Every fact on this site, with its evidence grade, its caveats, and a link to the source.
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.
Skin allergy / Measured in people or real products
In a separate 12-person treatment study, applying the same moisturizer three times a day for five days after sodium lauryl sulfate irritation accelerated skin barrier recovery: by day 8 the treated hand had significantly lower transepidermal water loss (p=0.012) and significantly higher (less depleted) skin hydration (p=0.001) than the untreated control hand, though blood flow normalized spontaneously on both hands regardless of treatment.
Moderate evidence.
Caveats
Single small trial (n=12), single lab, one moisturizer formulation, one irritant (SLS), healthy non-diseased skin only; blood flow showed no treatment effect at the end of treatment.
Source: Ramsing & Agner 1997, Acta Dermato-Venereologica Link to this fact
Skin allergy / Measured in people or real products
In a 2008 survey of 107 deodorants and antiperspirants stocked at US Walgreens pharmacies, 97/107 (90%) contained fragrance and 51/107 (47%) contained propylene glycol, far ahead of essential oils/biological additives (11/107, 10%), parabens (2/107, 2%), vitamin E (2/107, 2%), and lanolin (1/107, 1%).
Moderate evidence.
Caveats
Allergen presence came from a pre-existing NACDG-screening-panel database built from product labeling, not from the authors' own chemical analysis of the products; single US retailer, one time point (~2008).
Source: Zirwas & Moennich 2008, The Journal of Clinical and Aesthetic Dermatology Link to this fact
Skin allergy / Measured in people or real products
Only 8 of 107 surveyed deodorants/antiperspirants were free of both fragrance and fragrance-related ingredients (essential oils, biological additives), making them judged genuinely safe for patients with diagnosed fragrance allergy.
Moderate evidence: Database-derived allergen listing, not independent chemical verification; a 2008 US retail snapshot that will not reflect current formulations.
Source: Zirwas & Moennich 2008, The Journal of Clinical and Aesthetic Dermatology Link to this fact
Skin allergy / Measured in people or real products
In a clinical provocation study the authors relay secondhand, 20 deodorants applied to the axilla and forearm of 14 fragrance-sensitive patients produced a positive reaction in 60% of the deodorants tested, tracking the concentration of the allergen in the product rather than simply its presence.
Moderate evidence.
Caveats
Secondhand relay of Johansen et al. 1998's primary data; verified accurate against the primary (12/20 = 60%), now independently ingested as src-1998-deodorants-clinical-provocation-fragrance-sensitive.
Source: Zirwas & Moennich 2008, The Journal of Clinical and Aesthetic Dermatology Link to this fact
Skin allergy / Measured in people or real products
The same RCT found no significant effect of emollient use on egg-white IgE sensitization at 32 weeks (42%, 20/48, intervention vs 45%, 20/44, control; P=.88), and ovomucoid sensitization was numerically higher, not lower, in the emollient group (19%, 9/48, vs 6.8%, 3/44; P=.17, not significant).
Moderate evidence.
Caveats
Small sample after exclusions (n=48 vs 44); the ovomucoid difference did not reach statistical significance but is in the direction later confirmed, with tighter confidence intervals, by the EAT cohort and the BEEP RCT.
Source: Horimukai et al. 2014, Journal of Allergy and Clinical Immunology Industry-funded Link to this fact
Skin allergy / Measured in people or real products
In a post hoc analysis of the same trial, infants with AD/eczema by 32 weeks had significantly higher egg-white IgE sensitization than those without (56%, 24/43, vs 33%, 16/49; P=.043; OR 2.86, 95% CI 1.22-6.73), and any skin lesion (AD/eczema or skin rash) carried an even larger OR of 3.73 (95% CI 1.49-9.36) for sensitization versus no skin lesion, consistent across 20 of 25 different IgE cutoff values tested.
Moderate evidence: Post hoc, not a prespecified comparison; association, not proof that eczematous skin causes sensitization rather than the reverse.
Source: Horimukai et al. 2014, Journal of Allergy and Clinical Immunology Industry-funded Link to this fact
Skin allergy / Measured in people or real products
Infants in the daily-emollient arm of this RCT had significantly more parent-reported, doctor-diagnosed skin infections in year 1 than controls (15% vs 11%; mean 0.23 vs 0.15 infections per child; adjusted incidence rate ratio 1.55, 95% CI 1.15-2.09).
Moderate evidence.
Caveats
Skin infections were parent-reported (based on what a doctor told them), not independently verified by trial staff; this was nonetheless the trial's only statistically significant safety signal.
Source: Chalmers et al. 2020 (BEEP trial), The Lancet Link to this fact
What you can do / Self-reported survey
About twice as many Australians would prefer fragrance-free workplaces (42.8%) as fragranced ones (22.2%), and over three times as many prefer unscented flights (57.7% vs 16.3%).
Moderate evidence.
Source: Steinemann 2017, Preventive Medicine Reports Link to this fact
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.
Source: Steinemann 2018, Air Quality, Atmosphere & Health Link to this fact
What you can do / Measured in people or real products
Screening out products whose labels list 'fragrance' and a few other terms cut synthetic fragrance: 26 of 43 screened products had no detectable fragrance chemical, and high fragrance levels appeared 21 times in conventional samples vs 2 in screened ones.
Moderate evidence: Conventional composites vs single alternatives not directly comparable; did not remove parabens, phthalate substitutes.
Source: Dodson 2012, Environmental Health Perspectives 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.
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 / Measured in people or real products
Green, organic, or natural labels on baby products did not mean fewer released chemicals, so choosing products labeled fragrance-free (without essential oils) is the more reliable way to avoid scent chemicals.
Moderate evidence.
Caveats
Fragrance-free products were not tested directly for VOC emissions (Nematollahi 2018's own scope). Hamann 2015 shows a different but relevant caution: even 'fragrance-free' US pediatric products commonly contain non-fragrance contact allergens (80.8% of 52 had >=1 NACDG-tray allergen, mostly preservatives), so 'fragrance-free' is more reliable specifically against added-scent VOCs, not against contact allergens generally.
Source: Nematollahi 2018, Air Quality, Atmosphere & Health Link to this fact
What you can do / Measured in people or real products
Researchers recommend lower-terpene (less citrus/pine-scented) cleaners, diluting them, ventilating during and for hours after cleaning, cleaning when fewer people are home, and never running ozone generators or ionizers with these products.
Moderate evidence: Author recommendations derived from chamber chemistry, not tested as interventions.
Source: Singer 2006, Atmospheric Environment 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 / Review of other studies
People with suspected fragrance dermatitis should ask for patch testing that includes oxidized limonene and linalool, because standard fragrance screens miss many cases.
Moderate evidence.
Source: Sukakul 2024, Acta Dermato-Venereologica Industry-funded 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
People with unexplained dermatitis can ask for patch testing with oxidized limonene and linalool; standard screens can miss these allergies.
Moderate evidence.
Source: Bråred Christensson 2016, Contact Dermatitis Industry-funded Link to this fact
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
The phthalate most linked to fragrance (diethyl phthalate) fell by 27% in 3 days when girls avoided products listing fragrance unless labeled phthalate-free.
Moderate evidence: Multi-product swap; fragrance effect not isolated; other DEP sources remain.
Source: Harley 2016, Environmental Health Perspectives Link to this fact
What you can do / Journalism
Treat vague words like 'natural', 'green', 'eco-friendly' or 'for sensitive skin' as marketing, not evidence: read the ingredient list for parfum/aroma, essential oils, and named fragrance allergens. Even 'fragrance-free' can allow essential oils and multifunctional allergens such as benzyl alcohol.
Moderate evidence.
Caveats
The 'vague claims are unreliable' half rests on several independent primaries (Steinemann 2011, Nematollahi 2018, Dodson 2012, Klaschka 2016) and remains well supported. But the claim's own recommended action, 'read the ingredient list', is now shown by Noiesen 2007 (382 patch-test-confirmed allergic patients, 3 Danish clinics) to be difficult or extremely difficult for 46% of allergic patients overall, significantly worse for lower educational level (OR 1.85) and for formaldehyde/MDBGN allergy specifically (OR ~2 each). Per our grading rule, a claim with an unverified or now-shown-difficult part stays below strong.
Source: Dahl 2010, Environmental Health Perspectives Link to this fact
What you can do / Measured in people or real products
EPA's TEAM investigator recommended source control at home: stop using air fresheners and moth crystals, and air out dry-cleaned clothes.
Moderate evidence: Recommendation derived from source apportionment, not a tested intervention.
Source: Wallace 1991, Environmental Health Perspectives Link to this fact
What you can do / Measured in people or real products
Choose unscented feminine hygiene products rather than relying on organic or natural labels, and avoid frequent vaginal douching and feminine powder use: scented tampons had far more terpenes in product testing, and a separate NHANES biomarker study found frequent douching (2+ times/month) linked to 81% higher blood 1,4-dichlorobenzene (dose-response, p=0.04) and feminine powder use linked to 36% higher blood ethylbenzene.
Moderate evidence.
Caveats
The scented-tampon comparison rests on only 2 scented vs 20 unscented tampons (weak on its own); the douching/powder biomarker evidence is stronger (real blood measurements, dose-response for douching) but cross-sectional and self-reported, with mothballs/toilet deodorizers as an unruled-out alternate DCB source. The same biomarker study (Ding 2020) found NO significant blood-VOC association with tampon or pad use itself.
Source: Lin 2020, Environment International Link to this fact
What you can do / Review of other studies
If you have unexplained eczema, ask for patch testing that includes oxidized limonene and linalool, now recommended for the European baseline series.
Moderate evidence.
What you can do / Measured in people or real products
Don't run ozone-generating air purifiers while using scented cleaners: the particle burst from a limonene cleaner only happened when ozone was present, including from a commercial ozone-generating purifier.
Moderate evidence: One product; ozone-free run had no particle-number increase.
Source: Rossignol 2013, Atmospheric Environment Link to this fact
What you can do / Measured in people or real products
If you have eczema, ask for patch testing that includes oxidized linalool and limonene: they are not in every standard test series, so the allergy can be missed.
Moderate evidence: The authors say more clinical-relevance data are needed before routine screening.
What you can do / Review of other studies
If you are allergic to fragrance, check the full ingredient list of "fragrance-free" products and prescribed creams for benzyl alcohol, and ask for patch testing with your own products if reactions continue.
Moderate evidence.
Caveats
Practical clinical advice. Xu 2017 shows why the full list matters (45% of 'fragrance-free' US moisturizers had a fragrance cross-reactor or botanical), but Rodriguez 2024 notes several hundred label names signal fragrance, so a checked database may be more reliable than label reading. Noiesen 2007 (382 patch-test-confirmed allergic patients) now quantifies the difficulty of this specific action: 46% found reading ingredient labels difficult or extremely difficult overall, education-graded. It does not test benzyl alcohol allergy specifically or outcomes, so the grade is unchanged at moderate.
What you can do / Review of other studies
Occupational lung specialists treating irritable larynx syndrome recommend a 'low-scent' workplace policy or respiratory protection to limit exposure to triggers.
Moderate evidence: Clinical recommendation, not tested as an intervention.
What you can do / Review of other studies
Fragrance-free cosmetics and laundry products cut the main routes by which synthetic musks enter the body: skin contact and washed clothing.
Moderate evidence.
Caveats
Route inferred from exposure data; no intervention study of musk body burden. Hutter 2009 (100 Vienna adults) gives cross-sectional human support for the polycyclic musks specifically: monthly-frequency of body lotion and perfume use significantly predicted blood galaxolide/tonalide (beta=0.188-0.192, p<0.05); no cosmetics-use variable predicted nitro-musk (musk ketone/musk xylene) blood levels there. Lignell 2008 (101 Swedish mothers, milk 1996-2003) gives a second, milk-matched confirmation with per-product specificity: perfume use predicted HHCB and perfumed-laundry-detergent use predicted AHTN, but musk xylene showed no association with any product category tested. Still no before/after intervention trial for any musk, and the nitro-musk part of the action's benefit remains unverified in two independent studies now.
Source: Schmeiser 2001, International Journal of Hygiene and Environmental Health 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 / Review of other studies
If you have fragrance allergy, look for benzyl salicylate on the ingredient list (and hexyl salicylate, which cross-reacted with it in human tests); EU rules require named fragrance allergens to be declared above threshold.
Moderate evidence: Cross-reaction evidence: subjects induced with 30% hexyl salicylate reacted to 15% benzyl salicylate, in an industry report.
Source: RIFM Expert Panel / Belsito 2007, Food and Chemical Toxicology Industry-funded Link to this fact
What you can do / Animal study
Methyl salicylate (wintergreen oil) is a strong eye irritant in animal tests, causing irritation even at about 1%, and is toxic if swallowed; keep wintergreen oils and rubs away from children's eyes and mouths.
Moderate evidence: Rabbit eye tests (neat and 1.25% in alcohol); oral toxicity from acute rodent data and the well-known methyl salicylate poisoning literature outside this paper.
Source: RIFM Expert Panel / Belsito 2007, Food and Chemical Toxicology Industry-funded Link to this fact
What you can do / Measured in people or real products
The California Department of Public Health recommends enforced fragrance-free workplace policies, no air fresheners or fragranced cleaners, and better ventilation instead of odor masking.
Moderate evidence: Recommendation from a public-health agency based on surveillance, not an intervention trial.
What you can do / Review of other studies
Even the toxicologists who set these limits suggest stricter, setting-specific limits where people breathe through the mouth during exercise, such as sports halls, playgrounds, and schoolyards.
Moderate evidence: A proposal, not a finding; no values are given.
Source: Kleinbeck & Wolkoff 2024, Archives of Toxicology Industry-funded Link to this fact
What you can do / Self-reported survey
A fragrance-free sign is not enough on its own: Canadians with chemical sensitivities described workplaces and hospitals with 'scent-free' policies where staff still wore scents and scented cleaners stayed in use.
Moderate evidence: Qualitative focus groups, n=60 self-selected MCS/IAQ-affected Canadians; advocacy-funded.
Source: Roy 2026 Link to this fact
What you can do / Self-reported survey
Fragrance-free policies need to cover cleaning and laundry products, not just perfume: of 60 people who react to fragranced products, 50 named cleaning products, 47 perfume, and 41 laundry products as persistent triggers.
Moderate evidence: Self-selected Canadian sample (90% female); counts of participants naming a source, not exposure measurements.
Source: Roy 2026 Link to this fact
What you can do / Review of other studies
Smell scientists reviewing the evidence found that scenting workplaces to boost mood or productivity is not well supported, and noted that a chemically intolerant employee can react to a fragranced workplace.
Moderate evidence: Short narrative review; the positive-scent literature it weighs is small; no primary data.
Source: Dalton & Jaén 2010, Current Opinion in Allergy and Clinical Immunology Industry-funded Link to this fact
What you can do / Measured in people or real products
If you get recurring rashes, ask for patch testing: nickel and fragrance are the most common findings in the general population, and one fragrance test alone misses many fragrance allergies.
Moderate evidence.
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 / Review of other studies
If you are allergic to fragrance, dermatologists advise avoiding all fragrance rather than only the chemicals you tested positive to, and choosing products from a checked database such as the ACDS CAMP list or SkinSAFE instead of trusting 'fragrance-free' claims.
Moderate evidence.
Caveats
Expert advice, untested against label reading; COI: authors built/lead CAMP. Noiesen 2007 (382 patch-test-confirmed allergic patients) now quantifies why the review distrusts label reading: 46% of allergic patients found reading ingredient labels difficult or extremely difficult, education-graded, still 38% among fragrance-only patients. This corroborates the rationale for recommending a database over labels but does not test whether database-guided avoidance actually outperforms label reading on outcomes, so the grade stays moderate.
What you can do / Review of other studies
For fragrance-allergic people, dermatologists recommend removing diffusers, scented candles, room deodorizers, incense, and wax melts, switching household cleaners, wipes, and laundry products to fragrance-free, and bringing your own shampoo to the salon and your own oil to massages.
Moderate evidence: Expert advice; the salon point rests on a single exposure keeping skin flared up to ~4 weeks (clinical observation).
What you can do / Measured in people or real products
If a child develops unexplained breast tissue, tell the doctor about every product put on the skin, including homemade balms and essential-oil or 'natural' products; in one reported case the lavender balm came to light only after repeated questioning.
Moderate evidence: Practical advice from a case report; not evidence the oil was the cause.
Source: Henley 2007, New England Journal of Medicine Link to this fact
What you can do / Government agency
EPA's own first advice on indoor VOCs is to identify and remove the source, ventilate when products are used, and buy only what you will use soon, because even closed containers leak.
Moderate evidence: Generic VOC advice; EPA does not single out fragrance.
Source: US EPA 2026 Link to this fact
What you can do / Measured in people or real products
Ventilation and less ozone help: in the same test room, with lower ozone (25–30 ppb) and nearly 3× the air exchange, particle mass from perfume, hair spray, and body spray fell by more than half.
Moderate evidence: One supplementary run; ozone and ventilation changed together, so their separate effects are unknown.
Source: Wu 2024, Environmental Science & Technology Letters Link to this fact
What you can do / Review of other studies
Check ingredient lists of leave-on products such as makeup, powders, and glitter, not just scrubs, for plastic ingredients; ingredient-scanning apps such as Beat the Microbead flag them.
Moderate evidence: App described by the review; completeness of the app's polymer list not assessed.
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 / Government agency
Workplace accommodations for fragrance sensitivity do not have to be a building-wide ban: the US Labor Department's Job Accommodation Network lists scent-free meeting rooms, moving a worker away from air fresheners and vents, telework, air purifiers, signage, and staff education.
Moderate evidence: List of options, not tested for effectiveness.
What you can do / Review of other studies
Pediatric dermatologists advise that products for children be mild, slightly acidic, and fragrance-free.
Moderate evidence: Expert recommendation citing reviews (Kuller 2016, Fernandes 2011); the survey itself linked no product to any skin outcome.
Source: Melo 2020, Revista Paulista de Pediatria Link to this fact
What you can do / Measured in people or real products
Allergen-free moisturizers were no more expensive than others: the cheapest best-sellers with no common skin allergen were plain petroleum jelly and single-ingredient butters and oils, from about $0.28 an ounce.
Moderate evidence: 2016 prices; 'allergen-free' means no NACDG-series ingredient listed; natural oils vary in efficacy (olive oil may harm the barrier).
What you can do / Measured in people or real products
If you have fragrance allergy or eczema, don't rely on "fragrance free", "hypoallergenic" or "dermatologist recommended": in best-selling US moisturizers these claims often coexisted with listed skin allergens, so check the full ingredient list or a dermatologist-checked product list.
Moderate evidence: Advice follows from a label survey; not tested against reaction outcomes; two authors hold equity in a product-recommendation service.
What you can do / Animal study
Treat essential oils as perishable: keep bottles closed and don't keep old, long-opened oils for skin use, because their scent chemicals oxidize into skin allergens in air.
Moderate evidence: Mechanism shown in lab (open flasks); real-bottle oxidation rates and the benefit of these habits not tested.
Source: Hagvall 2008, Contact Dermatitis Industry-funded Link to this fact
What you can do / Measured in people or real products
Choose unscented tampons, liners, and pads, and read "fresh" on the pack as "fragranced": the allergens inside will not be listed.
Moderate evidence: Allergens shown in scented products only; unscented products were bought but not reported; no evidence that switching reduces dermatitis.
What you can do / Measured in people or real products
How much formaldehyde and particle pollution formed was set mainly by how much ozone was available, not by how much product was used, so running an ozone-generating air purifier or ionizer alongside scented cleaning products or air fresheners adds directly to indoor formaldehyde and particles.
Moderate evidence: Conclusion drawn from controlled chamber chemistry (ozone as the limiting reagent in every run), not tested as a real-world intervention.
Source: Destaillats 2006, Environmental Science & Technology Link to this fact
What you can do / Measured in people or real products
Take used paper towels, sponges, and mop water out of the room right after cleaning, ventilate during and after, and choose cleaners without 2-butoxyethanol (ethylene glycol monobutyl ether / butyl cellosolve on the label or SDS); avoid running ozone generators with terpene-scented products.
Moderate evidence: Author recommendations derived from chamber chemistry, not tested as interventions.
Source: Singer 2006, Indoor Air, Indoor Air Link to this fact
What you can do / Measured in people or real products
Being below a standard occupational exposure limit does not mean an irritant gas is safe for someone with asthma: chamber studies found severe asthma attacks from sulfur dioxide and sulfuric acid at concentrations at or below typical workplace limits for those substances.
Moderate evidence: Occupational limits are set for healthy workers by design; this is not itself an argument that the limits are wrong, only that they don't protect people with asthma.
Source: Johansson 2016, Critical Reviews in Toxicology Link to this fact
What you can do / Measured in people or real products
If you are diagnosed with oxidized-linalool contact allergy, avoiding products listing linalool or fragrance/parfum is worth doing even at low concentrations, since repeated use at product-realistic doses reproduced dermatitis in a clinical trial, and most participants who had already stopped using linalool-containing products reported their dermatitis improved.
Moderate evidence: Self-reported improvement on avoidance (4 of 5) is not blinded or controlled; the ROAT elicitation data (the stronger evidence) show reactions down to 0.3% oxidized linalool.
Source: Andersch Björkman 2014, Contact Dermatitis Link to this fact
What you can do / Measured in people or real products
Avoid frequent vaginal douching and feminine powder use as a modifiable source of blood VOC exposure, on top of existing medical advice against douching for infection risk.
Moderate evidence: Biomarker association from cross-sectional self-report data, not an intervention trial.
Source: Ding 2020, Journal of Women's Health Link to this fact
What you can do / Measured in people or real products
How often someone used body lotion and perfume was directly linked to how much of the synthetic musks galaxolide and tonalide were in their blood, giving direct human evidence that switching to musk-free lotions and perfumes could lower blood levels of these fragrance chemicals.
Moderate evidence: Cross-sectional frequency-of-use questionnaire, not an intervention; the link was not shown for musk ketone or musk xylene, only for the polycyclic musks.
Source: Hutter 2009, Science of the Total Environment Link to this fact
Information, not medical advice. See also: myths we won’t tell you.