Skincare Ingredients

Hexyl Laurate

Hexyl laurate is a fatty acid ester used primarily as an emollient and slip agent, typically at low-to-moderate concentrations in moisturizers and makeup where it is not pH-dependent or intrinsically reactive. In patch testing and clinical use, simple emollient esters like this are generally low irritants, with reactions more often related to individual intolerance or occlusion/acne rather than true irritant dermatitis. For severely compromised barrier skin (e.g., active eczema flares), I still assign a small nonzero risk, but overall it is very gentle for most sensitive users. Safety Notes: Hexyl laurate is used primarily as a lightweight emollient/skin-conditioning ester and slip agent, showing up at low levels (~0.1–1%) in leave-on serums/lotions and as part of fragrance or sensorial optimization in both leave-on and rinse-off formats. In commercial anhydrous oils, balm-to-oil cleansers, and high-slip body products, it is often used as a major emollient phase component, commonly in the 5–20% range, with observed consumer-available high-emollient systems reaching ~25% when the ester is a key carrier. There are no specific EU/FDA concentration caps for hexyl laurate in cosmetics, so the practical upper end is driven by sensorial goals, solvency, and compatibility with other oils/waxes rather than regulation.

Hexylresorcinol

Hexylresorcinol is a phenolic skin-brightening active (tyrosinase inhibitor) typically used around ~0.1–1% in leave-on products, where it can be effective but is not universally “non-irritating.” Clinical and post-market data suggest generally good tolerability, yet mild irritation (stinging/erythema) can occur in reactive or barrier-impaired skin due to its phenolic structure and active mechanism. Given real-world cumulative use with other actives (retinoids/acids) and higher-risk eczema populations, a mild irritancy score is the safer, clinically aligned call. Safety Notes: In commercial OTC skincare, hexylresorcinol is most commonly used as a leave-on brightening/spot-correcting active, with low-end inclusion around 0.05–0.1% in multi-active serums and moisturizers where it plays a supporting role. Higher-strength consumer products (typically targeted dark-spot serums and treatment creams) are commonly formulated at ~0.5% and can reach about 1.0% in specialized OTC formulations; above this level is uncommon due to solubility, sensory limits, and irritation risk. Rinse-off products generally sit toward the low end because of limited contact time, while leave-on treatments account for the upper end of the observed market range.

Himanthalia Elongata Extract

Himanthalia elongata (seaweed) extract is primarily used as a humectant/skin-conditioning and antioxidant ingredient, typically at low concentrations, and is generally well tolerated in standard patch-test experience. However, botanical/marine extracts contain complex polysaccharides, proteins, and trace iodinated/phenolic compounds that can trigger irritation or occasional allergic reactions in highly reactive or eczema-prone skin, especially in leave-on products. Given the variability in extract composition and the higher-risk sensitive-skin population, I rate it as mild rather than inherently gentle. Safety Notes: Himanthalia elongata (sea spaghetti) extract is most often used as a minor supporting marine/soothing antioxidant in leave-on creams/serums and rinse-off cleansers, commonly appearing near the end of the INCI list at ~0.0005–0.1% when supplied as a diluted glycerin/propylene glycol/water extract. Higher-strength consumer “marine/algae” masks, body creams, and concentrated ampoules using standardized or more concentrated extract solutions can reach ~1–5% active extract in the finished product; above this is uncommon in OTC due to cost, odor/color, and stability/sensory constraints. No specific EU/FDA maximum is set for this botanical extract beyond general cosmetic safety requirements, so the practical upper bound is market- and supplier-driven.

Hippophae Rhamnoides Fruit Extract

Hippophae rhamnoides (sea buckthorn) fruit extract is primarily used as an antioxidant/emollient botanical at low percentages, but as a complex plant extract it contains multiple bioactive compounds (including carotenoids and fatty acid fractions) that can trigger stinging or dermatitis in reactive or eczema-prone skin. Clinical experience and patch-testing patterns with botanicals show occasional irritant or allergic responses despite “natural” positioning, especially when barrier function is compromised or when combined with other actives. Given the non-zero but generally infrequent reaction rate at typical leave-on use levels, I rate it as mild rather than gentle for high-sensitivity populations. Safety Notes: In mass-market leave-on moisturizers, toners, and cleansers, Hippophae Rhamnoides (sea buckthorn) fruit extract is commonly used as a minor botanical at ~0.01–0.5% (often as part of a broader plant-extract blend), with rinse-off products frequently sitting at the very low end. Higher-strength consumer serums and facial oils marketed around “sea buckthorn” can reach several percent, and concentrated extract-based systems (especially glycerin/propylene glycol extracts or standardized extracts) are observed up to ~10% in OTC leave-on formulations, while true 100% sea buckthorn oil is a different INCI and not counted under this extract.

Histidine

MVP Approved - Histidine is a naturally occurring amino acid used in skincare for its hydrating and soothing properties, offering mild anti-aging support while being well-tolerated by most skin types.

Homosalate

Homosalate is an organic UVB filter typically used around 5–15% in sunscreens; at these leave-on concentrations it is generally well tolerated but can sting or cause irritant dermatitis in reactive or eczematous skin, especially on compromised barriers. Clinical patch-test data show low rates of true allergy, yet irritation and eye-area stinging are reported in real-world use, so I rate it as mild rather than gentle for highly sensitive populations. Safety Notes: In consumer sunscreen products, homosalate is commonly used as an organic UVB filter at low supporting levels (~0.1–1%) in multi-filter formulas and as a primary filter in the mid-to-high single digits. The highest concentrations observed in over-the-counter, general-public leave-on sunscreens in the US reach 10%, consistent with FDA OTC monograph limits; EU cosmetics rules no longer permit homosalate in sunscreen products, so current EU-market products are effectively 0%. Rinse-off products rarely use it, and when present it is typically at trace/low levels for incidental UV protection claims rather than primary SPF contribution.

Honey

Honey is primarily a humectant/emollient used from low percentages to much higher levels in masks, and while it’s generally well-tolerated, it is a complex natural mixture that can contain pollen/propolis-related impurities and trace proteins capable of triggering irritation or allergic contact reactions in a minority of users. In sensitive or eczematous skin, its sugar-rich, slightly acidic nature and potential contaminants can sting on compromised barriers, so it is not reliably “exceptionally gentle” across high-risk populations. Safety Notes: In mass-market formulations, honey is often used at very low levels (≈0.05–1%) primarily for marketing/label appeal and mild humectancy in cleansers, lotions, and shampoos, with higher functional use commonly in the 1–10% range for leave-on masks and moisturizers. Consumer-available wash-off masks and “honey pack” products frequently use 10–50% honey for sensorial/occlusive benefits, and some OTC products are essentially pure honey (≈95–100%) marketed for skin use (including manuka/raw honey jars used topically). The practical upper end is limited mostly by stickiness, crystallization, microbial management (water activity varies with dilution), and allergen/fragrance considerations rather than specific cosmetic regulatory caps.

Honey Extract

Honey extract is primarily a humectant/soothing marketing ingredient used at low percentages, but it is a complex natural mixture that can contain residual proteins, pollen/bee-derived contaminants, and trace compounds that increase variability between batches. In patch testing and real-world eczema populations, honey and related bee products can trigger irritant reactions or allergic contact dermatitis in a minority of users, especially on compromised skin. Given this sensitization potential despite generally good tolerability, I rate it as mild rather than “gentle” for high-risk patients. Safety Notes: In mass-market leave-on lotions/serums and shampoos/cleansers, honey extract is commonly used as a label-claim botanical at very low levels (~0.05–0.5%), reflecting typical supplier-recommended use rates for aqueous/glycerin-based extracts. Higher-strength consumer products marketed as honey/bee-derived humectant treatments (e.g., masks, sleeping packs, intensive creams) often use multi-percent levels, with the upper end around ~10% for “honey extract” (distinct from pure honey, which can be much higher). Rinse-off formats tend to sit lower than leave-on due to cost, tackiness, and wash-off dilution, while higher levels in leave-on products require tack/odor/color management and robust preservation due to sugar content in many extract types.

Hordeum Vulgare Extract

Hordeum vulgare (barley) extract is primarily a soothing/antioxidant botanical used at low concentrations in leave-on products, and it is generally well-tolerated in patch-test data. However, as a grain-derived plant extract containing multiple proteins and phenolic constituents, it carries a low but real risk of irritation or allergy in highly reactive or atopic individuals, especially with barrier compromise. Given sensitive-skin safety considerations and the variability of botanical extracts between suppliers, I rate it as gentle but not inert. Safety Notes: In mass-market leave-on creams/lotions and many rinse-off cleansers, Hordeum Vulgare (barley) extract is commonly used as a minor soothing/antioxidant botanical at very low levels (often around 0.001–0.1%), consistent with typical supplier-recommended use rates for plant extracts and its frequent placement low on INCI lists. Higher-end “botanical concentrate” serums, masks, and ampoules marketed around barley/seed extracts can push into the low single-digits, with observed consumer-available products reaching ~1–5% depending on extract form (e.g., glycerin/propylene glycol/water extracts vs powders). Levels above ~5% are uncommon in OTC skincare because botanical extract actives are usually delivered in diluted carrier solutions and higher loadings can create stability/odor/color and preservative-demand constraints.

Houttuynia Cordata Extract

Houttuynia cordata extract is typically used at low-to-moderate levels (often ~0.1–5%) as a soothing/anti-inflammatory botanical, and most users tolerate it well in leave-on products. However, as a complex plant extract containing multiple bioactive compounds, it carries a non-trivial risk of irritant or allergic contact dermatitis in highly reactive or eczema-prone patients, especially with frequent, multi-product exposure. For safety in sensitive populations, I rate it as gentle but not “very gentle” because botanicals are a common source of unpredictable reactions despite a calming marketing profile. Safety Notes: In commercial skincare, Houttuynia cordata extract is often used at very low levels (~0.01–0.1%) as a secondary soothing/antioxidant botanical in emulsions and cleansers, consistent with typical supplier use-level guidance for standardized extracts. Many K-beauty toners/serums list it as a featured calming ingredient and commonly land in the ~1–5% range, while consumer-available “single-ingredient/one-thing” essences, ampoules, and concentrated watery extracts frequently reach ~10–20% (with higher percentages generally being diluted extract solutions rather than pure dry extract). Leave-on products tend to sit higher than rinse-off due to contact time, but both forms exist across the low end of the range.

Hoya Lacunosa Flower Extract

Hoya Lacunosa Flower Extract is a botanical extract used mainly for marketing/sensory and potential antioxidant/soothing claims, typically at low concentrations, but it is not a standardized, well-characterized therapeutic active. Like many plant extracts, it contains complex mixtures of small molecules that can trigger irritant or allergic contact dermatitis in reactive or eczema-prone skin, and reliable human patch-test data are limited. Given the uncertainty and the higher baseline risk of botanicals in sensitized populations, I rate it as mild with occasional sensitivity possible. Safety Notes: Hoya Lacunosa Flower Extract is a niche botanical typically supplied as a diluted glycerin/propylene glycol/butylene glycol extract and is most often used at trace-to-low levels for marketing/skin-conditioning in leave-on products (serums, essences, creams), with some formulas listing it below 0.01% consistent with late-INCI placement. In consumer products positioned as “extract-forward” or single-hero botanical (often in watery toners/essences or lightweight serums), inclusion can reach around 0.5–2.0% active extract (as supplied), above which sensorial impact, odor/color, and preservation burden typically limit use; rinse-off products generally sit at the low end due to limited benefit from higher loading. No specific FDA/EU maximum is set for this botanical extract, so practical formulation constraints and market practice drive the observed upper bound.

Humulus Lupulus Extract

Humulus lupulus (hops) extract is typically used at low levels as a botanical antioxidant/soothing agent, but it contains resinous bitter acids and polyphenols that can act as irritants or allergens in reactive skin. Patch-test and case-report literature describes occasional allergic contact dermatitis to hops (including cross-reactivity with other Cannabaceae/plant allergens), making sensitivity possible even at modest concentrations. Given the variability of botanical extracts and higher risk in eczema-prone patients, I rate it as mild rather than gentle. Safety Notes: In mass-market leave-on skincare (creams/lotions/serums/toners) Humulus lupulus (hops) extract is commonly used as a supporting botanical at very low levels (~0.001–0.1%), often within multi-extract blends where it contributes soothing/antioxidant positioning. Higher concentrations are observed in consumer-available “botanical active” products (ampoules/serums, aftershaves, scalp tonics) and some natural/deodorant-style formulas where hops extract can be used for its deodorizing/antimicrobial marketing, reaching ~1–5% depending on extract type (e.g., glycerin/propylene glycol extracts) and sensorial constraints. There are no specific FDA/EU maximum limits for hops extract itself in cosmetics; practical upper limits are usually set by extract solvent system, odor/color, and irritation potential, with rinse-off formats typically tolerating the upper end more easily than leave-on.

Hyaluronic Acid

MVP Approved - Hyaluronic Acid is a hydrating humectant widely used in skincare to boost moisture and improve the appearance of fine lines, with excellent skin tolerance and minimal irritation potential.

Hydrated Silica

Hydrated silica is an inorganic absorbent/texture agent and, in oral-care and exfoliating products, commonly functions as an abrasive at a few to double‑digit percent; in leave-on skincare it’s typically lower but still can add friction and dryness. While it is generally low in true chemical irritancy or allergy, clinical experience and patch/usage testing show it can cause stinging or eczema flares in highly reactive or barrier-impaired skin, especially when rubbed (cleansers, scrubs, toothpaste). Given the risk is mechanical/irritation-in-use rather than inertness, I rate it as mild rather than exceptionally gentle. Safety Notes: In real-world consumer products, hydrated silica appears at very low levels (~0.1–1%) as a rheology modifier/soft-focus filler or mild absorbent in leave-on skincare (primers, mattifying lotions) and some cleansers. The highest OTC levels are found in abrasive polishing products—especially toothpastes and some exfoliating scrubs—where hydrated silica commonly functions as the primary abrasive at ~20–40% and can reach ~50–60% in high-abrasivity consumer toothpaste/powder formats. It is far less common to exceed low-single-digit percentages in leave-on skincare due to feel/whitening and stability constraints, whereas rinse-off and oral-care formats support much higher loadings.

Hydrogenated Castor Oil/Sebacic Acid Copolymer

Hydrogenated Castor Oil/Sebacic Acid Copolymer is a high–molecular weight film-forming/emollient polymer used primarily as a texture/viscosity modifier in leave-on products, typically at low percentages, and it is not an acid active at skin pH. Available safety/patch-test data for similar castor-oil–derived polymers and sebacic acid copolymers suggest low irritation potential, with reactions being uncommon and usually related to individual sensitivities rather than inherent irritancy. Given use on compromised skin in some formulations and the need to protect highly reactive eczema patients, I score it as very gentle but not fully inert due to rare idiosyncratic reactions. Safety Notes: In commercial skincare and color cosmetics this polymer is most often used as a structuring/film-forming rheology modifier, where it appears at low levels (~0.1–1%) in emulsions and serums to improve slip and stability. Higher levels (5–15%) are observed in anhydrous sticks, balms, and long-wear film-forming products where it functions as a primary gellant/structurant. The upper end (~20–25%) is seen in high-structure consumer-available balm/stick formats (leave-on), while rinse-off products typically sit at the low end due to cost and limited need for strong film/structure.

Hydrogenated Coco-Glycerides

Hydrogenated coco-glycerides are a waxy emollient/structuring agent (typically a blend of hydrogenated mono/di/triglycerides from coconut) used in leave-on products at a few percent up to higher levels in balms, and they are generally well-tolerated in patch testing with low intrinsic irritancy. In very reactive or eczema-prone skin, lipid blends can still occasionally provoke stinging or contact reactions due to individual sensitivity or formula interactions, so I do not score it as fully inert. Overall, its clinical profile aligns best with a very gentle, low-risk emollient when properly formulated. Safety Notes: In commercial skincare, hydrogenated coco-glycerides is used at low levels (~0.1–1%) as a viscosity builder/structuring wax and emollient in lotions, cleansers, and makeup where it functions as part of the oil-phase structurant system. Mid-range use (~2–15%) is common in richer creams, balm-to-milk cleansers, and anhydrous sticks where it contributes slip, payoff, and solidity. High-strength consumer products such as anhydrous cleansing balms, solid balms, and waxy body butter/stick formats can use it as a primary base/structurant, reaching ~30–50% in OTC products (leave-on and rinse-off), with the practical upper end set by desired hardness/melting behavior rather than specific regulatory limits.

Hydrogenated Didecene

Hydrogenated didecene is a saturated, non-volatile emollient/hydrocarbon used to improve slip and reduce transepidermal water loss, typically at a few percent up to higher levels in anhydrous formulas. As an inert, non-reactive lipid-like ingredient, it has a low rate of irritation in patch testing and is generally well tolerated even in sensitive skin, though very occlusive products can rarely contribute to discomfort or follicular issues in reactive individuals. Safety Notes: Hydrogenated didecene is used as a lightweight emollient/hydrocarbon oil; in many leave-on lotions, creams, and makeup it appears at low levels (~0.1–2%) primarily for slip and sensory optimization, and in rinse-off cleansers it is often around ~0.1–1% as a refatting agent. In consumer-available anhydrous/oil-rich products (lip oils/balms, cleansing oils/balms, barrier ointments, and some facial/body oils), it can be a major base emollient typically 10–30% and observed up to ~40% where it functions as a primary oil-phase component. There is no specific EU/FDA maximum limit for this cosmetic hydrocarbon ingredient; the practical upper bound is driven by product type (anhydrous vs emulsion) and desired viscosity/sensory profile.

Hydrogenated Farnesene

Hydrogenated farnesene is a saturated hydrocarbon emollient (squalane-like) typically used at a few percent up to higher levels as a lightweight skin-feel/occlusive agent, and hydrocarbons of this type are generally low on irritation in patch testing when properly purified. It is not an active, acid, or preservative, and it lacks the volatile/fragrant profile that commonly drives irritation; the main risk is rare intolerance or impurity-related reactions, so it fits a very gentle score for most sensitive-skin routines. Safety Notes: Hydrogenated farnesene (INCI often listed as Hydrogenated Farnesene/Neossance Hemisqualane) is used at low levels (~0.1–1%) as a lightweight emollient/slip agent or to aid pigment wetting and sensorial feel in serums, lotions, and cleansers, where it functions as a minor oil-phase component. In consumer-available leave-on oils, facial oils, and anhydrous balms marketed around “hemisqualane,” it commonly appears at higher levels (5–15%) and can be used up to ~20% as a primary emollient/hydrocarbon replacement while maintaining good spread and volatility; rinse-off formats generally sit toward the lower end due to cost and wash-off.

Hydrogenated Jojoba Oil

Hydrogenated jojoba oil is a saturated wax ester used as an emollient/texture agent, typically at a few percent to higher levels in balms, and it is generally well-tolerated and non-stinging even on compromised skin. However, despite a low irritancy profile in patch testing and broad clinical use, plant-derived lipids can still trigger rare irritant or allergic contact reactions in highly sensitized eczema patients, so it cannot be treated as fully inert. Safety Notes: Hydrogenated jojoba oil (jojoba esters) is commonly used at very low levels (~0.05–0.5%) as a slip/skin-feel modifier or structuring aid in leave-on emulsions and color cosmetics, and similarly low levels can appear in rinse-off cleansers. At the high end, consumer-available anhydrous balms, salves, stick products (lip balms, deodorant sticks), and high-wax barrier ointments can use hydrogenated jojoba oil as a primary structurant/emollient, reaching ~20–60% depending on hardness targets and blend with other waxes/butters. There is no specific EU/FDA maximum for this cosmetic ingredient, so the observed range is driven mainly by sensory and physical stability constraints (viscosity/gel strength) rather than regulation.

Hydrogenated Lecithin

Hydrogenated lecithin is primarily an emollient/barrier-supporting phospholipid used at low-to-moderate concentrations in creams and liposomal systems, and it is generally well tolerated in sensitive and compromised skin. Clinical and patch-test experience suggests a low irritation profile, with reactions being uncommon and usually related to individual contact allergy/sensitization to phospholipids/soy-derived components rather than inherent irritancy. Given the small but real risk in highly reactive eczema patients and leave-on use, I rate it as very gentle rather than inert. Safety Notes: In commercial skincare, hydrogenated lecithin is most often used as a lamellar/emollient co-emulsifier and barrier-supporting lipid at low levels (~0.05–0.3%) in leave-on lotions/serums and sometimes rinse-off cleansers. Higher levels (about 1–3%) are seen in lamellar creams, ceramide/lipid-repair systems, and liposome/encapsulation-style formulas where it provides structure and skin-feel; the upper end (~5%) occurs in consumer-available high-lipid barrier balms/cream concentrates and specialized lamellar bases. It is not specifically restricted by major cosmetics regulations, so the practical maximum is set by stability, viscosity, cost, and sensory limits rather than legal caps.

Hydrogenated Olive Oil

Hydrogenated olive oil is a saturated, waxy emollient/occlusive used to improve texture and reduce transepidermal water loss, typically at low-to-moderate concentrations in creams and balms. As a non-volatile lipid it has low inherent irritancy in patch testing, but in very reactive or eczematous skin it can occasionally contribute to follicular occlusion or barrier “stifling,” and rare olive-derived contact reactions have been reported. Given the overall low irritation potential yet non-zero risk in compromised skin, it fits best as very gentle rather than inert. Safety Notes: In commercial formulas, hydrogenated olive oil is used at very low levels (~0.1–1%) as a structuring/wax-like emollient in lotions, creams, and hair conditioners (both leave-on and rinse-off). Mid-range use (~2–20%) is common in richer balms, body butters, and stick products where it contributes to viscosity, glide, and occlusivity. The highest consumer-available levels (up to ~70–80%) are observed in anhydrous balm/stick formats and “butter” concentrates where it functions as a primary solid emollient/wax phase; there is no specific EU/FDA concentration cap beyond general cosmetic safety requirements.

Hydrogenated Olive Oil Unsaponifiables

Hydrogenated olive oil unsaponifiables are lipid-rich emollient fractions (e.g., squalene/sterols/tocopherols) typically used at low-to-moderate levels to support barrier function and reduce transepidermal water loss. Clinical experience and patch-test data for similar olive-derived unsaponifiable fractions show a low rate of irritant reactions, but rare sensitivity (including in highly reactive eczema skin) can occur due to botanical-origin variability and co-extracted minor components. Given its generally good tolerability yet non-zero risk in compromised barriers, it fits a very gentle score rather than inert. Safety Notes: In commercial skincare, hydrogenated olive oil unsaponifiables are most often used as a minor emollient/barrier-support lipid at very low levels (~0.05–0.5%) in lotions, serums, and cleansers where it supports skin feel and stability without greasiness. Mid-range use (~1–5%) is common in richer leave-on creams and balms, often as part of an “unsaponifiables/phytosterols” lipid complex. High-strength consumer products (overnight balms, barrier creams, and lipid concentrates) can reach about 8–10% before texture/waxiness and solubility constraints typically limit further increases; rinse-off products generally sit at the low end due to deposition and cost considerations.

Hydrogenated Palm Glycerides

Hydrogenated Palm Glycerides are a non-volatile, saturated lipid mixture used as an emollient/structurant in leave-on products, typically at a few percent to higher levels, and are generally well tolerated in patch testing with low inherent irritancy. In highly eczema-prone or follicularly reactive patients, heavy occlusive lipids can occasionally provoke stinging on fissured skin or trigger intolerance via occlusion/heat and barrier disruption in an already inflamed area, so I do not rate it fully inert. Overall, the clinical risk is low and consistent with a "very gentle" score for sensitive-skin use. Safety Notes: Hydrogenated Palm Glycerides is used as a lipid structurant/emollient and can appear at low levels (~0.1–1%) in lotions and facial creams to subtly thicken and improve slip. In anhydrous sticks/balms (lip balms, deodorant sticks, solid moisturizers) and some rich body butters, it is commonly used as part of the main structuring fat phase and can reach ~10–30% in consumer OTC products. Ranges are generally similar for leave-on and rinse-off, but the highest levels are most often observed in anhydrous leave-on formats where it functions like a waxy hardener.

Hydrogenated Palm Oil

Hydrogenated palm oil is a saturated, occlusive emollient/wax used to thicken and reduce transepidermal water loss, typically at low-to-moderate percentages in balms and creams. As a non-volatile lipid with minimal reactive chemistry, it has low inherent irritation in patch testing and is generally well tolerated even in sensitive skin. However, in eczema-prone patients it can occasionally contribute to follicular occlusion or product intolerance (often from the overall formula), so it is not scored as completely inert. Safety Notes: In commercial skincare, hydrogenated palm oil is often used at very low levels (~0.1–2%) as a structuring/waxy emollient in creams, lotions, and cleansers where it supports texture and stability without driving the sensory profile. At the high end, it can be a primary base fat in anhydrous sticks (lip balms, body balm sticks), heavy occlusive balms, and some soap/syndet-adjacent cleansing bars where the total hydrogenated vegetable fat phase can be very high; consumer OTC products using hydrogenated palm oil as a main structural lipid can reach ~50–80%. No specific FDA/EU maximum applies as it is generally permitted as a cosmetic ingredient, with practical limits set by hardness, crystallization behavior, and spreadability rather than regulation.

Hydrogenated Phosphatidylcholine

Hydrogenated phosphatidylcholine is a saturated phospholipid used in low concentrations as a barrier-supporting emollient, liposome/vesicle former, and penetration/texture aid; it is generally well tolerated in sensitive-skin and ophthalmic-type formulations. Clinical and patch-test data suggest a low irritation profile, but as a lipid-derived emulsifier/vehicle it can occasionally provoke stinging or rare contact reactions in highly reactive or compromised eczema skin, especially in leave-on products combined with other actives. Given that non-zero risk exists in severely sensitized populations, it is best classified as very gentle rather than inert. Safety Notes: In mass-market leave-on serums/creams and many emulsions, hydrogenated phosphatidylcholine is often used at very low levels (~0.01–0.1%) as a lamellar emulsion/skin-conditioning lipid or to support dispersion of actives. More “barrier repair,” liposomal/lamellar-structured, and phospholipid-rich concentrates marketed to consumers commonly run ~0.5–3%, with a small number of high-phospholipid OTC booster/ampoule-type products reaching ~5% where the phospholipid system is a primary structuring/encapsulation component. It is less common in rinse-off products and, when present, is typically toward the low end due to cost and rinse-away inefficiency.

Hydrogenated Polydecene

Hydrogenated Polydecene is an inert, highly refined synthetic hydrocarbon emollient used to reduce transepidermal water loss and improve slip, typically in leave-on products at several percent up to higher levels. In clinical use it is generally well-tolerated with a very low rate of irritation or sensitization because it is non-reactive and not a fragrance or preservative. I score it 0.1 (not 0.0) to reflect rare but possible intolerance in severely compromised or eczema-prone skin from occlusion or formulation context rather than intrinsic irritancy. Safety Notes: Hydrogenated polydecene is used at very low levels (~0.1–1%) as a slip/emolliency booster and solvent for lipophilic actives in serums, lotions, and some rinse-off cleansers. In anhydrous leave-on formats (facial oils, oil-serums, balms, hair oils/shine products) it can be a primary emollient/hydrocarbon substitute, commonly 20–70% and in some minimalist single-phase products reaching ~80–90% as the main carrier. It is not subject to a specific EU/FDA maximum for cosmetics, so the upper end is largely driven by sensorial goals, viscosity grade, and compatibility with the rest of the oil phase.

Hydrogenated Polyisobutene

Hydrogenated polyisobutene is a saturated, inert emollient/occlusive (often 1–30%+) used to reduce transepidermal water loss and improve slip, and it is generally non-reactive with a very low rate of irritation in patch testing and clinical use. It is non-volatile, non-acidic, and not a known sensitizer, making it suitable for compromised barriers, though rare individual intolerance or acne/follicular issues can occur. For severe sensitivity and post-procedure skin, I score it as exceptionally gentle rather than completely inert because real-world formulations and individual variability can still produce occasional reactivity. Safety Notes: Hydrogenated polyisobutene is used as an emollient/occlusive and slip agent; in many leave-on lotions, serums, and sunscreens it appears at low supporting levels around 0.1–2% to improve sensory feel and reduce tack. In richer creams, makeup, and hair/skin oils it commonly sits in the ~3–30% range, while in consumer lip oils/glosses, balm sticks, and anhydrous occlusive concentrates it can serve as a primary base oil and reach very high levels (50–90%). It is rarely used at high levels in rinse-off cleansers due to wash-off format and surfactant structure, but there are no specific EU/FDA concentration caps for this ingredient in cosmetics, so maximum levels are primarily determined by aesthetics and viscosity.

Hydrogenated Rapeseed Oil

Hydrogenated rapeseed oil is a saturated, high–molecular weight emollient/structuring lipid typically used at a few percent to improve texture and reduce transepidermal water loss, and it is generally well-tolerated in sensitive-skin moisturizers. True irritant reactions are uncommon, but in eczema-prone or highly reactive patients it can occasionally contribute to barrier occlusion-related discomfort or follicular issues, and rare allergy is possible due to trace impurities. Given these low but non-zero risks, it best fits a very gentle score rather than inert. Safety Notes: In commercial skincare, hydrogenated rapeseed oil is often used at very low levels (~0.1–2%) as a structuring/waxy emollient to adjust texture, viscosity, and payoff in lotions, cleansers, and cream-gel systems (leave-on or rinse-off). At the high end, it appears in consumer-available anhydrous/balm formats (cleansing balms, body balms, lip balms, solid moisturizers) where it can function as a primary or co-primary wax/oil structurant, reaching ~20–60% depending on the hardness/solid-stick target. There is no specific FDA/EU cosmetics concentration cap for this ingredient; practical limits are driven by sensorial properties, melting profile, and product type.

Hydrogenated Rice Bran Oil

Hydrogenated rice bran oil is a saturated/emollient lipid used in leave-on products typically at a few percent up to higher levels to improve barrier feel and occlusion; it is not an active and is generally well-tolerated in patch testing with low intrinsic irritancy. In severely reactive or eczema-prone patients, any occlusive lipid can occasionally sting on fissured skin or contribute to follicular irritation depending on the full formula, but the ingredient itself has a low likelihood of provoking irritation when properly formulated. Safety Notes: In commercial skincare, hydrogenated rice bran oil is most often used as a structuring emollient/consistency agent in O/W and W/O creams/lotions and cleansing balms, where it can appear at low levels (~0.1–1%) to tune slip and viscosity. At higher levels it is found in anhydrous balms, stick moisturizers, body butters, and cleansing balms as a primary lipid/structurant, commonly in the 10–30% range and up to ~40% in some high-occlusive consumer products. There are no specific FDA/EU cosmetic concentration limits for this ingredient; practical maxima are driven by texture, melting point, and application feel, with leave-on anhydrous formats typically reaching the highest use levels.

Hydrogenated Soybean Oil

Hydrogenated soybean oil is a saturated emollient/occlusive used in moisturizers and balms (often a few percent up to higher levels in ointment-like formulas) and is generally well-tolerated with low inherent irritancy. However, soybean-derived materials can rarely trigger allergic contact dermatitis in sensitized individuals, and occlusive oils can occasionally worsen folliculitis/acne in reactive skin, so it is not truly inert. For compromised or highly eczema-prone patients, I rate it as very gentle but not zero-risk. Safety Notes: In commercial skincare, hydrogenated soybean oil is often used at very low levels (~0.05–1%) as a structuring agent/opacifier or co-emollient in lotions, cleansers, and emulsions (leave-on and rinse-off). At the high end, it can function as a primary base/structurant in anhydrous products (lip balms, body butters, cleansing balms, solid sticks) where it can comprise the bulk of the formula, commonly 10–60% and in some minimalist/balm systems reaching ~80–90%. There is no specific EU/FDA concentration cap for this ingredient in cosmetics; practical limits are instead driven by texture, melting point, and compatibility with other waxes/oils.