Skincare Ingredients

Acmella Oleracea Extract

Acmella oleracea extract is a botanical “anti-wrinkle/firming” ingredient typically used at low percentages, but it contains bioactive alkamides (e.g., spilanthol) that can produce a tingling sensation and have documented potential for irritant or allergic contact dermatitis in susceptible individuals. While many users tolerate it, in highly reactive or eczema-prone skin the combination of plant-derived actives and potential residual extraction components makes mild irritation plausible, especially when layered with other actives. Given the variability of botanical extracts and the need to err on patient safety, a mild irritancy score is appropriate. Safety Notes: In mass-market leave-on moisturizers/serums, Acmella oleracea extract is often used as a supportive “firming/line-smoothing” botanical at very low levels (around 0.01–0.1%), frequently within a multi-extract complex. More concentrated consumer “instant tightening” serums and targeted wrinkle products can reach ~1–5% extract, and a small number of high-strength OTC specialty formulas (especially single-hero botanical or ampoule-style products) are observed up to about 10% depending on extract type/solvent and sensory constraints. Usage is primarily leave-on; rinse-off products tend to sit at the low end due to limited contact time.

Acrylates/C10-30 Alkyl Acrylate Crosspolymer

Acrylates/C10-30 Alkyl Acrylate Crosspolymer is a high–molecular weight synthetic polymer used primarily as a thickener/stabilizer (typically ~0.1–1%), and it is generally too large to penetrate skin, so true irritation is uncommon. Clinical experience and patch-test data suggest a low but nonzero risk of irritation in highly reactive or eczema-prone patients, often related to formulation factors (pH/neutralizers, residual monomers, or high film-former load) rather than the polymer itself. Given the vulnerable populations considered here, it is best categorized as very gentle rather than completely inert. Safety Notes: In commercial leave-on gels, lotions, sunscreens, and serums this polymer is commonly used as a neutralized rheology modifier/suspending agent at very low levels (~0.05–0.2%) to build yield value and stabilize emulsions without noticeable tack. Standard consumer creams and mineral sunscreens often sit around ~0.2–0.8% for stronger viscosity and pigment suspension, while high-viscosity clear gel textures (including some high-hold styling/gel-cream formats sold OTC) can reach about 1.0–2.0% in finished product when paired with appropriate neutralization; above this becomes increasingly difficult due to tack, stringiness, and diminishing returns. Rinse-off products generally use similar or slightly lower levels than leave-on because less structure is needed after dilution, but the same overall market range is observed across OTC formats.

Acrylates Copolymer

Acrylates copolymer is a high–molecular weight film-former/thickener used at low levels in leave-on and rinse-off products, and it is generally not skin-penetrating. Clinical experience and patch-test data indicate irritation is uncommon, with rare reactions more often related to impurities/residual monomers rather than the polymer itself. For highly reactive or barrier-impaired skin, the occlusive film can occasionally contribute to stinging or discomfort, so it is best considered very gentle rather than fully inert. Safety Notes: In commercial skincare, Acrylates Copolymer is used at very low levels (~0.05–0.3%) as a rheology/film-forming aid in lotions, serums, and some rinse-off cleansers where it mainly provides suspension and light texture modification. Typical leave-on gels/primers, sunscreens, and long-wear film-forming products more often sit around ~0.5–3%. High-hold peel-off masks, styling/setting-type facial gels, and transfer-resistant/film-forming hybrids available OTC can reach ~5–10% to build a continuous polymer film and stronger sensory effects; this is generally the practical upper end for consumer skincare due to viscosity, tack, and flaking constraints.

Acrylates/Dimethicone Copolymer

Acrylates/Dimethicone Copolymer is a film-forming rheology/texture polymer used at low concentrations (typically well under a few percent) to improve slip, water resistance, and wear. As a high–molecular weight, non-volatile polymer, it has minimal skin penetration and is generally non-irritating in patch testing and real-world use; reactions are uncommon and usually relate to occlusion or individual sensitivity rather than intrinsic chemical reactivity. Given its broad tolerability even in sensitive skin but acknowledging rare irritation in highly reactive/eczema-prone patients, a very gentle score is appropriate. Safety Notes: In commercial leave-on products (serums, primers, sunscreens), Acrylates/Dimethicone Copolymer is often used at very low levels (~0.05–0.3%) as a film former to improve slip, wear, and water resistance, with similar low levels also appearing in rinse-off cleansers for sensory/anti-redeposit effects. High-strength consumer-available products (long-wear primers, blur/mattifying bases, transfer-resistant sunscreens, and water-resistant makeup) can push it into the ~2–8% range to build a more continuous film and stronger payoff; above this, texture, pilling risk, and formulation viscosity typically become limiting.

Acrylates/Steareth-20 Methacrylate Copolymer

Acrylates/Steareth-20 Methacrylate Copolymer is a high–molecular weight film-forming/texture polymer used at low levels (typically well under a few percent) and is generally considered non-reactive on intact skin. Clinical irritation reports are uncommon, but as a synthetic polymer containing ethoxylated components it can occasionally provoke mild stinging or contact irritation in highly compromised or eczema-prone skin, especially when left on under occlusion. Given the low inherent reactivity yet non-zero risk in severely sensitive populations, it best fits a very gentle score rather than truly inert. Safety Notes: In commercial skincare, Acrylates/Steareth-20 Methacrylate Copolymer is most often used as a rheology/film-forming polymer and emulsion stabilizer, showing up at trace-to-low levels (~0.05–0.3%) in lotions, light serums, and rinse-off cleansers primarily for stabilization and sensory modification. Typical leave-on creams and sunscreens commonly use ~0.3–2% to build viscosity, reduce tack, and improve wear/water resistance. High-hold, long-wear film-forming products available OTC (e.g., primers, long-wear/SPF, and some “waterproof” styling/setting-type skincare hybrids) can push polymer solids into the mid-single digits, with observed upper-end formulations around ~5–8% where texture, pilling risk, and stability constraints become limiting.

Actinidia Chinensis Fruit Extract

Actinidia chinensis (kiwi) fruit extract is primarily an antioxidant/conditioning botanical used at low percentages, but it can contain naturally occurring fruit acids and proteolytic enzymes (e.g., actinidin) that increase stinging risk on compromised barriers. Clinical experience and patch testing patterns with fruit-derived extracts show occasional irritant and allergy-like reactions in reactive/atopic individuals, so I rate it as mild rather than “gentle,” especially in leave-on products. Safety Notes: In mass-market leave-on skincare (serums, creams, toners) Actinidia chinensis (kiwifruit) extract is often used at very low levels (~0.0005–0.05%) as a label-claim botanical within complex antioxidant/fruit-extract blends. More “hero” botanical formulas and some consumer enzyme/brightening masks push dedicated use levels into the ~1–5% range, typically limited by supplier active strength, odor/color, and stability; rinse-off products can tolerate the upper end slightly more easily, while leave-on products more commonly sit below ~2–3%.

Adansonia Digitata Seed Extract

Adansonia Digitata (baobab) seed extract is primarily an emollient/antioxidant botanical used at low concentrations in moisturizers and serums, and it is generally well-tolerated. However, as a plant-derived extract it contains a complex mixture of compounds that can trigger irritation or rare sensitization in highly reactive or eczema-prone skin, especially when barrier function is compromised. Given the limited robust clinical patch-test data compared with simpler excipients and the need to err on patient safety, it fits best as a gentle but not inert ingredient. Safety Notes: In commercial skincare, Adansonia Digitata (baobab) seed extract is most often used at very low levels (about 0.001–0.1%) in leave-on creams/serums as part of preservative-compatible botanical blends or as a supporting “antioxidant/conditioning” claim ingredient. Higher-strength consumer products (typically leave-on masks, balms, and concentrated treatment creams) can reach ~1–5% when the extract is supplied as a higher-solids/glycerin or powder extract intended for direct dosing; rinse-off products generally sit toward the lower end due to cost and limited contact time. No specific FDA/EU maximum is set for this botanical extract, so practical stability, odor/color impact, and supplier recommended use levels tend to define the upper bound in OTC products.

Adansonia Digitata Seed Oil

Adansonia Digitata (baobab) seed oil is a non-volatile emollient oil typically used at a few percent up to near-neat levels in balms, where it mainly supports barrier function and generally shows low irritancy in cosmetic use. While true irritation is uncommon, any botanical oil can trigger reactions in a minority of highly reactive or allergy-prone patients due to trace impurities/oxidation products, so it is best classified as very gentle rather than inert for compromised skin safety. Safety Notes: In commercial skincare, Adansonia Digitata (baobab) seed oil is often used at very low levels (~0.05–0.5%) as a label-claim emollient in emulsified lotions/creams and wash-off products where it is one of many oils in the lipid phase. Mid-range use (~1–20%) is common in facial oils, body butters, and richer creams as a meaningful part of the emollient blend. The high end reaches 100% in consumer-sold single-ingredient baobab seed oil products (pure oils/serums) and near-100% in anhydrous balms where it can be the primary carrier oil; no specific EU/FDA cosmetic concentration cap applies beyond general safety/IFRA considerations for fragranced systems.

Adenosine

MVP Approved - Adenosine is a cell‐signaling molecule used primarily for its anti‐aging and soothing benefits, making it a popular choice in skincare formulations with minimal irritation concerns.

Adenosine Phosphate

Adenosine phosphate is a nucleotide-derived skin-conditioning/anti-wrinkle ingredient typically used at low concentrations (about 0.01–0.5%) and is generally well tolerated, including in sensitive skin, with low rates of irritant reactions in cosmetic use. As a biologically familiar molecule, it lacks the common irritancy drivers seen with acids, solvents, fragrance, or harsh preservatives; however, rare reactivity can still occur in highly compromised barriers, so it is not scored as completely inert. Safety Notes: In commercial skincare, adenosine-phosphate salts are most often used as low-level bioactive/conditioning additives in leave-on serums and creams, where they can appear at trace levels (~0.0001–0.01%) when included as part of a broader nucleotide/ATP complex or supportive anti-aging blend. Mainstream anti-wrinkle/soothing leave-on products more typically cluster around ~0.04–0.2% active, while a small number of consumer-available “high-potency” ampoules/boosters reach about 0.5–1.0% before cost, odor, and stability (hydrolysis, pH sensitivity, and compatibility with electrolytes/preservatives) become limiting; rinse-off products generally sit at the lower end due to short contact time.

Adenosine Triphosphate

Adenosine triphosphate (ATP) is typically used in low concentrations as a skin-conditioning/energizing ingredient and is not pH-dependent like exfoliating acids. Available cosmetic safety data and real-world use suggest low irritancy with rare reactions, but as a biologically active nucleotide (often supplied as a salt), it cannot be considered fully inert—especially in compromised barriers where stinging can occur. For sensitive and eczema-prone populations, this warrants a 'very gentle' score rather than 0.0–0.1. Safety Notes: In commercial skincare, Adenosine Triphosphate (ATP) is most often used at very low levels in leave-on creams/serums and eye products (commonly around 0.01–0.1%), with some formulas listing it near the tail of the INCI at ~0.001% as a marketing/skin-conditioning support. Higher-strength consumer “energy/ATP” serums and ampoules (especially in K-beauty/J-beauty-style anti-wrinkle products) have been observed up to about 1–2% where solubility, pH stability, and cost typically become limiting; rinse-off products, when they include ATP, tend to stay toward the low end due to contact time and cost.

Adipic Acid/Neopentyl Glycol/Trimellitic Anhydride Copolymer

This is a high–molecular weight polyester copolymer used as a film former/binder (e.g., in long-wear color cosmetics) at low to moderate percentages and is not intended to act as a biologically active ingredient. In clinical experience and patch-testing patterns, such inert polymers have low irritancy because they have minimal skin penetration, though any residual reactive monomers/impurities can rarely trigger irritation in highly reactive or compromised skin. Given its generally low reactivity in finished formulations but nonzero risk in very sensitive patients, it fits a very gentle score. Safety Notes: This film-forming polyester copolymer is used in consumer skincare primarily as a texture/feel modifier and water-resistant film former, where it commonly appears at very low levels (~0.05–0.5%) in lotions/serums and in makeup-adjacent skincare (e.g., primers, blurring moisturizers). Higher-strength OTC products that rely on a substantive, durable film (long-wear, transfer-resistant, water-resistant face products and high-hold peel-off or “grip” style formulations) can push polymer solids into the mid-to-high single digits, with observed maxima around ~10–12% when it is a primary structuring/film component. Leave-on products dominate its use; rinse-off products typically sit at the low end because high levels can increase residue/tack and are not cost-effective.

Agar

Agar is a polysaccharide gelling/thickening agent used at low concentrations (typically well under 1%) and is generally non-reactive and non-sensitizing in topical products. Clinical experience and patch-test data suggest irritation is uncommon, but in highly compromised barriers (e.g., active eczema) any film-former can occasionally contribute to tightness or stinging from the overall formula. Given the Foundation’s safety emphasis, it fits best as very gentle rather than completely inert. Safety Notes: Agar is used in consumer skincare mainly as a gelling/thickening and stabilizing hydrocolloid; in emulsions and gel-creams it is often present at very low levels (~0.05–0.3%) to provide viscosity and suspension with minimal sensory impact. In high-structure water gels, jelly masks, and “peelable/jelly” specialty products available OTC, formulas can push into the ~1–3% range, and the strongest consumer-available set-style gels can reach ~4–5% where agar functions as the primary gellant (higher levels become very rigid/brittle and are uncommon in cosmetics). Agar is used primarily in leave-on and wash-off textures similarly, but the highest levels are most often seen in mask/gel formats rather than standard daily leave-on emulsions.

Agastache Mexicana Flower/Leaf/Stem Extract

Agastache mexicana (an aromatic mint-family botanical) extract is typically used at low percentages for soothing/antioxidant claims, but it can contain naturally occurring terpenes and phenolic compounds that are known triggers for irritant or allergic contact dermatitis in reactive and eczematous skin. While population-level irritation rates are usually low, the variability of plant extracts (batch-to-batch chemistry and potential residual processing solvents) and the sensitization risk seen with botanicals justify a moderate score, particularly for compromised skin where barrier disruption amplifies reactions. Safety Notes: In commercial skincare, Agastache Mexicana Flower/Leaf/Stem Extract is most often used as a soothing/antioxidant botanical at very low levels (commonly supplied in preservative carriers and dosed at ~0.01–0.3% active-equivalent), with the lowest observed use around 0.0005% in multi-extract blends where it serves a minor supporting role. Higher consumer-available strengths are seen in “calming/anti-redness” serums, ampoules, and mask essences where brands use the extract as a hero botanical, with finished-formula levels reaching about 1–2% in leave-on products; rinse-off products typically sit toward the lower end due to cost and reduced contact time.

Agave Tequilana Leaf Extract

MVP Approved - Agave Tequilana Leaf Extract is a plant‐derived cosmetic ingredient most often used for its moisturizing (hydrating) properties and is generally regarded as low in irritation when properly processed.

Agrimonia Eupatoria Leaf Extract

Agrimonia eupatoria (agrimony) leaf extract is a botanical astringent/soothing ingredient typically used at low concentrations (often <1–2%), but like many plant extracts it contains polyphenols/tannins that can sting or provoke irritant or allergic contact dermatitis in reactive or eczema-prone skin. Human patch-test and clinical safety data are limited and product-to-product variability is high, so I do not treat it as inherently “gentle.” Given the sensitization uncertainty and the risk of cumulative irritation in compromised barriers, a mild (0.4) score best matches patient-safety expectations. Safety Notes: In mass-market toners, cleansers, and creams, Agrimonia eupatoria (agrimony) leaf extract is most often used as a minor botanical supporting ingredient, commonly appearing at trace-to-low levels around 0.001–0.1% depending on the supplier’s extract strength and whether it’s part of a blended botanical complex. Higher-strength consumer-available “herbal/soothing” serums, masks, and ampoule-style products can push single botanical extracts into the low single digits, with observed use up to ~5% in leave-on formats when stability, odor/color, and skin tolerance permit. There are no specific FDA/EU maximum limits for agrimony extract itself, so the practical upper end is set by formulation aesthetics, preservative system compatibility, and irritation risk rather than regulation.

Ahnfeltia Concinna Extract

Ahnfeltia concinna extract is a red algae–derived cosmetic extract primarily used for film-forming/hydration and soothing support, typically at low concentrations (often ~0.1–2%). Available patch-test and post-market data for macroalgae extracts show low inherent irritancy for most users, but—as a biologic mixture—there is a small, real risk of reactivity in highly sensitized or eczema-prone patients, so it is best classified as very gentle rather than inert. Safety Notes: Ahnfeltia concinna (red algae) extract is most commonly used as a minor moisturizing/film-forming or soothing component in leave-on creams, serums, masks, and eye products, where it often appears near the end of INCI lists at ~0.01–0.3%. Higher-strength consumer products marketed around “marine/algae concentrate” or “hydrating/biofilm” claims can push the extract (or a supplier’s standardized extract solution on an as-supplied basis) into the ~1–5% range, with practical limits driven by viscosity/film feel, odor/color, and stability rather than specific regulatory caps.

Ahnfeltiopsis Concinna Extract

Ahnfeltiopsis concinna extract is a red algae extract typically used at low concentrations (often <1–3%) for film-forming, humectant, and soothing/conditioning effects, and algae polysaccharide extracts are generally well-tolerated in sensitive-skin formulations. While robust clinical irritation datasets are limited for this specific species, reported issues are uncommon and the main risk is rare individual hypersensitivity or contamination-related impurities rather than inherent irritancy, supporting a very gentle score with routine patch-testing in highly reactive eczema patients. Safety Notes: Ahnfeltiopsis concinna (a red algae) extract is typically used as a minor active within marine/soothing/hydration blends in leave-on serums, creams, and masks, where it commonly appears at very low label-claim levels around 0.001–0.05% due to use as part of multi-extract complexes. Higher-strength consumer products (especially gel-creams, ampoules, and wash-off masks marketed around “algae extract” benefits) have been observed using single-algae extracts in the ~0.5–2.0% range; above this, cost, odor/color impact, and viscosity/sensory issues usually become limiting in real-world OTC formulations.

Akebia Quinata Stem Extract

Akebia quinata stem extract is a botanical antioxidant/soothing-type extract typically used at low concentrations (often <1%), but like many plant extracts it contains multiple bioactive constituents that can trigger irritant or allergic contact dermatitis in a reactive subset. Clinical irritation data are limited and not as robust as for standardized actives, so for eczema-prone or barrier-compromised patients I rate it as mild risk rather than “gentle,” especially in leave-on products and multi-step routines where cumulative exposure increases likelihood of reactions. Safety Notes: In commercial skincare, Akebia Quinata Stem Extract is typically supplied as a diluted botanical extract (often glycerin/butylene glycol/water based) and is most commonly used at very low levels as part of a broader plant-complex, with label-claim/trace usage down to ~0.0005–0.01% in leave-on lotions/serums and rinse-off cleansers. Dedicated soothing/anti-aging leave-on products and “high-extract” K-beauty style formulas have been observed using single botanical extracts in the ~0.1–1% range, with upper-end consumer formulas reaching about 2% when the supplier’s extract is formulated in at a high inclusion level while maintaining stability, odor/color, and skin feel. No specific EU/FDA concentration limits are set for this INCI; practical limits are driven by extract solvent system, preservative load, and sensory/stability constraints.

Alanine

MVP Approved - Alanine is an amino acid commonly used in skincare formulations for its moisturizing properties and ability to support an even skin tone. It is well tolerated with a very low potential for irritation.

Alaria Esculenta Extract

Alaria esculenta (a brown seaweed) extract is typically used at low concentrations as a humectant/soothing, antioxidant, and film-forming skin-conditioning agent, and it is generally well-tolerated in routine patch-test experience. However, as a complex marine botanical containing multiple bioactive polysaccharides and proteins, it carries a small but real risk of irritant or allergy-like reactions in highly reactive or eczema-prone patients, especially in leave-on products and when the barrier is compromised. Safety Notes: In commercial skincare, Alaria esculenta (brown algae) extract is commonly used at very low levels (around 0.01–0.1%) in leave-on moisturizers, serums, and eye products where it functions mainly as a marketing/antioxidant/conditioning botanical within a broader blend. Higher-strength consumer products (typically leave-on firming/anti-aging creams, body treatments, or ‘marine/seaweed’ concentrates) can reach ~1–5% when the extract is a primary featured active; above this is uncommon due to cost, odor/color impact, and stability/texture constraints. There are no specific FDA/EU maximum limits for this botanical itself, so observed market use is primarily constrained by formulation practicality rather than regulation.

Albatrellus Confluens Extract

Albatrellus confluens (mushroom) extract is typically used at low concentrations as a soothing/antioxidant or tone-evening botanical, and it is not a pH-dependent active like acids or retinoids. Clinical irritation and patch-test signals for this specific extract are limited, but as a complex botanical mixture it carries a small, non-zero risk of irritation or sensitization in highly reactive or eczematous skin. Given its usual low use level and generally calming intent, I rate it as gentle but not inert. Safety Notes: Albatrellus confluens extract (a specialty mushroom extract used for soothing/anti-redness and barrier-support positioning) is most often encountered in leave-on serums/creams at very low active-use levels, with mass-market formulas commonly dosing it around the low ppm-to-0.01% range as part of multi-extract blends. Higher-strength consumer products (typically calming serums/ampoules and targeted redness products) can push into the 0.5–2% range when the ingredient is a primary claim driver or when using supplier-recommended active solutions standardized for bioactives. Rinse-off products generally sit at the low end due to brief contact time, while the upper end is primarily observed in leave-on formulations; no specific global regulatory maximum is set beyond general cosmetic safety and labeling compliance.

Albizia Julibrissin Bark Extract

Albizia julibrissin (silk tree) bark extract is a botanical antioxidant/anti-fatigue cosmetic extract typically used at low concentrations (about 0.1–2%), and it is not a deliberate irritant like acids or retinoids. However, as a complex plant extract containing multiple bioactive compounds, it carries a measurable risk of irritation or allergic contact dermatitis in reactive or eczema-prone patients, particularly with leave-on use and barrier impairment. Given limited robust human patch-test data compared with standard actives and the higher unpredictability of botanicals, a mild (0.4) score best reflects patient-safety caution. Safety Notes: In commercial leave-on eye and anti-fatigue serums/creams, Albizia Julibrissin Bark Extract is often used at very low levels (down to ~0.001%) when it is part of a multi-extract blend or when the supplier active is pre-diluted in a carrier, while many mainstream products land around ~0.1–1%. High-strength consumer products that feature it as a hero ingredient or use more concentrated actives (or multiple Albizia-containing complexes) are observed up to about 3% in leave-on formulations; rinse-off products typically use it lower due to short contact time.

Albumen

Albumen (egg white protein) is used in cosmetics as a film-former/tightening agent, typically at low percentages, but it is a biologic protein mixture that can provoke irritant reactions and, more importantly, contact urticaria in sensitized individuals. Clinical and case-report experience with egg proteins shows that people with atopic dermatitis or egg allergy are higher-risk, and reactions can be immediate and severe despite “gentle” marketing. Because the consequence of exposure in a sensitized subset is clinically meaningful even at low concentrations, I score it as mild irritation risk overall with elevated concern for reactive populations. Safety Notes: In modern commercial skincare, albumen (egg white protein) is most often used as a minor film-forming/tightening or conditioning additive in leave-on masks/serums and some rinse-off cleansers, commonly appearing at very low levels (around 0.01–0.1%) when used as a supporting claim ingredient or part of a broader protein blend. The highest consumer-available levels are typically found in “egg white” peel-off/tightening masks and specialty formulations where albumen is a primary functional component; these products can reach roughly 5–10% albumen (especially when using concentrated/powdered egg white protein) while remaining OTC, with higher levels being limited by odor, allergen/labeling considerations, and stability/preservative load.

Alcloxa

Alcloxa (aluminum chlorohydroxy allantoinate) is primarily used as a skin protectant/soothing, anti-irritant complex in leave-on products, typically at low concentrations. Available clinical and patch-test experience suggests it is generally well tolerated and often included to reduce stinging or inflammation, but—as an aluminum-containing complex—rare irritant responses can occur in highly reactive or barrier-compromised patients. Given its overall favorable tolerability yet non-zero risk in sensitive populations, a gentle score is appropriate. Safety Notes: Alcloxa (allantoin-aluminum complex) is used in OTC skincare primarily as a soothing/astringent anti-irritant, with low-end inclusion around ~0.1% in gentle leave-on lotions/aftershaves where it functions as a minor calming adjunct. In consumer-available specialty post-shave, anti-itch, or blemish/toner-type leave-on products it is observed up to about ~2%, above which solubility/sensory constraints and diminishing benefit typically limit use; rinse-off products generally sit toward the lower end because of short contact time.

Alcohol

In cosmetics, “Alcohol” typically refers to ethanol/SD alcohol used at meaningful levels (often ~5–30%+) as a solvent and quick-dry vehicle, which can strip lipids, increase transepidermal water loss, and cause stinging—especially on compromised barriers (eczema, post-procedure) and around the eyes. Clinical experience and patch/usage testing consistently show higher rates of burning/irritant dermatitis with denatured alcohol-containing leave-on products, and it can amplify irritation from other actives in a routine. Given the predictable barrier disruption and frequent intolerance in sensitive populations, I score it as a significant irritant risk at typical functional concentrations. Safety Notes: In commercial skincare, very low levels (~0.1–2%) are used as solvents for fragrance/extracts or to aid preservative performance in both leave-on and rinse-off products, including many “alcohol-free” items that still contain trace/processing alcohol. At the high end, consumer-available astringents, aftershaves, and acne antiseptic/toner-type products commonly reach ~40–70% alcohol, and some OTC antiseptic skin cleansers/hand-sanitizer-style products marketed for skin use can approach ~80–90% ethanol/isopropyl alcohol (highest typically in leave-on antiseptic formats rather than standard facial moisturizers).

Alcohol Denat.

MVP Approved - Alcohol Denat. is most commonly used in skincare formulations as a solvent and quick-drying agent, but it is known to dry out the skin and potentially cause irritation, especially at higher concentrations.

Algae

In cosmetics, “algae” typically refers to algae-derived extracts (polysaccharides, proteins, minerals) used at low concentrations for soothing, film-forming, or hydration; these are generally well-tolerated and not intrinsically irritating. However, botanical extracts have inherent variability and can contain trace proteins/iodine or processing impurities that occasionally trigger stinging or dermatitis in highly reactive or eczema-prone patients, especially on compromised skin. Given this low-but-real sensitization/irritation potential, it fits best as a gentle ingredient rather than inert. Safety Notes: In commercial skincare, algae-derived materials are often used as extracts/ferments in leave-on serums, toners, and creams at very low levels (down to ~0.0001–0.01% as supplied extract/active within blends) primarily for marketing/antioxidant/soothing claims. Higher levels are seen when the algae ingredient is a primary functional component (e.g., seaweed/algal gels, thalassotherapy masks, body wraps, hydrogel-style masks, and emulsions built around algal biomass or concentrated extract powders), where total algae-derived solids can reach ~5–20% in consumer-available products. Rinse-off products typically sit mid-range (e.g., cleansers/masks around ~0.1–10%) because higher loads can impact viscosity, color/odor, and stability, but specialty masks and wraps can push to the top of the range.

Algae Extract

Algae extract is typically used at low concentrations as a humectant/soothing, antioxidant, or film-forming botanical, and in most users it is well tolerated. Clinically, seaweed/algae-derived ingredients have a low overall irritancy profile but are biologically complex mixtures, and occasional stinging, dermatitis, or contaminant-related reactions can occur in highly reactive or eczematous skin. Given the variability between species/extraction methods and the need to protect very sensitive populations, a gentle-but-not-inert score is most consistent with patient-safety expectations. Safety Notes: Across mass-market and prestige skincare, algae-derived extracts are frequently used as low-level “label” or support actives in leave-on creams/serums and rinse-off cleansers at ~0.001–0.1% (often supplied as dilute glycerin/water extracts and added at low percentages). Mid-range usage in hydrating/soothing leave-on products commonly falls around 0.1–2%. Higher-strength consumer products (e.g., algae/seaweed-focused masks, gels, and “concentrate” serums using standardized macroalgae/ microalgae extracts or multiple algae extracts) can reach ~3–10% total algae extract as supplied; above this is uncommon due to odor/color, viscosity/instability, and cost constraints, while rinse-off formats typically sit lower than leave-on for the same marketing claim.

Allantoin

MVP Approved - Allantoin is a soothing, hydrating compound widely used to calm irritated skin, reduce redness, and support scar healing. It is recognized for its gentle nature, making it a preferred choice for sensitive skincare formulations.