an emulsifier/emollient, typically at low single-digit percentages in leave-on and rinse-off products. Available safety and patch-test experience suggest a low rate of irritation and sensitization, with occasional reactivity possible in highly compromised barriers (e.g., active eczema) more from formulation context than the ingredient itself. Given its generally good tolerability but non-zero risk in severely sensitive patients, it fits a "very gentle" score rather than inert. Safety Notes: Sucrose distearate is used in commercial skincare primarily as a nonionic emulsifier/co-emulsifier and emollient structurant; in many leave-on lotions/creams and cleansing emulsions it appears at low supporting levels around 0.05–0.5% (often paired with other emulsifiers). Higher-strength consumer products such as rich body butters, cold-cream style cleansing creams, and anhydrous-to-emulsion balms or massage/cleansing creams can use it as a primary structuring/emulsifying wax in the ~3–8% range to build viscosity and stabilize high oil loads. Rinse-off and leave-on products both use it, but the upper end is most often observed in heavy, high-oil leave-on or cleansing cream formats rather than light fluids.

Sucrose Laurate

Sucrose laurate is a non-ionic sugar ester surfactant/emulsifier used in leave-on creams and some cleansers, typically at low single-digit percentages, where it is generally well tolerated. Compared with harsher anionic surfactants, patch-testing and clinical use suggest a low but real potential for irritation, especially in compromised barriers (eczema) or when part of a multi-surfactant system. Given its surfactant nature and cumulative routine exposure, I rate it as gentle but not inert. Safety Notes: In commercial skincare, sucrose laurate is most often used as a mild nonionic surfactant/solubilizer or emulsion stabilizer at very low levels (about 0.05–0.5%) in leave-on lotions/serums and micellar-type systems to aid clarity, feel, and stability. Rinse-off cleansers and wash-off masks commonly use ~1–5% as part of the primary surfactant/emulsifier system, while consumer-available “high-mildness” sulfate-free cleansers, cleansing oils/balms, and specialty self-emulsifying formulations can reach ~8–10% without being professional-only. There is no specific FDA/EU cosmetic maximum for sucrose laurate; the practical upper limit is typically set by texture/viscosity, phase behavior, and irritation potential in the finished system.

Sucrose Stearate

Sucrose stearate is a non-ionic sugar–fatty acid ester used mainly as an emulsifier and mild surfactant, typically at low percentages in leave-on and rinse-off products. Human patch-testing and clinical use data generally show low irritation potential, but as a surfactant/emulsifier it can occasionally contribute to stinging or barrier disruption in highly reactive or eczematous skin when combined with other irritants. Given its broad tolerability yet non-zero risk in compromised barriers, it fits best as very gentle rather than inert. Safety Notes: In commercial skincare, sucrose stearate is most often used as a co-emulsifier/texture modifier at very low levels (~0.05–0.3%) in lotions, serums, and cleansers where it supports stability and slip without materially impacting sensorials. Mid-range use (~0.5–3%) is common in creams and milky emulsions as part of the primary emulsifier system. The highest consumer-available levels observed (~5–8%) occur in anhydrous cleansing balms, solid cleansing bars, and high-structuring oil-to-milk cleanser formats where sucrose esters act as principal emulsifiers/structurants; this applies to both leave-on and rinse-off, though the top end is more typical for rinse-off and cleanser-convertible products.

Sulfur

Sulfur is a keratolytic/antimicrobial acne and seborrheic dermatitis active typically used around ~2–10% in leave-on products and higher in short-contact preparations, where dryness, peeling, stinging, and erythema are common—especially on compromised or eczematous skin. Clinical experience and patch-testing data support that it is not merely “gentle” despite being common in OTC treatments, and cumulative barrier stress (often alongside retinoids/acids/benzoyl peroxide) increases irritancy risk. Given its frequent, clinically meaningful irritation in sensitive populations, it warrants a significant irritancy score. Safety Notes: In consumer skincare, sulfur is found at very low levels (~0.1–0.5%) in gentle leave-on spot treatments, masks, and cleansers where it supports oil-control/deodorizing and blemish care with reduced odor/irritation. Typical OTC acne products commonly use 2–5% sulfur, and the strongest widely available consumer formulations reach 10% sulfur (the upper end commonly seen for OTC acne treatments in the US and aligned with long-standing monograph use). Rinse-off products may use similar or slightly higher apparent loadings for performance but practical limits (odor, grittiness, instability) usually keep marketed consumer skincare at or below 10%.

Superoxide Dismutase

Superoxide dismutase is an antioxidant enzyme used in low topical concentrations (typically fractions of a percent) to help reduce oxidative stress, and it is generally well-tolerated in clinical and cosmetic use with low rates of irritant reactions. However, as a bio-derived protein (often from yeast/bacterial sources) it can occasionally trigger stinging or hypersensitivity in highly reactive or barrier-impaired skin, so it is not truly inert. In sensitive populations, the main risk is rare delayed sensitization or reactions to the delivery system rather than intrinsic irritancy, supporting a very gentle score. Safety Notes: In commercial skincare, Superoxide Dismutase (SOD) is most often used as a low-dose antioxidant/soothing active in leave-on serums and creams, commonly in the 0.001–0.02% range, with the lowest observed levels (~0.0001%) appearing when it is part of multi-enzyme or fermented/botanical complexes. High-strength consumer-available antioxidant serums and ampoules (non-prescription) have been marketed up to ~0.05–0.10% SOD (typically via stabilized SOD actives or encapsulated forms), with stability and cost usually preventing meaningfully higher true SOD loadings in OTC products; rinse-off products tend to sit at the low end due to short contact time.

Symphytum Officinale Callus Culture Extract

Symphytum officinale (comfrey) callus culture extract is a botanical skin-conditioning ingredient typically used at low concentrations, but botanical extracts have variable composition and can trigger irritant or allergic contact dermatitis in reactive or eczematous skin. While callus culture sources may reduce some contaminants compared with whole-plant extracts, comfrey-derived materials can still contain sensitizing constituents, so I score it as mild with occasional sensitivity possible and recommend caution in compromised skin. Safety Notes: In commercial skincare, Symphytum officinale (comfrey) callus culture extracts are commonly supplied as glycerin/butanediol/water-based solutions and are typically dosed at very low levels (around 0.0005–0.05% active extract) in mass-market leave-on products as a label/soothing support ingredient. Specialty K-beauty and “skin regeneration” serums/ampoules can push the use level to ~0.5–2% when the supplier’s recommended maximum is used and the product is positioned around the plant cell culture complex. Rinse-off products generally sit toward the low end due to short contact time, while higher levels are predominantly observed in leave-on essences, serums, and creams.

Synthetic Beeswax

MVP Approved - Synthetic beeswax is a vegan, petroleum/coal-derived alternative to natural beeswax that functions primarily as an occlusive and emollient in cosmetic formulations, with an overall low risk of irritation.

Synthetic Fluorphlogopite

Synthetic Fluorphlogopite is a synthetic mica used as a pigment/texture enhancer in makeup and skincare, typically at low-to-moderate percentages, and it is largely chemically inert with very low rates of true irritant or allergic reactions in patch testing. The main safety concern is mechanical irritation (grittiness or particle fallout) around the eyes or on compromised skin rather than chemical reactivity. Given its generally excellent tolerability but non-zero risk in highly reactive or barrier-impaired patients, it fits best as very gentle rather than completely inert. Safety Notes: In commercial skincare and color-cosmetic hybrid products, synthetic fluorphlogopite is used at very low levels (~0.01–0.5%) as a subtle slip/soft-focus additive in emulsions (primers, moisturizers, body lotions) and at moderate levels (~1–10%) in illuminating skincare (highlighters, glow primers, tinted moisturizers). The highest consumer-available levels occur in anhydrous or low-water makeup formats used on skin (pressed/loose powders, highlighters, eyeshadows marketed as skincare-adjacent), where mica-like filler loads commonly reach ~15–35% depending on shade and effect; rinse-off cleansers typically sit at the low end because the sensorial/optical benefits are transient.

Synthetic Wax

Synthetic waxes (e.g., polyethylene or synthetic beeswax substitutes) are high–molecular weight, inert film-formers used at a few percent up to higher levels in balms to thicken and reduce transepidermal water loss, and they are not common primary irritants in patch testing. The main risk in very reactive or eczema-prone patients is occlusion-related heat/friction aggravation or impurity/residual monomer contamination, which is uncommon but possible, so I cannot rate it as completely inert. Overall, at typical cosmetic grades and concentrations, true irritation potential is exceptionally low. Safety Notes: In commercial skincare and lip products, synthetic waxes (e.g., polyethylene, microcrystalline-type synthetics, synthetic beeswax alternatives) appear at very low levels (~0.05–0.5%) as rheology modifiers/opacifiers and slip agents in lotions, creams, and some cleansers (rinse-off usually at the low end). Higher levels are common in anhydrous leave-on formats where wax is a primary structurant—lip balms/sticks, salves, barrier balms, and solid cleansers—typically ~10–25%, with observed consumer-available high-wax sticks and balm/occlusive formulas reaching ~30–35%. Exact workable maxima depend on wax type/melting point and desired payoff, but these upper levels are routinely achievable in OTC anhydrous systems.

Tagetes Erecta Flower Extract

Tagetes erecta (marigold) flower extract is primarily used as a botanical antioxidant/skin-conditioning agent, typically at low concentrations, but it contains multiple bioactive terpenoids and carotenoid-associated fractions that can act as sensitizers in reactive skin. Patch-test and clinical experience with botanicals show a non-trivial risk of irritation or allergic contact dermatitis in eczema-prone or highly sensitized patients, especially in leave-on products and in routines already using other actives. Given patient-safety considerations and the variability of extract composition, I rate it as moderate irritation potential requiring patch testing for sensitive skin. Safety Notes: In commercial skincare, Tagetes erecta (marigold) flower extract is most often used as a minor soothing/antioxidant botanical within multi-extract blends, with effective-in-formula use levels commonly starting around 0.001–0.05% in leave-on creams/serums and similar or lower in rinse-off cleansers due to brief contact time. Higher-strength consumer products (typically “botanical active” serums, after-sun products, and mask/ampoule-style leave-ons) can reach ~0.5–2.0% when the extract is a named hero ingredient or when suppliers recommend higher dosing for standardized lutein/phenolic content; above this is uncommon in OTC due to solubility, odor/color impact, and sensitization/irritancy risk typical of concentrated botanical extracts.