Don’t take our word for it. Here’s every fact on this site, with its evidence grade, its caveats, and a link to the source, so you can check us.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
Hidden ingredients / Measured in people or real products
In Belgium, about 1 in 10 topical (skin-applied) pharmaceutical products, wound-healing ointments, NSAID gels, antiseptics, antihemorrhoidals, even corticosteroid-antibiotic creams, listed a fragrance ingredient, sometimes disclosed only as the single word "Perfume".
Strong evidence: 370/3,820 products in a Belgian label survey (2009); a label/composition survey, not chemical analysis; historical product list, not a current market snapshot.
Hidden ingredients / Measured in people or real products
A single undisclosed "Perfume" in one antibiotic-corticosteroid cream (Mycolog/Triadcortyl) caused allergic reactions in 34 patients, more than any other product in a 30-year clinic series, and its 28-ingredient composition was only obtained by directly asking the manufacturer, not from the label.
Strong evidence: Single-clinic case series; one product's undisclosed formula, not a general claim about all perfume-labeled products.
Hidden ingredients / Review of other studies
The glycol-ether solvent propylene glycol methyl ether (PGME), mostly used in industrial coatings and cleaners, is officially listed as a possible 'fragrance ingredient' in cosmetics, and a Swiss survey found it making up 30–50% of one perfume.
Moderate evidence: INCI function listing plus one Swiss product survey (Dentan 2000, cited secondhand); US registry shows only nail-product uses.
Source: CIR 2008, International Journal of Toxicology Industry-funded Link to this fact
Hidden ingredients / Review of other studies
Several hundred different label names can signal fragrance (chemical names, over 50 essential oils by common or Latin name, and synonyms such as aroma, parfum, perfume, and scent), so dermatologists say allergic patients are very unlikely to find fragrance-free products by reading labels alone.
Moderate evidence: Expert opinion.
Hidden ingredients / Self-reported survey
About a third of the personal care products people actually used were not in EWG's Skin Deep database at all, including 39% of perfumes and nearly all intimate-care products, so their hazards could not be rated.
Moderate evidence: Database coverage as of July 2022; EWG has since added products.
Source: Barrett 2025, Journal of Exposure Science & Environmental Epidemiology Link to this fact
Hidden ingredients / Measured in people or real products
Lab tests commissioned by US campaigners found 38 chemicals not listed on the label of at least one of 17 popular perfumes; 10 of them had no toxicity study in PubMed.
Moderate evidence.
Caveats
NGO report (Campaign for Safe Cosmetics and EWG), not peer reviewed; one purchase per product; 'secret' means absent from at least one product's label; detection is not exposure or harm.
Source: Sarantis et al. 2010 (Not So Sexy) Link to this fact
Hidden ingredients / Measured in people or real products
Benzyl alcohol, a fragrance allergen dubbed the "covert fragrance," was found in 32 of 533 US baby and children's personal care products (6%) with no "fragrance," "perfume," or "parfum" wording anywhere on the label.
Moderate evidence: Doesn't establish whether these products are marketed "fragrance-free"; measures label wording, not chemical content verification.
Hidden ingredients / Other evidence
Products labeled 'fragrance free' have been shown to still contain fragrance ingredients, used as preservatives, masking perfumes, or botanicals.
Moderate evidence: Secondary citation of Scheinman's clinical observations, not this review's own new data.
Source: Johansen 2003, Am J Clin Dermatol 4(11):789-798, American Journal of Clinical Dermatology Link to this fact
Hidden ingredients / Other evidence
Even "unscented" or "fragrance-free" products may contain a perfume or essential oil added specifically to mask the unpleasant odor of the product or its other ingredients.
Moderate evidence: General statement in a narrative review, not a count of how many fragrance-free-labeled products actually contain a masking fragrance.
Source: de Groot 2020, Dermatitis 31(1):13-35, Dermatitis® Link to this fact
Hidden ingredients / Review of other studies
In the EU, an entire perfume or fragrance composition can be declared on the ingredient list as the single word 'parfum' or 'aroma', legally hiding every chemical in it except the handful of allergens that must be named separately.
Moderate evidence: Restates the regulation's text; not new data, and the same point is made by other evidence base sources.
Source: Tegengif 2022 Link to this fact
Hidden ingredients / Advocacy group testing
Auditing the printed ingredient lists of 20 popular perfumes sold in Belgium, Denmark, and the Netherlands against 13 official and NGO hazard lists (EDC lists, EU harmonized classifications, the SVHC candidate list, the EU fragrance-allergen list, environmental-persistence lists) turned up 26 problematic substances across the 20 products.
Moderate evidence.
Caveats
Based on declared ingredient lists only, not chemical analysis of the products; every label also carries the undisclosed catch-all 'Parfum', so true chemical content is larger than what was audited.
Source: Tegengif 2022 Link to this fact
Hidden ingredients / Advocacy group testing
Only 2 of the 20 tested perfumes contained no suspected endocrine-disrupting chemical (EDC) on their declared ingredient list; the other 18 contained at least one.
Moderate evidence: Counts declared ingredients only; a perfume could contain additional undisclosed EDCs hidden under 'Parfum'.
Source: Tegengif 2022 Link to this fact
Hidden ingredients / Other evidence
Oak moss absolute, jasmine absolute, tuberose oil, cassie absolute, and wintergreen oil, all perfumery materials, are also US food flavorings; the 2020 industry survey reports only tiny volumes (oak moss 34 kg, cassie 29 kg, jasmine absolute 100 kg, tuberose 0.8 kg a year, wintergreen oil 700 kg), or about 0.08 to 72 millionths of a gram per person per day.
Moderate evidence: Food-use volumes from a voluntary industry survey (corrected by an assumed 80% response); says nothing about fragrance volumes, where these materials are used far more.
Source: Guengerich 2026 (FEMA Expert Panel), Food and Chemical Toxicology Industry-funded Link to this fact
Hidden ingredients / Measured in people or real products
All 17 tested perfumes, colognes, and body sprays contained at least one synthetic musk; Galaxolide was in 15 and was not on any of those 15 labels.
Moderate evidence: Qualitative detection; musk concentrations are not reported; one sample per product.
Source: Sarantis et al. 2010 (Not So Sexy, Canadian edition) Link to this fact
Hidden ingredients / Measured in people or real products
All 17 everyday product perfumes (shampoos, baby bath, lotions, deodorants) contained at least one of the fragrance-mix allergens by GC-MS, about 2.6-2.8 on average; geraniol was in 12 of 17.
Moderate evidence: Single manufacturer's lower-priced perfumes, 1990s Denmark; oak moss not analyzed; concentrations are in the perfume, not the finished product.
Source: Johansen 1997, Contact Dermatitis Link to this fact
Hidden ingredients / Measured in people or real products
In the 17 product perfumes the quantified fragrance-mix allergens ranged from about 0.005% to 1.35% w/v of the perfume, with the highest being amyl cinnamal (1.35%) in a creme rinse perfume and eugenol 0.39% in the same perfume.
Moderate evidence: Concentration in the perfume concentrate, not in the finished product; some entries detected but not quantifiable due to interference.
Source: Johansen 1997, Contact Dermatitis Link to this fact
Hidden ingredients / Other evidence
Limonene, linalool and Lyral are fragrance ingredients commonly found in personal care products, processed foods and beverages, and perfumes, and the society judges them relevant for many patch-tested patients.
Moderate evidence: Committee judgment based on cited reviews; no product-survey data in this paper.
Hidden ingredients / Review of other studies
Galaxolide and Tonalide are used in perfumes, cleaning products, detergents and cosmetics, so they are typically covered by the single word 'fragrance' on a label.
Moderate evidence: Statement is in the paper's introduction and describes use, not what any given label discloses; this study measures no exposure.
Source: Schreurs 2005, Toxicological Sciences Link to this fact
Hidden ingredients / Other evidence
Limonene and beta-pinene scent terpenes were measurable in every perfume, deodorant and cleaning liquid tested (about 0.1-0.3% and 0.04-0.65% of product weight), even though labels only say 'fragrance' or, for the cleaners, name limonene.
Moderate evidence.
Caveats
Six products; GC-MS of three terpenes only, so other scent chemicals are unmeasured; alpha-pinene was below the detection range. The abstract's beta-pinene range (0.4-0.7%) differs from Table 1 (0.04-0.65%).
Hidden ingredients / Other evidence
A 2015 student lab analysis of 12 popular US perfumes and body sprays found 14-33 separate organic chemicals in each product (130 in all), while US law lets the label say just "fragrance".
Weak evidence: Identities are unconfirmed library matches and were never published; counts depend on the detection threshold. Pair with Steinemann 2011 rather than citing alone.
Source: Lee 2015, Young Scientist Journal (Vanderbilt University) Link to this fact
Hidden ingredients / Self-reported survey
In this Swedish sample the diethyl phthalate metabolite MEP was not higher with fragrance use in mothers or children; it was higher with sunscreen (mothers) and eye make-up (children, only 6 users), in contrast to US studies where perfume use was the strongest MEP predictor.
Weak evidence.
Caveats
Frequency-of-use question rather than 24-hour recall, very few weekly fragrance users (5 children), borderline CIs, Swedish MEP far below US levels; a null in a small sample, not evidence that perfume is free of DEP.
Source: Larsson 2014, Environment International Link to this fact
Hidden ingredients / Other evidence
GC-MS of the tested perfume listed 18 library-matched volatiles by peak-area percent, including linalool, methyl ionones, linalyl anthranilate, Ambrox and macrocyclic musk-type compounds (wiki reading of library names), with the largest peak 26.9% of area.
Weak evidence.
Caveats
Peak area is not concentration; several formulas and library scores in the table look wrong (one match score of 198); ethanol and solvent not reported; identification is by library match only.
Source: Al-Sowayan 2026, Frontiers in Pharmacology Link to this fact
Information, not medical advice. See also: myths we won’t tell you.