Dr. Scholl's Severe Cracked Heel Repair Restoring Balm

What the evidence says

The cited CIR safety review concludes that propylene glycol is generally nontoxic, noncarcinogenic, and does not cause dermal sensitization at the concentrations used in cosmetics, but it notes that irritation concerns remained. The panel's conclusion of safety was conditional on formulations being nonirritating, meaning irritation potential at certain concentrations or on compromised skin is acknowledged but not fully quantified in this abstract. No dose-response data, population specifics, or irritation thresholds are given in the available text.

Context

Used in both rinse-off and leave-on products across a wide concentration range; irritation risk, where it exists, rises with concentration and is more relevant to leave-on use on sensitive or broken skin.

What the evidence says

We haven’t found a source for this one that you can open and check, so we’re not summarizing the evidence.

Look it up yourself — starting points, not our findings: PubChem · PubMed

Context

Present in nearly all rinse-off and leave-on products; its listing high on an ingredient list simply reflects that it makes up most of the product's weight, not a formulation choice worth scrutinizing.

What the evidence says

The CIR safety panel reviewed urea used in cosmetics at concentrations of 0.01% to 10% and concluded it is safe as used, based on absorption, toxicity, genotoxicity, reproductive, and carcinogenicity data. Some irritation was reported in a few studies at higher concentrations (20% and above) and burning sensations were noted mainly in treatment of already-diseased skin rather than typical cosmetic use, but the panel found no genotoxic or carcinogenic concern at use levels. The report also notes urea can increase skin penetration of other applied chemicals, which formulators are advised to consider.

Context

Effect and irritation potential are dose-dependent: a 2-5% concentration in a daily lotion behaves very differently from a 20-40% concentration in a targeted foot cream or callus treatment. Leave-on use is the relevant context here since urea's job is ongoing hydration or exfoliation.

What the evidence says

The CIR safety panel reviewed Sodium Stearate as used in cosmetics and concluded it is safe in current practices of use and concentration when formulated to be non-irritating and non-sensitizing. Animal and human skin tests found Sodium Stearate to be non-irritating or only mildly so at use concentrations (100% in rabbits; low-concentration aqueous solutions and a 7% stick deodorant showed minimal to moderate erythema in a minority of subjects, described as low potential for irritation). Dermal absorption through rat and human skin was noted, but no systemic toxicity, genotoxicity, or carcinogenicity concerns specific to Sodium Stearate were reported at cosmetic exposure levels.

Context

Found in both rinse-off products like bar soaps and leave-on creams and lotions, where its role is purely structural rather than active.

What the evidence says

One of the most studied humectants in cosmetics. CIR has reviewed it as safe for use in cosmetic products. Occasional reports of mild irritation or a sticky feel exist at high concentrations, but no established safety concern at typical use levels.

Context

Works in both rinse-off and leave-on products. At very high concentrations in low-humidity conditions it can theoretically pull water out of skin rather than in, but this is not how it behaves at the levels used in commercial formulas.

What the evidence says

The CIR safety panel found glyceryl laurate safe as used in cosmetics, noting it is generally not irritating at concentrations found in cosmetic products. Moderate erythema was seen in repeat-insult patch tests only at concentrations higher than those used in cosmetics, and the panel's overall safety finding covers glyceryl laurate specifically (excluding only glyceryl arachidonate). The report also notes strong hemolytic activity in an in vitro sheep erythrocyte assay, a laboratory finding not tied to a specific topical-use risk.

Context

Used in both rinse-off and leave-on formulas, generally at low concentrations as a co-emulsifier or texture aid rather than a primary active.

What the evidence says

The CIR safety assessment reports Magnesium Aluminum Silicate was a weak primary skin irritant in rabbits with no cumulative irritation in guinea pigs, caused only minimal eye irritation in a Draize test, showed no teratogenic or adverse fetal effects in mice, and produced no adverse effects when applied topically to human skin daily for one week. Inhalation toxicity and pneumoconiosis findings in the same document relate to occupational dust exposure during mining and processing, not to cosmetic use. Based on these cosmetic-relevant findings, the CIR Expert Panel concluded the ingredient is safe as used in cosmetic formulations.

Context

Used at low percentages, mainly in rinse-off and leave-on lotions and masks. It is not absorbed through skin in any meaningful way and is considered inert from a toxicological standpoint at cosmetic levels.

What the evidence says

The Cosmetic Ingredient Review panel has assessed cetyl alcohol as safe for use in cosmetics. It is a very low-level irritant and only rarely causes contact allergy, mostly in people with already-compromised skin who are exposed to many products.

Context

Used in both rinse-off and leave-on products at concentrations typically well under 10%. Its safety profile does not meaningfully change with exposure route because it is not readily absorbed and is not reactive on skin.

What the evidence says

The SCCS and CIR consider phenoxyethanol safe at concentrations up to 1 percent, the limit set in the EU and widely followed elsewhere. Concerns raised in some consumer discourse about infant exposure stemmed from a 2008 French health agency caution for products used on the diaper area of infants; subsequent reviews, including by the SCCS, reaffirmed the 1 percent limit as safe across ages.

Context

The 1 percent concentration cap is the key context: safety assessments are tied to that limit, and it applies in both rinse-off and leave-on products.

What the evidence says

Cosmetic safety panels (CIR, 2001 and 2023) concluded peppermint oil is safe in cosmetics at current use concentrations (up to 3% rinse-off, 0.2% leave-on) provided products are formulated to be non-sensitizing, and animal studies found it was not a sensitizer at 8% in a maximization protocol. However, a large patch-test registry study found a 0.6% allergic reaction rate among 28,128 patients tested with 2% peppermint oil, with reactions most often linked to oral hygiene products, lip products, and foods, and nearly a third of reactions rated strong or extreme. This indicates a real but low-frequency contact sensitization risk at normal cosmetic exposure, rather than a settled absence of concern.

Context

Effects are concentration dependent: trace amounts for scent in a rinse-off shampoo pose little concern, while higher concentrations in a leave-on lip or skin product are more likely to cause tingling, redness, or irritation in sensitive users. Not generally recommended for use near the eyes or on infants.

What the evidence says

The CIR Expert Panel's safety assessment concluded that available test data were sufficient to support the safety of allantoin and its related complexes at the concentrations used in cosmetics, with allantoin itself used up to 2% in over 1,300 products. The abstract does not describe specific adverse findings or mechanisms of concern. It notes data gaps for two minor allantoin complexes (galacturonic acid and polygalacturonic acid), but these do not apply to allantoin itself.

Context

Used across rinse-off and leave-on products alike, generally at low concentrations (0.1–2%) where its main role is calming rather than active treatment.

What the evidence says

A large North American patch-test study found that ethylhexylglycerin caused allergic patch-test reactions in only 0.25% of tested patients, a rate the authors describe as similar to other low-allergenic preservatives like parabens and phenoxyethanol. When reactions did occur, they were most often linked to personal care products such as moisturizers, lotions, and creams, and were judged clinically relevant in about 80% of positive cases. This is a single retrospective patch-test dataset without dose-response or long-term outcome data, and it indicates a rare but real contact-allergy potential rather than a common or well-established risk.

Context

Used in both rinse-off and leave-on products, almost always at concentrations under 1%, paired with a primary preservative rather than replacing one.

What the evidence says

Lavender oil is a recognized contact allergen for a subset of users, particularly as it ages and oxidizes, and the SCCS has flagged fragrance allergens including its component linalool for labeling requirements. It is not considered broadly hazardous at cosmetic concentrations, but sensitization risk is real and dose-dependent.

Context

Relevant mainly in leave-on products, where prolonged skin contact increases the chance of sensitization in susceptible individuals; rinse-off exposure is lower risk. Fresh, well-stored oil carries lower allergenic potential than oxidized oil.

What the evidence says

The Cosmetic Ingredient Review Expert Panel assessed magnesium sulfate used as a bulking agent at concentrations up to 11% in leave-on and 25% in rinse-off products and concluded it is safe in current cosmetic use. Supporting data cited include a negative mouse skin irritation study and a negative in vitro sensitization assay at 50% concentration, plus clinical patch-test experience showing no sensitization potential from magnesium salts. The assessment is a single expert panel review of available data rather than new large-scale human trials, but it directly addresses the concentrations and exposure route (leave-on and rinse-off cosmetic use) relevant to consumers.

Context

Used in both rinse-off and leave-on products, typically at modest concentrations where it functions as a texture modifier rather than an active ingredient.

What the evidence says

A small study applied cocoa butter under occlusive patches to the upper back of 6 participants and used reflectance confocal microscopy to count microcomedones, finding a statistically significant increase in microcomedone number and diameter compared to untreated skin over 2-4 weeks. This is a surrogate marker (microcomedone counts) rather than a clinical acne outcome, the sample size is very small, and patch occlusion is not representative of typical leave-on cosmetic use. Two larger randomized trials testing cocoa butter lotion/cream for stretch mark prevention in pregnant women did not report any adverse skin effects, but they were not designed to assess comedogenicity.

Context

Used mainly in leave-on products like balms, body butters, and lip products, where its richness is the whole point. Concentration is typically high since it is often a primary base ingredient rather than a minor additive.

What the evidence says

The CIR safety assessment reviewed animal and human data on Tocopheryl Acetate at the concentrations used in cosmetics (up to 36% in formulations) and found it was generally not irritating or sensitizing to skin, with reproductive and developmental toxicity tests negative, and clinical studies showed it was not an irritant or sensitizer. One animal test did show sensitization and one photocarcinogenesis study showed non-dose-related enhancement, but the panel concluded the overall data supported safety as used in cosmetic formulations. The assessment is a 2002 industry-sponsored ingredient review rather than independent long-term human outcome data.

Context

Common in leave-on products such as moisturizers and serums, typically at low percentages where it functions mainly as a preservative for the oils rather than a treatment ingredient.