Skincare Ingredients

Poncirus Trifoliata Fruit Extract

Poncirus trifoliata (trifoliate orange) fruit extract is a citrus-derived botanical used at low concentrations for antioxidant/brightening claims, but citrus extracts commonly contain sensitizing/irritating constituents (e.g., limonene/linalool-type terpenes and other aromatic compounds) and can provoke reactions in eczema-prone patients. While not as predictably irritating as exfoliating acids, real-world patch testing and clinical experience with citrus botanicals show a meaningful risk of irritation or allergic contact dermatitis in reactive individuals, especially when layered with other actives. Given patient-safety priorities for severely sensitive skin, this warrants a moderate score and a patch-test-first approach. Safety Notes: In commercial skincare, Poncirus trifoliata (trifoliate orange) fruit extract is most commonly used as a minor botanical active/soothing or anti-sebum support, often appearing in leave-on toners/serums/creams at very low label-declaration levels (~0.0005–0.05%) when supplied as a dilute carrier-based extract. Higher-dose consumer products marketed as “pore/tightening,” “clarifying,” or “botanical active” treatments (typically leave-on masks/ampoules/serums) can reach ~1–5% when using standardized glycerin/butylene glycol extracts; above this is uncommon due to odor/color, potential irritation from citrus-associated constituents, and diminishing formulation stability. Rinse-off cleansers typically sit toward the lower end because contact time is short and surfactant systems limit botanical loading.

Populus Tremuloides Bark Extract

Populus tremuloides (aspen) bark extract is used mainly as a “natural preservative”/antimicrobial and soothing botanical, typically at low percentages, but it contains phenolic salicylate-like constituents that can behave as mild exfoliating/irritant actives depending on extract standardization. Clinical experience with botanicals shows a non-trivial rate of stinging or dermatitis in highly reactive or eczema-prone patients, especially when combined with other actives or compromised barriers. Given variability between suppliers and the plausible salicylate-related reactivity, I score it as mild with occasional sensitivity possible. Safety Notes: In commercial skincare, Populus Tremuloides (Aspen) Bark Extract is most often used as a “natural preservative/booster” or soothing botanical at very low levels, commonly around 0.01–0.3% in leave-on creams/serums and rinse-off cleansers. Higher-strength consumer products (especially “preservative-free”/natural systems, acne/clarifying toners, and exfoliating masks) can push total aspen bark extract to ~1–5% depending on extract potency/solvent system, with higher levels more typical in rinse-off or water-based leave-on products where odor/color and irritation are managed. No specific FDA/EU maximum is set for this botanical itself, so practical limits are driven by supplier use recommendations, stability, and skin tolerance rather than regulation.

Poria Cocos Extract

Poria Cocos Extract is a fungal (mushroom) extract used mainly for soothing/antioxidant and skin-conditioning benefits, typically included at low concentrations in leave-on products. Available clinical and patch-test data do not suggest it is a common irritant, but as a complex botanical/fungal extract it can contain multiple constituents that occasionally provoke irritation or allergy in highly reactive or eczema-prone patients. Given the low typical use level and generally good tolerability—but nonzero sensitization potential—I rate it as very gentle rather than inert. Safety Notes: In commercial skincare, Poria cocos extract is most often used as a minor soothing/brightening botanical in multi-extract blends and can appear at very low label-levels (~0.0005–0.05%) in leave-on serums, toners, and creams where it functions mainly as a supportive claim ingredient. More dedicated “mushroom” or TCM-inspired soothing/brightening leave-on products use it as a primary botanical, commonly around ~0.1–2% (as the supplied extract), with a small number of consumer-available concentrated formulas reaching ~3–5% when built around a standardized extract or high-load botanical complex. Rinse-off cleansers/masks typically sit toward the lower half of the range due to short contact time and cost/solubility constraints, while the highest levels are predominantly seen in leave-on emulsions/serums.

Poria Cocos Sclerotium Extract

Poria Cocos Sclerotium Extract is a fungal (mushroom) sclerotium extract used primarily for soothing/anti-inflammatory and barrier-support claims, typically at low concentrations in leave-on products. Available safety and patch-test experience for mushroom-derived polysaccharide-rich extracts suggests low irritancy overall, but as a biologically derived botanical/extract it carries a small, non-zero risk of contact irritation or allergy in highly reactive or eczematous patients. Given that sensitization to extracts can occur despite “calming” marketing, I rate it as very gentle but not inert. Safety Notes: Poria Cocos Sclerotium Extract appears in commercial skincare products across a wide concentration spectrum. At the low end (0.1-0.5%), it functions as a supporting botanical ingredient in multi-component serums and moisturizers for its anti-inflammatory and skin-soothing properties. High-strength formulations, particularly in K-beauty and specialty brightening/anti-aging products, utilize concentrations up to 10% where it serves as a primary active ingredient for its polysaccharide content, moisture-retention properties, and tyrosinase inhibition effects. Both leave-on and rinse-off products span this range, though higher concentrations are predominantly found in leave-on serums and ampoules.

Porphyra Umbilicalis Extract

Porphyra umbilicalis (red algae) extract is typically used at low concentrations as an antioxidant/soothing, film-forming humectant, and it is generally well-tolerated in standard leave-on products. However, botanical extracts can trigger stinging or dermatitis in a small subset of highly reactive or eczema-prone patients due to variable bioactive compounds and potential trace impurities, so I score it as gentle rather than “very gentle” for compromised skin. Safety Notes: In real-world OTC skincare, Porphyra Umbilicalis Extract (red algae/nori extract) is often used as a minor antioxidant/soothing adjunct in leave-on moisturizers, serums, and sunscreens at ~0.01–0.1%, reflecting supplier-recommended use levels and cost/odor/color constraints. More “algae-forward” consumer formulations (e.g., hydrating masks, gel-creams, after-sun and anti-pollution products) commonly run ~0.5–1.5% when the extract is a featured claim ingredient. The upper end (~3%) is observed in high-strength OTC leave-on products marketed around marine/algae actives; higher levels are uncommon due to stability, sensory (marine odor, tack), and potential color shift, and rinse-off formats typically sit toward the lower-to-mid part of the range because of short contact time.

Porphyridium Cruentum Extract

Porphyridium cruentum extract (a red microalgae extract rich in polysaccharides) is typically used at low concentrations as a film-forming/hydrating, soothing adjunct, and it is not an intrinsically reactive active like acids or retinoids. Available cosmetic safety and patch-test experience suggests low irritation potential for most users, but as a biologic extract it can occasionally trigger reactivity in highly sensitized or eczema-prone patients, so it cannot be scored as inert. Safety Notes: Porphyridium cruentum (red microalgae) extract is typically used as a minor active/marketing extract in leave-on serums, creams, and eye products, often dosed at very low levels (around 0.0005–0.05%) when supplied as a pre-diluted glycerin/propylene glycol extract or when used primarily for antioxidant/soothing claims. Mainstream consumer formulations more commonly sit around ~0.05–1% depending on the supplier’s recommended use level and the potency/standardization of the extract. High-strength consumer-available products (especially niche “algae concentrate” serums/masks) can reach ~2–5% when using a concentrated, non-presolubilized extract; rinse-off products generally stay toward the lower end due to cost and reduced deposition time.

Portulaca Oleracea Extract

Portulaca oleracea (purslane) extract is primarily a soothing/antioxidant botanical used at low levels (typically <1–3%) in leave-on products, and it is generally well-tolerated with a low rate of irritation in patch-test and consumer-use contexts. However, as a complex plant extract it can still trigger occasional irritant or allergic reactions in highly reactive/eczema-prone individuals depending on extraction solvents and co-occurring plant constituents, so it is not scored as inert. Safety Notes: In mass-market and prestige leave-on products (serums, creams, toners), Portulaca Oleracea Extract is commonly used as a soothing/antioxidant botanical at very low levels (often ~0.01–0.1%) as part of multi-extract blends where it functions primarily for marketing and minor skin-calming support. Higher-strength consumer products—typically “cica/soothing” ampoules, concentrated gel serums, and sensitive-skin formulas—use it at ~1–5% when the supplier extract is a standard liquid/glycolic extract; above ~5% is uncommon in OTC products due to formula stability, odor/color impact, and diminishing returns (noting that marketed “10%” claims are often for a complex or ferment rather than pure Portulaca extract). Rinse-off products (cleansers/masks) tend to sit toward the low end because of short contact time, while leave-on products occupy most of the upper range.

Potassium Acetate

Potassium acetate is primarily a buffering/tonicity-adjusting salt used at low concentrations, but as an ionic electrolyte it can increase stinging on compromised barriers (eczema, post-procedure) and in leave-on products. Human irritation is generally low in intact skin, yet clinical experience with salts and acetate systems supports occasional sensitivity (burning/stinging) in reactive individuals, especially when combined with other actives. Given patient-safety considerations for highly sensitive populations, I score it as mild rather than “gentle.” Safety Notes: In commercial skincare, potassium acetate is most often encountered at trace-to-low levels (~0.01–0.3%) as a buffering/ionic strength adjuster in leave-on lotions/serums and some rinse-off cleansers, where it supports pH control and formulation stability without materially affecting sensorials. Higher concentrations are seen in specialized OTC products such as de-odor/foot-care or astringent/salt-based toning formulations and certain high-electrolyte gels, where total acetate salt load can reach a few percent; ~5% represents the upper end observed in consumer-available products before tackiness/irritation risk and stability/compatibility constraints typically limit further increases.

Potassium Ascorbyl Tocopheryl Phosphate

Potassium Ascorbyl Tocopheryl Phosphate is a stable, water-soluble vitamin C/E derivative used mainly for antioxidant/brightening benefits, typically around ~0.5–5%. Compared with low-pH L-ascorbic acid, it is generally better tolerated and not inherently exfoliating, with low rates of stinging in patch/consumer-use contexts. However, in highly reactive or eczema-prone skin any vitamin C derivative can still trigger mild transient sting or redness, so it is best classified as gentle rather than exceptionally gentle. Safety Notes: In commercial skincare (primarily leave-on serums, lotions, and eye products), Potassium Ascorbyl Tocopheryl Phosphate is commonly used at very low levels (~0.01–0.1%) as an antioxidant/skin-conditioning co-active and to support formula claims when paired with other vitamin C derivatives. Higher-strength consumer-available brightening/antioxidant products typically use ~1–3%, with the upper end around ~5% observed in specialty/high-strength OTC leave-on formulations; above this, solubility, cost, and sensory/stability constraints usually limit further increases. It is uncommon in rinse-off at meaningful levels, where it is typically kept at the low end due to short contact time.

Potassium Aspartate

Potassium aspartate is a potassium salt of the amino acid aspartic acid, used primarily as a humectant/skin-conditioning electrolyte in low concentrations, and it is generally well tolerated in patch-testing and routine cosmetic use. It is not an acid exfoliant at typical formulation pH and lacks the barrier-disruptive activity seen with stronger actives, so irritation risk is low. In severely compromised or highly reactive eczema skin, any ionic salt can occasionally sting, so I score it as very gentle rather than inert. Safety Notes: Potassium aspartate is most commonly used as an amino-acid-derived humectant/skin-conditioning electrolyte within amino-acid complexes or NMF-style blends, where it can appear at trace-to-low levels (~0.001–0.05%) in leave-on moisturizers, toners, and serums (and similarly in rinse-off cleansers). Higher-strength consumer products that emphasize “amino acid/electrolyte” hydration or use concentrated amino-acid complexes can reach ~0.5–2.0% potassium aspartate in leave-on formats, with practical upper limits driven by ionic strength, tack/skin feel, and pH/compatibility rather than specific regulatory caps.

Potassium Azeloyl Diglycinate

Potassium azeloyl diglycinate is a water-soluble azelaic-acid derivative used for brightening, sebum control, and anti-inflammatory support, typically around 2–10% in leave-on products, and is generally better tolerated than azelaic acid because it is not used at low pH. Clinical and real-world sensitive-skin use suggests a low but non-zero risk of stinging or dryness, especially on compromised barriers or when combined with other actives, so it fits a "gentle" rather than "very gentle" score for patient safety. Safety Notes: In commercial leave-on products (serums, lotions, tone-correcting/anti-blemish gels), potassium azeloyl diglycinate is observed at low levels around 0.1–0.5% when used as a supporting brightening/sebum-balancing adjunct, often alongside niacinamide and other humectants. Most mainstream formulations cluster around ~1–5% for noticeable oil-control/clarifying and tone-evening claims, while high-strength consumer-available specialty products (concentrated serums/ampoules) reach about 10%, which is near the upper end seen due to solubility, sensory tack, and pH/ionic compatibility constraints in leave-on systems; rinse-off cleansers typically sit toward the lower end of this range.

Potassium Benzoate

Potassium benzoate is a benzoate preservative typically used around ~0.1–0.5% and is generally well tolerated, but it can sting on compromised skin because benzoates can convert to benzoic acid depending on formula pH and skin conditions. Clinical and consumer patch testing suggests low overall irritancy, yet eczema-prone or barrier-impaired patients can experience burning or dermatitis more often than with truly inert humectants/emollients. Given preservative-related sensitivity risk in reactive populations, I rate it as mild rather than gentle. Safety Notes: In consumer skincare, potassium benzoate is used primarily as a preservative (benzoate system) and is most often seen around ~0.1–0.5%, with low-end usage (~0.05%) appearing in multi-hurdle formulas (e.g., combined with potassium sorbate/phenoxyethanol, chelators, low pH) in both rinse-off and leave-on products. High-end consumer-available products (especially “natural/ECO” or organic-leaning leave-on lotions/serums and some rinse-off cleansers relying on benzoate/sorbate systems) can reach ~1.0% total potassium benzoate to meet preservation needs at acidic pH, staying within common regulatory expectations for benzoic acid/benzoate use in cosmetics.

Potassium Chloride

Potassium chloride is an inorganic electrolyte used in cosmetics mainly as a viscosity/tonicity adjuster, typically at low concentrations where it is generally well tolerated and not a common cause of true allergic contact dermatitis. However, like other salts it can sting and increase dryness on compromised barriers (eczema, post-procedure skin) due to osmotic effects, so I do not score it as fully inert for highly reactive patients. Safety Notes: In consumer skincare, potassium chloride is most often used at very low levels (trace to ~0.1%) as an electrolyte/tonicity adjuster or to support viscosity in surfactant systems, so the lowest observed commercial use is around 0.001% where it functions as a minor ionic strength modifier. Higher levels are seen primarily in rinse-off cleansers, bath/shower products, and some salt/electrolyte-focused body products where it can be used as part of the salt system to thicken or adjust osmolarity, reaching about 1–5% in OTC products; leave-on products rarely exceed ~0.5–1% due to potential sting/irritation and tack/salt feel at higher ionic strength.

Potassium Citrate

Potassium citrate is primarily a pH adjuster/buffering agent used at low concentrations, and it is generally well-tolerated in leave-on and rinse-off products when formulations are kept near skin-physiologic pH. Irritation is uncommon but can occur in highly compromised barriers (e.g., active eczema) if it contributes to stinging in an already disrupted skin environment or if overall formula pH/ionic strength is poorly balanced. Given its low intrinsic reactivity but nonzero stinging potential in sensitive populations, it fits best as very gentle rather than inert. Safety Notes: Potassium citrate is most commonly used as a buffering/pH-adjusting salt in leave-on and rinse-off products, where it often appears at trace-to-low levels (~0.01–0.3%) as part of a citrate buffer system alongside citric acid and/or sodium citrate. In higher-alkalinity or strongly buffered consumer products (e.g., some cleansers, shaving products, depilatories, and select high-buffer or salt-rich specialty formulations), total use can reach the low single digits, with observed upper-end OTC formulations around ~3–5% when significant buffering/ionic strength is needed. It is not subject to a specific EU/FDA max concentration limit as a cosmetic ingredient, so practical limits are typically driven by pH targets, ionic strength, sensorial effects, and compatibility/stability rather than regulation.

Potassium Hydroxide

MVP Approved - Potassium Hydroxide is primarily used as a pH adjuster in cosmetic formulations and, while it is highly alkaline and can be irritating at elevated concentrations, it is generally safe when used at low, well‐controlled levels.

Potassium Lactate

Potassium lactate is a humectant and buffering agent commonly used in leave-on products at low-to-moderate levels (often ~1–5%) and is generally well tolerated, even in sensitive skin. However, as a salt of lactic acid it can increase stinging on compromised barriers (eczema, post-procedure) and higher concentrations can be irritating due to osmotic effects and pH/ionic strength, so it is not fully inert. Given its overall good tolerability but real sting potential in reactive populations, a gentle-but-not-exceptional score is most consistent with patient-safety data. Safety Notes: In commercial skincare, potassium lactate is most often used as a minor pH adjuster/humectant at trace-to-low levels (~0.05–0.5%) in cleansers, toners, and emulsions, where the lactate function is supportive rather than a headline active. Higher levels are seen in strongly humectant, NMF-style body lotions/hand creams and some urea/lactate foot creams where lactate salts are used for moisturization and mild keratolytic support; consumer-available leave-on products are commonly 2–5% and can reach ~10–12% when formulated for very dry/rough skin with appropriate buffering (higher levels are limited mainly by tack, saltiness/irritation risk, and pH/stability constraints). No specific global maximum is universally set for potassium lactate in cosmetics (it is generally allowed), so observed limits are primarily practical/formulation-driven rather than regulatory.

Potassium Laurate

Potassium laurate is a potassium soap (fatty acid salt) used as a cleansing surfactant; at typical functional levels in cleansers/soap systems it can be strongly defatting and inherently alkaline, both of which disrupt the stratum corneum and increase stinging and barrier damage. Clinical experience and patch-test/irritancy data for soap-type anionic surfactants consistently show higher irritation potential than milder syndets, especially in eczema and compromised skin. Because exposure is often repeated and cumulative in routines (handwashing, facial cleansing), I score it high for sensitive-skin safety. Safety Notes: Potassium laurate is a soap-type anionic surfactant used primarily in rinse-off cleansers (liquid soaps, acne washes, and some traditional/“natural” cleansing gels); in multi-surfactant systems it can appear at low levels (~0.1–1%) as a secondary surfactant/pH-dependent soap fraction. At the high end, consumer-available liquid castile/soap concentrates and high-alkali facial/body washes can reach roughly 10–25% potassium laurate (or equivalent active soap content) when formulated as true soap-based cleansers; it is uncommon in leave-on products due to high alkalinity/irritation potential and stability constraints, so leave-on uses are typically at the low end if present at all.

Potassium Myristate

Potassium myristate is a potassium soap/surfactant (fatty acid salt) used primarily for cleansing and emulsification; in typical leave-on or cleansing concentrations it can be distinctly alkaline and disrupt the stratum corneum lipids. Clinically, soap-based surfactants are well known to increase transepidermal water loss and sting/burn in eczema and compromised skin, with higher risk of irritant contact dermatitis compared with milder syndets. Given its cleansing role and barrier-disruptive potential—especially in reactive or eczematous patients—a notable irritancy score is warranted. Safety Notes: Potassium myristate is most commonly used as an anionic soap/surfactant and co-emulsifier; in many leave-on creams/lotions it appears at low levels (~0.1–1%) as a stabilizer/structurant or part of an emulsifier system. In rinse-off cleansing formats (facial cleansers, shaving soaps/creams, and soap-based bars/liquid soaps), consumer products can use much higher levels because it is a primary cleansing surfactant, with high-strength soap-based systems reaching ~10–30% as part of the total fatty-acid soap content. There is no specific EU/FDA maximum concentration limit for potassium myristate itself in cosmetics; practical upper bounds are driven by pH/irritation, bar integrity, and overall surfactant system design.

Potassium Phosphate

MVP Approved - Potassium Phosphate is used in cosmetic formulations as a buffering/pH‐adjusting agent to maintain product stability and support the skin’s natural acid mantle, resulting in minimal irritation risk when used at appropriate concentrations.

Potassium Sorbate

Potassium sorbate is an antifungal preservative typically used around ~0.1–0.3% (sometimes up to ~0.5%) and is generally well tolerated, but it has a documented history of stinging/irritation in leave-on products, especially at lower pH where sorbic acid is more active. Patch test data and real-world use show occasional irritant reactions (and rarer allergic contact dermatitis), with higher risk in eczema-prone or barrier-impaired skin. Given those vulnerable populations and the frequency of use across routines, I rate it as mild rather than “gentle.” Safety Notes: In commercial cosmetics, potassium sorbate is most often used as a supplemental preservative in water-based, low-pH systems (effective mainly below ~pH 6), with many leave-on lotions/serums and rinse-off cleansers using ~0.05–0.30% when paired with other preservatives or multifunctionals. The lowest market observations are around 0.05% in “mild/natural” or multi-hurdle preserved formulas, while the highest OTC consumer products (including some natural/organic-style creams, toners, and masks) reach about 0.8–1.0% to compensate for limited preservative options and higher microbial risk, constrained by solubility/irritation and pH requirements.

Potassium Stearate

Potassium stearate is a soap/surfactant (fatty acid potassium salt) commonly used in cleansers and shaving products; at functional levels it can raise pH and increase cleansing power, which can disrupt the stratum corneum and sting compromised or eczematous skin. While not a frequent allergen, soap-based surfactants are well known to cause irritant contact dermatitis in reactive individuals, especially with repeated exposure or in leave-on residue situations. Given the predictable barrier-disrupting potential in sensitive-skin routines, I score it as mild rather than gentle. Safety Notes: Potassium stearate is most commonly used as a soap/neutralized fatty acid structurant and emulsifier, and in leave-on creams/lotions it is typically present at low levels (~0.1–2%) to aid texture, lamellar structure, and stability without excessive alkalinity. In rinse-off cleansing products (bar soaps, shaving soaps/creams, and soap-based facial/body cleansers), potassium stearate can be a primary surfactant/soap base and is observed at much higher levels, commonly in the 5–15% range and reaching about 20% in high-soap, high-alkali consumer shaving soaps/cleansers. Very high levels are constrained in leave-on products due to pH/irritation risk and emulsifier balance, so the upper end primarily reflects rinse-off formats.

Potassium Thiocyanate

Potassium thiocyanate is an inorganic thiocyanate salt used infrequently in cosmetics (more often as a chemical reagent), and salts like this can be irritating to skin and especially to eyes/mucosa at the concentrations needed to function. Human irritation data in routine skincare use is limited, and given its potential for stinging/irritant contact dermatitis in compromised barriers, I score it as a notable-risk ingredient requiring cautious use and patch testing. Safety Notes: Potassium thiocyanate is an uncommon cosmetic salt, but it appears at trace-to-low levels in niche leave-on serums/creams (often as part of antimicrobial/enzyme-supporting or “saliva/lactoperoxidase-system”-inspired concepts), where it is typically used around 0.001–0.1% due to irritation potential and the desire to limit thiocyanate load. Higher-strength consumer-available products that explicitly include thiocyanate as an active/functional salt have been observed up to about 1–2% (usually water-based leave-on treatments), with rinse-off formats generally staying toward the lower end because performance can be achieved with less contact time. There is no widely used, harmonized cosmetic maximum specific to potassium thiocyanate in major regulations, so market maxima are primarily constrained by tolerability, odor/taste considerations, and overall formulation safety assessments.

Potentilla Erecta Root Extract

Potentilla erecta (tormentil) root extract is primarily an astringent/soothing botanical rich in tannins and polyphenols, typically used at low percentages in leave-on products. While not a classic high-risk allergen like fragrance oils, tannin-heavy astringent botanicals can sting on compromised barriers (eczema, post-procedure) and have documented potential for irritant reactions and occasional contact sensitivity in patch testing. Given sensitive-skin populations and routine layering, I score it as mild due to plausible stinging/dryness and low-but-real sensitization risk. Safety Notes: In commercial skincare, Potentilla erecta (tormentil) root extract is commonly used as an astringent/soothing botanical, with many leave-on and rinse-off products including it at very low label-levels (often part of multi-extract blends) around 0.001–0.1%. More “active botanical” formulas (toners/serums/spot products and some masks) use higher levels, most often ~0.5–2%, and a small number of consumer-available, high-botanical or tannin-focused products reach about 3–5% depending on extract type/solids and tolerability. No specific FDA/EU maximum applies to this INCI, so the upper end is typically constrained by sensory astringency, color/odor, and stability/compatibility rather than regulation.

PPG-12/SMDI Copolymer

MVP Approved - PPG-12/SMDI Copolymer is a synthetic polymer used primarily as a film-forming and stabilizing agent in skincare products, valued for its ability to enhance hydration with a low irritancy profile.

PPG-14 Butyl Ether

PPG-14 Butyl Ether is a glycol-ether emollient/solvent used to improve slip and solubilize oils, typically at low single-digit percentages in leave-on products. Glycol ethers are generally low-irritancy but can cause stinging or barrier disruption in reactive or eczematous skin, especially when combined with other solvents or surfactants in a routine. Given sensitive-skin and compromised-barrier populations, I rate it as mild with occasional sensitivity possible. Safety Notes: PPG-14 Butyl Ether is used in consumer skincare primarily as a lightweight emollient/solvent and slip agent; in many leave-on serums, lotions, and sunscreens it appears at trace-to-low levels (often ~0.05–1%) to improve spreadability and pigment/UV filter wetting. In real-world commercial products where it functions as a primary emollient/vehicle (e.g., silicone-free primers, body lotions, makeup-adjacent skincare, and some spray/oil-gel textures), it is commonly seen in the mid-single digits and can reach ~10–15% in high-slip, fast-drying leave-on formulations. Rinse-off products typically sit toward the low end because the sensorial benefit is less retained and formulas rely more on surfactant systems for primary structure.

PPG-20 Methyl Glucose Ether

PPG-20 Methyl Glucose Ether is a nonionic humectant/solvent used in leave-on and rinse-off products typically around ~0.5–10% to improve slip and solubilize ingredients. As a larger, sugar-derived propoxylated ether, it is generally well-tolerated with low rates of irritant reactions in cosmetic use, but surfactant-adjacent solubilizers can still sting or provoke mild irritation in compromised eczema skin or on damaged barriers, especially in multi-active routines. Given sensitive-skin safety considerations, I rate it as gentle rather than exceptionally gentle. Safety Notes: In commercial skincare, PPG-20 Methyl Glucose Ether is most often used as a humectant/solubilizer and sensorial emollient at low levels (~0.1–1%) in leave-on lotions/serums and as a co-solvent in micellar waters and toners. It is also used at higher levels (5–15%) in consumer-available high-slip moisturizers, makeup primers, and some cleansing creams where it contributes glide, solubilization, and reduced tack; above ~15% is uncommon due to viscosity/feel constraints and diminishing returns. This range reflects observed OTC leave-on and rinse-off products rather than prescription or in-office formulations.

PPG-24-Glycereth-24

PPG-24-Glycereth-24 is a synthetic polyether humectant/solubilizer used in leave-on products at low-to-moderate concentrations to improve slip and help disperse oils and fragrances. Polyether surfactant-like materials of this type are generally well tolerated in patch testing, but can cause mild stinging or irritation in compromised barriers (eczema, post-procedure) due to solvent/solubilizing effects and potential impurities. Given sensitive-skin safety considerations and its functional role that can increase penetration of other irritants, a gentle-but-not-inert score is most consistent. Safety Notes: PPG-24-Glycereth-24 is most commonly used as a solubilizer/humectant/emollient co-solvent and sensory modifier, so it appears at very low levels (~0.05–0.3%) in leave-on toners, mists, and serums primarily to aid fragrance/oil solubilization and improve slip. In richer leave-on creams/lotions and some cleansing formats it is frequently used around 0.5–3% to boost glide and reduce tack; in high-slip primers, makeup/skin “smoothing” products, and certain anhydrous or low-water silicone-compatible blends available OTC, concentrations up to ~6–8% are observed to deliver a pronounced feel and solubilization capacity without being prescription/pro-only.

PPG-26-Buteth-26

MVP Approved - PPG-26-Buteth-26 is a synthetic polymer used primarily as a surfactant, solubilizer, and emulsifier in cosmetic formulations, noted for its conditioning properties and low likelihood to cause irritation.

PPG-2-Deceth-30

PPG-2-Deceth-30 is a nonionic surfactant/solubilizer used at low levels (often <1–5%) to disperse oils and fragrance, and surfactants as a class can disrupt the stratum corneum barrier and sting on compromised skin. Patch-test and clinical experience generally place ethoxylated/propoxylated surfactants as low-to-moderate irritants, with risk increasing in leave-on products and in eczema-prone or post-procedure patients. Given the need to account for reactive populations and cumulative routine exposure, I score it as mild rather than “gentle.” Safety Notes: PPG-2-Deceth-30 is a nonionic surfactant/solubilizer commonly used in leave-on serums, sprays, micellar-type waters, and makeup removers at low levels (~0.1–1%) to solubilize fragrance/oils and aid clarity. In higher-solubilizer load clear oil-in-water solutions (e.g., cleansing oils that self-emulsify, heavy fragrance solubilization systems, and some high-foaming rinse-off cleansers), consumer products can reach several percent, with upper-end commercial use observed around ~5–8% where it functions as a primary solubilizer/surfactant. There is no specific EU/FDA concentration limit for this ingredient beyond general safety requirements, so practical upper limits are driven by irritation potential, viscosity/clarity targets, and formula aesthetics.

PPG-2 Hydroxyethyl Cocamide

PPG-2 Hydroxyethyl Cocamide is a nonionic surfactant/foam booster used in rinse-off cleansers and shampoos (often a few percent) to improve mildness and texture. While generally less irritating than anionic surfactants, surfactant exposure is a well-established trigger for stinging and barrier disruption in eczema and highly reactive skin, especially with frequent cleansing or in leave-on residues. Given its role as a cleansing aid with documented potential for irritant contact dermatitis in susceptible users, I rate it as mild (0.4). Safety Notes: PPG-2 Hydroxyethyl Cocamide is used primarily as a nonionic surfactant/foam booster and viscosity builder in rinse-off cleansers (shampoos, body washes, facial cleansers), where it can appear at low levels (~0.1–0.5%) as a secondary co-surfactant in mild formulas. In mainstream consumer cleansing products it is commonly around ~1–5%, while high-foam/high-viscosity concentrated wash bases and some sulfate-free systems sold retail can reach ~10–15% as a primary/major secondary surfactant; leave-on use is uncommon and typically kept at trace to very low levels due to surfactant-related irritation potential.