Skincare Ingredients

Phenylethyl Resorcinol

Phenylethyl resorcinol is a skin-brightening tyrosinase inhibitor typically used around ~0.1–1% in leave-on products. In clinical and consumer use it is generally well-tolerated, but as a phenolic/resorcinol derivative it can still trigger stinging, redness, or eczema flares in reactive or compromised skin, especially when combined with other actives (retinoids, acids) or in impaired barriers. I score it as mild because irritation is not expected in most users, yet is plausible and clinically relevant in sensitive-skin populations. Safety Notes: In consumer brightening/anti-spot leave-on serums and creams, phenylethyl resorcinol is commonly present at low levels around 0.05–0.2% as a supportive tyrosinase-inhibiting active, aligning with typical supplier guidance and stability/sensory constraints. Numerous OTC dark-spot correctors and specialty pigment products use 0.5% and up to about 1.0% in leave-on formats as the practical high end observed in the market; higher levels are uncommon due to irritation risk and formulation challenges. Rinse-off cleansers, when present, tend to sit at the low end of this range because of short contact time and cost.

Phenylpropanol

Phenylpropanol is an aromatic alcohol used primarily as a preservative/solvent (often around ~0.3–1%) and, like other small alcohols, can provoke stinging or irritant contact dermatitis in reactive or barrier-impaired skin. While generally tolerated at typical cosmetic concentrations, patch-test and real‑world reports support a non-trivial irritation risk in eczema-prone patients, especially when layered with other actives or on compromised skin. Safety Notes: Phenylpropanol is used in cosmetics primarily as a preservative/antimicrobial booster and odor-masking solvent, with many mainstream leave-on lotions, serums, and rinse-off cleansers using it around 0.05–0.30% as part of multi-component preservation systems. Higher-strength consumer-available formulations (especially “preservative-free”/alternative-preservative positioning and some wipes, toners, and aqueous leave-on products) can push it into the ~0.5–1.2% range to support microbial control, though sensory irritation and fragrance-like character typically limit use much above ~1% in broad-market products. No specific EU “Annex V” maximum applies to phenylpropanol as a listed preservative, so observed use levels are driven mainly by efficacy testing (challenge tests), pH/solubility, and tolerability rather than a hard regulatory cap.

Phenyl Trimethicone

MVP Approved - Phenyl Trimethicone is a silicone-based ingredient used to improve product spreadability and create a lightweight, non-greasy barrier that helps retain moisture. It is recognized for its low potential for irritation.

Phloretin

Phloretin is a polyphenol antioxidant typically used around ~0.5% in serums, often in hydroalcoholic or acidic vitamin C systems that can amplify stinging on compromised skin. While it is not a classic high-risk allergen, clinical experience and patch-testing patterns with antioxidant blends show occasional irritation in reactive/eczema-prone users, especially when layered with other actives. Given its common formulation context and the need to protect highly sensitive patients, a mild irritation score is warranted. Safety Notes: In commercial skincare, phloretin is most often used as a leave-on antioxidant active at low levels (commonly 0.3–1.0%) due to solubility/oxidation limits and frequent pairing with vitamin C/E/ferulic; at the low end, it appears in multi-antioxidant or brightening serums/creams where it is a supporting ingredient around 0.01–0.1%. The highest consumer-available products observed push to about 2% in anhydrous or high-solvent systems (e.g., alcohol/propylene glycol) to maintain solubility and stability; higher than this is uncommon in OTC due to formulation challenges rather than specific regulatory caps. Rinse-off products tend to use lower levels than leave-on because of limited contact time and cost/solubility considerations.

Phosphatidylcholine

Phosphatidylcholine is a skin-identical phospholipid used in liposomes/emulsions and barrier-support formulas, typically at low single-digit percentages, and is generally well tolerated in sensitive and compromised skin. Clinical experience and patch-testing data suggest a low rate of irritation, but rare reactions can occur due to source impurities (e.g., soy/egg derivatives) or oxidation products in poorly stabilized formulas. Given its overall biocompatibility yet non-zero risk in highly reactive patients, it fits a very gentle score rather than inert. Safety Notes: In mass-market moisturizers, serums, and cleansers, phosphatidylcholine is most often used as a minor emulsifier/liposome component or skin-conditioning phospholipid at very low levels (typically around 0.01–0.3%), so 0.01% captures the low end seen in INCI-listed phospholipid blends. Higher-strength consumer products marketed as phospholipid/liposome delivery systems, barrier-repair concentrates, or “lecithin/phosphatidylcholine” boosters commonly use ~1–3% active phosphatidylcholine, with some specialty leave-on formulations reaching about 5% before texture, odor, and oxidative stability constraints become limiting. Rinse-off products tend to sit at the lower end because the benefit is primarily formulation-aiding, whereas leave-on lipid concentrates and liposomal serums account for the upper end.

Phospholipids

Phospholipids (e.g., lecithin-derived) are barrier-supportive emulsifiers/liposome-formers typically used at low to moderate concentrations (~0.1–5%) and are generally well-tolerated, including in sensitive-skin formulations. Clinical experience and patch-test data suggest low inherent irritancy, but because commercial phospholipid sources (soy/egg/sunflower) can carry trace impurities and rare allergenicity, a small risk of reactivity remains, warranting a very gentle (not inert) score. Safety Notes: In commercial skincare, phospholipids are often used at very low levels (~0.05–0.5%) as emulsifier co-surfactants, skin-conditioning lipids, or as part of liposome/encapsulation systems where the INCI appears but the active payload is small. Many leave-on barrier serums/creams and “lamellar” moisturizers use ~1–5% phospholipids (often via hydrogenated lecithin or phosphatidylcholine-rich blends) to build liquid-crystal structures and improve skin feel. High-strength OTC specialty products (liposomal bases, phosphatidylcholine concentrates, and some massage/oil-gel or ampoule-style formulas marketed for barrier repair) can reach ~10–20% total phospholipids, with higher levels being uncommon due to viscosity/texture limits, oxidation control needs, and cost; rinse-off formats typically sit at the lower end because of wash-off and surfactant system constraints.

Phosphoric Acid

Phosphoric acid is primarily used as a pH adjuster/buffer (often ~0.1–1% in leave-on products, sometimes higher in rinse-off), and as an inorganic acid it can sting and irritate compromised skin depending on final formula pH. Clinical experience and patch-test data across acids show irritation risk rises as pH drops, with burning/stinging more likely in eczema, post-procedure, or barrier-impaired patients even at low concentrations. Because its safety is highly pH-dependent and it can contribute to cumulative acid load in routines, I rate it as a notable irritant requiring careful formulation and cautious use in very sensitive skin. Safety Notes: In consumer skincare, phosphoric acid is most often used as a pH adjuster/buffer in cleansers, toners, and lotions at very low levels (~0.01–0.3%), where it contributes negligible exfoliation and primarily controls finished-product pH. The highest OTC levels observed are in strong at-home chemical exfoliants/peels and some wart/callus-type cosmetic acids marketed to consumers, where phosphoric acid can be present at several percent up to ~10% in leave-on or short-contact formats; above this, products tend to fall into professional-use or non-cosmetic categories and are less common due to irritation/corrosivity constraints and pH limits.

Phyllanthus Emblica Fruit Extract

Phyllanthus emblica (amla) fruit extract is primarily an antioxidant/brightening botanical used in leave-on products typically around ~0.1–2%, but it naturally contains polyphenols and vitamin-C–like acidic constituents that can sting compromised barriers. While generally well-tolerated, botanical extracts have a meaningful rate of irritant and occasional allergic contact reactions in eczema-prone patients, so I score it as mild risk rather than “gentle,” especially in multi-active routines. Safety Notes: In commercial skincare, Phyllanthus emblica (amla) fruit extract is commonly used as an antioxidant/brightening botanical at very low levels (around 0.01–0.1%) in multi-botanical serums, moisturizers, toners, and rinse-off cleansers where it functions mainly as a label claim and supportive antioxidant. Mid-range leave-on formulas typically use ~0.2–3% depending on extract potency/standardization and sensory constraints. High-strength consumer-available “amla” brightening serums/masks and concentrated botanical treatments can reach about 5–10% extract (or equivalent active solids), with higher levels becoming limited by color/odor, polyphenol-driven instability, and potential for tack/irritation rather than regulation.

Phyllostachys Bambusoides Extract

Phyllostachys bambusoides (bamboo) extract is primarily used as an antioxidant/soothing botanical in leave-on products, typically at low concentrations (often <1–2%). While generally well-tolerated, botanical extracts contain multiple bioactive constituents and have documented, though uncommon, irritation/sensitization potential on patch testing—especially in eczema-prone or highly reactive skin. Given the variability in extract composition and the need to err on patient safety, I rate it as gentle but not exceptionally inert. Safety Notes: In commercial skincare, Phyllostachys Bambusoides (bamboo) extract is most often used as a minor botanical/antioxidant or soothing claim ingredient in leave-on lotions/toners/serums and rinse-off cleansers at very low levels (~0.001–0.1%), reflecting typical supplier-recommended use rates and the fact that many brands dose complex botanical extracts sparingly. Higher-strength consumer-available formulas (especially “bamboo water/extract” hydrating essences, gel masks, and some clean-beauty products that emphasize the extract as a featured botanical) can reach ~1–5% when the extract is a standardized liquid extract; above this is uncommon due to cost, color/odor, solubility, and stability constraints rather than regulatory limits. This range applies primarily to leave-on products; rinse-off products typically cluster toward the low end.

Physalis Angulata Extract

Physalis angulata extract is a botanical anti-inflammatory/soothing ingredient typically used at low concentrations, but as a plant extract it contains multiple bioactive compounds with batch-to-batch variability. Human irritation data are limited compared with standardized actives, and plant extracts can trigger irritant or allergic contact dermatitis in eczema-prone patients, especially in leave-on routines and on compromised skin. Given the uncertainty and sensitization potential despite generally gentle positioning, a mild-risk score is the safest clinically. Safety Notes: In commercial skincare, Physalis angulata extract is most often used as a botanical soothing/anti-inflammatory active at very low levels (often as part of a multi-botanical blend), with effective inclusion commonly starting around 0.001–0.01% in leave-on creams/serums and higher in rinse-off products where cost and odor/color control drive lower use. High-strength OTC positioning (e.g., “concentrated” soothing serums/ampoules or products built around a single featured botanical) can reach ~1–3% active extract depending on the supplier’s solvent system and solids content, with higher practical limits typically set by stability, sensory impact, and potential for botanical-related irritation rather than specific regulatory caps.

Phytantriol

Phytantriol is a cosmetic humectant/solvent and penetration-support ingredient typically used around 0.1–5% in hair and skin products, and it is generally well tolerated in patch testing with a low rate of irritation or sensitization. However, because it can enhance delivery of other actives and is not fully “inert,” highly reactive or barrier-impaired patients may experience mild stinging or cumulative irritation in multi-active routines. For patient safety in severe sensitivity populations, I score it as gentle but not exceptionally gentle. Safety Notes: In commercial leave-on hair/scalp and skincare products, phytantriol is most often used as a low-level performance booster/solubilization and delivery aid, with observed use starting around ~0.05–0.1% in serums, conditioners, and tonics where it supports deposition of actives (e.g., panthenol/niacinamide) and moisturization. High-strength consumer-available formulations (especially hair/scalp treatments, anti-breakage serums, and some emulsified leave-on concentrates) commonly top out around 3% and can reach ~5% when positioned as a primary functional humectant/conditioning co-active. Rinse-off products typically sit toward the lower-mid portion of the range due to wash-off and cost/benefit, while the upper end is predominantly leave-on systems; phytantriol is not specifically restricted by major cosmetics regulations, so practical formulation limits (sensory, solubility/phase behavior, and cost) tend to define the ceiling.

Phytic Acid

Phytic acid is a mild chelating agent and gentle exfoliant/brightening active, typically used around ~0.5–2% in leave-on products (often at an acidic pH where it is functional). Clinical and post-market experience suggests it is generally well tolerated and often less stinging than stronger AHAs, but it can still cause transient stinging, dryness, or eczema flares in very reactive or barrier-compromised skin—especially when layered with other acids/retinoids. Given its pH-dependent activity and real-world cumulative irritation risk, I rate it as mild rather than fully gentle. Safety Notes: In commercial skincare, phytic acid is often used at very low levels (~0.05–0.3%) as a chelator/antioxidant support ingredient in leave-on serums/creams and some cleansers, where it primarily boosts stability and complements brightening systems. Dedicated brightening/exfoliating leave-on products commonly use ~0.5–2%, and the highest consumer-available “high-strength” peels/acid treatments reach about 3–5% (typically buffered and formulated to an acidic pH) to balance efficacy with irritation and stability constraints. Higher levels are uncommon in OTC due to solubility/pH control needs and tolerability; extreme concentrations are more typical of professional-only chemical peel systems, which are excluded here.

Phytonadione

Phytonadione (vitamin K1) is typically used in low concentrations (often ~0.05–1%) for anti-redness/bruising support, but it is a bioactive molecule and not truly inert. Clinical experience and patch-testing reports indicate it is generally well tolerated, yet irritant and occasional allergic contact dermatitis reactions have been documented (especially in very reactive or eczema-prone skin), so I score it as mild rather than “gentle” for patient safety. Safety Notes: Phytonadione (vitamin K1) is used in OTC cosmetics primarily in leave-on eye creams, “bruise/dark circle” serums, and post-procedure soothing products, where it is often present at very low levels (~0.0001–0.01%) due to cost, oil-solubility, and color/oxidation stability constraints. Higher-strength consumer-available formulations (typically anhydrous/oily serums, balms, or specialty creams marketed for redness/bruising appearance) are observed up to about 0.1–0.2%, above which stability and staining risk increase and products are uncommon in general retail. Rinse-off use exists but is rarer and usually at the low end since deposition is limited versus leave-on systems.

Phytosphingosine

MVP Approved - Phytosphingosine is a naturally occurring lipid used in skincare to support and repair the skin barrier, enhance hydration, and soothe irritation while also offering anti-acne and mild anti-aging benefits.

Phytosphingosine Phosphate

Phytosphingosine phosphate is a skin-identical, barrier-supporting sphingolipid derivative typically used at low levels (generally well under 1%) in soothing/barrier-repair formulas. Available irritation and sensitization data for phytosphingosine-type lipids suggest low irritancy in normal use, with reactions uncommon and usually tied to the overall formula rather than the molecule itself. For highly reactive or eczema-prone skin I still avoid calling it “exceptionally gentle,” but at typical concentrations its intrinsic irritation potential is very low. Safety Notes: In commercial leave-on barrier-repair and anti-redness products, Phytosphingosine Phosphate is typically used as a low-level skin-conditioning/anti-inflammatory lipid adjunct, with trace-to-low inclusion around 0.001–0.01% reflecting cost, potency, and use as part of a ceramide/lipid complex. Higher-strength consumer-available serums and concentrated barrier treatments have been observed up to ~0.1–0.2% in finished product, generally in anhydrous/oil-dispersion or well-solubilized systems to manage stability and salt/ionic interactions. Rinse-off products, when used, tend to sit near the low end due to short contact time and deposition limitations.

Phytosterols

Phytosterols are lipid-derived skin-conditioning/barrier-support ingredients typically used at low concentrations (about 0.1–3%) in creams and serums, where they generally reduce irritation rather than provoke it. Human patch testing and clinical use data suggest a low incidence of irritant reactions, with allergy/sensitization being uncommon but possible in highly reactive or plant-allergic individuals due to source impurities. Given their overall favorable tolerability in eczema-prone skin yet non-zero risk in sensitized populations, a very gentle score is most clinically appropriate. Safety Notes: In consumer skincare, phytosterols are commonly used as barrier-supporting, anti-irritant lipid actives and appear at low levels (~0.05–0.3%) in moisturizers/cleansers where they function mainly as supportive emollient-lipid components within complex blends. Typical leave-on barrier creams and sensitive-skin serums more often land around ~0.5–2% (sometimes declared as plant sterols or within sterol-rich complexes), consistent with levels explored in cosmetic research for barrier and redness benefits. High-strength OTC specialty balms, body butters, and lipid concentrates marketed for very dry/eczema-prone skin can reach about ~3–5% phytosterols (or equivalent active sterol fraction), with higher levels becoming uncommon due to waxy feel, solubility/phase-behavior constraints, and cost rather than regulatory limits.

Phytosteryl Macadamiate

Phytosteryl macadamiate is a fatty sterol ester used primarily as an emollient/skin-conditioning agent, typically at low percentages to improve slip and barrier feel. As a non-volatile lipid with no exfoliative or pH-dependent activity, it has low inherent irritancy in patch-testing experience and is generally well tolerated even in sensitive routines. Rare reactions can still occur in highly reactive or allergy-prone individuals (e.g., to complex lipid sources), but overall the irritation potential at typical use levels is very low. Safety Notes: In commercial leave-on products (lotions, creams, facial oils/serums, lip care), Phytosteryl Macadamiate is often used at low levels (~0.05–0.5%) as an emollient/skin-conditioning lipid and to boost barrier feel without materially changing viscosity. Mid-range use (~1–5%) is common in richer barrier creams and nourishing balms, while the highest consumer-available levels (~8–10%) are observed in anhydrous or high-oil-phase balms/sticks and intensive repair products where it functions as a primary emollient structurant; rinse-off products typically sit at the low end due to cost and deposition limits.

Phytosteryl/Octyldodecyl Lauroyl Glutamate

Phytosteryl/Octyldodecyl Lauroyl Glutamate is a lipid-based amino acid derivative used primarily as an emollient/surfactant-like skin-conditioning agent, typically at low percentages in creams and cleansers. In standard patch-test experience, this class of glutamate-derived mild surfactants/emollients is generally well tolerated with low irritation potential, though reactive eczema-prone skin can still experience stinging if the overall formula is compromised or used on barrier-damaged areas. Given its non-acidic, non-volatile profile and typical low use levels, it aligns best with a very gentle score while still acknowledging rare sensitivity in highly reactive patients. Safety Notes: Phytosteryl/Octyldodecyl Lauroyl Glutamate is a lipidic amino-acid–derived emollient/skin-conditioning agent most commonly used in leave-on creams, lotions, and makeup to improve barrier feel and slip; in mass-market products it often appears at low supportive levels around 0.05–0.5%. Higher-end barrier-repair balms, rich moisturizers, and cushiony makeup bases sometimes push it into the 2–8% range to build a more substantive, lamellar, oil-gel texture and reduce tack while boosting moisturization. Rinse-off products generally sit at the lower end due to cost-benefit and wash-off, while the highest observed consumer-available usage is in anhydrous/very rich leave-on systems.

Picea Abies Wood Extract

Picea abies (Norway spruce) wood extract is a botanical mixture (often containing resin acids/phenolic compounds) used at low levels for antioxidant/soothing or “natural” positioning, but such complex plant extracts have meaningful variability and a non-trivial rate of irritant or sensitization reactions in eczema-prone skin. While not as predictably irritating as strong acids or retinoids, conifer-derived constituents are well-documented causes of contact dermatitis in susceptible individuals, so I score it as moderate and patch-test-worthy for sensitive or compromised skin. Safety Notes: In commercial skincare, Picea abies (Norway spruce) wood extract is most often used as a minor botanical/antioxidant or soothing component in leave-on creams/serums and aftershaves at very low levels (commonly ~0.01–0.1%), with the lowest observed listings consistent with trace inclusion in multi-extract blends around 0.001%. Higher-strength consumer products (typically leave-on serums/ampoules or “concentrate” style formulas) can reach the low single-digit percentages when the extract is a featured active or when high-dose glycerin/butanediol extracts are used; the upper end observed in OTC products is about 5% before sensorial, color/odor, and irritation/stability constraints usually limit further increases. No specific EU/FDA maximum is set for this INCI beyond general cosmetic safety requirements, so practical formulation limits primarily determine the market ceiling.

Pinene

Pinene (alpha/beta-pinene) is a volatile terpene used primarily as a fragrance component/solvent in very low concentrations, but it is a well-documented skin irritant and can act as a sensitizer, with irritation and allergic contact dermatitis reported especially when oxidized. In sensitive or eczema-prone skin, terpene fragrances have a higher likelihood of stinging and barrier disruption and can add meaningful cumulative irritancy in a routine even at low levels. Given its fragrance-type use and the established irritant/sensitization profile, it warrants a significant-risk score for patient safety. Safety Notes: In consumer skincare, pinene is most commonly present as a trace constituent of essential oils/fragrance blends and botanical extracts, yielding finished-product levels around ~0.0001–0.05% in leave-on and rinse-off products. Higher levels occur when pinene (or pinene-rich terpene fractions) is used deliberately as a fragrance component/terpene solvent in niche “natural” balms, body oils, and some rinse-off cleansing products, where total terpene levels can approach ~0.2–1.0% before odor/irritation/sensitization constraints become limiting (IFRA fragrance practices typically keep leave-on usage lower than rinse-off).

Pinus Densiflora Leaf Extract

Pinus densiflora (pine) leaf extract is primarily used as an antioxidant/soothing botanical at low concentrations, but as a complex plant extract it can contain resin acids/terpenoid constituents that are known triggers for irritant and allergic contact dermatitis in reactive or eczematous skin. Clinical patch-testing literature broadly supports higher reaction rates for botanical extracts versus inert bases due to variable composition and sensitizer contamination, so for patient-safety in sensitive populations I rate it as a moderate irritant with patch testing recommended. Safety Notes: In mass-market leave-on products (toners, emulsions, creams) Pinus densiflora leaf extract is often used as a minor botanical claim ingredient at very low levels (down to ~0.0001–0.01%), especially when supplied as a dilute carrier-based extract within a multi-extract blend. Dedicated “pine/cica forest” style serums, ampoules, and calming masks marketed around the extract commonly place it higher, typically ~0.1–2%, with some high-strength consumer OTC formulas using concentrated extract solutions equivalent to ~3–5% to support antioxidant/soothing positioning. Rinse-off cleansers/shampoos generally sit toward the lower end due to limited contact time, while leave-on serums/masks drive the upper end; no specific EU/FDA concentration cap applies beyond general safety substantiation.

Pinus Palustris Oil

Pinus palustris (longleaf pine) oil is an essential oil/fragrant terpene mixture (commonly rich in alpha-pinene and related compounds) used at low percentages for scent or botanical marketing, but it is a well-recognized irritant in leave-on products and can sting compromised skin. Essential oils and terpene-rich oils also carry nontrivial sensitization risk (allergic contact dermatitis) in patch testing populations, and reactions are more likely in eczema-prone patients and when layered with other actives. Given its fragrance-function with meaningful irritancy/sensitization potential even at typical concentrations, I score it as high risk for sensitive skin. Safety Notes: In mainstream personal-care products, Pinus palustris (longleaf pine) oil is typically used as a fragrance/essential-oil component at trace levels (often ~0.0005–0.05%), especially in leave-on lotions/creams and facial products where sensitization risk drives very low use levels. Higher concentrations are most often found in rinse-off formats (soaps, body washes, scalp cleansers) and “natural” balm/oil blends marketed to consumers, where pine oils can reach ~0.5–3% as a primary aromatic/functional essential oil component; above this, tolerability and IFRA-related fragrance allergen constraints generally limit broad consumer use, particularly for leave-on products.

Piper Nigrum Seed Extract

Piper nigrum (black pepper) seed extract is typically used in small amounts for “stimulating/warming” or antioxidant claims, but it contains piperine and other pungent constituents that can activate irritant pathways (stinging, burning, erythema), especially on compromised barriers. Patch-test and real‑world use reports show higher reactivity risk than bland botanicals, and in eczema/prone-to-react skin it can contribute to cumulative irritation when layered with other actives. Given the predictable sensory irritation profile and heightened risk in sensitive populations, it warrants a significant irritancy score. Safety Notes: In mass-market leave-on skincare, Piper nigrum (black pepper) seed extract is most often used as a minor supporting botanical (warming/microcirculation or “energizing” claim) at very low levels around 0.0005–0.05%, especially when supplied as a solvent-diluted extract. Higher-strength consumer products (e.g., body firming/“heat” gels, cellulite/massage creams, and some rinse-off scrubs) can reach ~0.5–2% extract to deliver a perceptible sensory effect, with practical upper limits driven by irritation/sensitization risk and fragrance-like IFRA considerations depending on extract composition. Rinse-off products may tolerate the upper end more readily than face leave-on products, which typically stay below ~0.5%.

Piperonyl Glucoside

Piperonyl glucoside is a glycosylated aromatic compound typically used at low percentages as a solubilizer/fragrance-modifying or sensorial agent; these small, more lipophilic aromatics (even when glucosylated) can still trigger stinging or dermatitis in highly reactive skin. While robust irritation datasets are limited compared with major surfactants or humectants, the structural similarity to fragrance-type aromatics warrants caution, especially in eczema patients and when combined with other potential irritants in a routine. Given the uncertainty and the need to protect sensitized populations, I score it as mildly irritating rather than assuming it is inert. Safety Notes: In commercial skincare, piperonyl glucoside is most often used as a skin-brightening/anti-dark-spot active (often alongside niacinamide, vitamin C derivatives, or exfoliating acids) and appears at low levels (~0.01–0.1%) in multi-active leave-on serums and creams where it functions as a supportive booster. Higher-strength consumer-available dark-spot correctors and targeted hyperpigmentation serums have been marketed around ~0.5–2% to drive visible efficacy while managing sensory and stability constraints typical for leave-on formats. It is uncommon in rinse-off at meaningful levels; when present, it is generally at the low end due to limited contact time.

Pistacia Lentiscus Gum

Pistacia Lentiscus Gum (mastic gum) is a resinous film-former/perfuming botanical extract typically used at low levels, but resins and plant-derived gum fractions contain complex terpenoid components that can trigger irritant reactions and occasional allergic contact dermatitis in reactive or eczema-prone skin. Patch test literature and clinical experience with similar resinous botanicals support a non-trivial sensitivity risk despite “natural” positioning, especially with leave-on use and a compromised barrier. Given the potential for both immediate stinging and delayed sensitization in sensitive populations, I score it as mild rather than gentle. Safety Notes: In commercial skincare, Pistacia Lentiscus Gum (mastic gum) is most often used as a minor film-former/sebum-control/skin-smoothing active or as part of a supplier blend, with effective label-declared use levels commonly starting around 0.01–0.1% in leave-on serums, emulsions, and primers. Higher-strength consumer products (typically leave-on “pore refining” or mattifying treatments) have been marketed around ~1–2%, and the upper end observed in OTC products reaches about 3% where sensory, tack/film, and solubility/stability constraints usually become limiting. It is uncommon in rinse-off at meaningful levels because benefits are primarily film-forming/leave-on sensory, so the practical market maximum is driven more by aesthetics and formulation robustness than by regulatory limits.

Pistacia Vera Seed Oil

Pistacia Vera (pistachio) seed oil is primarily an emollient used at meaningful levels in moisturizers and facial oils, and while most users tolerate it, it is a tree-nut–derived lipid with documented potential for contact allergy or irritant flares in reactive/eczema-prone skin. Patch test data for nut oils is limited and real-world reactions are idiosyncratic, so I score it as mild: generally low irritation potential but non-trivial risk in highly sensitive or allergic populations, especially with leave-on use over compromised skin. Safety Notes: In commercial skincare it is commonly used as a low-level emollient/skin-conditioning oil in creams, lotions, and cleansers where it can appear at trace-to-sub-1% levels (typically ~0.05–0.5%) to support sensorial feel and marketing claims. At the high end, it is sold directly to consumers as 100% pistachio seed oil (single-ingredient facial/body oils) and also appears at very high levels (often 30–80%) in oil serums, balms, and anhydrous leave-on blends. There are no specific FDA/EU concentration caps for this fixed oil in cosmetics; practical limits are driven by product type (rinse-off tends to be lower, leave-on anhydrous products can be very high) and stability/odor/sensory considerations.

Pisum Sativum Extract

Pisum sativum (pea) extract is typically used at low concentrations as a soothing/antioxidant or film-forming conditioning agent, and it is generally well tolerated in clinical use with a low rate of irritant reactions. However, as a plant-derived extract containing multiple bioactive fractions, it carries a small but real risk of irritation or allergy in highly reactive or eczema-prone patients (including potential legume-related sensitization), so it cannot be treated as inert. In cumulative routines, this remains a low-risk component, but I score it as gentle rather than very gentle to reflect the non-zero sensitization potential. Safety Notes: In commercial skincare, Pisum Sativum (pea) extract is often used as a supporting botanical/skin-conditioning active in multi-extract blends, where finished-product use levels commonly fall in the ~0.001–0.1% range (especially in serums, eye products, and moisturizers that list it mid-to-late INCI). Higher-strength OTC leave-on products marketed for firming/anti-glycation or “peptide/plant protein” benefits can use concentrated pea extract or hydrolysates at ~1–5% when the supplier material is standardized but still cosmetically acceptable. It is less commonly driven to very high levels in rinse-off due to cost and minimal contact time, but the upper end is primarily observed in leave-on formulations.

Plankton Extract

Plankton Extract is typically used at low concentrations as a conditioning/soothing bioferment in moisturizers and serums, and it is generally well-tolerated in clinical use with low rates of irritant reactions. However, as a complex marine-derived mixture (proteins/polysaccharides/trace components), it carries a small but real risk of irritation or sensitization in highly reactive or eczema-prone skin compared with truly inert bases. Considering compromised skin barriers and cumulative exposure in routines, I rate it as gentle but not exceptionally gentle. Safety Notes: In mass-market leave-on skincare (serums, creams) and rinse-off cleansers, plankton/algae ferment-type extracts are often used at very low “labeling” levels (down to ~0.0001–0.01%) as part of multi-extract blends or to support marketing claims. Most mainstream formulas cluster around ~0.05–1% depending on supplier strength and whether it’s a concentrated ferment (e.g., “plankton ferment/lysate”) versus a dilute extract. High-strength consumer-available boosters/ampoules and mask/serum concentrates can reach ~2–5% active extract/ferment (not including the solvent carrier), with higher levels generally limited by odor/color, stability, and cost rather than specific regulatory caps.

Plantago Lanceolata Leaf Extract

Plantago lanceolata (plantain) leaf extract is primarily a soothing, anti-inflammatory botanical used at low concentrations (often ~0.1–2%) in leave-on products. While generally well-tolerated, botanicals can still trigger irritant or allergic contact dermatitis in a subset of sensitive or eczema-prone patients due to naturally occurring sensitizing constituents and variability in extract composition. Given the real-world risk of delayed sensitization despite its “calming” reputation, I rate it as gentle but not exceptionally inert. Safety Notes: In mass-market leave-on creams/lotions/toners, Plantago lanceolata (plantain) leaf extract is commonly used as a low-level soothing/botanical marketing component, often around 0.001–0.1% active extract (frequently within a broader botanical blend). Higher concentrations are seen in “botanical concentrate” serums, calming gels, and some natural/organic brands that dose single-plant extracts at ~1–5% (especially when using glycerin/water extracts standardized as a cosmetic ingredient rather than pure dry extract). Rinse-off cleansers typically sit toward the lower end due to brief contact time and cost, while high-end leave-on products can support the upper end provided odor/color and stability are managed.

Pleiogynium Timoriense Fruit Extract

Pleiogynium timoriense (a botanical fruit extract) is typically used at low concentrations as an antioxidant/conditioning agent, but like many fruit extracts it can contain variable phenolics/organic acids that increase sting risk on compromised or eczematous skin. There is limited standardized human patch-test/HRIPT data specific to this extract, so patient-safety practice is to score it as mild rather than assume inertness, especially in leave-on formulas and when combined with other actives. Safety Notes: Pleiogynium timoriense fruit extract is a niche botanical typically supplied as a diluted glycerin/propylene glycol or butylene glycol extract and is most often used as a label-claim antioxidant/soothing component in leave-on serums/creams at trace-to-low levels (~0.0005–0.1%). Higher consumer-available “botanical concentrate” leave-on products and ampoules can push specialty fruit extracts into the ~1–3% range when the supplier extract is not highly standardized, while rinse-off products generally sit at the lower end due to limited contact time and cost/benefit.