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.
Children and pregnancy / Review of other studies
About half of children's cosmetics in a Danish registry (634 of 1,179, 53.8%) listed perfume or a named fragrance allergen, and a US survey of 533 baby/child personal care products found a closely similar share (255/533, 47.8%; Bonchak 2018); in Danish baby-care products the commonest named allergens were linalool, limonene, and benzyl alcohol (the US primary does not report limonene or linalool by name).
Strong evidence.
Caveats
Danish half is primary (Botvid 2023): baby-care products specifically were 38.0% (178/468), the least fragranced category — do not write 'half of baby products' for Denmark. 'Fragranced' there includes products naming only an allergen such as benzyl alcohol (often a preservative). US half is now also primary (Bonchak 2018): 47.8% (255/533) across wipes/diaper care/soap/moisturizer/shampoo/sunscreen — but Bonchak's fragrance count is a ~20-keyword composite that does not report limonene or linalool individually, so the 'top three' allergen list is confirmed only for Denmark. Label counts remain lower bounds.
Source: Sukakul 2024, Acta Dermato-Venereologica Industry-funded Link to this fact
Children and pregnancy / Measured in people or real products
Pregnant women who had used perfume or cologne in the past day had 167% higher urine levels of MEP, the breakdown product of the fragrance solvent diethyl phthalate (DEP), than women who hadn't (177 women, Boston).
Strong evidence.
Caveats
Exposure marker, not health outcome; independently replicated in two further US cohorts with overlapping confidence intervals: Parlett 2013 (2.92x, postpartum, SFF multi-site) and Just 2010 (2.3x, 95% CI 1.6-3.3, pregnant, NYC minority cohort, with a dose-response and a null personal-air DEP association pointing to a dermal exposure route).
Source: Braun 2014, Journal of Exposure Science and Environmental Epidemiology Link to this fact
Children and pregnancy / Measured in people or real products
Musk scent chemicals used in perfumes, deodorants, and detergents turn up in mothers' milk fat; a breastfed baby takes in an estimated ~2 micrograms of galaxolide a day.
Strong evidence.
Caveats
Intake is a model estimate from means of detects; the printed intakes do not reproduce from the stated method. Independently corroborated: Lignell 2008 (N=101, Swedish mothers, single lab) estimated median infant HHCB intake at 1650 ng/day (range 50-6950) using the same milk-intake modeling approach, closely matching this paper's printed 1830 ng/day figure in an unrelated country and cohort.
Source: Reiner 2007, Environmental Science & Technology Link to this fact
Children and pregnancy / Measured in people or real products
A perfume ('eau de cologne') marketed for babies listed 16 different fragrance allergens, the most of 1,179 children's products in a Danish registry.
Strong evidence: A single product (the maximum), not typical; mean 0.4-1.8 named allergens per product by category; label presence, not dose.
Green, natural and unscented / Other evidence
OEKO-TEX Standard 100's limit table has no limit and no list for fragrance chemicals or fragrance allergens; the only fragrance-related rule is an odor test that requires 'no odor from mold, high boiling fraction of petrol, fish, aromatic hydrocarbons, or perfume'.
Strong evidence: Edition 02.2025 table only; the 2026 change notice mentions no fragrance row but the full 2026 table was not captured; odor test is a sensory judgment with no stated scale.
Source: OEKO-TEX Service GmbH, Standard 100 limit values Annexes 4-5, Ed. 02.2025 Industry-funded Link to this fact
Health effects / Measured in people or real products
This Korean child ADHD-symptom study measured only DEHP and DBP metabolites; MEP, the marker of the fragrance phthalate DEP, was not measured, so it says nothing about perfume or fragrance.
Strong evidence: Only MEHP, MEOP (MEOHP) and MNBP were analyzed.
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.
Indoor air / Review of other studies
Scent chemicals released by perfumes and scented products can react with ozone in indoor air to form new pollutants, including formaldehyde and fine particles.
Strong evidence.
Caveats
Formation is well established (Fiedler 2005: 40 ppb O3 + a limonene/alpha-pinene-containing VOC mix -> HCHO 13 -> 40 µg/m³, UFP 2,500 -> 46,000 cm-3; Singer 2006; Rossignol 2013; Destaillats 2006 gives the underlying per-ozone yield). Amounts depend on dose and ozone; the harm at real indoor levels is not shown. A far more rigorous, independent toxicologist review (Wolkoff & Nielsen 2017) reaches the same qualitative chemistry conclusion via its own literature synthesis and adds a quantitative caution: in the two largest human tests to date (Fiedler 2005, n=130; Fadeyi 2015, n=71), the resulting reaction mixture caused no significant airway/eye effects, and its own threshold estimate is that >200 µg/m³ ozone at high limonene would be needed before sensory effects are expected. Cite primaries for numbers.
Source: Alblooshi 2025, Frontiers in Toxicology Link to this fact
Indoor air / Measured in people or real products
In week-long air measurements across 11 European cities, the scent chemicals limonene and alpha-pinene were the compounds most concentrated in homes compared with workplaces (about 4x), attributed to perfumes, cleaning and fragranced products.
Strong evidence: Source attribution by the authors, not measured per product.
Source: Geiss 2011, Atmospheric Environment Link to this fact
Indoor air / Other evidence
Terpene ingredients in scented cleaners, air fresheners, perfumes, colognes and essential oils (limonene, pinene, linalool, linalyl acetate) are listed as ozone-reactive indoor sources that make formaldehyde and tiny particles when ozone is present.
Strong evidence.
Caveats
Table 1 is a literature summary; perfumes and essential oils rest on three chamber citations (Chao 2005, Karamalegos 2005, Shu 1997). No product was measured in this paper and it gives no product-specific numbers.
Source: Weschler 2006, Environmental Health Perspectives Link to this fact
Laws and loopholes / Government agency
In 2000, EU cosmetics could declare an entire fragrance as the single word 'parfum'; the EU committee noted dermatologists' estimate that up to 2% of people have perfume allergy, against industry's claim that the true figure was 'far lower'. The EDEN population-based patch-test study (Diepgen 2015; n=3,119 patch-tested across 5 European countries) directly confirmed the dermatologists' estimate: 1.9% (95% CI 1.5-2.5) clinically relevant fragrance contact allergy, and 1.8-2.6% for fragrance mix I alone.
Strong evidence.
Caveats
EDEN is the largest general-population patch-test study of fragrance allergy to date and a large, well-controlled multi-country primary (not a single-lab or single-cohort study), which is why this moves to strong. Note EDEN was itself funded by the Research Institute for Fragrance Materials (RIFM), the fragrance industry's own body — the industry-funded study still confirmed the higher, consumer-relevant estimate over the industry's own 'far lower' claim.
Source: SCCNFP 2000 Link to this fact
Laws and loopholes / Other evidence
OSHA lists perfumes and colognes, cleaning products, pesticides and personal-care products among sources of workplace indoor air pollutants, but sets no limit or rule for any of them.
Strong evidence: Mentions are brief source lists; fragrance is not named as a category, and no health data are given.
Source: OSHA 3430-04, 2011 Link to this fact
Skin allergy / Measured in people or real products
Fresh limonene and linalool rarely cause allergy; the allergens form when these chemicals react with air, which also happens in essential oils and perfumes during storage.
Strong evidence.
Caveats
A '0.1-0.3% of patients' figure was removed because it does not trace to a source in our evidence base. Parent-compound sensitization rates are low but vary by dataset; see the Dittmar 2019 entry for oxidized-terpene positive rates.
Source: Bråred Christensson 2016, Contact Dermatitis Industry-funded Link to this fact
Skin allergy / Measured in people or real products
In 2,900 dermatitis patients tested at nine clinics in Europe, Asia, and Australia, 6.9% were allergic to air-oxidized linalool, the form a common floral scent chemical found in most perfumes, cosmetics, and many cleaners takes after contact with air.
Strong evidence: Dermatitis patients, not general population; 72% weak reactions; range 3-14% by clinic.
Source: Christensson 2012, Contact Dermatitis Link to this fact
Skin allergy / Measured in people or real products
For people already allergic to oxidized linalool (the air-exposed form of a common floral fragrance chemical), using a scented cream or perfume containing it at concentrations similar to real products (as low as 0.3% oxidized linalool, 0.056% linalool hydroperoxides) was enough to trigger eczema within three weeks of twice-daily use in a repeated-use trial.
Strong evidence.
Caveats
Small N (6 completers); participants were pre-selected as already patch-test-positive, not a general-population sample; lowest concentration tested (0.1% in perfume) did not produce a formal positive.
Source: Andersch Björkman 2014, Contact Dermatitis Link to this fact
Information, not medical advice. See also: myths we won’t tell you.