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.
What you can do / Self-reported survey
Most people would rather have fragrance-free spaces: 65% prefer fragrance-free airplanes, 61% hotels, 51% health care, and 48% workplaces, against 16-22% who prefer them fragranced.
Moderate evidence: Preference survey, adults 18-65.
Source: Steinemann 2019, Air Quality, Atmosphere & Health Link to this fact
What you can do / Self-reported survey
People with asthma back fragrance-free spaces by wide margins: 66.2% vs 16.1% for fragrance-free workplaces and 72.1% vs 14.8% for fragrance-free health care.
Moderate evidence.
Caveats
Subgroup of a self-reported US online survey (2016, adults 18-65, Survey Sampling International panel); asthma is self-reported, and these are stated preferences, not measured behavior.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
What you can do / Self-reported survey
Swedes overwhelmingly prefer scent-free spaces: 80.2% vs 6.0% for airplanes, 77.7% vs 9.8% for hotels, and 64.1% vs 14.0% for health care.
Moderate evidence: Self-reported online survey of Swedish adults 18-65 (2017, n = 1,100, Survey Sampling International panel); stated preferences, not measured behavior.
Source: Steinemann 2018 (Sweden), Air Quality, Atmosphere & Health Link to this fact
What you can do / Measured in people or real products
Perfume was the strongest single predictor of diethyl phthalate exposure, so skipping perfume and fragranced personal care products is the most obvious way to lower it.
Moderate evidence: Association only; not tested as an intervention.
Source: Parlett 2013, Journal of Exposure Science and Environmental Epidemiology Link to this fact
What you can do / Self-reported survey
More UK adults prefer fragrance-free over fragranced workplaces (44.7% vs 23.3%), health care (43.3% vs 26.7%) and airplanes (61.9% vs 18.4%).
Moderate evidence: Pluralities, not majorities, for workplace and health care; preference, not health benefit.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
What you can do / Measured in people or real products
Taking the air freshener out of the car removes its main added chemical: without one, in-car limonene was about 5-6 ug/m3.
Moderate evidence: Small pilot; limonene only.
What you can do / Measured in people or real products
Using fewer scented personal care products is likely to lower phthalate and paraben levels, because levels tracked the number of products used.
Moderate evidence: Association; not tested as an intervention here (see HERMOSA).
Source: Braun 2014, Journal of Exposure Science and Environmental Epidemiology Link to this fact
What you can do / Measured in people or real products
When 100 teenage girls swapped their usual personal care products for ones labeled free of phthalates, parabens, triclosan, and oxybenzone for just 3 days, levels of these chemicals in their urine fell by 27-45%.
Moderate evidence: No control arm, 100 Latina girls in one town, 3 days, summer.
Source: Harley 2016, Environmental Health Perspectives Link to this fact
What you can do / Measured in people or real products
Musk levels in blood and milk seem to track current personal-care product use rather than lifetime storage: Hutter 2009 found that how often people used perfume and body lotion significantly predicted their blood levels of the polycyclic musks (galaxolide, tonalide) in 100 adults, so choosing fragrance-free personal care and laundry products during pregnancy and breastfeeding is a plausible way to lower a mother's musk levels and, in turn, transfer to the baby.
Moderate evidence.
Caveats
Route inferred in Reiner 2007 from the absence of an age trend in milk, and now supported by direct product-use data in two independent populations and matrices: Hutter 2009 (blood, non-pregnant Vienna adults) and Lignell 2008 (101 Swedish mothers, milk itself — the exact matrix this claim concerns). Lignell 2008 found perfume-use frequency predicted HHCB and perfumed-laundry-detergent use predicted AHTN in milk, but no product-use variable predicted musk xylene, matching Hutter's blood-based polycyclic/nitro split. Still correlational and cross-sectional; no study has measured milk musk levels before and after a change in a mother's product use, and no cosmetics-use variable has ever predicted a nitro musk in either study.
Source: Reiner 2007, Environmental Science & Technology Link to this fact
What you can do / Self-reported survey
Support for fragrance-free health care and workplaces is not limited to people with symptoms: in Germany roughly 70% of those who backed them reported no fragrance-related health effects themselves.
Moderate evidence: Our arithmetic from Table 5; preference, not outcome; German workplace support was only 33.2% (30.6% against, 35.3% unsure).
Source: Klaschka 2020, Environmental Sciences Europe Link to this fact
What you can do / Self-reported survey
Fragrance-free health-care policies should cover cleaning and laundry products, not just staff perfume; Canadian advocates ask for exactly this, and people who react name cleaning products as their most common trigger (50 of 60).
Moderate evidence: Advocacy position plus a self-selected focus-group sample; no evidence yet that policies reduce exposure or symptoms.
What you can do / Measured in people or real products
If you have known fragrance allergy, ask your pharmacist or read the full leaflet (not just the outer box) for topical medicines, and request fragrance-free formulations for wound care, NSAID gels, and antiseptics where alternatives exist; if a topical medicine causes a rash, ask for patch testing with the actual product and its individual ingredients, not just the standard fragrance mix.
Moderate evidence: Practical advice drawn from a single clinic's experience; a negative fragrance-mix patch test does not rule out fragrance allergy from a specific product.
What you can do / Self-reported survey
Many allergic patients who read ingredient labels still don't fully trust them: in one study only about half of patients affirmatively agreed that ingredient labels are accurate, so persistent reactions despite careful label reading are not necessarily a reading mistake.
Moderate evidence: Self-reported trust, not a test of actual label accuracy; the study does not adjudicate whether distrust reflects real label errors or post-hoc reasoning from continued reactions.
What you can do / Review of other studies
Never mix chlorine bleach with ammonia or acidic cleaning products, since this releases chlorine gas or trichloramine, both strong respiratory and eye irritants documented to cause acute lung injury in cleaners and housewives.
Moderate evidence: Drawn from background literature the authors cite (occupational case reports and reviews), not from new data collected in this study.
Source: Nickmilder, Carbonnelle & Bernard 2007, Pediatric Allergy and Immunology Link to this fact
What you can do / Measured in people or real products
Read the ingredient list for the named allergens rather than trusting marketing words like 'sensitive' or 'soft' on a deodorant label; in one German sample, products carrying such words were no less likely to contain perfume or a strong allergen than the market as a whole.
Moderate evidence: Single-country label survey; does not establish the words are misleading everywhere, only in this sample.
Source: Klaschka 2012, International Journal of Hygiene and Environmental Health Link to this fact
What you can do / Measured in people or real products
Choosing an unscented candle over a scented one made from the same wax measurably lowers the release of combustion pollutants (VOCs, PAHs, formaldehyde), based on this chamber study, though unscented candles still produce carbon dioxide, carbon monoxide, nitrogen oxides, and ultrafine particles from ordinary combustion.
Moderate evidence: Demonstrated for purpose-built research candles across 4 wax types and 5 fragrance families, not verified for any specific retail candle brand.
Source: Salthammer 2021, Environment International Industry-funded Link to this fact
What you can do / Review of other studies
The main BPA exposure routes this review names are ingestion of food and beverages from polycarbonate plastic containers and epoxy-lined cans, plus dermal or inhalation contact with BPA in thermal receipt paper and household dust, rather than fragranced personal-care products specifically.
Moderate evidence: Sourced from the review's introduction, which itself cites general BPA exposure literature rather than PCOS-specific measurements.
What you can do / Government agency
HUD's own 1991-92 guidance gives two concrete examples of reasonable accommodation for chemically sensitive tenants: (1) a tenant sensitive to pesticides can ask for advance notice before the building is fumigated and for boric acid to be substituted for the chemicals normally used; (2) an applicant sensitive to carpet chemicals can ask the housing provider what type of carpeting is used throughout the building before deciding whether to rent.
Moderate evidence.
Caveats
These are HUD's own worked examples from internal guidance, not a binding regulation with a fixed list of required accommodations; HUD explicitly says reasonableness depends on the individual's circumstances and is bounded by undue financial/administrative burden.
Source: HUD guidance (1991) Link to this fact
What you can do / Self-reported survey
65.5% of autistic adults would support a fragrance-free workplace policy and 77.2% would prefer fragrance-free health care facilities and professionals, compared with 46.1% and 45.8% support among non-autistic adults.
Moderate evidence: Stated preference, not an intervention study; self-report survey.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
What you can do / Review of other studies
Most dry-cleaning alternatives to perc are not proven safer: a 2016 review found the long-term health effects of hydrocarbon solvents 'not well understood', flagged siloxane D5 (GreenEarth) as bioaccumulative, and listed chronic effects for hydrocarbons and liquid CO2 as 'unknown'.
Moderate evidence.
Caveats
Secondary review funded by Australian Wool Innovation (wool industry body); 'systematic' is a self-label with no study counts or appraisal; relies on agency, trade and manufacturer sources. 'Unknown' means not studied, not shown harmful; much of the hazard data comes from agency and manufacturer documents.
Source: Troynikov 2016, Journal of Environmental Management Industry-funded Link to this fact
What you can do / Other evidence
In a stationary SUV, running the ventilation in outside-air (external inflow) mode gave total VOC levels about 56-57% of those in the other modes, and 7 of 8 health-relevant VOCs fell; the recirculation setting cut particles by 43-51% but kept recirculating benzene and phenol from the car's own materials.
Moderate evidence.
Caveats
One medium SUV, one spray, engine on only for these runs, parked; the paper words the 56-57% figure both as 'to' and 'by' (abstract vs Results/Conclusion), so the size of the effect is unclear; not tested while driving.
Source: Lee 2024, Science of The Total Environment Link to this fact
What you can do / Other evidence
Do not use homeopathic products in place of medical care for chronic, serious, or potentially serious conditions; the Australian NHMRC (2015) advised against this, and EASAC warns that using them can delay appropriate evidence-based care.
Moderate evidence: Policy advice from public bodies; individual placebo-responsive symptoms may improve, which EASAC acknowledges.
Source: EASAC 2017, EASAC Statement (September 2017) Link to this fact
What you can do / Other evidence
FDA says homeopathic injectables and eye products are higher-risk because they bypass the body's natural defenses; in 2019 FDA found non-sterile homeopathic eye drops (Puriton) contaminated with Bacillus and with a pH high enough to risk corneal scarring and vision loss.
Moderate evidence: Based on FDA testing of samples from specific products described in warning letters; not all eye products.
Source: FDA 2022 Homeopathic Drug Products guidance Link to this fact
What you can do / Other evidence
To earn EWG Verified a personal care product must score 'green' (1 or 2 on a 1-10 scale) in EWG's Skin Deep database and avoid EWG's unacceptable ingredients.
Moderate evidence: Score is a weight-of-evidence hazard rating from ingredients, not a measured exposure; product-level sensitization data can cut the allergy component by 50%.
Source: EWG 2026, EWG program criteria (PDF) Link to this fact
What you can do / Other evidence
In a Rutgers/Columbia questionnaire study, people who always or usually consulted health apps or websites used personal care products with lower average Skin Deep hazard scores than those who rarely did.
Moderate evidence.
Caveats
Cross-sectional, one university community; the apps use the same label information the score uses, so part of the link is built in; lower score does not equal lower measured exposure.
Source: EWG 2025 (Friedman & Huang), EWG news (web page) Link to this fact
What you can do / Other evidence
Suffolk County's 2018 report sorted perchloroethylene into its red (least preferable) category for both human health and environment, and liquid carbon dioxide into green for both.
Moderate evidence.
Caveats
A county health department's qualitative color code built from other agencies' reviews, not a measured or quantitative risk ranking; data volume differs a lot by solvent (decades for perc, little for newer ones). No industry funder named.
Source: SCDHS 2018 Link to this fact
What you can do / Other evidence
Do not use unapproved homeopathic eye drops to treat cataracts or other eye disease; see an eye-care professional and report reactions to FDA MedWatch.
Moderate evidence: Advice follows from FDA's unapproved-drug and route-of-administration statements; no harm data in the letter.
Source: FDA warning letter 708635 (25 Aug 2025), FDA warning letter (MARCS-CMS 708635), 25 August 2025 Link to this fact
What you can do / Other evidence
In 400 men, each additional type of personal care product used in the past day went with about 12% higher urinary MEP and 14 to 29% higher parabens.
Moderate evidence: Observational; crude count of products; same cohort and lab as the women's study, so not independent replication.
Source: Nassan 2017, Environmental Health Perspectives Link to this fact
What you can do / Other evidence
The industry panel warned that cetrimonium bromide and palmitoyl carnitine can enhance skin penetration of other chemicals (phenylazoaniline, benzocaine, benzoic acid), so products combining them with ingredients whose safety depends on low absorption need careful formulation.
Moderate evidence.
Caveats
Penetration enhancement shown in artificial membranes (enhanced below 0.5%, inhibited above 1.0%); no human product data. CIR is financed by the Personal Care Products Council, the cosmetics industry trade association.
Source: Becker et al. 2012 (CIR), Int J Toxicol, International Journal of Toxicology Industry-funded Link to this fact
What you can do / Other evidence
The committee's recommendations ask Health Canada to consider guidance on how to approach MAiD requests when suffering is predominately derived from an unmet social need (e.g., housing), and ask the Ontario Ministry of Health and Ontario Health to consider a provincially coordinated MAiD care system with interprofessional assessment and enhanced care coordination for people with unmet social needs such as housing.
Moderate evidence: All recommendations are worded "to consider"; the report does not say whether any recipient responded.
Source: Ontario MDRC Report 2024-3 (OCC, 2024; non-official copy) Link to this fact
What you can do / Measured in people or real products
Parabens are cosmetic and personal-care preservatives, not fragrance ingredients, so this child-behavior study provides no evidence about perfume or fragrance.
Moderate evidence: Paper measured only methyl-, ethyl- and propylparaben; no fragrance compounds, phthalates or MEP.
Information, not medical advice. See also: myths we won’t tell you.