Skincare Ingredients

Calcite

Calcite (calcium carbonate) is primarily an inert mineral filler/opacifier or mild abrasive, typically used at low-to-moderate percentages in powders, creams, and some cleansers. Clinical experience and patch testing data suggest it has low intrinsic irritancy, but its particulate/abrasive nature can aggravate compromised barriers (eczema, post-procedure) via mechanical irritation, especially with friction. Given sensitive-skin safety priorities, I rate it very gentle but not fully inert. Safety Notes: In commercial skincare, calcite (calcium carbonate mineral) is most often used at trace-to-low levels (~0.01–1%) as a mineral filler/opacifier or to support sensorial/soft-focus effects in leave-on creams and makeup-adjacent skincare. Mid-level use (1–15%) is common in rinse-off cleansers and scrubs where it contributes mild abrasive/polishing and bulking. The highest consumer-available levels are found in high-solids powdered cleansers, polishing masks, and tooth/skin-adjacent paste products where calcite can function as the primary abrasive/bulking phase, reaching ~30–70% depending on format; higher levels are limited by spreadability, grittiness, and suspension stability in conventional emulsions.

Calcium Aluminum Borosilicate

Calcium Aluminum Borosilicate is an inert mineral/synthetic mica-like glass used in cosmetics as a pigment/pearlizing filler, typically present at low-to-moderate percentages in color products and considered non-reactive with minimal skin penetration. Clinical irritation potential is generally low, but fine particulate minerals can cause mild mechanical irritation or dryness on compromised barriers (e.g., eczema, post-procedure) and may irritate periocular skin in some users, so I do not score it as fully inert for highly sensitive populations. Safety Notes: Calcium Aluminum Borosilicate is used as an effect pigment/extender (often in pearlescent/mica-like composites) and appears at trace-to-low levels (~0.01–0.5%) in skincare where it’s included mainly for subtle optical blur or glow (e.g., primers, tinted moisturizers, illuminating lotions, some sunscreens). In high-impact consumer color cosmetics that are still OTC (highlighters, shimmer powders, eye shadows, luminous pressed/loose powders), it can be a major component of the powder phase and is commonly seen in the 5–25% band, with some effect-pigment–heavy formulas reaching ~30–35%. Rinse-off products rarely use it, and when they do (shimmer body washes/soaps) it is typically kept low for suspension and rinse-off aesthetics.

Calcium Ascorbate

Calcium ascorbate is a buffered, less acidic vitamin C salt typically used in leave-on products at low-to-moderate concentrations, and it is generally better tolerated than L-ascorbic acid because it does not require a very low pH to function. Clinical and real-world use suggest a low but real risk of stinging/irritant dermatitis in highly reactive or barrier-impaired skin, especially when layered with other actives or on eczematous areas. Given this modest irritation potential despite its “gentler” profile, it fits best as a gentle ingredient with minimal risk rather than exceptionally gentle. Safety Notes: In commercial skincare, calcium ascorbate (a vitamin C derivative/salt) is most often used at low levels (about 0.05–1%) as an antioxidant/label-claim vitamin C source in emulsions, toners, and some cleansers where it may also support formula stability. Higher-strength OTC leave-on “vitamin C” serums and powders marketed as gentler alternatives to L-ascorbic acid have been observed up to ~5–10% calcium ascorbate, with the practical upper end limited by solubility, ionic interactions (electrolyte load), pH buffering, and potential grittiness/instability in water-rich systems. There is no specific EU/FDA maximum for calcium ascorbate in cosmetics, so the market range is driven primarily by formulation feasibility and product positioning rather than a hard regulatory cap.

Calcium Carbonate

Calcium carbonate is primarily a mineral abrasive/bulking agent used in products like toothpastes, powders, and some cleansers; it is generally non-sensitizing but can be physically irritating when particles are coarse or used with friction on compromised skin. Clinically, irritation is typically mechanical (dryness, micro-abrasion, stinging on eczematous or barrier-impaired areas) rather than allergic, so while many tolerate it well, reactive or broken skin can flare—warranting a mild score for safety. Safety Notes: In commercial skincare, calcium carbonate appears at very low levels (~0.1–1%) mainly as an opacifier/whitener, rheology modifier, or mild buffering/absorbent in creams and cleansers. The highest consumer-available levels are found in rinse-off dentifrices (toothpastes) and some exfoliating/cleansing powders where it functions as the primary abrasive/filler, commonly ~20–50% and observed up to ~60% in high-abrasive whitening formulations. It is uncommon in leave-on facial products above a few percent due to sensory/whitening and particulate residue, so the upper end of the range is largely driven by rinse-off oral care and wash-off exfoliant formats.

Calcium Chloride

Calcium chloride is a highly water-soluble inorganic salt used mainly as a viscosity/texture modifier or electrolyte, typically at low concentrations in cosmetics, where it is usually tolerated. However, as an osmotic, ionically active compound it can sting on compromised skin (eczema, fissures, post-procedure) and can cause mild irritant reactions in patch/irritation testing at higher exposures, so it is not truly “inert” for sensitive populations. Given the need to err on patient safety, I rate it as mild with occasional sensitivity possible in reactive individuals. Safety Notes: In consumer skincare, calcium chloride is most often used at very low levels (around 0.01–0.3%) as an electrolyte/viscosity modifier in surfactant-based cleansers and some masks, where small additions materially change rheology and foam. Higher consumer-available uses are seen in rinse-off products (cleansers, scrubs, mask washes) and occasional specialty exfoliating/“detox” masks where salts are used at percent levels, with practical upper bounds around 3–5% due to irritation potential, tackiness, and destabilization risks in leave-on emulsions. Leave-on products rarely exceed ~1% in practice, while the highest strengths are predominantly rinse-off.

Calcium Gluconate

Calcium gluconate is primarily a skin-conditioning/humectant salt used at low concentrations in cosmetics and is generally well tolerated, with low rates of irritation in leave-on products. However, as an ionic salt it can cause mild stinging or dryness in very compromised barriers (e.g., active eczema or post-procedure skin), so it is not completely inert. Given sensitive-skin safety considerations and occasional reactivity in barrier-impaired patients, it fits best as very gentle rather than inert. Safety Notes: In commercial skincare, calcium gluconate most often appears as a low-level skin-conditioning/buffering mineral salt in leave-on creams/lotions and some cleansers, commonly at trace to sub‑0.5% levels (with the lowest observed around ~0.01% in multi-ingredient formulas). Higher-strength consumer-available products (e.g., mineral/“calcium” serums, barrier-support concentrates, and some body creams) can use it in the ~1–5% range, with ~5% representing the upper end typically seen before solubility/ionic strength and sensory constraints become limiting. It is used in both leave-on and rinse-off products, but the highest levels are more often in leave-on emulsions/serums where the marketing claim is mineral replenishment/barrier support.

Calcium Pantothenate

Calcium pantothenate (a stable salt form of vitamin B5) is primarily used as a skin-conditioning/humectant support ingredient, typically at low concentrations, and has a strong track record of good tolerability in patch testing and clinical use. True irritation or allergy is uncommon, but in highly reactive or eczematous skin any leave-on ingredient can occasionally sting on compromised barrier, so it is not fully inert. Considering its generally low reactivity yet non-zero potential on broken skin, it fits a very gentle (0.2) score. Safety Notes: In commercial skincare, calcium pantothenate (a salt form of vitamin B5) is most often used at very low levels as a supportive skin-conditioning/claim ingredient in multi-component creams, lotions, toners, and cleansers, with observed inclusions down around 0.0005–0.01% in broad-ingredient-list formulas. Leave-on products commonly sit in the ~0.05–0.5% band, while higher-strength OTC “B5/panthenate” serums, barrier creams, and scalp/anti-hair-fall type leave-ons can reach about 1–2% before solubility/salt load and sensory constraints typically limit further increases; rinse-off formats are usually at the low end due to short contact time. No specific EU/FDA cosmetic maximum applies, so the upper end is driven mainly by stability/solubility and product aesthetics rather than regulation.

Calcium PCA

Calcium PCA is a skin-conditioning humectant (a PCA salt, related to natural moisturizing factors) typically used at low percentages in moisturizers and serums, where it is generally well tolerated. Clinical experience and patch-testing data for PCA salts suggest a low inherent irritation potential, though any electrolyte/humectant can occasionally sting on severely compromised or fissured eczema skin. Given rare but plausible stinging in highly reactive patients while remaining broadly safe, it fits best as very gentle rather than inert. Safety Notes: In commercial skincare, Calcium PCA (a mineral salt of pyrrolidone carboxylic acid) is most often used as a minor component of NMF/mineral complexes in leave-on moisturizers, serums, and toners, where it commonly appears around 0.01–0.1% at the low end (often as part of multi-PCA/mineral blends). Higher-strength consumer products marketed for barrier support, sebum-balancing, or acne-prone skin may use roughly 0.5–3% in leave-on emulsions/gel creams; above this, formulators more commonly switch to sodium PCA or reduce levels due to solubility/ionic-strength and sensory constraints. Rinse-off products typically sit at the lower end because contact time is short and salts can affect surfactant viscosity and feel.

Calcium Sodium Borosilicate

Calcium Sodium Borosilicate is an inert glass/mineral used mainly as a cosmetic filler or shimmer pigment (often a few percent in makeup), and it is generally not chemically reactive on skin. However, as a particulate it can cause mild mechanical irritation or micro-abrasion in highly reactive or compromised skin (especially around eyes or on eczematous areas), so it is not scored as fully inert for patient-safety reasons. Safety Notes: Calcium sodium borosilicate is used primarily as a pearlescent/brightening filler (often as micronized glass or as part of composite “powder” blends) in color cosmetics and some leave-on skincare; at the low end it appears as a trace opacifier/soft-focus additive in serums, primers, and lotions around ~0.01–0.5%. The highest consumer-available levels are seen in high-payoff illuminators, highlighters, shimmery body products, and some pressed/loose powders where borosilicate glass can be a major component of the powder phase, commonly ~5–20% and occasionally up to ~25% in shimmer-heavy products. It is uncommon in rinse-off products except at low levels for optical effect, since high loads provide little benefit and can feel gritty.

Calendula Officinalis Flower Extract

Calendula officinalis flower extract is used mainly as a soothing/anti-inflammatory botanical at low concentrations, but it is a plant extract containing multiple potential sensitizing compounds. Clinical experience and patch-test literature document allergic contact dermatitis in a subset of users (notably those with Asteraceae/ragweed sensitivity), so while many tolerate it, reactive or eczematous skin can flare. Given this non-trivial sensitization risk despite its “gentle” marketing, I rate it as mild irritancy potential. Safety Notes: In mass-market leave-on creams/lotions, toners, and rinse-off cleansers, calendula extract is frequently used as a secondary soothing botanical at very low levels (often ~0.001–0.1%), especially when supplied as a dilute glycerin/propylene glycol extract. In more botanical-forward OTC products (calendula gels, barrier creams, baby/soothing balms, and “high botanical content” serums), finished-product levels commonly run ~0.5–2% with some formulations reaching ~3–5% when the supplier extract is standardized and used as a key claim ingredient. There is no specific EU/FDA maximum for the extract itself in cosmetics; practical upper use is typically limited by odor/color, solubility, and potential sensitization risk, with higher levels more common in leave-on than rinse-off products.

Calendula Officinalis Flower Oil

Calendula flower oil is primarily used as a soothing/emollient botanical, but as an oil-based plant extract it contains multiple bioactive constituents (including terpene/resin fractions) that can act as irritants or allergens, especially in leave-on products. Patch-test and clinical reports document allergic contact dermatitis and cross-reactivity in Asteraceae/Compositae-sensitive individuals, and these reactions can be severe in eczema-prone skin even at low typical use levels. Because sensitization risk is meaningful and hard to predict without history, I score it as a notable irritant requiring careful introduction and patch testing. Safety Notes: In mass-market and sensitive-skin products, calendula flower oil is often used as a minor soothing/fragrance-supporting lipid at trace-to-low levels (typically around 0.001–0.1%), especially in leave-on creams/lotions and baby-style barrier products where potential sensitization from botanicals is managed by keeping levels low. In natural/organic balms, facial oils, and anhydrous salves marketed around calendula, the oil can be a primary functional emollient and is observed up to ~5% in OTC consumer products (higher levels are more commonly achieved by using calendula-infused carrier oils rather than pure essential-type material). Rinse-off formats (cleansers/body wash) generally sit at the low end due to cost and limited deposition, while leave-on oils/balms account for the upper end.

Calluna Vulgaris Flower Extract

Calluna Vulgaris (heather) flower extract is typically used at low concentrations as a botanical antioxidant/soothing agent, but plant extracts contain multiple bioactive compounds (e.g., polyphenols) that can trigger stinging or contact dermatitis in reactive or eczema-prone skin. While not a high-risk irritant like acids or surfactants, the variability of botanical extracts and documented potential for sensitization in fragranced/plant-derived ingredients warrants a mild score for patient safety. Safety Notes: In commercial skincare, Calluna vulgaris (heather) flower extract is most often used as a minor botanical additive in multi-extract blends for leave-on creams/serums and rinse-off cleansers at ~0.0005–0.05% (as supplied), where it functions mainly for marketing/antioxidant-support claims. Higher concentrations are found in consumer-available “botanical concentrate” serums, masks, and soothing creams where the extract (typically glycerin/propylene glycol or water-based, non-standardized) is used at ~1–5% to support antioxidant/anti-redness positioning. There is no specific EU/FDA concentration limit for this plant extract; practical upper use is constrained by odor/color, tack/solvent load, and stability/compatibility rather than regulation, and rinse-off products typically sit toward the lower end of the range.

Calophyllum Inophyllum Seed Oil

Calophyllum Inophyllum Seed Oil (tamanu oil) is an emollient lipid typically used around ~1–10% (sometimes higher) for barrier support and soothing claims. Despite being a carrier oil, it contains a complex mixture of bioactive constituents that have documented potential for contact allergy/irritant reactions in susceptible users, and flare risk is higher in eczema-prone skin where barrier impairment amplifies responses. In routine leave-on use, most tolerate it, but the sensitization/irritation signal is significant enough to classify it as mild rather than gentle for highly reactive patients. Safety Notes: In commercial skincare, Calophyllum Inophyllum Seed Oil (tamanu oil) is used at very low levels (~0.05–0.2%) as a supportive lipid/marketing oil in emulsions, serums, and lotions where it’s one of many botanical oils. More commonly it appears around 0.5–10% in leave-on moisturizers, barrier creams, balms, and facial oils to deliver emolliency and a characteristic sensorial profile. The upper end reaches 100% in consumer-available single-ingredient “pure tamanu oil” products and near-neat anhydrous blends marketed as treatment oils (typically leave-on); rinse-off cleansers/soaps may include it but generally at lower percentages due to cost and wash-off.

Calycophyllum Spruceanum Bark Extract

Calycophyllum spruceanum (capirona) bark extract is a botanical antioxidant/soothing-type extract typically used at low percentages, but published human irritation/sensitization data are limited compared with well-characterized dermatologic actives. Because bark extracts can contain variable polyphenols/alkaloid-like constituents and are more prone to batch-to-batch variability, they can trigger stinging or dermatitis in highly reactive or eczematous skin despite being marketed as “gentle.” Given the uncertainty and the higher-risk population (compromised barrier), a mild irritancy score is most consistent with cautious patient safety. Safety Notes: Calycophyllum spruceanum bark extract (commonly marketed as “Dragon’s Blood”/Sangre de Grado–type antioxidant/soothing extract) is most often used at very low levels in multi-ingredient serums/creams where the INCI is supported by a diluted commercial extract, with finished-product use levels commonly down around 0.0005–0.05% for leave-on products. Higher-strength OTC “Dragon’s Blood” booster serums and targeted calming/anti-redness concentrates have been observed using roughly 0.5–3% finished-product addition to achieve a strong marketing/claims position, with rinse-off formats typically clustering toward the lower end due to short contact time and cost.

Camelina Sativa Seed Oil

Camelina sativa seed oil is an emollient lipid used at moderate-to-high levels in moisturizers to reduce transepidermal water loss; as a non-volatile, non-fragrant fixed oil it is generally well-tolerated and not intrinsically irritating. Clinical experience and patch-test data for similar seed oils suggest low rates of irritation, but eczema-prone patients can still react to botanical trace components or oxidation byproducts in poorly stabilized oils. Given real-world variability in refinement and stability, I rate it very gentle but not fully inert. Safety Notes: In commercial skincare it appears at very low levels (~0.1–0.5%) as a supporting emollient in complex creams/lotions where multiple plant oils are used, and commonly around 1–10% in moisturizers, facial oils-in-water emulsions, and barrier-repair products. High-strength consumer products include anhydrous facial/body oils and balms where camelina is the primary oil phase (typically 30–80%), and single-ingredient/“100% camelina seed oil” products sold OTC reach 100%. It is primarily a leave-on emollient; rinse-off cleansers usually keep it low (often ≤1–5%) due to surfactant system constraints and sensorial considerations.

Camellia Japonica Flower Extract

Camellia japonica flower extract is a botanical antioxidant/soothing additive typically used at low concentrations, but plant extracts contain complex mixtures (including polyphenols and trace fragrance-like constituents) that can provoke irritant or allergic contact dermatitis in reactive and eczematous patients. While most users tolerate it, clinical patch-testing experience with botanicals supports a non-trivial sensitization risk compared with inert humectants/emollients, so I rate it as mild rather than “gentle” for compromised skin. Safety Notes: In mass-market leave-on products (toners/lotions/serums) Camellia japonica flower extract is often used as a label-claim botanical at very low levels (down to ~0.0001–0.01%) when supplied as a preserved, glycerin/butanediol-diluted extract and positioned among many other botanicals. More performance-oriented or “single-hero” botanical formulas (especially K-beauty/J-beauty essences, ampoules, and some masks) commonly use ~0.5–2%, with observed high-strength OTC products reaching ~5% when the extract is standardized/diluted and the base can tolerate the added solvent load; rinse-off products generally sit toward the lower half of the range due to cost and limited contact time.

Camellia Japonica Seed Oil

Camellia Japonica Seed Oil is primarily an emollient/occlusive lipid used at relatively high concentrations in moisturizers and cleansing oils, and it is generally well-tolerated in sensitive-skin populations. Irritation and true allergy are uncommon but can occur (often related to individual plant-oil sensitivities or oxidation byproducts), so it is not scored as inert; overall it fits a very gentle profile for daily use with low but nonzero risk. Safety Notes: In commercial skincare it appears at very low levels (~0.1–1%) as a label-claim emollient in lotions, serums, cleansers, and shampoos/conditioners where the primary oil phase is built from other esters/oils. Mid-range use (~2–20%) is common in facial oils, cleansing oils/balms, and richer creams as a substantive emollient. The upper end includes consumer-sold single-ingredient camellia (tsubaki) seed oil products marketed as 100% oil for face/hair/body; this ingredient is not specifically concentration-limited by major cosmetic regulations, so the practical maximum is neat oil.

Camellia Oleifera Leaf Extract

MVP Approved - Camellia Oleifera Leaf Extract is a gentle, antioxidant-rich ingredient commonly used for anti-aging and soothing benefits in skincare formulations.

Camellia Sinensis Leaf Extract

Camellia sinensis (green tea) leaf extract is primarily an antioxidant/soothing botanical used at low concentrations (often <1–5%) and is generally well-tolerated in clinical use. However, as a complex plant extract containing polyphenols and other constituents, it has a small but real risk of irritation or allergic contact dermatitis in highly reactive or eczema-prone patients, especially in leave-on products and when combined with other actives. Given this nonzero sensitization potential despite overall good tolerability, it fits best as a gentle (not inert) ingredient. Safety Notes: In mass-market cleansers, toners, and emulsions, Camellia sinensis (green tea) leaf extract is often used at very low levels (~0.0005–0.05%) as a label/antioxidant-support botanical, especially when supplied as a dilute liquid extract in glycerin/butanediol. Leave-on serums, essences, and targeted antioxidant products commonly use ~0.1–2%, while high-strength consumer-available “green tea” concentrates and ampoules can reach ~3–5% when formulators use higher-active extracts (often standardized) and manage color/odor and polyphenol stability; rinse-off formats generally sit lower than leave-on due to limited contact time.

Camellia Sinensis Seed Oil

Camellia sinensis (tea) seed oil is a non-volatile emollient lipid typically used at a few percent up to higher levels in moisturizers, and it is generally well-tolerated with low irritancy in clinical and consumer use. However, like other plant oils, it can still trigger irritation or allergy in a small subset of highly reactive or eczema-prone patients (often related to individual sensitization or impurities/oxidation), so it is not considered completely inert. In routine leave-on use it is usually compatible with sensitive skin, but patch testing is prudent in severely compromised barriers. Safety Notes: In mass-market leave-on skincare (creams/lotions/serums), Camellia Sinensis Seed Oil is often used as a minor emollient/skin-feel modifier or as part of a botanical oil blend, with commercial products commonly starting around 0.05–0.5%. Many consumer face oils, balms, and cleansing oils position it as a primary lipid and use it in the ~5–50% range, while single-ingredient cosmetic oils marketed for facial/hair use are sold as 100% Camellia Sinensis Seed Oil. There are no specific EU/FDA cosmetic concentration limits for this non-restricted plant oil; practical upper use is mainly constrained by product format (leave-on vs rinse-off) and sensory/stability considerations.

Camphor

Camphor is a counterirritant/fragrance-like terpene used in topical analgesics and “cooling” products (often ~0.1–3% in cosmetics; higher in OTC rubs), and it commonly causes stinging/burning on compromised skin. Clinical experience and patch testing literature support irritant contact dermatitis risk, with occasional allergic reactions, and it can significantly flare eczema due to sensory nerve activation. Given its high likelihood of irritation in sensitive or barrier-impaired users and frequent inclusion in multi-ingredient rubs, it warrants a high irritancy score. Safety Notes: In mainstream cosmetics and personal care, camphor is most often present at trace levels (~0.01–0.1%) as a fragrance/masking component in creams, lotions, and hair/scalp products, with some anti-blemish or cooling leave-on products commonly around ~0.1–1%. The highest consumer OTC concentrations are seen in topical analgesic/rub products (e.g., camphor/menthol/methyl salicylate rubs) where camphor is typically 3–11% and 11% is a common labeled maximum in widely sold OTC products; higher levels are generally restricted to drugs/professional use and are not typical for cosmetic leave-on skincare due to irritation/sensitization risk.

Cananga Odorata Flower Extract

Cananga odorata (ylang-ylang) flower extract is primarily used for fragrance and contains volatile aromatic constituents (e.g., linalool, benzyl benzoate/benzyl alcohol derivatives, isoeugenol-type components) that are well-documented triggers of irritant and allergic contact dermatitis, especially in eczema-prone skin. Even at typical low use levels in leave-on products, cumulative exposure across routines and oxidation of fragrance components can meaningfully increase sensitization risk. Given its fragrance role and clinically recognized allergen potential, it warrants a significant irritancy score for sensitive and compromised skin. Safety Notes: In mainstream leave-on skincare (creams/serums/toners) and rinse-off products, Cananga Odorata (ylang-ylang) flower extract is most often used as a fragrance/botanical label-claim at very low levels (typically around 0.0001–0.05%), especially when supplied as a dilute extract in a solvent base. Higher-strength consumer-available “botanical” or aromatherapy-leaning leave-on oils/balms and some natural deodorants can reach about 0.5–1.0% extract in the finished product, with the upper end constrained by sensitization/IFRA-aligned allergen considerations even though the extract itself is not a globally fixed-limit ingredient under EU/FDA cosmetics rules.

Candelilla/Jojoba/Rice Bran Polyglyceryl-3 Esters

Candelilla/Jojoba/Rice Bran Polyglyceryl-3 Esters is a plant-derived polyglyceryl ester blend used primarily as an emollient and co-emulsifier/texture agent, typically at low to moderate percentages in leave-on products, and it is not a pH-dependent active. Polyglyceryl esters and waxy lipid esters generally show low irritation and low sensitization rates in patch testing, but lipid-derived blends can still trigger occasional reactivity in highly compromised eczema skin due to barrier disruption and individual allergy profiles. Given the very low inherent irritancy yet non-zero risk in severely reactive populations, it fits best as 'very gentle' rather than inert. Safety Notes: In commercial products this polyglyceryl ester blend is typically used as a lipophilic emulsifier/structuring agent at low levels (~0.1–1%) in lotions/creams and as a co-emulsifier or emollient modifier in leave-on skincare. Higher levels (5–15%) are common in anhydrous balms, cleansing balms, and stick products where it contributes to wax-like structure and slip, and the upper end (~20–25%) is observed in high-structure consumer sticks/balms where it functions as a primary structurant alongside other waxes and butters. No specific EU/FDA concentration limit is set for this ingredient, so the practical maximum is governed by texture, stability, and spreadability rather than regulation.

Cannabis Sativa Seed Oil

Cannabis sativa seed oil is primarily an emollient/occlusive lipid used at moderate-to-high levels in moisturizers and is generally well tolerated, including in barrier-impaired skin, with low rates of irritant reactions in clinical use. However, as a botanical-derived, unsaponified oil rich in polyunsaturated fatty acids, it can rarely trigger irritation or allergic contact dermatitis (often related to oxidation products/impurities), so it is not truly “inert” for highly reactive eczema populations. For patient safety in severe sensitivity, I score it as gentle but not exceptionally gentle. Safety Notes: In commercial skincare, Cannabis Sativa (Hemp) Seed Oil is often used at very low levels (~0.05–0.5%) as a label/marketing lipid or emollient component within complex oil blends, especially in leave-on lotions/serums and some rinse-off cleansers. Mid-range use (1–20%) is common where it functions as a meaningful emollient/skin-conditioning oil in creams, balms, and facial oils. The upper end reaches 100% in consumer-sold single-ingredient hemp seed oil products and near-neat anhydrous body/facial oils (typically leave-on); there is no specific EU/FDA cosmetic concentration cap for the seed oil itself beyond general safety and impurity/THC compliance considerations.

Canola Oil

Canola oil is a triglyceride-rich emollient used at high concentrations (often 5–100%) to reduce dryness and support barrier function, and it is generally well tolerated in leave-on products. However, like other botanical oils it can occasionally provoke irritation or contact allergy in highly reactive or eczema-prone individuals due to minor constituents/oxidation byproducts, so it is not truly inert. In sensitive-skin safety scoring, this places it as very gentle rather than risk-free. Safety Notes: In commercial skincare, canola oil is used at very low levels (~0.05–0.5%) as a minor emollient/skin-feel modifier in emulsions and cleansers, often alongside other triglyceride oils. It also appears at moderate levels (1–20%) in lotions, creams, and cleansing oils/balms, while the upper end reflects consumer-available single-ingredient body oils and DIY-positioned products sold as 100% canola oil (leave-on or rinse-off depending on use). There are no specific EU/FDA cosmetic concentration caps for canola oil; practical limits are driven by sensorial profile, oxidation stability, and intended format.

Caprae Lac

Caprae Lac (goat milk) is used as a skin-conditioning/emollient ingredient and may contain lactose, milk proteins, and naturally occurring organic acids that can be mildly irritating, especially on compromised barriers. While many users tolerate it at typical cosmetic levels, animal-derived milk components can trigger stinging or eczematous flares in reactive or atopic individuals (irritant and, less commonly, allergy-mediated), so I rate it as mild rather than “gentle” for sensitive-skin safety. Safety Notes: Caprae Lac (goat milk) is used in consumer skincare either as a minor “milk extract”/powdered additive at trace-to-low levels (~0.01–1%) in leave-on creams/serums and many rinse-off cleansers, or as a primary marketing-active in goat-milk soaps, masks, and lotions where the milk (fresh, reconstituted powder, or concentrated milk fractions) can be a major phase component. In real-world OTC products, high-strength bar soaps and some lotions commonly reach ~5–20% and a small number of specialty ‘goat milk’ formulations list milk high in the composition, supporting upper-end use around ~30% (higher is uncommon due to odor, microbial load/preservation demand, and stability/processing constraints).

Caprooyl Sphingosine

Caprooyl sphingosine is a ceramide/sphingolipid-derived barrier-supporting ingredient typically used at low concentrations (often around ≤1%) to improve moisturization and barrier function rather than exfoliate or alter pH. Available use-history and patch-testing experience suggest a low rate of irritation, with most reactions being uncommon and more consistent with rare individual intolerance or formula-level factors. Given its lipidic, barrier-repair role but acknowledging that even biomimetic lipids can rarely sting on compromised eczema skin, it best fits a very gentle (0.2) score. Safety Notes: Caprooyl sphingosine is a ceramide/sphingolipid analog typically used at trace levels as part of barrier-repair lipid systems in leave-on moisturizers and serums; in mass-market products it is often present around 0.0005–0.005% as a minor component of a lipid blend. Higher-strength OTC barrier creams and concentrated ceramide complexes can reach ~0.01–0.05% when the ingredient is deliberately dosed for skin-feel and barrier support, with practical limits driven by cost, solubility/processing, and oxidative/stability considerations. Rinse-off products, when used, are generally at the low end due to brief contact time and cost-benefit.

Caprooyl Tetrapeptide-3

Caprooyl Tetrapeptide-3 is a lipopeptide signal peptide used in anti-aging/hair-support products, typically at very low concentrations (often well under 1%) in leave-on formulas, and peptides of this class are generally well tolerated in clinical/consumer use. While irritation is uncommon, the caproyl (fatty-acyl) modification and leave-on exposure mean a small subset of highly reactive or eczema-prone patients can experience stinging or dermatitis, so it is not truly inert. Given the low typical dose but nonzero risk in compromised skin, a gentle (0.3) score best matches patient-safety expectations. Safety Notes: Caprooyl Tetrapeptide-3 is most often used in leave-on anti-aging/firming serums and eye products at very low active levels because it is typically supplied as a diluted solution (often in glycerin/water) and is effective in the ppm-to-low-0.01% range in commercial formulas. In mass-market products the true neat-peptide level commonly lands around ~0.0001–0.01%, while higher-strength consumer “peptide booster”/specialty treatments can reach ~0.05–0.1% neat active when the supplier blend is heavily dosed. Rinse-off use is uncommon and generally sits at the low end due to brief contact time and cost.

Caprylhydroxamic Acid

Caprylhydroxamic acid is a preservative/chelating antimicrobial typically used at low levels (~0.1–0.3%, often paired with glycols), and while generally well tolerated, it has documented potential to sting and trigger irritant reactions in compromised skin. In leave-on products and in eczema-prone or barrier-impaired users, cumulative exposure alongside other preservatives/solvents can increase reactivity, so I rate it as mild rather than “gentle” from a patient-safety perspective. Safety Notes: In commercial cosmetics, caprylhydroxamic acid is most often used as a preservative booster/chelating antimicrobial in leave-on and rinse-off products at ~0.10–0.20%, with the lowest observed levels around 0.05% in formulas that rely on synergistic preservative systems (e.g., glycols, organic acids) and low-water-activity designs. High-strength consumer-available formulations (especially “preservative-free”/alternative preservation systems and some wipes/cleansers) can reach about 0.25–0.30% to achieve broad preservation performance, with practical upper bounds driven by solubility, sensory/irritation risk, and pH-dependent efficacy rather than a specific global maximum limit.

Caprylic Acid

Caprylic acid (octanoic acid) is a medium-chain fatty acid used as an emollient component, pH adjuster, or antimicrobial/solubilizing aid, typically at low percentages, but in leave-on products it can still sting or burn on compromised barriers. Clinically, fatty acids and surfactant-like lipids can be irritant on eczematous or post-procedure skin, and caprylic acid’s acidity and membrane-disruptive antimicrobial behavior increases that risk compared with inert emollients. Given real-world use in multi-ingredient routines and the heightened vulnerability of sensitive-skin populations, a moderate irritancy score is the safer benchmark-aligned assessment. Safety Notes: In commercial skincare, caprylic acid is most often used at very low levels (about 0.05–1%) as an emollient/co-emulsifier, pH-aiding fatty acid, or antimicrobial-supporting component in leave-on creams/lotions and rinse-off cleansers. Higher levels are mainly seen in consumer-available high-strength exfoliating/anti-acne blends and “acid” treatment products where caprylic acid is used as part of an AHA/BHA/FFA acid system or solvent-like fatty acid phase; these can reach roughly 10–20% in leave-on formulations, with rinse-off products typically trending lower due to irritation and sensorial constraints. Caprylic acid is not subject to a specific EU/FDA max concentration limit as a standalone cosmetic ingredient, but practical upper use levels are constrained by skin tolerance, odor, and formulation stability.