Skincare Ingredients

PPG-3 Benzyl Ether Myristate

PPG-3 Benzyl Ether Myristate is primarily an emollient/slip agent used in leave-on products at low-to-moderate concentrations, and it is generally not a primary irritant in standard patch-testing experience. However, as a benzyl ether–containing, lipophilic surfactant-like ester, it can occasionally sting or trigger irritation in compromised barriers (eczema, post-procedure) and may contribute to comedogenic/occlusive discomfort in some patients. Given real-world cumulative exposure in routines and the need to err on patient safety for highly reactive skin, it fits best as a gentle-but-not-inert ingredient. Safety Notes: PPG-3 Benzyl Ether Myristate is used as a lightweight emollient/solvent and slip agent, and in mass-market leave-on lotions, sunscreens, primers, and makeup it is commonly present at low levels (~0.1–2%) to improve spreadability and sensory profile. Higher levels are found in silicone-free anhydrous/low-water oil gels, makeup bases, and specialized “dry oil” style leave-on products where it can function as a primary emollient phase component, reaching ~10–20% in consumer OTC formulations; rinse-off products typically sit toward the lower end because benefits are short contact-time and cost is a constraint.

PPG-5-Ceteth-20

PPG-5-Ceteth-20 is a nonionic surfactant/solubilizer used in cleansers and emulsions (often ~0.5–5%), and surfactants can disrupt the stratum corneum and sting compromised skin despite being "mild". Human patch-test and use data generally show low-to-moderate irritation potential, but eczema-prone or barrier-impaired patients can react, especially in leave-on products or in combination with other detergents. Given its functional role and cumulative routine exposure risk, a mild score is safest for sensitive-skin assessment. Safety Notes: PPG-5-Ceteth-20 is a nonionic surfactant/solubilizer typically used at very low levels (~0.05–0.5%) in leave-on lotions/serums to solubilize fragrance or small amounts of oil, and around ~0.5–5% in rinse-off cleansers and emulsified creams as a co-surfactant/emulsifier. In consumer-available high-surfactant systems (e.g., makeup removers, micellar/cleansing concentrates, and some high-detergency cleansers), it can be pushed into the ~10–15% range to drive solubilization and cleansing performance without being prescription or professional-only.

PPG-6-Decyltetradeceth-30

MVP Approved - PPG-6-Decyltetradeceth-30 is a synthetic polymer used primarily as an emulsifier and surfactant to stabilize cosmetic formulations, with no confirmed direct skincare benefits from multiple reputable sources.

Proline

MVP Approved - Proline is a non-essential amino acid used in skincare for its collagen-supporting and moisture-retaining properties. It is well tolerated with minimal irritancy risk in typical formulations.

Propanediol

MVP Approved - Propanediol is a versatile skincare ingredient used primarily as a humectant and solvent to enhance product texture and moisture delivery while being well-tolerated on sensitive skin.

Propolis Extract

Propolis extract is used for soothing/antimicrobial benefits (commonly ~0.1–5%), but it is a well-documented contact allergen with positive patch-test reactions reported, especially in individuals with eczema, impaired barriers, or other bee-product sensitivities. While many users tolerate it, the risk of delayed sensitization and subsequent flare-ups is clinically meaningful, so I score it as a notable irritant requiring careful introduction and patch testing in sensitive populations. Safety Notes: In mass-market and sensitive-skin leave-on products (toners/lotions/serums), propolis extract is often used at low supportive levels (~0.05–1%) due to allergen potential and variability of resinous extracts, with many formulas clustering around 0.5–5%. High-strength consumer products marketed as “propolis ampoules/essences” or “propolis syrups” can reach ~10–30% when using standardized propolis extract solutions (typically in water/glycerin/propylene glycol), while rinse-off cleansers and masks more commonly sit in the lower end because of short contact time.

Propylene Carbonate

Propylene carbonate is primarily a solvent/penetration aid used at low percentages in cosmetics, and it is generally tolerated but not completely inert. Patch-test and safety reviews describe it as a mild irritant in some individuals (especially with occlusion or compromised barriers), with sensitization being uncommon. Given its solvent nature and the higher risk profile in eczema or post-procedure skin when combined with other actives, a mild irritancy score is the safest clinically-aligned assessment. Safety Notes: In consumer cosmetics, propylene carbonate is most often used as a co-solvent/viscosity reducer and delivery aid, where it appears at low levels (~0.05–1%) in leave-on serums/creams and color cosmetics to help solubilize lipophilic actives or improve spread. Higher levels (5–20%) are observed in OTC specialty products such as spot treatments, nail/lacquer-related cosmetics, and some high-solvent anhydrous systems where it functions as a primary solvent; above ~20% is uncommon in mainstream skincare due to sensory/irritation and formulation balance constraints. No specific EU/FDA concentration cap is generally assigned to propylene carbonate as a cosmetic ingredient, so market use is mainly limited by tolerability and product type (leave-on tending lower than rinse-off/solvent-heavy formats).

Propylene Glycol

Propylene glycol is a common humectant/solvent typically used around ~1–10% (sometimes higher) and is generally well tolerated, but it is also a recognized irritant for a meaningful minority of users, especially on compromised skin or at higher concentrations/occlusion. Patch testing and clinical experience show it can trigger irritant dermatitis and occasionally contact allergy in sensitive populations (including eczema patients), so I rate it as mild rather than “gentle” for patient-safety. Safety Notes: In commercial skincare, propylene glycol is often used at very low levels (~0.1–1%) as a solvent/humectant or to aid preservation and fragrance/actives solubilization, including in both leave-on lotions/serums and rinse-off cleansers. Typical mainstream leave-on products commonly sit around 2–15%, while higher levels are seen in fast-drying hydroalcoholic gels, makeup/skin prep products, and some OTC antifungal/medicated-style creams where propylene glycol functions as a solvent and penetration enhancer. Consumer-available extremes reach roughly 40–60% in certain specialty gels/solutions (still OTC), whereas concentrations above this are uncommon in skincare due to tack/irritation and sensorial limits; no specific EU/FDA maximum is set for propylene glycol in cosmetics, but practical tolerability drives the upper end.

Propylene Glycol Dibenzoate

Propylene Glycol Dibenzoate is primarily an emollient/plasticizer used in low percentages to improve slip and film properties, and it is not an “active” with intentional exfoliating or keratolytic effects. While generally tolerated, benzoate esters can cause occasional irritant contact dermatitis in reactive or eczematous skin, particularly with leave-on exposure and cumulative barrier stress from the overall routine. Given the limited robust human patch-test data compared with more common emollients and the need to err on patient safety in compromised skin, a mild irritancy score is appropriate. Safety Notes: Propylene Glycol Dibenzoate is an aromatic benzoate ester used mainly as a plasticizer/solvent and fragrance fixative; in skincare it is most often present at very low levels (≈0.05–1%) as part of a fragrance/solvent system in leave-on lotions and creams. Higher levels are seen in niche OTC anhydrous fragrance oils, balm/oil formats, and some specialty emollient concentrates where benzoate esters can function as the primary solvent/emollient phase, reaching the low-to-mid teens (around 10–15%). This ingredient is uncommon in rinse-off cleansing products and, when used there, is typically at the low end due to solubility and sensorial constraints.

Propylene Glycol Dicaprylate/Dicaprate

Propylene Glycol Dicaprylate/Dicaprate is a lipophilic ester emollient used mainly to improve slip and reduce tack, typically at a few percent up to ~10% in leave-on products. As a high–molecular weight, non-volatile ester, it has low water solubility and minimal penetration, and patch test/clinical use experience generally supports a low irritation profile compared with free propylene glycol. Rare irritation can occur in highly reactive or barrier-impaired eczema patients (often from overall formula load/occlusion rather than intrinsic reactivity), so it is best classified as very gentle but not completely inert. Safety Notes: Propylene Glycol Dicaprylate/Dicaprate is a lightweight emollient/ester used as a slip agent and oil-phase solvent; in mass-market leave-on lotions/serums it is often present at low levels (~0.1–2%) to improve sensory feel and aid dispersion of lipophilic ingredients. In anhydrous facial oils, makeup primers, cleansing balms, and high-slip silicone-free emulsions it can function as a primary emollient, with consumer-available formulas commonly reaching ~10–25% and specialty anhydrous or balm formats observed up to ~40%. Rinse-off products typically sit at the lower end due to cost/phase balance, while the highest levels are mainly in leave-on or anhydrous systems.

Propylene Glycol Isoceteth-3 Acetate

Propylene Glycol Isoceteth-3 Acetate is a nonionic surfactant/solubilizer-emollient ester typically used at low percentages, where it is usually well tolerated but can contribute to barrier disruption when combined with other cleansing agents. Surfactant-like ingredients and ethoxylated derivatives have a measurable rate of irritant reactions in sensitive/eczema-prone skin, especially with leave-on exposure or compromised barriers. Given the lack of extensive, ingredient-specific clinical irritancy data and the known behavior of similar solubilizers, a mild irritancy score is the safest clinically-aligned choice. Safety Notes: Propylene Glycol Isoceteth-3 Acetate is used commercially as a solubilizer/emollient and fragrance-oil carrier, where it often appears at very low levels (~0.05–0.5%) in leave-on moisturizers/serums primarily to aid solubilization and sensory slip. In higher-solvent or fragrance-bearing systems (e.g., makeup primers, facial oils/essences, and some rinse-off cleansers) it is used more substantively as part of the oil/solvent phase, with observed consumer-available products reaching ~5–8% while still maintaining acceptable stability and skin feel. There is no specific EU/FDA maximum concentration limit for this ingredient as such; practical upper use is driven by irritation potential and compatibility with the overall surfactant/oil system, especially in leave-on products.

Propylene Glycol Isostearate

Propylene Glycol Isostearate is an emollient/surfactant (propylene glycol ester of isostearic acid) typically used at low-to-moderate levels in creams, cleansers, and makeup to improve slip and solubilize oils. It is generally well tolerated and not a classic sensitizer, but as a propylene-glycol–derived ester it can still trigger mild irritation or stinging in highly reactive or compromised skin, especially in leave-on products or when combined with other irritants. Given sensitive-skin and eczema populations, I rate it as gentle but not inert. Safety Notes: Propylene Glycol Isostearate is typically used as an emollient/skin-conditioning agent and nonionic co-emulsifier/solubilizer, and in many leave-on creams/lotions it appears at low secondary levels around 0.05–1% to support feel and emulsification. In richer anhydrous or water-in-oil style balms/cleansing creams and some high-slip makeup/skin-prep products, market-observed usage can climb into the mid-to-high single digits, with upper-end consumer formulations reaching ~10–15% when it functions as a primary emollient/texture modifier. No specific FDA/EU maximum concentration limit is generally assigned to this ingredient as a cosmetic, so practical limits are usually set by sensorial impact, compatibility, and irritation potential in leave-on products.

Propylene Glycol Laurate

Propylene Glycol Laurate is a surfactant/emollient ester used in cleansers and as a solubilizer/emulsifier, typically at low single‑digit percentages, where it can disrupt barrier lipids more than simple emollients. While not a classic high-rate allergen, surfactant-type ingredients show measurable irritancy in patch testing and can sting or provoke flares in eczema-prone or compromised skin, especially in leave-on products or when combined with other irritants. Given sensitive-skin safety considerations and cumulative routine exposure, it warrants a mild irritancy rating. Safety Notes: Propylene Glycol Laurate is used commercially as a lipophilic emollient/skin-feel modifier and solubilizer/coupling agent, so it appears at very low levels (~0.05–0.5%) in leave-on serums/lotions and cleansing products to aid solubilization and reduce tack. In consumer-available products where it functions as a primary emollient or co-surfactant (e.g., cleansing oils, makeup removers, anhydrous balms, and some high-slip body products), it is seen in the mid-to-high single digits and can reach ~10–15% in high-emolliency OTC formulations; higher levels are uncommon due to sensorial, viscosity, and phase-behavior constraints rather than specific regulatory limits.

Propylene Glycol Stearate

Propylene Glycol Stearate is primarily an emollient/emulsifier used at low levels in leave-on and rinse-off products (commonly ~0.5–5%) to improve texture and stability. As a fatty acid ester, it is generally non-sensitizing and shows low irritation potential in patch testing compared with free propylene glycol, though very reactive or eczema-prone skin can still experience occasional irritation from emulsifier systems. Given typical concentrations and its low inherent reactivity, it fits a very gentle profile while still acknowledging rare sensitivity in compromised barriers. Safety Notes: Propylene Glycol Stearate is used in consumer skincare primarily as an emollient/co-emulsifier and pearlizing/structuring agent; in leave-on creams/lotions it is commonly present at low levels around 0.1–1% to support emulsification and skin feel. In rinse-off cleansers/body washes and some richer OTC creams, higher levels (typically ~2–6%) are used to build viscosity/opacity and improve slip, with high-structuring/pearlized consumer formulations occasionally reaching about 10% total usage without being professional- or prescription-only.

Propyl Gallate

Propyl gallate is an antioxidant preservative used at low levels (typically ~0.01–0.1%) but has a documented history of causing contact dermatitis and positive patch-test reactions in a subset of users. While many tolerate it, its sensitization/allergen potential makes it a moderate-risk ingredient for eczema-prone or highly reactive skin, warranting patch testing and cautious use. Safety Notes: Propyl gallate is used as an oil-phase antioxidant to slow rancidity of unsaturated oils, fragrances, and certain actives; in mainstream leave-on and rinse-off cosmetics it is often present at trace-to-low levels (≈0.001–0.05%) consistent with typical antioxidant dosing and finished-product labeling practices. High-strength OTC niche formulations (especially anhydrous/oily products like balms, oil serums, and some specialty creams) have been observed/formulated up to about 0.5% to protect high-oxidation-risk lipid systems, which aligns with common industry upper-use limits for propyl gallate in cosmetics. Usage is primarily in leave-on oil-rich products, but similar low dosing can appear in rinse-off products when lipid/fragrance oxidation protection is needed.

Propylheptyl Caprylate

Propylheptyl caprylate is a non-volatile emollient ester used to improve slip and reduce greasiness, typically incorporated at a few percent up to ~10% in leave-on products. As a fatty ester, it is generally well-tolerated with low irritancy in clinical and consumer use, but any lipid-based emollient can occasionally sting or trigger intolerance on severely barrier-compromised or eczematous skin. Given that small but real reactivity is possible in highly sensitized patients, it rates as very gentle rather than inert. Safety Notes: Propylheptyl caprylate is used as a lightweight emollient/solvent and sensory modifier; in many commercial leave-on formulas (serums, lotions, sunscreens, makeup) it appears at low levels (~0.1–2%) mainly to improve slip and reduce tack. Mid-range usage (3–20%) is common in creams and color cosmetics as part of the emollient phase. High-strength consumer products such as anhydrous face oils, balm sticks, cleansing oils/balms, and silicone-free primers can use it as a primary emollient/texture base, reaching ~30–60% in OTC retail products; rinse-off can skew higher when used as a major oil-phase carrier.

Propylparaben

Propylparaben is a preservative typically used at low concentrations (generally well under 1%) and is considered low-irritancy in standard patch-testing and clinical use compared with many alternative preservatives. While true allergy/sensitization can occur (including in eczema-prone patients), it is uncommon and propylparaben more often presents as a rare delayed allergic reaction than as an inherent irritant. Given its broad tolerability at typical use levels but nonzero sensitization risk, it fits best as very gentle rather than inert. Safety Notes: In commercial cosmetics, propylparaben is often used at very low levels (around 0.001–0.01%) as part of a blended preservative system (commonly with methylparaben and/or other boosters) in both leave-on and rinse-off products. Higher-strength consumer formulations have been marketed near the upper regulatory limits for parabens in the EU/UK (propylparaben typically allowed up to 0.14% as acid, when used alone; or 0.8% total for mixtures of certain parabens subject to individual limits), so the top end reflects real-world products formulated to the maximum permitted levels for robust preservation.

Protease

Protease is an enzymatic exfoliant used to break down keratin/protein debris at low percentages, but as an active enzyme it can disrupt the stratum corneum and provoke stinging, erythema, and barrier compromise in sensitive or eczematous skin. Enzymes (including proteases) are also well-recognized irritants and potential sensitizers in exposure contexts, and on compromised skin the irritation risk increases significantly, especially when layered with other exfoliants or acids. Given its active, barrier-altering mechanism and higher-risk profile for reactive populations, it warrants a significant-irritancy score. Safety Notes: In commercial skincare, proteases are most often used as enzymatic exfoliants in leave-on serums/creams and especially in rinse-off enzyme cleansers/masks/powders, where effective levels can be extremely low due to high catalytic activity (down to ~0.0001% active enzyme). Higher-strength consumer products—typically powdered enzyme exfoliants and wash-off masks—can reach about 0.5–2% protease/enzyme complex on an as-sold basis, though actual active enzyme content may be lower depending on dilution, carriers, and activity units. Leave-on formats usually sit at the low end because of irritation risk and stability constraints (pH, preservative compatibility), while rinse-off products tolerate the upper end of the observed market range.

Prunella Vulgaris

Prunella vulgaris (self-heal) is typically used as a botanical extract for soothing/antioxidant benefits at low concentrations, but like many plant extracts it contains multiple bioactive phenolics that can trigger irritant or allergic contact dermatitis in a reactive subset. Human patch-test data for this specific extract is limited and formulations vary widely, so I score it as mild: generally well tolerated, yet not reliably “non-irritating” for eczema-prone or highly sensitized patients, especially in leave-on products or layered routines. Safety Notes: In commercial skincare, Prunella vulgaris is most often supplied as an extract (water/glycerin/butylene glycol based) and is frequently used at very low levels (~0.001–0.1%) in leave-on toners/serums as a supporting botanical/soothing antioxidant alongside other extracts. At the high end, consumer-available “single-extract” or herb-focused ampoules/essences and some K-beauty soothing gels can reach ~1–5% extract, with a small number of high-strength formulations listing Prunella vulgaris extract around 10% (typically still an extract solution rather than neat plant solids); rinse-off products are generally on the lower half of the range due to cost/benefit and wash-off dilution. No specific FDA/EU maximum applies to Prunella vulgaris itself, so the upper end is primarily constrained by extract solvent system, sensory/stability, and irritation risk.

Prunus Amygdalus Dulcis Fruit Extract

Prunus amygdalus dulcis (sweet almond) fruit extract is primarily used as a skin-conditioning botanical at low concentrations, and while many tolerate it well, botanical extracts contain multiple proteins/polyphenols that can provoke irritant or allergic responses in reactive and atopic (eczema-prone) skin. Clinical experience and patch-test data across plant-derived ingredients support a non-trivial sensitization risk compared with inert humectants/emollients, especially in compromised barriers and when layered with other actives. Given the potential for delayed sensitization and cross-reactivity in nut/seed-allergic individuals, I score it as mild rather than “gentle.” Safety Notes: In commercial skincare, Prunus Amygdalus Dulcis (Sweet Almond) Fruit Extract is most often used as a minor botanical “support” ingredient in lotions/serums/cleansers at trace levels (commonly ~0.001–0.1%), consistent with typical supplier recommended use rates for plant extracts and INCI listings near the end of the deck. Higher concentrations are seen in consumer-available botanical-focused creams, masks, and soothing leave-on products where the extract is a featured active (typically ~1–5%); above this is uncommon due to limited incremental benefit versus using almond oil, plus stability/odor/color and preservative-load constraints. This range applies primarily to leave-on products; rinse-off products generally sit toward the low end because of short contact time and cost/performance tradeoffs.

Prunus Amygdalus Dulcis Oil

Prunus Amygdalus Dulcis (sweet almond) oil is primarily an emollient used at high concentrations (often 5–100%) and is generally well-tolerated, but it is not inert. Clinical experience and patch testing show a low-to-moderate risk of irritation or allergic contact dermatitis in reactive individuals, particularly those with eczema or nut-protein sensitivity due to potential trace protein contaminants. Given frequent use in leave-on products and the high-stakes population of compromised skin, a mild irritancy score is warranted. Safety Notes: In mass-market leave-on creams/lotions/serums, Prunus Amygdalus Dulcis (Sweet Almond) Oil is often used at very low levels (~0.05–0.5%) as an emollient/skin-feel modifier within larger oil phases, with many formulas clustering around 1–10%. At the high end, it is widely sold to consumers as a single-ingredient “sweet almond oil” body/hair oil, where it can be 100%, and it is also commonly the dominant carrier oil in anhydrous balms and cleansing oils (often 30–90%+). No specific EU/FDA concentration cap applies for this cosmetic ingredient; practical limits are driven by product format (rinse-off vs leave-on) and desired texture/occlusivity.

Prunus Armeniaca Kernel Extract

Prunus armeniaca (apricot) kernel extract is typically used at low concentrations as an emollient/skin-conditioning botanical, but kernel-derived botanicals can contain allergenic proteins and trace aromatic constituents that increase reactivity risk compared with inert oils. Patch-test and clinical experience show occasional irritation or allergic contact dermatitis in sensitized individuals (especially those with eczema or barrier disruption), so while often tolerated, it is not reliably “gentle” for highly reactive skin. Safety Notes: In mass-market leave-on creams/lotions/serums and rinse-off cleansers, Prunus Armeniaca (Apricot) Kernel Extract is most often used as a label-supporting botanical at very low levels (around 0.001–0.1%), consistent with typical supplier recommended use rates for plant extracts and the low levels implied by INCI placement. Higher concentrations (1–5%) are observed in consumer-available “botanical-rich” masks, balms, and specialty soothing/nourishing creams where the extract is a primary marketing active, with the upper end constrained by stability/odor/color impact and potential sensitization from kernel-derived constituents. This range reflects OTC products; it excludes professional-only peels/treatments and distinguishes extract usage from apricot kernel oil, which is commonly used at much higher percentages.

Prunus Armeniaca Kernel Oil

Prunus Armeniaca (apricot) kernel oil is a lipid emollient typically used at several percent up to high levels in creams/oils, and it is generally well-tolerated with low inherent irritancy because it does not rely on low pH or reactive actives. However, like other nut/seed oils it can trigger irritation or allergic contact reactions in a minority of highly reactive or eczematous patients (especially if oxidized or minimally refined), so it is best classified as gentle rather than universally inert. Safety Notes: In commercial skincare, apricot (Prunus armeniaca) kernel oil is frequently used as a minor emollient/skin-feel modifier in lotions, creams, and cleansers at very low levels (~0.05–1%), especially when it is one of many botanical oils in a blend. At the high end, it is widely sold to consumers as a pure carrier oil and as the primary oil phase in facial/body oils, where it commonly reaches 50–100% in leave-on products; rinse-off products typically sit lower due to surfactant systems and cost/viscosity constraints.

Prunus Domestica Seed Extract

Prunus domestica (plum) seed extract is typically used at low concentrations as a botanical antioxidant/skin-conditioning agent, but seed-derived extracts can contain trace aromatic compounds and processing residues that increase reactivity compared with inert emollients. While broad clinical irritation data are limited, botanicals are a common source of unpredictable stinging or dermatitis in eczema-prone patients, especially in leave-on formulas and when layered with other actives. Given the uncertainty and the higher risk profile of plant extracts in compromised skin, a mild irritancy score is the safest clinically-aligned assessment. Safety Notes: In commercial skincare, Prunus domestica (plum) seed extract is most often used as a low-level antioxidant/conditioning botanical in leave-on creams, serums, and eye products, commonly appearing in the 0.001–0.1% range when supplied as a diluted extract in a carrier. Higher-strength consumer products (typically facial oils, balms, and “plum” repair serums) may use concentrated oil/extract blends or “active botanical” phases that bring the effective seed-extract input up to ~1–5% without entering professional-only territory. No specific EU/FDA maximum applies to this extract; practical upper limits are driven by sensory/oxidative stability and supplier-recommended use levels.

Prunus Domestica Seed Oil

Prunus domestica (plum) seed oil is an emollient lipid typically used at a few percent up to ~100% in facial oils, and as a refined triglyceride-rich oil it is generally well-tolerated and supports barrier function. However, like other botanical seed oils it can contain trace aromatic components and is susceptible to oxidation, which can increase stinging/irritation risk in highly reactive or eczematous skin. Clinically, it fits a “gentle” profile for most users, but not completely inert for severely sensitized populations. Safety Notes: In commercial cosmetics, Prunus domestica (plum) seed oil is often used at trace-to-low levels (~0.05–0.5%) as a label-claim emollient component within broader oil blends in creams, lotions, and hair products (leave-on) or as a minor refatting oil in rinse-off cleansers. At the high end, it is widely sold directly to consumers as a 100% neat facial/body oil and is also used at very high levels (typically ~50–99%) in anhydrous oil serums, balms, and lip oils where it serves as the primary emollient. No specific EU/FDA concentration cap is generally applied to this fixed vegetable oil beyond standard cosmetic safety and impurity/allergen considerations.

Prunus Persica Leaf Extract

Prunus persica (peach) leaf extract is a botanical soothing/antioxidant additive typically used at low concentrations, but peach-derived plant materials can contain sensitizing constituents and show occasional positive reactions in patch testing, especially in atopic (eczema-prone) individuals. Because botanicals have variable composition and can trigger delayed hypersensitivity or stinging on compromised barriers despite being marketed as “gentle,” I rate it as mild with a meaningful but not frequent irritation risk in sensitive skin. Safety Notes: In commercial skincare, Prunus Persica (Peach) Leaf Extract is most often used as a low-level botanical supporting ingredient in leave-on lotions/serums and rinse-off cleansers, where it commonly appears in the ~0.001–0.5% range and can be present at trace levels (~0.0001%) when part of a blended preservative/soothing botanical complex. High-strength consumer-available products marketed as botanical/“single-extract” boosters or concentrate ampoules can push total extract (as supplied) into the ~1–5% range, with practical limits driven by odor/color, solubility, and batch-to-batch variability rather than specific regulatory caps.

Prunus Serotina Bark Extract

Prunus Serotina (wild cherry) bark extract is a botanical astringent/soothing agent typically used at low concentrations, but bark extracts contain complex phenolics and can carry allergenic/sensitizing fractions with batch-to-batch variability. In sensitive and eczema-prone skin, botanicals are a common cause of delayed allergic contact dermatitis on patch testing, so despite “gentle” marketing, this warrants a moderate irritancy score and a patch test recommendation. Safety Notes: In commercial skincare, Prunus serotina (wild cherry) bark extract is most often used as a minor botanical supporting ingredient in leave-on lotions/serums and rinse-off cleansers, where it commonly appears at very low levels (down to ~0.0005–0.01%) consistent with label-order placement and typical supplier-recommended use rates for botanical extracts. Higher levels are seen in consumer-available “botanical active” toners, masks, and concentrated serums that feature the extract (often as a glycerin/propylene glycol extract), where practical formulation constraints (odor/color, tannin/astringency, solubility, and irritation potential) generally cap real-world use around ~1–5%. There is no specific EU/FDA maximum for this INCI itself; the observed upper end reflects market practice rather than a hard regulatory limit.

Prunus Serotina Fruit Extract

Prunus Serotina (wild black cherry) fruit extract is typically used at low concentrations as a botanical antioxidant/skin-conditioning agent, but botanical extracts have variable composition and can contain trace sensitizing components (e.g., aromatic constituents) depending on extraction and standardization. Clinical patch-test data for this specific extract is limited, so for highly sensitive or eczematous skin I treat it as a mild but real risk rather than inherently “gentle,” especially in leave-on products and when layered with other actives. Safety Notes: In commercial skincare, Prunus serotina (wild black cherry) fruit extract is most often used as a minor botanical claim ingredient in multi-extract blends, where the effective in-formula level commonly falls in the ~0.0001–0.1% range (especially in leave-on lotions/serums and rinse-off cleansers). Higher concentrations are observed in consumer-available “botanical/fruit extract” toners, masks, and serums that are positioned as high-natural-content formulas, where single extracts can be used at ~1–5% depending on supplier potency and solvent system. There are no specific FDA/EU cosmetic maximum limits for this INCI, so upper use is primarily constrained by stability, color/odor impact, and irritation potential in leave-on products.

Pseudoalteromonas Ferment Extract

Pseudoalteromonas ferment extracts are used at low levels as skin-conditioning/soothing bioferments (often in the ~0.1–2% range) and are generally well tolerated in clinical use. However, as a complex marine-derived ferment containing multiple biomolecules, it carries a small but real risk of irritation or sensitization in highly reactive or eczema-prone patients (especially when skin barrier is compromised). Given that unpredictability typical of ferments, I rate it as gentle but not “very gentle.” Safety Notes: In commercial skincare, Pseudoalteromonas Ferment Extract is typically supplied as an aqueous/glycolic vendor blend and is often dosed at very low levels (around 0.001–0.05%) in mass-market moisturizers/serums where it appears low on the INCI list, especially in leave-on anti-aging/soothing products. Many supplier technical recommendations and common prestige formulations cluster around ~0.1–1% active blend addition, while a smaller set of high-strength consumer-available serums/ampoules and post-procedure-style barrier products push into the ~2–5% range (generally leave-on; rinse-off products tend to sit at the low end due to contact time and cost). There is no specific FDA/EU concentration cap for this INCI, so the upper end is practically limited by supplier blend composition, stability/viscosity/odor, and cost rather than regulation.

Pseudozyma Epicola/Argania Spinosa Kernel Oil/Olive Fruit Oil/Sunflower Seed Oil/(Angelica Gigas/Licorice/Lithospermum Erythrorhizon) Root Ferment Extract Filtrate

This is a lipid-rich ferment filtrate (often used at low percentages) combining common emollient oils with a yeast ferment and multiple botanical root extracts; while the oils themselves are generally well-tolerated, botanical extracts and ferments add a measurable risk of irritation or allergy in eczema-prone and highly reactive skin. Patch-test data for individual botanicals (e.g., licorice/Angelica/Lithospermum derivatives) show occasional sensitization, and complex multi-component ferments increase unpredictability compared with single-ingredient emollients. In real-world routines, barrier-compromised users may experience stinging, redness, or delayed dermatitis, so I rate it as mild rather than gentle. Safety Notes: This is a multi-component fermented oil/extract filtrate typically supplied as a pre-blended complex and used at low inclusion levels in mass-market leave-on products (essences, serums, lotions) around ~0.05–0.5% to support marketing claims without materially impacting texture/odor or stability. In higher-end or “fermented oil complex” focused products, inclusion commonly rises to ~1–3%, and I have observed specialty consumer-available leave-on formulations using up to ~5% when the complex is a hero ingredient and the base emulsion/oil phase is designed to accommodate it. Rinse-off uses, when present, tend to stay toward the low end due to cost and limited deposition, but the upper range is primarily driven by leave-on products.