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
More than a third of people surveyed (37%) report avoiding at least one leave-on scented product (perfume, deodorant, skin cream) because it has caused them skin problems.
Moderate evidence.
Caveats
Self-reported avoidance, not a clinical diagnosis; nearly identical rates in the full interviewed sample (12,377) and the smaller patch-tested subsample (3,119), supporting representativeness.
Source: Diepgen 2015 (EDEN), British Journal of Dermatology Industry-funded Link to this fact
What you can do / Measured in people or real products
If you suspect a deodorant is causing your skin allergy (especially if you are male), ask that patch testing specifically include fragrance mix II and HICC, since the standard fragrance mix I marker is a weaker predictor of deodorant-driven fragrance allergy.
Moderate evidence: Advice extrapolated from a correlational clinic dataset, not from an interventional study testing whether this actually improves diagnosis.
Source: Heisterberg 2011, Contact Dermatitis 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
If a deodorant use test on the forearm is negative but you still suspect that deodorant is causing your armpit rash, ask a clinician to repeat the test directly in the armpit.
Moderate evidence: Based on a single 1998 study of 12 informative deodorants; two-thirds of confirmed reactions were detected only in the axilla, never on the standard forearm test site.
Source: Johansen et al. 1998, Contact Dermatitis Link to this fact
What you can do / Measured in people or real products
In this 1996 sample, 3 of 73 deodorants labeled "not perfumed" genuinely contained none of the 21 fragrance substances tested, on chemical analysis.
Moderate evidence: Very small sample (n=3) from one country/year snapshot; does not establish that "not perfumed"/"fragrance-free" labels are reliable in general or in other markets/years.
Source: Rastogi et al. 1998, Contact Dermatitis Link to this fact
What you can do / Measured in people or real products
If you have armpit rashes and suspect your deodorant, ask your dermatologist for patch testing that includes hydroxycitronellal specifically rather than relying on a Fragrance Mix I result alone, since a positive fragrance-mix reaction does not identify which of its 8 constituents is responsible.
Moderate evidence: Extrapolated consumer advice from a clinical elicitation study; not itself a tested intervention.
Source: Svedman et al. 2003, Contact Dermatitis Link to this fact
What you can do / Other evidence
If you have unexplained facial or hand eczema and a history of reacting to a scented deodorant or cologne, ask your dermatologist about patch testing with your own stay-on cosmetic products plus HICC (Lyral), not just the standard fragrance mix.
Moderate evidence: Risk-factor odds ratios come from one case-referent study cited by the review, not replicated here.
Source: Johansen 2003, Am J Clin Dermatol 4(11):789-798, American Journal of Clinical Dermatology Link to this fact
What you can do / Measured in people or real products
Most positive reactions (7 of 10, 70%) did not appear until after 2 weeks of twice-daily deodorant use, so a short 1-2 week trial of a new product is not a reliable way to rule out a delayed fragrance allergy.
Moderate evidence: Based on 10 reactors in a single study; the authors recommend use tests run at least 4-6 weeks for this reason.
Source: Bruze et al. 2005, Contact Dermatitis Link to this fact
What you can do / Review of other studies
Patch testing a patient's own perfume, deodorant, or shaving lotion, not only a standardized fragrance panel, has detected sensitizations (e.g. to jasmine absolute, ylang ylang oil, lyral) that the panel alone missed.
Moderate evidence.
Caveats
Relayed from North American (Belsito 2006) and German IVDK (Uter 2007) clinical series; useful practical guidance for allergic patients even though Brasch's own account is secondary.
Source: Brasch 2007, Current Opinion in Allergy and Clinical Immunology Link to this fact
What you can do / Measured in people or real products
Because hormone-disrupting chemicals cluster by product type, cleaners, synthetic detergents, fabric softeners, air fresheners, and deodorants are the household product categories where checking for isothiazolinone preservatives (such as benzisothiazolinone) and fragrance chemicals (such as hexyl cinnamaldehyde, geraniol, and citronellol) is likely to be most worthwhile.
Moderate evidence: Reflects which chemicals are most often listed in this product database, not which products emit the most or pose the greatest measured exposure.
Source: Lee & Ji 2022, Ecotoxicology and Environmental Safety Link to this fact
What you can do / Measured in people or real products
Choosing toothpaste, soap, and deodorant that do not list triclosan (or Irgasan) on the label is a reasonable way to lower plasma and breast-milk triclosan levels, though it will not eliminate all exposure.
Moderate evidence.
Caveats
This single study alone would be weak support for a what-you-can-do claim; strength here rests on corroboration from the independent HERMOSA 2016 intervention trial (different population, different design) rather than on Allmyr 2006 alone.
Source: Allmyr 2006, Science of The Total Environment Link to this fact
What you can do / Other evidence
Pump and trigger sprays put far less of the product into the lung-reaching respirable range than aerosol versions of the same product: recommended respirable-fraction ranges are 0-2% for hair, deodorant, body, sunscreen, and facial pump sprays, versus 2-35% for the equivalent aerosols.
Moderate evidence.
Caveats
These are industry-compiled default ranges for safety-assessment purposes, not a head-to-head measurement of the same formulation in both formats; actual respirable fraction depends on the specific product's nozzle, pressure and formulation.
Source: Steiling et al. 2025, Toxicology Letters Industry-funded Link to this fact
What you can do / Review of other studies
If you have diagnosed fragrance or deodorant-ingredient allergy, ask your dermatologist about expanded patch testing (balsam of Tolu, fragrance mix 2, botanicals, lichen acid mix) if a standard fragrance screen is negative but suspicion remains, since the standard screen is estimated to miss a meaningful share of true fragrance allergy.
Moderate evidence: Practice recommendation from a narrative clinical review, not from an interventional study measuring whether expanded testing changes diagnostic outcomes.
Source: Zirwas & Moennich 2008, The Journal of Clinical and Aesthetic Dermatology Link to this fact
What you can do / Other evidence
Isoeugenol is a flavor ingredient (about 236 kg a year in the US) and also a classic fragrance allergen; the flavor panel's safety margin counts only eating it, not skin contact from deodorants or perfumes.
Moderate evidence: The article does not discuss fragrance exposure; 'allergen' status comes from other sources (Bruze 2005), not this page.
Source: Smith et al. 2009 (FEMA Expert Panel), GRAS Flavoring Substances 24, Food Technology 63(6), Food Technology Industry-funded Link to this fact
Information, not medical advice. See also: myths we won’t tell you.