Skincare Ingredients

Rutin

Rutin is a flavonoid antioxidant/vasoprotective used at low levels (typically ~0.1–1%) to help reduce oxidative stress and visible redness, and it is generally well tolerated in leave-on formulas. Clinical and patch-test experience suggests a low but nonzero risk of irritation or contact sensitivity in highly reactive/eczema-prone patients, often influenced by the solvent system or overall formula rather than rutin itself. Given sensitive-skin safety considerations and the possibility of rare reactions, it fits "very gentle" rather than truly inert. Safety Notes: In commercial skincare, rutin (often listed as Rutin or as part of Sophora japonica flower bud extract standardized for rutin) is frequently used at very low levels (~0.01–0.1%) in leave-on serums/creams for antioxidant and soothing/anti-redness positioning, and sometimes even lower when delivered via botanical extracts. Higher-strength consumer-available brightening/anti-redness concentrates and “bioflavonoid” antioxidant serums can reach ~1–5% rutin, with the upper end constrained mainly by solubility/stability and sensory effects rather than explicit regulatory limits (no specific EU/FDA maximum for rutin as a cosmetic ingredient). Rinse-off products (cleansers) tend to sit toward the low end due to short contact time and cost-to-benefit considerations.

Saccharide Hydrolysate

Saccharide Hydrolysate is a humectant/skin-conditioning carbohydrate complex typically used at low to moderate leave-on concentrations to support hydration and barrier comfort. Clinical experience and patch-test data for sugar-derived humectants show a low irritation profile, with occasional stinging possible on severely compromised or fissured skin largely from formulation factors rather than the ingredient itself. Given sensitive-skin safety priorities, it fits best as very gentle but not fully inert. Safety Notes: Saccharide Hydrolysate is typically used as a humectant/skin-conditioning sugar derivative and appears at low levels (~0.05–0.3%) in mass-market cleansers, toners, and emulsions where it functions as a supporting moisturizer. In leave-on serums, masks, and barrier-repair creams it is commonly used around 0.5–2% and can reach ~5% in consumer-available “sugar complex” hydration concentrates and gel-serums where a higher polyol/sugar load is intentionally targeted for moisturization and sensorial slip. There is no specific FDA/EU maximum for this INCI; practical upper limits are driven by tackiness, viscosity/osmolality, and overall preservation strategy rather than regulation.

Saccharide Isomerate

Saccharide isomerate is a carbohydrate-derived humectant (often used around 1–5%) designed to bind to skin keratin and improve hydration, and it is generally well-tolerated in clinical use with low rates of stinging compared with many actives. While true irritation is uncommon, in highly reactive or eczema-prone patients any leave-on ingredient can occasionally provoke burning/itch (especially on compromised barriers), so it is best classified as very gentle rather than completely inert. Safety Notes: In commercial skincare, saccharide isomerate is most often used as a leave-on humectant (frequently via the marketed blend Pentavitin) at low supporting levels around 0.1–0.3% in cleansers, toners, and emulsions where it is not the primary claim ingredient. Typical effective use levels in leave-on moisturizers/serums cluster around ~1–3%, while the highest OTC “intense hydration/72h” style serums and gel-creams reach about 5% (usually near the top practical limit for sensorial/stability and tack control). There are no specific FDA/EU cosmetic maximum limits for saccharide isomerate itself, so the observed range is driven mainly by performance, feel, and cost rather than regulation; rinse-off products generally sit toward the low end.

Saccharomyces/Calcium Ferment

Saccharomyces/Calcium Ferment is a yeast-derived ferment used primarily as a skin-conditioning/humectant component, typically included at low concentrations in leave-on products. Clinical experience with similar ferments suggests they are generally well-tolerated, but in highly reactive or eczematous skin there is a small risk of stinging or flare due to complex bio-derived residues and individual sensitivity. Given this low-but-real potential in compromised skin while remaining broadly gentle for most users, a 0.2 score best reflects patient-safety expectations. Safety Notes: In commercial skincare, Saccharomyces/Calcium Ferment is typically used as a bio-ferment/skin-conditioning active at very low levels (around 0.01–0.1%) in multi-ingredient essences, toners, creams, and rinse-off cleansers where it functions mainly as a supportive conditioning component. Higher-strength consumer products marketed around “ferments” (leave-on essences/serums and some sheet mask essences) commonly place it in the ~1–3% range, with a practical top end around ~5% in OTC leave-on formulas due to odor/color, stability, and preservative/bioburden constraints typical of ferment-derived materials.

Saccharomyces Cerevisiae Extract

MVP Approved - Saccharomyces Cerevisiae Extract (Yeast Extract) is a fermented yeast derivative used primarily for its hydrating, anti-aging, and soothing (irritation‐reducing) properties, with a very low potential for skin irritation.

Saccharomyces/Copper Ferment

Saccharomyces/copper ferment is used as a skin-conditioning/antioxidant ingredient delivering bioavailable copper at low levels, typically in leave-on formulas. While ferments are often well-tolerated, they can trigger stinging or dermatitis in reactive or eczema-prone skin, and trace metal content (copper) plus residual fermentation byproducts can increase irritancy compared with inert humectants. Given the potential for reactivity in compromised barriers and the variability inherent to ferment-derived materials, I score it as mild rather than gentle. Safety Notes: In mass-market leave-on serums, moisturizers, and eye products, Saccharomyces/Copper Ferment is most often used as a trace-level bio-ferment/skin-conditioning active around ~0.05–0.5%, frequently alongside other ferments and humectants. Consumer-available ‘copper’ recovery/anti-aging serums and ampoules sometimes push the supplier-recommended use levels into the low single digits, with the highest-strength OTC products observed around ~3–5% when the ferment is a primary marketing active and the formula is designed to manage odor/color and metal-ion compatibility (generally leave-on; rinse-off cleansers typically sit at the low end due to short contact time).

Saccharomyces Ferment Filtrate

Saccharomyces Ferment Filtrate is a yeast-derived ferment used mainly as a humectant/skin-conditioning “postbiotic” at low-to-moderate concentrations and is generally well tolerated in clinical use. However, ferment extracts can contain a complex mixture of bioactive components and trace impurities that occasionally trigger stinging, flushing, or eczema flares in highly reactive patients, and rare allergy to yeast-related constituents is possible. Given this low but real risk in compromised barriers, I rate it as gentle rather than very gentle. Safety Notes: In commercial skincare, Saccharomyces Ferment Filtrate is commonly used as a minor “ferment/yeast extract” component in emulsions and cleansers, with low-end usage around 0.1–1% to support marketing claims and mild conditioning. Many leave-on essences/serums use mid-range levels (often several percent to a few tens of percent) when the ferment is a primary featured ingredient. The highest consumer-available strengths are ferment-first watery essences/ampoules where the filtrate can serve as a large portion of the base (commonly 50–80% depending on supplier-grade solids and dilution), while rinse-off products typically sit toward the lower end due to cost and wash-off exposure.

Saccharomyces Ferment Lysate Filtrate

Saccharomyces Ferment Lysate Filtrate is a yeast-derived ferment used primarily for barrier support and soothing/hydration, typically at low percentages (often ~0.5–5%) in leave-on products. Clinical experience and patch-testing data generally show low irritation potential, but as a bio-ferment mixture it can occasionally provoke stinging or reactions in highly reactive or eczema-prone patients due to residual metabolites/impurities. In real-world routines (often layered with acids/retinoids), I score it as gentle rather than very gentle to reflect that small but meaningful risk in compromised skin. Safety Notes: In commercial skincare, Saccharomyces Ferment Lysate Filtrate is commonly used as a bio-ferment/skin-conditioning active at low supportive levels (~0.1–1%) in moisturizers, toners, and cleansers (rinse-off formulas often sit toward the low end due to wash-off and cost). Higher-strength consumer-available essences/ampoules and “ferment-focused” serums are frequently positioned with ferment filtrates/lysates as major formula components, and market examples support levels in the ~5–20% range when supplied as diluted trade ingredients intended for direct addition. Above ~20% is uncommon in OTC because many supplier materials are aqueous blends with formulation constraints (preservation, odor/color, and stability), and products typically achieve higher impact by combining multiple ferments rather than pushing a single filtrate higher.

Saccharomyces/Iron Ferment

Saccharomyces/iron ferment is typically used at low levels as a skin-conditioning/antioxidant or “energizing” ferment, but it contains a complex mixture of bioactive metabolites and trace metals that can be unpredictable in highly reactive skin. While most users tolerate ferments well, clinical experience and patch-testing trends show a meaningful minority of sensitive/eczema-prone patients experience stinging, flushing, or dermatitis from yeast-ferment derivatives (and metal-associated reactivity), especially when the barrier is compromised. Given the variability between batches and the higher-risk population focus, I rate it as mild with occasional sensitivity possible. Safety Notes: In commercial skincare, Saccharomyces/Iron Ferment is typically used as a trace-level bioferment/skin-conditioning component in complex blends, where it can appear around 0.001–0.1% (especially in leave-on serums/creams and occasionally in rinse-off cleansers at very low levels). High-strength consumer products that spotlight “ferments” (leave-on essences/ampoules) can include multi-percent use levels of a ferment filtrate/ferment complex, with observed top-end use around ~5% when the ingredient is supplied as a cosmetic-grade ferment material rather than a 100% active. There is no specific FDA/EU maximum concentration limit for this INCI; practical limits are driven by odor/color, potential metal-related reactivity, and overall formula stability/compatibility.

Saccharomyces Lysate

Saccharomyces lysate is a yeast-derived ferment/lysate used in low concentrations as a skin-conditioning, barrier-supporting, humectant-like ingredient, and it is generally well-tolerated in clinical and consumer use. However, because it contains a complex mixture of yeast cell components, it has a small but real risk of irritation or allergy in highly reactive/atopic individuals compared with truly inert excipients. Scoring it as gentle (0.3) reflects its typically low irritancy while acknowledging sensitization potential in compromised eczema-prone skin. Safety Notes: In commercial skincare, Saccharomyces Lysate (a yeast-ferment/lysate skin-conditioning ingredient) is often used at low supportive levels around 0.05–0.5% in mass-market moisturizers, cleansers, and toners where it functions as part of a broader “ferment” complex. Most leave-on serums/essences that feature ferments more prominently tend to fall ~1–5% active lysate (or lysate equivalent), while high-strength consumer “ferment/biome” concentrates and ampoules can reach about 10% where odor, color, and stability/compatibility constraints become limiting. There is no specific FDA/EU maximum limit for this INCI; practical formulation and sensory constraints typically set the upper bound, and both rinse-off and leave-on products use it with higher levels more common in leave-on concentrates.

Saccharomyces/Magnesium Ferment

Saccharomyces/Magnesium Ferment is a bioferment used mainly as a skin-conditioning/humectant and mineral-delivery component, typically present at low percentages in leave-on products and generally considered well-tolerated. However, ferment-derived mixtures can contain residual proteins/organic acids and variable byproducts that occasionally trigger stinging or flare reactions in highly reactive or eczematous skin, so it is not truly “inert.” Given the overall low but non-zero irritation risk in sensitive populations and routine layering with other actives, a gentle-but-cautious score is appropriate. Safety Notes: In commercial skincare, Saccharomyces/Magnesium Ferment is typically supplied as a dilute ferment filtrate or solution and is most often used at low inclusion levels (~0.05–0.5%) in leave-on serums/creams and some rinse-off cleansers where it functions as a skin-conditioning/mineral/ferment-derived bioactive. Higher-strength consumer products (mainly leave-on essences/ampoules marketed around “ferments/minerals”) can reach ~2–5% active addition, with levels above this uncommon due to raw material solids load, odor/color, and stability/sensory constraints; there is no specific EU/FDA maximum, so the practical upper limit is formulation-driven.

Saccharomyces/Manganese Ferment

Saccharomyces/Manganese Ferment is a yeast-ferment trace mineral complex used at low levels mainly for antioxidant/skin-conditioning benefits, and ferments are generally well-tolerated in most leave-on products. However, fermented extracts can contain biologically active byproducts and residual proteins that occasionally trigger stinging or dermatitis in highly reactive or eczema-prone skin, so I do not consider it “very gentle” across compromised barriers. In real-world routines it is typically a low contributor to irritation, but patch testing is prudent for patients with severe sensitivities. Safety Notes: In commercial skincare, Saccharomyces/Manganese Ferment is typically supplied as a dilute aqueous/glycerin ferment filtrate and is most often used at very low levels in leave-on serums/creams (trace levels around 0.0005–0.05%) as an antioxidant/skin-conditioning support. More prominent “ferment complex” positioning in consumer-available essences and ampoule-style products commonly places it around ~0.1–1%. High-strength consumer products that center on ferments (while still OTC) can reach ~2–5% of the ferment ingredient as-supplied, with higher use levels mainly limited by odor/color, tackiness, and overall formula stability rather than specific regulatory concentration caps.

Saccharomyces/Potassium Ferment

Saccharomyces/potassium ferment is a yeast-derived ferment filtrate used as a conditioning/humectant component, typically at low percentages, but ferments contain complex mixtures (proteins/peptides, organic acids, residual cell components) that can trigger stinging or dermatitis in reactive or eczema-prone skin. Clinical experience and patch-test literature on yeast/ferment derivatives show they are usually tolerated yet not reliably "inert," with occasional irritation or sensitization reported. Given the unpredictability of ferment byproducts and heightened risk in compromised barriers, I rate it as mild rather than gentle for patient safety. Safety Notes: In commercial skincare, Saccharomyces/Potassium Ferment is most often used as a bio-ferment/conditioning active at low levels (~0.1–1%) in leave-on toners, essences, serums, and moisturizers, where it functions as part of a broader fermented-complex. Higher-strength consumer-available products (primarily leave-on ampoules/essences marketed around “ferments” or “probiotic/biome” benefits) can reach ~5–10% when the ingredient is supplied as a standardized ferment filtrate and the formula is built around it; above this, odor, color, and stability/preservative loading typically become limiting in OTC formats. Rinse-off cleansers commonly sit toward the low end due to short contact time and cost/compatibility considerations.

Saccharomyces/Xylinum/Black Tea Ferment

Saccharomyces/Xylinum/Black Tea Ferment (kombucha ferment) is primarily used as an antioxidant/humectant “ferment filtrate” at low percentages, and it is generally well-tolerated in the broader population. However, ferments are complex mixtures that can contain organic acids and bioactive byproducts that occasionally trigger stinging or flare-ups in highly reactive or eczematous skin, especially when the finished formula’s pH is on the lower side or combined with other actives. Given the non-zero risk of irritant reactions in compromised skin despite its “gentle” marketing, a mild irritancy score is most consistent with patient-safety caution. Safety Notes: In commercial leave-on skincare (essences, serums, creams), this kombucha-type ferment is commonly used as a supplier active or bioferment at low inclusion for skin-conditioning and antioxidant positioning, with market-observed use starting around 0.05–0.1% as a label-claim supporting ingredient. Most mainstream products cluster in the ~0.5–3% range, while high-strength consumer-available “ferment/essence” formulas and brand hero ferments can reach about 5–10% when the ferment is the primary featured active and odor/stability are managed. Use in rinse-off products is typically at the low end because benefits are primarily marketed for leave-on contact time.

Salicin

Salicin (a willow bark–derived beta-hydroxy-like precursor) is used as a keratolytic/anti-inflammatory exfoliating active, typically around ~0.1–2%, and can increase stinging and dryness in compromised barriers similarly to other exfoliants. Clinical and consumer experience show it is generally milder than salicylic acid but still capable of provoking irritation in eczema-prone or highly reactive skin, especially when layered with retinoids, acids, or benzoyl peroxide. Given its active, exfoliation-adjacent behavior and real-world cumulative irritation risk, a moderate score with patch testing is the safest assessment. Safety Notes: In commercial skincare, salicin (the defined beta-glucoside salicyl alcohol, distinct from generic “willow bark extract”) is typically used at very low levels (~0.01–0.2%) in gentle toners, essences, and daily moisturizers where it supports mild exfoliation/soothing without appreciable irritation. Higher-strength consumer leave-on acne/exfoliating serums and targeted treatments are commonly formulated around ~0.5–1.0% salicin, with a small number of specialty OTC products reaching about 2.0% as an upper end due to solubility, sensory/irritation limits, and the fact that many brands switch to salicylic acid for higher keratolytic strength. Rinse-off cleansers generally sit toward the lower half of the range because of short contact time, while the highest levels are observed in leave-on formats.

Salicornia Herbacea Extract

Salicornia herbacea (glasswort/sea asparagus) extract is typically used at low concentrations as a humectant/soothing, barrier-supporting botanical (often noted for osmolytes/minerals) rather than as a strong active. Clinical irritation and patch-test signals are generally low for this type of non-fragrant plant extract, but as a botanical mixture it still carries a non-zero risk of irritation or allergy in highly reactive/eczema-prone patients, especially in compromised skin or when layered with other actives. Safety Notes: In commercial moisturizers/serums, Salicornia Herbacea Extract is commonly used as a marketing-supporting osmoprotective/hydration botanical at very low levels (often ~0.01–0.1%), especially when supplied as a diluted glycerin/water extract. Higher-strength consumer leave-on formulas (hydrating concentrates, barrier creams, ampoules) occasionally use the extract at ~1–3%, and I have observed up to ~5% in niche “high-botanical-load” products; rinse-off formats tend to sit at the lower end due to short contact time and cost. No specific EU/FDA maximum is set for this botanical extract, so the practical upper bound is driven by supplier form, stability/sensory limits, and irritation risk.

Salicylic Acid

MVP Approved - Salicylic acid (BHA) is widely used for its exfoliating, pore-clearing, and sebum-regulating properties, making it a go-to ingredient for acne-prone and oily skin.

Salicyloyl Phytosphingosine

Salicyloyl phytosphingosine is a lipid/ceramide-like derivative used at low levels to support barrier function while providing mild keratolytic/anti-acne activity from the salicyloyl moiety. While generally better tolerated than free salicylic acid due to its lipophilic, larger structure and lower effective acid exposure, the salicylate component can still provoke stinging or eczema flares in highly reactive skin, especially when layered with other actives. Given the potential for occasional sensitivity in compromised skin despite typically low concentrations, a mild irritancy score is warranted. Safety Notes: In commercial skincare, salicyloyl phytosphingosine is typically used as a low-dose ceramide/skin-barrier active and anti-blemish support ingredient, most often in leave-on moisturizers/serums at trace to very low levels (~0.0005–0.05%), frequently within multi-component ceramide complexes. Higher-strength consumer products (usually leave-on acne/texture serums or targeted treatments) have been observed up to ~0.5%, with practical upper limits driven by cost, solubility/dispersion constraints, and irritation risk; rinse-off formats generally sit toward the lower end due to short contact time.

Salix Alba Bark Extract

Salix Alba (willow) bark extract is used for keratolytic/anti-inflammatory effects via salicylate-related constituents, and in leave-on products it can function as a mild exfoliating active depending on extraction and concentration. Clinical and real-world reports show it can sting or irritate compromised skin (eczema, barrier damage) and can trigger reactions in salicylate-sensitive individuals, especially when combined with other exfoliants or retinoids. Given variable standardization and nontrivial risk in sensitive populations, it merits a moderate irritancy score with patch testing recommended. Safety Notes: In commercial products, Salix Alba (Willow) Bark Extract is often used as a supporting botanical at very low levels (~0.01–0.1%) in cleansers, toners, and multi-extract blends where it functions mainly as a soothing/marketing extract. Mid-range leave-on acne/clarifying products commonly use ~0.5–3% depending on extract strength/standardization, while the highest consumer-available “willow bark”/BHA-alternative serums and targeted treatments can reach ~5–10% of the extract (especially when standardized and positioned as a primary active). There is no specific EU/FDA maximum for the extract itself; practical limits are driven by supplier recommended use levels, salicylate content, odor/color, and irritation risk, with higher levels more typical in leave-on targeted products than in rinse-off.

Salix Alba Bark Powder

Salix Alba (willow) bark powder is used as a botanical exfoliant/soothing agent and a natural source of salicylates; real-world use levels vary, but when formulated for exfoliation its salicylate content can contribute to stinging and barrier disruption similar in direction (though typically weaker and less standardized) than salicylic acid. Clinical and patch-test experience with botanical extracts/powders shows a meaningful rate of irritation and occasional allergic contact dermatitis in eczema-prone and highly reactive skin, and the variability of raw plant material increases unpredictability. Given sensitive-skin safety and the potential for cumulative irritation when combined with other actives, a patch test is warranted. Safety Notes: In commercial products, Salix Alba (Willow) Bark Powder is most often used at very low levels (~0.01–0.5%) in leave-on toners/serums and lotions where it functions as a botanical exfoliating/soothing support ingredient rather than a primary active. Higher levels (1–10%) are observed in consumer-available “powdered” masks, scrub/exfoliant powders, and some bar/cleansing formats where insoluble botanical powders are used for marketing/storytelling and mild physical exfoliation; these higher loadings are more typical for rinse-off or short-contact products due to sensory, stability, and potential irritation considerations. There is no specific EU/FDA maximum for this botanical powder, so the upper end is constrained mainly by product aesthetics, safety testing, and irritation risk rather than a hard regulatory cap.

Salix Alba Extract

Salix alba (willow) extract is typically used for soothing/anti-inflammatory claims and sometimes as a mild keratolytic due to salicylate/polyphenol content, usually at low concentrations (<1–2%). While generally well tolerated, botanical extracts have meaningful rates of irritation and occasional allergic contact dermatitis in reactive or eczema-prone patients, and salicylate-containing extracts can sting on compromised skin. In real-world routines that also include acids/retinoids, it can add to cumulative irritation risk, warranting a mild (not “gentle”) score for safety. Safety Notes: In commercial skincare, Salix Alba (willow) extract is often used as a minor soothing/“natural salicylate” supporting ingredient in leave-on lotions, toners, and cleansers at ~0.01–0.5%, where it mainly serves marketing/skin-feel claims rather than being the primary active. Higher-strength consumer products marketed for oily/acne-prone skin (serums, toners, peel-like pads) commonly use ~1–5% of the extract, and a small number of “high potency” botanical formulas and masks reach about 10% extract (typically as a standardized glycerin/propylene glycol extract), still OTC and distinct from regulated salicylic acid drug-acne concentrations.

Salix Nigra Bark Extract

Salix Nigra (black willow) bark extract is commonly used as a “natural salicylic” exfoliating/anti-acne active; depending on standardization it can deliver salicylates and other phenolics at leave-on concentrations that meaningfully increase stinging and barrier disruption risk. Patch-test and clinical experience show botanical extracts can provoke irritant reactions and occasional allergy, and salicylate-containing extracts are more problematic in eczema-prone or compromised skin and when layered with other exfoliants/retinoids. Given its active-like keratolytic intent, variable composition, and higher risk in sensitive populations, it warrants careful introduction. Safety Notes: In mass-market and prestige cleansers/toners/lotions, Salix Nigra (willow) bark extract is frequently used as a low-level botanical supporting ingredient around 0.01–0.5% (often within multi-extract blends), especially in leave-on products where the extract is not the primary active. Higher-strength OTC “natural BHA/clarifying” serums, masks, and spot treatments marketed around willow bark can reach ~1–5% extract, with a small number of consumer-available formulas listing willow bark extract at very high levels up to about 10% (typically depending on supplier standardization and solvent system). There is no specific EU/FDA maximum for this botanical itself; practical limits are driven by extract composition, salicylate content/claims positioning, color/odor, and irritation risk, with rinse-off products generally tolerating the upper end more readily than leave-on.

Salvia Hispanica Seed Oil

Salvia Hispanica (chia) seed oil is an emollient lipid typically used at a few percent up to higher levels in moisturizers, and it is generally well-tolerated with low inherent irritancy because it is not pH-dependent or an exfoliating/keratolytic active. Clinically, irritation is uncommon but not impossible—plant-derived oils can trigger stinging or contact dermatitis in a reactive/eczema population, and highly unsaturated oils may be less tolerated on severely compromised barriers—so I rate it as gentle rather than exceptionally gentle. Safety Notes: In commercial products, Salvia Hispanica (Chia) Seed Oil is often used as a minor emollient/marketing lipid in emulsions and cleansers at ~0.05–0.5%, with many leave-on moisturizers and serums commonly formulating it around 1–10% as part of the oil phase. High-strength consumer products include facial oils/balms and “100% chia seed oil” single-ingredient oils sold at retail, which represent the practical maximum (near/at 100% for anhydrous leave-on formats), while rinse-off products generally sit at the low end due to deposition and cost considerations.

Salvia Officinalis Extract

Salvia officinalis (sage) extract is used as a botanical antioxidant/astringent in low concentrations, but it contains multiple aromatic/phenolic constituents that can be irritant and has documented potential for allergic contact dermatitis in sensitized individuals. In eczema-prone or barrier-impaired skin, even rinse-off/leave-on products with botanical extracts can contribute to cumulative irritation, especially when layered with other actives. Given real-world variability in extract composition and the non-trivial sensitization risk, a moderate score is most appropriate for patient safety. Safety Notes: In mass-market leave-on skincare (creams/serums/toners) Salvia officinalis (sage) extract is frequently used as a minor botanical supporting ingredient at very low levels (~0.0005–0.05%), often as part of multi-extract blends or to support fragrance/antioxidant/soothing claims. Typical stand-alone positioning in consumer products lands around ~0.1–1%, while high-strength consumer-available formulations (e.g., botanical-focused serums, scalp tonics, and some rinse-off cleansers/shampoos designed around herbal actives) can reach ~2–5% extract depending on extract type and supplier standardization. There is no specific EU/FDA cosmetic maximum for the extract itself, but practical upper limits are usually driven by odor/color, tannin/polyphenol load, and irritation/sensitization risk in leave-on products.

Salvia Sclarea Oil

MVP Approved - Salvia Sclarea Oil (Clary Sage Oil) is primarily used as a fragrance and aromatherapeutic ingredient in skincare formulations, though its essential oil nature may lead to mild irritation if not properly diluted.

Sambucus Canadensis Extract

Sambucus canadensis (elderberry) extract is a botanical antioxidant/soothing claim ingredient typically used at low concentrations, but like many plant extracts it contains a complex mixture of phenolics and other constituents that can trigger stinging or dermatitis in reactive or eczema-prone skin. Clinical patch-test data for this specific extract is limited, so safety assessments rely on the broader pattern that botanicals show occasional irritancy/allergy despite “gentle” marketing. Given the uncertainty and the meaningful risk of idiosyncratic reactions in highly sensitive patients, I rate it as mild rather than inherently gentle. Safety Notes: In mass-market lotions, toners, cleansers, and shampoos, Sambucus canadensis (elderberry) extract is typically used as a minor botanical supporting ingredient at ~0.001–0.1% active extract (often supplied as a dilute glycerin/propylene glycol or water-based extract, so the as-supplied addition may be higher). In more botanical-forward leave-on serums/masks and “superfruit antioxidant” products sold OTC, concentrated extracts are sometimes used around ~1–3%, with occasional high-strength formulas reaching ~5% when stability/odor/color and skin tolerance allow. No specific global maximum is set for this INCI in EU/FDA cosmetics, so practical formulation constraints largely define the observed upper end.

Sambucus Nigra Flower Extract

Sambucus nigra (elderflower) extract is a botanical soothing/antioxidant additive typically used at low concentrations, but like many plant extracts it contains multiple bioactive compounds that can trigger irritant or allergic contact dermatitis in reactive or eczema-prone skin. Clinical patch-test experience with botanicals shows a non-trivial subset of sensitized individuals react despite “gentle” marketing, and cumulative exposure in multi-extract formulas increases risk. Given patient-safety priorities for highly sensitive populations, this warrants a mild irritancy score rather than being treated as universally gentle. Safety Notes: In mass-market leave-on creams/lotions/cleansers, Sambucus Nigra (Elderflower) Extract is commonly used as a minor botanical supporting ingredient at ~0.01–0.5%, reflecting typical supplier-recommended use levels for water/glycerin-based extracts and the fact it is often listed mid-to-late INCI. Higher-strength consumer-available “botanical concentrate” serums, toner/essence style products, and mask-type formulations can reach ~1–5% when the extract is a primary positioning ingredient (especially in hydroglycolic extracts), while concentrations above this are uncommon due to formula stability/sensory constraints and diminishing formulation benefit. No specific FDA/EU maximum is set for this INCI, so the observed range is largely driven by supplier guidance, stability, and product aesthetics rather than regulatory caps.

Sapindus Mukorossi Peel Extract

Sapindus mukorossi (soapnut) peel extract is rich in saponins and is primarily used as a natural surfactant/cleansing agent, which can disrupt barrier lipids similarly to other detergents at functional use levels. Clinical experience and patch-test literature with saponin-containing botanicals show a meaningful risk of irritant dermatitis, especially on eczema-prone or compromised skin and in leave-on exposure. Given its detergent-like mechanism and the higher vulnerability of sensitive-skin populations, it warrants a careful-introduction score. Safety Notes: In mass-market leave-on skincare (serums, toners, lotions) Sapindus mukorossi (soapnut) peel extract is typically used as a secondary botanical/surfactant-supporting extract at very low levels (about 0.01–0.5%), largely for label/marketing and mild cleansing/conditioning claims. In rinse-off cleansers and “natural”/concentrated liquid soap or shampoo-type products marketed to consumers, higher loads are seen when it functions as a primary saponin source, with some high-strength products using roughly 3–10% extract (or equivalent solids) to deliver noticeable foaming/cleansing; above this, sensorial/irritation and solubility/stability constraints usually limit use in OTC cosmetics.

Saponaria Officinalis Extract

Saponaria officinalis (soapwort) extract is used primarily as a natural surfactant/foaming agent due to its saponin content, which can disrupt stratum corneum lipids and increase stinging/dryness even at modest concentrations in cleansers or “gentle” formulas. Botanical extracts also carry variable composition and a measurable risk of irritant reactions in eczema-prone or barrier-compromised patients, especially with repeated exposure in multi-step routines. Given its detergent-like activity and higher risk in sensitive-skin populations, a moderate score is warranted and patch testing is prudent. Safety Notes: Saponaria Officinalis Extract (soapwort) is typically used as a mild botanical surfactant/foaming and cleansing-support extract, so it often appears at trace to low levels (~0.0005–0.1%) in leave-on toners/creams and as a label-claim botanical in complex blends. In rinse-off cleansers/shampoos/body washes, usage more commonly falls around ~0.1–2%, with the highest consumer-available “botanical/heritage soapwort” cleansing products and concentrated natural cleansers reaching ~3–5% when the extract is a primary functional component. No specific EU/FDA concentration limit applies, so the upper end is mainly constrained by irritation potential, odor/color, and formula stability/clarity.

Sarcosine

Sarcosine (N-methylglycine) is a small amino-acid derivative used in cosmetics mainly for sebum control and as a mild conditioning/humectant component, typically at low percentages. Available safety/patch-test experience suggests it is generally well tolerated and not a common irritant or sensitizer at typical leave-on levels, but any bioactive sebum-regulating ingredient can sting or provoke dryness in highly reactive or barrier-impaired skin when layered with other actives. To protect eczema-prone patients while staying consistent with clinical tolerability, I score it as very gentle rather than inert. Safety Notes: In commercial consumer skincare, sarcosine is most often used as a sebum-regulating/amino-acid active in leave-on products (serums, moisturizers, acne/oil-control treatments), where low-end usage is commonly around 0.05–0.2% as a supportive ingredient in multi-active formulas. Higher-strength consumer-available targeted oil-control/blemish formulations and some concentrated serum formats reach ~1–3%, with 3% representing the upper end seen in OTC retail products before sensory/stability constraints and diminishing returns typically limit further increases; rinse-off cleansers generally sit toward the low end due to short contact time.