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.
Children and pregnancy / Measured in people or real products
Three in four children's cosmetics (295 of 398, 74.1%) on sale in a Brazilian city listed "parfum/fragrance" on the label, including 90% of children's shampoos and 79% of baby wet wipes.
Moderate evidence.
Caveats
Label count only, one city, lower bound. Scope also excludes perfume/cologne, which 65.9% of children in the same city used (Melo 2020). A US survey of a broader category mix of personal-care products (Bonchak 2018, n=533) found a lower fragrance-keyword prevalence (48%), and Denmark's named-allergen tally found 53.8% (Botvid 2023) — country, category mix and label-counting method all move this figure, so 74.1% should not be read as a universal children's-cosmetics rate.
Source: Uber 2024, Jornal de Pediatria (Rio de Janeiro) Link to this fact
Children and pregnancy / Measured in people or real products
Childcare air had about three times more limonene than new California homes (33 vs 11 µg/m³), which the authors link to frequent cleaning.
Moderate evidence: Comparison with a different study (Offermann 2009); daytime vs 24-h sampling.
Children and pregnancy / Measured in people or real products
Pregnant women who used lotion had 111% higher butyl paraben, a preservative that weakly mimics estrogen.
Moderate evidence: Exposure marker only.
Source: Braun 2014, Journal of Exposure Science and Environmental Epidemiology Link to this fact
Children and pregnancy / Measured in people or real products
In a US study, baby boys whose mothers had higher levels of several phthalates in their urine during pregnancy had a shorter distance between the anus and genitals, a sign of reduced male-hormone action during development in animal studies. A much larger (N=753), purpose-designed prospective follow-up by the same research group (TIDES, Swan 2015) confirmed this specifically for DEHP metabolites (a PVC plasticizer), with a significant, dose-responsive association at about half the original exposure level. It found no association for diethyl phthalate (DEP), the phthalate used in fragrance, nor for the other three phthalates (DBP, BBzP, DiBP) that had appeared linked in the original small study.
Moderate evidence.
Caveats
Swan 2005: 85 mother-son pairs, one urine sample, association. Swan 2015/TIDES (N=753, primary source, reconciled 2026-09-27): DEHP metabolites replicated (P=0.008-0.036); DEP/MEP null (P=0.374/0.953); DBP/BBzP/DiBP also non-significant as continuous associations in this larger cohort. US EPA (Radke 2018) rates DBP/DEHP-AGD moderate and DEP-AGD slight, consistent with this primary. Do not use this study for a fragrance/DEP claim; the replicated component is DEHP, a plasticizer, not a fragrance ingredient.
Source: Swan 2005, Environmental Health Perspectives Link to this fact
Children and pregnancy / Review of other studies
Synthetic musks reach mothers and babies mainly through the skin (cosmetics and clothes washed in scented detergent), not through food.
Moderate evidence.
Caveats
Inferred from absence in sea fish and no nursing-duration effect in newborns' fat; Reiner 2007 reaches the same conclusion. Hutter 2009 (100 Vienna adults, blood + cosmetics-use questionnaire) found cosmetics-use frequency significantly predicted only polycyclic-musk (galaxolide, tonalide) blood levels, not nitro-musk (musk ketone, musk xylene) levels. Lignell 2008 (101 Swedish mothers, milk) replicates this exact split in the matrix that actually reaches the infant: perfume use predicted HHCB, perfumed-laundry-detergent use predicted AHTN, but no product-use variable predicted musk xylene. No study has directly tested a dietary/food route for any musk in any of these populations, so 'not through food' remains an inference from the absence of nitro musks in sea fish (Schmeiser 2001), not a measured food-vs-skin comparison.
Source: Schmeiser 2001, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Review of other studies
As of 2019, the evidence that lavender or tea tree oil causes breast growth in young children consisted only of case reports: 11 children described in detail in 4 papers, with no controlled study.
Moderate evidence: Systematic review of case reports; undercounts (one included paper reports ~20 more cases in clinic tallies).
Source: Hawkins 2020, Complementary Therapies in Medicine Industry-funded Link to this fact
Children and pregnancy / Animal study
In the only independent animal experiment on the question, female rats housed with a lavender-oil diffuser from weaning reached puberty about 4.6 days earlier than unexposed rats (33.8 vs 38.4 days), with luteinizing hormone about 35% higher and follicle-stimulating hormone about 45% higher and no difference in body weight.
Moderate evidence: Five rats per group, one species, one sex, a single dose that was never measured in the cage air; no human data. The paper's abstract mislabels which group was exposed how.
Source: Kim & Lim 2022, Journal of Korean Medical Science Link to this fact
Children and pregnancy / Animal study
The effect appeared through breathing the air rather than through skin contact, which matters because the main scientific defense of lavender products is that too little gets through the skin to do anything.
Moderate evidence: Rat study; the inhaled dose was not measured, and no one has measured what a real room diffuser puts into the air either.
Source: Kim & Lim 2022, Journal of Korean Medical Science Link to this fact
Children and pregnancy / Animal study
In the same industry study's one-generation rat screen, the highest linalool dose (800 mg/kg/day, high enough to make the mother rats visibly ill) produced more stillbirths, worse pup survival in the first four days and pups that stayed smaller throughout nursing; the authors call follow-up testing 'mandatory' before this can be dismissed.
Moderate evidence.
Caveats
Only at a maternally toxic dose, orders of magnitude above any human exposure, in a screening study with few litters; the authors attribute it to maternal toxicity. Not a consumer risk claim.
Source: Hareng 2024, Archives of Toxicology Industry-funded Link to this fact
Children and pregnancy / Measured in people or real products
In a Danish/multi-country test of 25 children's cosmetics and cosmetic-toys, all 7 hydro-alcoholic children's fragrance products (5 eau de toilette, 1 eau de parfum, 1 roll-on deodorant) contained the allergen geraniol, and a separate children's toy-cosmetic perfume-blending kit's lilac essence contained cinnamic alcohol at 3.7% — about 4.6x (the paper's abstract states "by a factor of 5") the IFRA guideline of 0.8%.
Moderate evidence.
Caveats
Now sourced from the primary study (Rastogi 1999; n=25 products, Denmark/Germany/England/Sweden, 1997-98) rather than relayed via a review. Single small study, not replicated: strength stays moderate per the grading rule. The geraniol finding is for regular children's fragrance products, not toys; only 1 of 3 toy-perfume-set essences had the elevated cinnamic alcohol — the review's original "cosmetic-toy perfumes" framing conflated the two.
Source: Pastor-Nieto 2021 (Rastogi 1999), Current Treatment Options in Allergy Link to this fact
Children and pregnancy / Animal study
When rats were fed the sunscreen ingredient 4-MBC from before conception through pregnancy and nursing, male offspring reached puberty later and had smaller prostates as adults; the lowest dose that did this was 7 mg/kg/day, and for the related compound 3-BC it was 0.24 mg/kg/day, the lowest dose tested.
Moderate evidence.
Caveats
Long Evans rats, dietary dosing so intake is estimated; tables give direction of change only, no effect sizes or group sizes for most endpoints; female puberty was unaffected; 3-BC effects are non-monotonic and no NOAEL was established.
Children and pregnancy / Animal study
Developmental exposure to 4-MBC changed the activity of estrogen-controlled genes in the adult offspring's uterus, prostate and hypothalamus, erased the normal male-female difference in hypothalamic progesterone-receptor mRNA, and changed how those tissues later responded to an estrogen challenge.
Moderate evidence.
Caveats
Rat only; real-time PCR mRNA endpoints, no protein or functional behavior measured; gene-expression endpoints gave the same lowest effective dose as the classical endpoints, so they did not lower the threshold.
Children and pregnancy / Self-reported survey
In a Brazilian hospital survey, caregivers said two in three children aged 14 and under (182 of 276, median age 4) wore perfume.
Moderate evidence: One Curitiba tertiary-hospital clinic sample, 2015-16; 'perfume' undefined; no frequency, age or sex breakdown; count identical to children's shampoo (possible copy error).
Source: Melo 2020, Revista Paulista de Pediatria Link to this fact
Children and pregnancy / Self-reported survey
A quarter of Brazilian children in a hospital survey (71 of 276) already wore make-up, starting at a median age of 4, usually because the child asked for it (75% of users).
Moderate evidence: One hospital sample; caregiver report; frequency not asked.
Source: Melo 2020, Revista Paulista de Pediatria Link to this fact
Children and pregnancy / Measured in people or real products
In a Danish registry of 1,179 cosmetics marketed for children, more than half (634, 53.8%) listed perfume or a named fragrance allergen, and nearly half (550, 46.6%) named at least one of the 26 EU-listed fragrance allergens.
Moderate evidence.
Caveats
Label tally from a user-scanned consumer-app registry (2015-22), not market-weighted; 'fragranced' includes products naming only benzyl alcohol (often a preservative); sub-threshold allergens not declared.
Children and pregnancy / Measured in people or real products
93% of children's facial-care products in a Danish registry (80 of 86, almost all lip balms) listed fragrance, averaging nearly two named fragrance allergens each.
Moderate evidence: Label data; n=86; registry sample.
Children and pregnancy / Review of other studies
Balsam of Peru, a strong skin sensitizer that the fragrance industry's own standards body (IFRA) had recommended banning, was an ingredient of popular US diaper-rash ointments in the 1990s, applied under occlusion to inflamed infant skin.
Moderate evidence: One clinical commentary citing one 1990 case series (Fisher); current diaper-rash product formulations were not checked for this page.
Source: Scheinman 1999, Journal of the American Academy of Dermatology Link to this fact
Children and pregnancy / Measured in people or real products
In a US label survey of 533 personal care products marketed for babies and children, 48% (255/533) contained a fragrance-category allergen and 55% (294/533) contained at least one of eight screened contact allergens.
Moderate evidence.
Caveats
Single US retail platform (Drugstore.com/Walgreens), one 2018 snapshot; fragrance is a ~20-keyword composite tally, not a per-chemical breakdown; no chemical verification of labels.
Children and pregnancy / Measured in people or real products
Cheaper baby and children's personal care products contain significantly more contact allergens than pricier ones: products with two or more screened allergens averaged $1.39 per ounce versus $4.35 per ounce for products with none.
Moderate evidence.
Caveats
Correlation only, no mechanism tested; a similar but non-significant trend was found in adult moisturizers (Xu 2017), so the effect size and significance may not generalize beyond baby products.
Children and pregnancy / Measured in people or real products
Pregnant women who used perfume in a 48-hour window had 2.3 times higher urinary levels of MEP, the breakdown product of the fragrance solvent diethyl phthalate (DEP), than non-users, in a study of 186 low-income African American and Dominican pregnant women in New York City — independently replicating the same finding in a Boston fertility-clinic cohort (Braun 2014, 167% higher) and a postpartum cohort (Parlett 2013, 2.92x).
Moderate evidence: Exposure marker only, no health outcome; single cohort, cross-sectional; 95% CI 1.6-3.3 overlaps Braun 2014 and Parlett 2013.
Source: Just 2010, Journal of Exposure Science and Environmental Epidemiology Link to this fact
Children and pregnancy / Measured in people or real products
More frequent perfume use tracked higher urinary MEP in pregnant women in a clear dose-response pattern.
Moderate evidence: N=128 subset; exposure marker only, no health outcome.
Source: Just 2010, Journal of Exposure Science and Environmental Epidemiology Link to this fact
Children and pregnancy / Measured in people or real products
In an ordinary primary-school classroom, children were exposed to ultrafine-particle bursts reaching 140,000 particles per cubic centimeter during art activities, the highest classroom particle level measured among the wiki's school-exposure studies — with no health outcome measured.
Moderate evidence.
Caveats
Exposure measurement only; no symptom, lung-function or biomarker data were collected; one school; the specific art-material source was not identified (only 4 of ~30 paints/glues were tested, none containing limonene).
Source: Morawska 2009, Environmental Science & Technology Link to this fact
Children and pregnancy / Measured in people or real products
In a 1999 European lab test, all 7 children's hydro-alcoholic fragrance products (eau de toilette, eau de parfum, roll-on deodorant) contained the allergen geraniol, and a children's toy perfume-blending kit's "lilac essence" contained cinnamic alcohol at 3.7% — about 4.6x (the paper's abstract states "by a factor of 5") the industry's own 0.8% safety guideline.
Moderate evidence.
Caveats
N=25 products total, n=7 hydro-alcoholic products and n=1 toy item for the two headline numbers; single small study (Denmark/Germany/England/Sweden, 1997-98), not replicated for this specific product set.
Children and pregnancy / Measured in people or real products
Everyday children's shampoos, shower gels, creams and lotions rarely contained fragrance-mix allergens — cinnamic alcohol, cinnamic aldehyde and isoeugenol were absent from every sample tested — while the notable allergen exposure was concentrated in perfume-type products and one toy.
Moderate evidence: N=5 shampoos/shower gels, n=4 creams/lotions; small sample.
Children and pregnancy / Measured in people or real products
In a small pilot study of 14 Washington DC childcare facilities, chloroform – a byproduct of the chlorine bleach used to clean – was found in every single air sample, at levels averaging 1.4-1.8 times higher than in a comparable California childcare study.
Moderate evidence: Small unfunded pilot (14 facilities), single-day snapshot, convenience sample; measured no fragrance chemicals at all.
Source: Quirós-Alcalá 2016, Environmental Research Link to this fact
Children and pregnancy / Measured in people or real products
Two no-lye hair relaxer kits marketed for children had the highest measured levels of chemicals banned in EU cosmetics or listed under California's Proposition 65 (DEHP, nonylphenol, o-phenylphenol, diethanolamine) of any products tested in this study.
Moderate evidence: N=3 relaxer kits (2 marketed for children); no health outcome measured in children who used these products.
Children and pregnancy / Measured in people or real products
In a Czech birth cohort of 3,411 children (ELSPAC-CZ), each 1-SD increase in an 18-product household chemical exposure score measured at 6 months raised the odds of intermediate-onset transient wheeze (adjusted OR 1.27), early-onset persistent wheeze (adjusted OR 1.36) and intermediate-onset persistent wheeze (adjusted OR 1.23) through age 5, and those persistent wheeze phenotypes carried 5-8x higher odds of a doctor-diagnosed asthma by age 7 (pediatrician records, not self-report).
Moderate evidence.
Caveats
Single prospective cohort; exposure and wheeze through age 5 are maternal self-report (only the school-age asthma outcome is medically ascertained); the asthma link runs through the wheeze phenotype, not directly from exposure to asthma, and the paper's own direct exposure-to-asthma model was underpowered. Independently replicates the Canadian CHILD cohort (Parks 2020), which together raises the combined wheeze/asthma claim to strong (see regrade on src-2024-cleaning-products-chemistry-indoor-air-quality-health).
Source: Mikeš 2019, Science of the Total Environment Link to this fact
Children and pregnancy / Self-reported survey
Mothers who use cleaning sprays during pregnancy have infants with higher odds of both a lower respiratory tract infection (29% higher, OR 1.29) and wheezing (37% higher, OR 1.37) in their first year of life, in a pooled analysis of four Spanish birth cohorts (n=2,292); prenatal solvent use also raised wheezing odds (30% higher) and prenatal air freshener use raised LRTI odds (29% higher).
Moderate evidence.
Caveats
Single research group/dataset (pooled INMA cohorts, all Spanish, one study design), self-reported exposure and outcome by mothers, and only 12-18 month follow-up (no atopy or physician-diagnosed asthma measured). Consistent in direction with two other independent cohorts (Parks 2020, Canada; Mikeš 2019, Czech Republic) that measured early-postnatal rather than prenatal exposure, which is why the combined three-cohort claim is graded strong elsewhere while this single-paper prenatal-specific finding stays moderate.
Source: Casas 2013, International Journal of Public Health Industry-funded Link to this fact
Children and pregnancy / Self-reported survey
In a random sample of Swedish teenagers aged 13-19, about 1 in 6 (15.6%) said they were bothered by strong odors such as perfume, cleaning agents or flower scents, most often affecting the nose.
Moderate evidence: Single-item self-report; general odor sensitivity, not fragranced-product-specific; one Swedish town.
Source: Andersson 2008, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Self-reported survey
Teenage girls reported chemical sensitivity about twice as often as boys (20.6% vs 9.9%), and being female, being sensitive to noise, or having probable anxiety each roughly doubled the odds of reporting it.
Moderate evidence: Logistic regression with low explanatory power (Nagelkerke R2=0.092); only modeled for the general-CS outcome.
Source: Andersson 2008, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Measured in people or real products
In a US EPA/CDC study of 33 breastfeeding women, phthalate breakdown products were detected in fewer than 10% of breast milk samples and were essentially absent from saliva, even though the same women had detectable phthalate metabolites in nearly all of their urine samples.
Moderate evidence.
Caveats
Small pilot study (n=33, two visits); the metabolites reported for milk are four DEHP-derived oxidative metabolites, not MEP (the fragrance phthalate DEP's metabolite), which was analyzed only in urine.
Source: Hines 2009, Environmental Health Perspectives Link to this fact
Children and pregnancy / Measured in people or real products
In a large US study of 753 pregnant women and their newborns, higher first-trimester urinary levels of DEHP (a plasticizer found in PVC, food packaging and some medical devices, not primarily a fragrance ingredient) were associated with a shorter anogenital distance in baby boys, a sign of reduced male-hormone action during development, replicating an earlier smaller study at about half the exposure level.
Moderate evidence.
Caveats
Single first-trimester urine sample per mother; association, not proof of causation; cohort was largely White, college-educated and married, limiting generalizability; effect sizes were smaller than in the earlier, smaller cohort (Swan 2005).
Children and pregnancy / Measured in people or real products
In the same large study (N=753), urinary levels of diethyl phthalate (DEP), the phthalate most strongly and consistently tied to perfume and fragranced personal-care product use, showed no association with anogenital distance in baby boys — the largest and best-controlled human test yet of this specific fragrance-phthalate reproductive claim, in the same boys where DEHP did show an effect.
Moderate evidence.
Caveats
A null result in one (albeit the largest) cohort cannot fully rule out an effect at higher exposure levels than this population had; two smaller medium-confidence cohorts (Odense, SELMA) were also null, per US EPA's review.
Children and pregnancy / Review of other studies
The developing fetal and infant brain is far more vulnerable to industrial-chemical injury than the adult brain: the placenta is not an effective barrier to most industrial chemicals, the blood-brain barrier is not fully formed until about 6 months after birth, and lipophilic persistent chemicals concentrate in breast milk at up to 100-fold the mother's bodyweight-adjusted exposure.
Moderate evidence.
Caveats
General toxicological vulnerability argument for industrial chemicals (lead, methylmercury, PCBs, arsenic, toluene are the paper's 5 confirmed causes); does not measure or name any fragrance ingredient. Should not be cited as fragrance-specific evidence.
Source: Grandjean & Landrigan 2006, Lancet Link to this fact
Children and pregnancy / Measured in people or real products
In 101 Swedish first-time mothers tested over seven years, women who used perfume once a week or more had significantly higher levels of the musk chemical galaxolide (HHCB) in their breast milk than women who used it less often.
Moderate evidence: Product-use data from a N=44 subset; cross-sectional association, not an intervention; adjusted for sampling year.
Source: Lignell 2008, Environmental Science & Technology Link to this fact
Children and pregnancy / Measured in people or real products
Mothers who used perfumed laundry detergent had significantly higher levels of the musk chemical tonalide (AHTN) in their breast milk than mothers who used unscented detergent.
Moderate evidence: Product-use data from a N=44 subset; cross-sectional association, not an intervention; adjusted for sampling year.
Source: Lignell 2008, Environmental Science & Technology Link to this fact
Children and pregnancy / Measured in people or real products
In a national Canadian survey of 98 baby care products, diaper cream — not fragrance — was the largest single modeled source of infant dermal DEP exposure, contributing about half of babies' modeled total.
Moderate evidence: Exposure model uses non-Canada-specific consumer-use-pattern data and a fixed 5% skin-absorption assumption for all phthalates; it is a modeled dose, not a measured biomarker.
Source: Koniecki 2011, Environmental Research Link to this fact
Information, not medical advice. See also: myths we won’t tell you.