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 / Measured in people or real products
Using less shower product and running the bathroom fan both lower the fragrance-terpene peak: emissions scaled with product amount, and halving ventilation raised the modeled limonene peak from about 375 to 495 ppb.
Weak evidence: Amount-scaling from one person's shower; ventilation effect is modeled; no health outcome measured.
What you can do / Test-chamber measurement
Keeping indoor ozone low (no ozone-emitting 'air purifiers' or ionizers) limits both skin-oil chemistry and fragrance-terpene chemistry indoors, because ozone starts both chains.
Weak evidence: This paper makes no recommendation; the ozone-generator advice comes from Singer 2006, and the ventilation/ozone trade-off is our inference.
What you can do / Review of other studies
If you want to avoid persistent fluorinated ingredients, check cosmetic labels for 'PTFE', 'polytetrafluoroethylene', or names containing 'perfluoro-' or 'polyfluoro-'.
Weak evidence.
Caveats
Namazkar 2024 found INCI names for PFAS ingredients can themselves be ambiguous or incorrect (an apparent isomer mismatch for a silane; an undisclosed shorter chain-length range for a phosphate ester), and found unlabeled residual PFCA impurities in nearly every PFAS-containing cosmetic tested (5 of 6 products), which were far more dermally bioaccessible (43-76%) than the labeled ingredient itself (negligible bioaccessibility). Label-reading is a reasonable screen for intentionally added, correctly-named PFAS but does not detect the unlabeled residual impurities this paper shows can be present and bioaccessible regardless of which PFAS is named.
Source: Jomaa 2024, Journal of the Netherlands Society of Toxicology (JNST) Industry-funded Link to this fact
What you can do / Lab study (cells or chemistry)
Only 6 of 42 perfumes tested were comparatively low in hazardous compounds across ten lab tests, which suggests lower-hazard perfumes can be made.
Weak evidence: Products not named, so consumers cannot identify the cleaner ones; in vitro only.
Source: Morlock & Heil 2025, Journal of Chromatography A Link to this fact
What you can do / Instrument measurement
A filter-only HEPA air purifier kept fine-particle readings near zero after hair and nail products were used together in a small closed room.
Weak evidence: Flow-to-volume ratio far above any real home or salon; VOC removal by the carbon filter not credible for acetone/formaldehyde.
What you can do / Review of other studies
Fragrance-free policies are easier to make work when they start with a needs assessment and an inventory of the cleaning and personal products in use, involve employees in drafting, and agree how violations are handled before launch.
Weak evidence: Lessons from unnamed organizations; no outcome data.
What you can do / Review of other studies
Close fragranced products after use and discard them about a year after opening to limit exposure to oxidized allergens.
Weak evidence.
Caveats
Expert advice; no study tests whether it reduces dermatitis. The assumed mechanism (in-bottle oxidation during storage) has now failed two industry market surveys rather than one: Kern 2014 (fine fragrances, antiperspirants, 9 months accelerated storage) and Natsch 2019 (104 products including creams and lotions, two fine fragrances tracked 3-6 years at room temperature) both found no hydroperoxide accumulation with age or storage time. The advice may still be reasonable for essential oils and raw materials (which do carry hydroperoxide, e.g. lavandin ~220 ug/g), just not via this specific in-bottle mechanism for finished consumer products. Both studies are industry-funded (IDEA consortium: Givaudan, Firmenich, IFF, IFRA) and not independently replicated, and say nothing about essential oils, raw materials, or product categories outside fine fragrances/antiperspirants/creams/lotions. Kern 2014 and Natsch 2019 are both industry studies (Givaudan / IDEA consortium) with Natsch as a co-author on both, so they are not independent replications of each other.
Source: Pastor-Nieto 2021 (Klaschka 2010), Current Treatment Options in Allergy Link to this fact
What you can do / Measured in people or real products
Moisturizers that listed alcohol or 'alcohol denat.' near the top of the ingredient list delivered far more ethanol to a mannequin's nose; products with no listed alcohol gave almost none.
Weak evidence: 16 products, qualitative (Fig. 4, no statistic); ethanol hidden inside 'parfum' is not visible on labels; absolute ethanol doses are disputed.
What you can do / Measured in people or real products
'Agua de violetas' colognes marketed to Hispanic families, including preparations made for babies, are a specific consumer product worth asking about if a young child has unexplained breast growth.
Weak evidence: Based on 2 of 3 case reports from one clinic; not every bottle sold under this name contains lavender oil.
Source: Diaz 2016, Journal of Pediatric Endocrinology and Metabolism Link to this fact
What you can do / Hypothesis
If you already notice fragrance-related symptoms, do not expect awareness alone to change your exposure — most Germans who link their own symptoms to fragrance still use fragranced products at or above the average rate; choosing fragrance-free products and spaces is the step that actually reduces exposure.
Weak evidence: Author's recommendation, drawn from the self-exposure paradox in this survey; not itself tested as an intervention.
Source: Klaschka 2020a, Environmental Sciences Europe Link to this fact
What you can do / Review of other studies
If households switch from fragranced to fragrance-free laundry detergent, modeling suggests dryer-vent limonene emissions across a whole city or state could drop substantially — an estimated 1.58 tons per year for metropolitan Melbourne, or 8.66 tons per year for the state of California.
Weak evidence.
Caveats
This is a modeled extrapolation, not a measurement: it multiplies a mean vent concentration from just 2-6 households (one grab sample each) by census household counts and usage-rate assumptions, with no confidence interval or sensitivity analysis anywhere in the calculation; the Melbourne input is dominated by a single outlier household roughly 11 times the other three.
Source: Goodman, Nematollahi & Steinemann 2020/2021, Air Quality, Atmosphere & Health Link to this fact
What you can do / Review of other studies
Wearable personal chemical-exposure monitors with audible threshold alarms ("eNose"-type devices) are proposed as a future tool to help people track real-time chemical exposure and correlate it with symptom onset, alongside biomarker testing (blood/urine for substances or metabolites) when intoxication is suspected.
Weak evidence.
Caveats
A forward-looking recommendation in the review's discussion/outlook section, not a validated or clinically deployed diagnostic tool; no accuracy, sensitivity, or outcome data for any such device is cited.
Source: Rossi 2018, Journal of Occupational & Environmental Medicine Link to this fact
What you can do / Review of other studies
Because people with MCS describe both a fear of asking for accommodations (risking hostility) and a fear of staying silent (risking worsening symptoms), workplaces and services that proactively offer fragrance-free accommodation without requiring the person to ask remove one source of this dilemma.
Weak evidence.
Caveats
Qualitative theme ('suppressing vs expressing needs', 9 findings/5 studies) describing participants' experience, not a tested intervention; no study in this review evaluated an accommodation policy's effect. Downgraded moderate→weak 2026-09-27 (Jev audit): the accommodation recommendation is an inference, not a finding.
Source: Driesen 2020, Journal of Psychosomatic Research Link to this fact
What you can do / Measured in people or real products
A small trial found that a nasal spray containing hyaluronic acid, used daily for a month, reduced smell-detection thresholds and improved smell-disorder and anxiety questionnaire scores in MCS patients compared with a saline spray.
Weak evidence: Single small trial (29 treated/30 controls per this review's own Table 1) from one research group, not independently replicated; not an approved or established MCS treatment.
Source: Palmieri et al. 2020, Reviews on Environmental Health Link to this fact
What you can do / Review of other studies
For people whose fragrance/chemical reactions have a strong anxiety or panic component, mental-health referral, stress management, relaxation training, graded psychological desensitization to trigger odors, and (if needed) low-dose SSRIs are a recommended management approach, used alongside (not instead of) ruling out and treating any real underlying allergic or respiratory disease.
Weak evidence.
Caveats
The author states outright that research on mental-health treatment efficacy specifically in IEI is limited, because many affected patients decline psychiatric referral; the recommendation rests on case reports and phobia-treatment analogy, not controlled trials in this population.
Source: Binkley 2023, Journal of Allergy and Clinical Immunology: In Practice Industry-funded Link to this fact
What you can do / Test-chamber measurement
Accurate, calibrated information about a real chemical exposure (e.g., explaining that mild effects now do not imply long-term harm) can reduce reported irritation and symptoms compared with giving no information at all.
Weak evidence.
Caveats
Single lab study of naive volunteers under brief controlled exposure; may not generalize to real workplaces, longer exposures, or people who already have symptoms from an exposure. Downgraded to weak 2026-09-28 (Jev audit): the action goes beyond what this paper itself tested.
Source: Dalton et al. 1997, Int Arch Occup Environ Health 69:407-417 Industry-funded Link to this fact
What you can do / Measured in people or real products
People whose breathing symptoms are triggered by scents or chemical irritants, but whose standard asthma tests (spirometry, methacholine challenge) come back normal, can ask a specialist about objective sensory-hyperreactivity testing, such as a capsaicin cough-sensitivity challenge, rather than assuming the symptoms are either undiagnosed asthma or purely psychological.
Weak evidence: Capsaicin cough-challenge testing is a research protocol developed and used mainly by this one Swedish research group, not a routine or widely available clinical test.
Source: Millqvist, Bende & Löwhagen 1998, Allergy Link to this fact
What you can do / Government agency
As of 1998, EPA planned to expand its voluntary consumer-labeling initiative beyond pesticides to labels on household and other consumer products such as cleaning agents and latex paint, aiming to give clearer hazard information, especially for children.
Weak evidence.
Caveats
A stated 1998 plan/intention, not a completed program; the paper does not report whether or how it was implemented, and no fragrance-specific labeling requirement is described anywhere in the paper.
Source: Goldman 1998, Environmental Health Perspectives Link to this fact
What you can do / Review of other studies
Close deodorant containers after use and replace them about a year after opening: two of the most common deodorant fragrances (limonene, linalool) are rated weak allergens fresh but oxidize in air into much stronger sensitizers.
Weak evidence.
Caveats
Klaschka relays this oxidation chemistry from prior studies (Karlberg 1994, Matura 2005, Skold 2008), already in our evidence base; she adds no new dose data of her own. Downgraded to weak 2026-09-28 (Jev audit): the action goes beyond what this paper itself tested.
Source: Klaschka 2012, International Journal of Hygiene and Environmental Health Link to this fact
What you can do / Other evidence
Because the association tracked frequency of use in a dose-response pattern, using fewer personal care products or using them less often is the lowest-regret step for someone concerned about a possible link to lung function.
Weak evidence: The study did not test whether reducing use reverses any effect; this is an inference from an observational dose-response pattern, not a tested intervention.
Source: Dales 2013, Annals of Epidemiology Link to this fact
What you can do / Measured in people or real products
Running an ozone-generating device (an ionizer, or some 'air purifiers') at the same time as using citrus- or terpene-scented cleaning or personal-care products creates the same class of reaction-product nanoparticles studied here; keeping the two apart in time, or ventilating, avoids generating them.
Weak evidence.
Caveats
This study alone did not find a significant health effect from the terpene+ozone arm; the precautionary action is supported by the wider ozonolysis-SOA literature in our evidence base (see transformation-products), not by this study's HRV result in isolation. Downgraded to weak 2026-09-28 (Jev audit): the action goes beyond what this paper itself tested.
Source: Hagerman et al. 2014, Atmospheric Environment Link to this fact
What you can do / Other evidence
Because leave-on skin products with large use amounts (body lotion, fine fragrance) drove the highest modeled fragrance-ingredient exposure in this industry model — not air-care products, which had the highest in-product concentrations but low exposure due to no skin contact — a reasonable consumer heuristic is that layering multiple fragranced skin products likely matters more for aggregate systemic fragrance exposure than using a scented candle or air freshener.
Weak evidence.
Caveats
Derived inference from a single industry model covering 8 ingredients; not validated against measured exposure; does not address inhalation health effects, only relative modeled systemic dose.
Source: Safford 2017, Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
What you can do / Hypothesis
Unlike outdoor air pollutants such as vehicle exhaust, people can directly reduce their exposure to limonene at home by limiting use of strongly limonene-scented personal-care products and household cleaners.
Weak evidence: This is the authors' own inference from a cross-sectional association, not a tested intervention; no randomized avoidance trial has been done, though the authors call for one.
Source: Dales & Cakmak 2019, Environmental Pollution Industry-funded Link to this fact
What you can do / Lab study (cells or chemistry)
People on long-term BAK-preserved eye drops (e.g., for glaucoma or dry eye) with ocular surface concerns may want to ask their prescriber about preservative-free formulations.
Weak evidence.
Caveats
Based on an in vitro cell-culture study, not a clinical trial; supports a conversation with a prescriber, not a self-directed switch, and does not establish that any specific preservative-free product (including the study's own TBE formulation) is proven safer in practice.
Source: Kabashima 2020, Journal of Ocular Pharmacology and Therapeutics Industry-funded Link to this fact
What you can do / Measured in people or real products
Powder laundry detergents had the lowest average common-allergen count of any subgroup surveyed (0.75/product) and contained none of the preservative allergens (MI, BIT, MCI/MI, phenoxyethanol) tracked in this study; their only common allergen was fragrance, present in 3 of 4 products.
Weak evidence: Very small subgroup (n=4); one 2019 US best-seller sample, not necessarily generalizable to all powder detergents.
What you can do / Measured in people or real products
Regularly cleaning a dryer's lint trap and keeping vent ducting short and well-maintained is associated with differences in how much microfiber reaches the outside vent, based on comparing two homes with different dryer ages and duct setups.
Weak evidence.
Caveats
This is a two-home comparison, not a tested intervention — the study did not clean or modify ducting and measure a before/after change, so this is an inference from correlation, not a demonstrated fix.
Source: Kapp & Miller 2020, PLOS ONE Industry-funded Link to this fact
What you can do / Measured in people or real products
Keeping candles away from drafts, fans, open windows, and foot traffic that make the flame flicker can substantially cut soot, fine-particle, and particle-bound PAH exposure, since flame disturbance alone (independent of which candle is burned) was the single largest factor increasing these emissions in this chamber study.
Weak evidence.
Caveats
Based on chamber simulation of flame disturbance via a rotating fan, not a home-scale test of specific draft sources; does not address NOx or formaldehyde exposure, which were unaffected by burn disturbance in this study. Graded weak: what-you-can-do resting on one chamber study.
What you can do / Review of other studies
Because this industry classification describes average sensitization thresholds measured in previously unexposed volunteers, not the much lower doses that can trigger a reaction in someone already allergic, a patch-test-confirmed fragrance-allergic consumer should avoid a flagged chemical entirely rather than assume any low listed concentration is safe for them personally.
Weak evidence.
Caveats
This point is not stated by this paper itself; it follows from this evidence base's existing analysis (register entry C112) of the induction-versus-elicitation gap in fragrance industry risk assessment generally.
Source: Na et al. 2022, Dermatitis Industry-funded Link to this fact
What you can do / Lab study (cells or chemistry)
Patients on long-term BAC-preserved eye drops (e.g., for glaucoma) who have corneal or ocular-surface concerns can ask their prescriber about preservative-free alternatives.
Weak evidence.
Caveats
This is a discussion-with-clinician action, not a claim that BAC-preserved drops are unsafe at typical clinical use; based on an in-vitro model plus prior clinical ocular-surface-disease literature the paper cites, not a clinical trial of this specific outcome. Graded weak (orchestrator): in-vitro, 2-donor study alone.
Source: Umetsu et al. 2024, Graefe's Archive for Clinical and Experimental Ophthalmology Link to this fact
What you can do / Measured in people or real products
People patch-tested positive to isoeugenol or Fragrance Mix I should avoid isoeugenol-containing deodorants entirely rather than relying on IFRA-compliant "low" concentrations, since the current 0.02% cap sits inside the range this study showed can elicit reactions in sensitized users.
Weak evidence: Extrapolated consumer advice from a clinical elicitation study; not itself a tested intervention. Graded weak: what-you-can-do resting on one small ROAT study.
Source: Bruze et al. 2005, Contact Dermatitis Link to this fact
What you can do / Lab study (cells or chemistry)
Choosing a roll-on or stick deodorant instead of a spray from the same product line may reduce exposure to the estrogen-active fragrance ingredients this one lab's testing found concentrated in sprays.
Weak evidence.
Caveats
Rests on a single lab's testing of 25 German products; dispenser-type differences most likely reflect how much fragrance a given carrier formulation needs, not a demonstrated safety difference, and this has not been independently replicated or linked to any human exposure or health outcome.
What you can do / Measured in people or real products
Keeping a scented candle unlit doesn't necessarily stop it from adding VOCs to a room's air — one product in this study off-gassed heavily even unlit, so if you want to avoid a candle's chemical emissions, removing the product from the room (not just leaving it unlit) is what this data suggests actually helps.
Weak evidence.
Caveats
Based on one lab's measurements of six specific products in Korea; whether unlit off-gassing in an actual room reaches similar relative levels to what was measured in this study's small chamber has not been tested here.
Source: Ahn et al. 2015, Journal of Hazardous Materials Link to this fact
What you can do / Review of other studies
Ventilate rooms during and after burning scented candles, and prefer higher-quality or unscented candles over cheap paraffin-based scented ones, as a general precaution against indoor chemical accumulation.
Weak evidence.
Caveats
General precaution suggested by the review authors; rests on this single hypothesis paper's synthesis, not on a study measuring outcomes from these actions, and does not itself establish a bladder-cancer risk reduction.
Source: Adamowicz 2019, Cancer Prevention Research Link to this fact
What you can do / Animal study
People who work for hours daily near burning scented candles under high job stress (for example, spa, hospitality, or restaurant staff who tend candle displays), rather than casual home users, are the population most directly addressed by this animal model, and may want to reduce burn time or improve ventilation in that specific occupational setting.
Weak evidence.
Caveats
Based on a single small, unreplicated mouse study using an occupational-intensity exposure chamber; no human occupational data were collected, and the specific candle's composition was not disclosed.
Source: Chandrasekaran 2021, Current Research in Toxicology Link to this fact
What you can do / Advocacy group testing
This report recommends free consumer apps (Yuka, Tox Fox, Kemiluppen) and trusted ecolabels (Nordic Swan, EU Ecolabel) or fragrance-free certification labels (Asthma Allergy Denmark, Allergy Certified) as ways to identify or avoid suspected EDCs and allergens in personal care products.
Weak evidence: The report does not test whether using these apps or labels measurably reduces a person's chemical exposure or biomarkers.
Source: Tegengif 2022 Link to this fact
What you can do / Self-reported survey
Keeping scented-candle sessions shorter (well under 60 minutes) may reduce symptom risk somewhat, since the longest-duration group (>60 min per session) showed the largest (though not statistically significant) increases in headache, sneezing, and wheezing odds.
Weak evidence.
Caveats
Rests on one small, non-representative, single cross-sectional survey; none of the duration-based odds ratios reached statistical significance (all 95% CIs crossed 1), so this is a plausible precaution, not an established dose threshold.
Source: Al Khathlan et al. 2023, BMC Public Health Link to this fact
What you can do / Lab study (cells or chemistry)
Cold-atmospheric-plasma deodorizing devices are an emerging non-chemical, non-fragrance approach to underarm odor control worth watching as an alternative to conventional antimicrobial/fragranced antiperspirants.
Weak evidence.
Caveats
Based on one prototype tested only against cultured bacteria and porcine skin dosed with synthetic odor compounds; no human trial, no skin-safety or allergy testing, and the device generates ozone (a known respiratory irritant) as part of its mechanism.
Source: Bok et al. 2024, Scientific Reports Link to this fact
What you can do / Other evidence
Airing out a room after burning scented candles helps remove residual chemical compounds produced during burning.
Weak evidence: Common-sense ventilation advice; not independently quantified in this editorial or checked against primary ventilation-effect data in this evidence base.
Source: Nazir et al. 2024, Annals of Medicine & Surgery Link to this fact
What you can do / Other evidence
People should use scented candles with caution in closed spaces and should refrain from using them around vulnerable groups such as pregnant women, children, the elderly, and people with pre-existing cardiopulmonary conditions.
Weak evidence: A precautionary recommendation, not based on a candle-specific dose-response or exposure-outcome study in any of the named vulnerable groups.
Source: Singh 2023, Environmental Science & Technology Link to this fact
What you can do / Other evidence
A structured home walkthrough that identifies and removes common VOC sources (mothballs, scented cleaning and personal-care products, candles, garage-stored chemicals) and separates stored chemicals from living space (e.g., moving gasoline/solvents/paints to detached storage) reduced measured indoor VOC levels in the homes studied.
Weak evidence.
Caveats
Professional testing and a trained team delivered this intervention over 5 visits across a year; the paper does not test which individual component (removal vs. substitution vs. new storage vs. counseling) drove the VOC reduction. Evidence is one small uncontrolled case series.
Source: Rincón et al. 2024, Primary Health Care Research & Development Link to this fact
What you can do / Review of other studies
Because diet is the main route of human exposure to BPA and phthalates from food packaging, avoiding microwaving food in plastic, cutting back on canned food, and choosing glass, stainless-steel, or aluminum containers instead of plastic can reduce dietary exposure to these obesogenic chemicals.
Weak evidence.
Caveats
This reduces measured chemical exposure; no trial has tested whether making this switch actually changes body weight or obesity risk in people. The review infers this from exposure routes; it cites no intervention study measuring the reduction.
Source: Dalamaga 2024, International Journal of Molecular Sciences Link to this fact
What you can do / Review of other studies
At least 25% (and likely closer to 50%) of the sunscreen applied to skin washes off during sea bathing, and an estimated 35+ kg of sunscreen is deposited per day for every 1,000 people visiting a single beach, so choosing physical sun protection (clothing, hats, shade) over reapplying sunscreen right before swimming directly reduces this wash-off pathway into marine water.
Weak evidence.
Caveats
Wash-off fraction estimates vary between the cited studies (25% vs approx. 50%); the beach-deposition figure is a modeled estimate, not a direct field measurement of ecological harm This action is the ingest's inference from a review's cited wash-off and modeled deposition figures; no study tested it.
Source: Hodge 2025, Marine Pollution Bulletin Link to this fact
What you can do / Review of other studies
The study's authors argue that reducing DEHP/plastic-related cardiovascular mortality requires regulation (banning or restricting DEHP in products, improving labeling), better waste management, and international cooperation such as the UN's Global Plastics Treaty negotiations, rather than relying on individual consumer avoidance alone.
Weak evidence: This is the authors' policy recommendation; no intervention was tested in this study.
What you can do / Government agency
A patient with fragrance/chemical sensitivity asking a clinic to have staff avoid fragrance for one scheduled appointment is asking for something narrower than a facility-wide rule, and DOJ's 1995 'usually not reasonable' answer was addressed to the broader framing, not this narrower one.
Weak evidence: DOJ never separately analyzed the narrower, one-appointment request; this is an inference from reading the letter against its own attached correspondence, not a DOJ holding.
Source: DOJ TAL605, 1995 Link to this fact
What you can do / Self-reported survey
Perfume is most often sprayed on the neck and throat, then the arms — close to the nose and mouth — so people concerned about fragrance inhalation might consider applying it lower on the body or on clothing instead.
Weak evidence: Based on where 326-340 already-regular perfume users in one US industry survey said they applied product, not on any measurement of how application site changes inhaled dose.
Source: Loretz 2006, Food and Chemical Toxicology Industry-funded Link to this fact
What you can do / Measured in people or real products
A typical day's use is about 4 g for facial cleanser, about 14 g (median 10.6 g) for hair conditioner, and about 0.04 g for powder eye shadow, based on a two-week diary-and-weighed-container study of nearly 300 regular US users of each product using their own regular brand.
Weak evidence.
Caveats
Rests on this single 2008 industry study of women-only, US-only, already-regular users of that specific product category; amounts are ratio estimates from total container weight change over two weeks, not measured per application.
Source: Loretz 2008, Food and Chemical Toxicology Industry-funded Link to this fact
What you can do / Self-reported survey
Women with longer, thicker, or curlier hair used noticeably more hair conditioner overall than women with short, fine, or straight hair, while hair oiliness, dryness/damage, and color treatment showed no clear effect on the amount used.
Weak evidence: Rests on this single 2008 industry study's self-reported hair-characteristic categories (box-plot comparison), not a controlled or dose-response analysis.
Source: Loretz 2008, Food and Chemical Toxicology Industry-funded Link to this fact
What you can do / Government agency
Frozen and fatty packaged foods in printed cartonboard (frozen foods, jellies, savory snacks, high-fat items like chocolate) were the categories a UK FSA survey found most likely to carry benzophenone residue from printing-ink migration; fresh or non-printed-packaging foods are a lower-exposure alternative for anyone wanting to reduce incidental dietary intake.
Weak evidence.
Caveats
Based on one national survey's positive-detection rates by food category, not a dose-response health-outcome study Graded weak: what-you-can-do resting on one survey relayed through the IARC monograph.
Source: IARC 2013 Link to this fact
What you can do / Review of other studies
The Endocrine Society recommends that regulatory agencies and civil society organizations support consumer-facing programs like the US EPA's Safer Choice and develop educational materials so consumers can identify and adopt safer product alternatives.
Weak evidence.
Caveats
A general recommendation, not a specific list of safer cosmetic or fragrance alternatives; Safer Choice itself is a voluntary EPA labeling program, not a cosmetics-specific standard.
Source: Endocrine Society 2025 Link to this fact
What you can do / Self-reported survey
If you want to try a pleasant scent at bedtime, this one small study suggests a diffuser-style, indirect delivery may feel more pleasant than a nasal clip or pillow spray (pillow spray was linked to worse self-reported sleep), but don't expect it to change your sleep architecture, and there's no data here on whether it's safe to breathe nightly.
Weak evidence: Rests on one small, non-randomized, industry-funded study with a null objective outcome; not replicated.
Source: Li et al. 2025, Scientific Reports Industry-funded Link to this fact
What you can do / Self-reported survey
People pursuing an MCS accommodation in Canada should ask healthcare providers to document functional limitation, not just a diagnosis, and should keep a written record of every accommodation request and outcome, since the legal duty to accommodate turns on function and this study found requests and refusals were often repeated five or more times.
Weak evidence.
Caveats
Drawn from one self-report survey's qualitative themes and the authors' own policy recommendations, not tested as an intervention; rests on a single small, advocacy-recruited study.
Source: Diallo 2026 Link to this fact
What you can do / Measured in people or real products
Before applying moisturizer to an infant's skin, wash hands thoroughly, and give careful consideration to both the frequency and the type of product used, per the study authors' own cautious recommendation.
Weak evidence.
Caveats
This recommendation rests on one observational cohort (plus a matching but non-significant RCT signal from BEEP); it is not established clinical guidance, and moisturizers remain first-line treatment for infants who already have eczema.
Source: Perkin 2021 (EAT cohort), Journal of Allergy and Clinical Immunology Link to this fact
What you can do / Measured in people or real products
Choosing cellulosic-fiber (cotton, viscose) rather than synthetic (nylon, polyester) next-to-skin clothing may reduce how much nonpolar ketone and aldehyde sweat odor is released into the air shortly after exercise, based on one lab study's yarn-bundle sorption/release measurements.
Weak evidence.
Caveats
Rests on one lab study using isolated yarn bundles (not real garments) and a sterile synthetic sweat solution with no bacterial component, which is the actual source of most real-world body odor; not yet tested on worn clothing or replicated by an independent group.
Source: McQueen 2024, Textile Research Journal Link to this fact
What you can do / Measured in people or real products
In laboratory testing on one sunscreen spray, fitting a tapered external tube over the spray-can nozzle reduced the modeled number of submicron particles reaching the respiratory tract by about 89% and the mass reaching it by about 66%, without reducing the amount of product delivered.
Weak evidence.
Caveats
Single chamber study, single lab, one primary test product; only partially cross-checked (one alternate tube geometry) on two other product types; the modification is a research prototype, not available on any commercial product; authors call the work a proof-of-concept.
Source: Dai et al. 2026, ACS Environmental Au Link to this fact
What you can do / Review of other studies
NRDC's 2007 report recommends avoiding air fresheners altogether or, if used, choosing products with the lowest measured phthalate levels and favoring ventilation over added fragrance to address household odors.
Weak evidence: An advocacy organization's risk-averse recommendation, not a demonstrated dose-response health benefit from switching products.
Source: NRDC 2007, Clearing the Air Link to this fact
What you can do / Measured in people or real products
Daily application of a fragrance-free emollient to a newborn with a family history of atopic dermatitis may reduce the baby's risk of developing eczema in the first several months of life, based on this one trial.
Weak evidence.
Caveats
Rests on one single-center trial of one specific product in a high-risk Japanese population; the much larger BEEP RCT (10x the sample, a different emollient) found no eczema-prevention benefit at all, and some evidence of increased skin infections — present both results together, not this one alone.
Source: Horimukai et al. 2014, Journal of Allergy and Clinical Immunology Industry-funded Link to this fact
What you can do / Self-reported survey
Migraineurs who notice perfume, paint/varnish, gasoline, or bleach smells before their attacks may want to keep a trigger diary, since these were the most common self-reported odor triggers in one clinic sample.
Weak evidence.
Caveats
Rests on a single non-random clinic sample (n=200, one Brazilian city, 2011); a personal pattern should be confirmed prospectively, not assumed from one study, and may reflect premonitory-phase symptom misattribution rather than a true external trigger.
What you can do / Self-reported survey
A person who notices odor aversion (or light/sound sensitivity, or food craving) starting hours before a migraine headache can consider it a possible early-warning premonitory symptom of the attack, not necessarily proof that the odor, light, or food caused the attack.
Weak evidence: Based on a retrospective association in one tertiary-care cohort; does not establish that recognizing premonitory symptoms changes outcomes.
Source: Schulte 2015, The Journal of Headache and Pain Link to this fact
What you can do / Self-reported survey
Migraineurs who notice their attacks are triggered by specific odors (most commonly perfume, cleaning products, cigarette smoke, or vehicle exhaust in this sample) may reasonably consider reducing exposure to those specific triggers as a low-cost self-management step.
Weak evidence: Based on self-reported association in one clinical sample, not a controlled-avoidance or provocation trial; benefit of avoidance was not tested.
Source: Fornazieri 2016, Headache: The Journal of Head and Face Pain Link to this fact
What you can do / Measured in people or real products
Parents who want to reduce infant phthalate exposure can limit the number of infant care products used on their baby and avoid applying lotion or powder unless medically indicated.
Weak evidence: This is the study authors' own recommendation, not a tested intervention; it is based on the correlational findings in the same study.
Source: Sathyanarayana et al. 2008, Pediatrics Link to this fact
Information, not medical advice. See also: myths we won’t tell you.