Synthetic Fragrance is the New Second-Hand Smoke
As someone who gets migraines and feels sick after smelling many common synthetically fragranced products, I suppose I’m a little biased, but I think that even for those that don’t get migraines, being exposed to these chemicals constantly is objectively bad for you. I think, years from now, treat synthetic fragrance similarly to how we currently regulate and avoid exposure to second-hand smoke.
Fragrance chemicals are everywhere & We Don’t Get to Know What’s In them
More than 2,000 distinct chemicals can hide behind the word “fragrance” on a label; none are required to be individually listed as ingredients in the U.S.
National surveys show that roughly one‑third of adults report headaches, respiratory distress, or other health problems when they breathe fragranced air.
Because scented products sell better, these chemicals are now found in cosmetics, air fresheners, cleaners, detergents, candles, kitty litter, diapers, “odor‑blocking” garbage bags, feminine hygiene products, nail polish, and just about everything else, creating involuntary, chronic exposure everywhere, reminiscent of the indoor‐smoking era. 🫠
Primary emissions & secondary pollution
Fragranced products emit dozens to hundreds of volatile organic compounds (VOCs) such as limonene, α‑pinene, and ethanol. Indoors, these VOCs react with background ozone to create secondary pollutants—including formaldehyde and ultrafine particles—at concentrations comparable to those produced by indoor cigarette smoke. 👀
Documented Health Impacts from Fragrance
| Pathway | Key chemicals | Evidence of harm |
|---|---|---|
| Respiratory & neurological | Terpenes, ethanol, aldehydes | 64 % of asthmatics report symptoms from fragranced air; general‑population studies link exposures to migraines, nasal irritation, and lost workdays. |
| Endocrine disruption & fertility | Phthalate diluents (DEP, DBP), synthetic musks (HHCB/galaxolide, AHTN) | Human biomonitoring correlates daily perfume & lotion use with higher urinary phthalate metabolites and reduced fecundability; musks and phthalates mimic or block steroid hormones. |
| Carcinogenic contamination | Benzene (aerosol propellants), 1,4‑dioxane, formaldehyde | 2022–2024 recalls of dry shampoos, spray deodorants, and acne products after FDA and independent labs detected benzene—prompting multimillion‑dollar class actions. |
| Bioaccumulation & persistence | Polycyclic musks (galaxolide/HHCB) | Detected in >90 % of U.S. breast‑milk samples; SC Johnson announced a phase‑out after classification as persistent, bio‑accumulative, and toxic (PBT). |
Comparing Second-hand Smoke Exposure to Synthetic Fragrance
| Second‑hand smoke | Synthetic fragrance |
|---|---|
| Complex, proprietary mixture of hundreds of combustion chemicals | Complex, proprietary mixture of hundreds of synthetic aroma chemicals + contaminants |
| Ubiquitous in the 20th‑century indoor environment | Ubiquitous in 21st‑century indoor environments (homes, offices, schools, transit) |
| Health effects even at low, involuntary exposures (asthma, cancer, cardiovascular disease) | Health effects reported at common indoor concentrations; endocrine, respiratory, neurologic, and potential carcinogenic risks |
| Long fight for disclosure, ventilation, and smoke‑free policies | Ongoing campaigns for full fragrance‑ingredient disclosure, fragrance‑free workplaces, and regulation of indoor VOCs |
Both exposures are largely involuntary for bystanders, accumulate indoors, and can harm vulnerable groups (infants, pregnant women, asthmatics) at doses below those causing obvious irritation—core reasons public‑health researchers draw the analogy.
Fertility Clinics & IVF “No Fragrance” Policies
Did you know that you’re not allowed to wear scented products like cologne or lotion in IVF/Fertility clinics?
Embryos are exquisitely sensitive to volatile organic compounds (VOCs). Experiments show that total VOC levels just 1 ppm in incubator air can be directly toxic to pre‑implantation embryos, and clinic audits now recommend keeping the lab atmosphere below 100 ppb—far lower than typical indoor perfume concentrations. Even modest spikes in aldehydes or terpenes have been linked to lower fertilization, blastocyst‑formation and pregnancy rates. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov
Because perfumes, colognes, scented lotions, hair products and even fragranced laundry detergents are major indoor VOC emitters, most modern IVF centres have adopted strict fragrance‑free policies for anyone who enters the embryology suite:
Pacific Centre for Reproductive Medicine (Canada) designates the entire clinic “scent‑free”—staff and patients alike are asked to avoid perfumes, deodorants, body lotions, aftershave and to wash their scrubs in fragrance‑free detergent, specifically to “limit VOCs that can affect embryo growth.” pacificfertility.ca
Industry guidance for IVF laboratory design likewise lists cosmetics, perfume and cologne alongside cigarette smoke as prohibited sources of VOC contamination, recommending clean‑room style positive‑pressure HVAC to prevent infiltration. linkedin.com
Many commercial IVF air‑quality vendors and clinic blogs explicitly warn that “fragrances shouldn’t be used in IVF centres,” noting documented drops in pregnancy success when scent‑related VOCs rise in the lab. fertynest.com vigiesolutions.com
Typical rules posted at fertility clinics therefore read much like a chemical clean‑room protocol:
| Banned or restricted item | Reason in an IVF lab |
|---|---|
| Perfume, cologne, body spray | Terpenes and phthalates off‑gas into air and culture media |
| Scented deodorant, lotion, hair products | Continuous VOC release from skin and hair |
| Recently dry‑cleaned or fragranced‑detergent clothing | Residual solvents transfer to lab air |
| Air fresheners, scented sanitizer, candles | High terpene/alcohol emissions overwhelm filters |
Embryos have no immune or detoxification defenses, so IVF facilities treat fragrance chemicals with the same caution once reserved for second‑hand smoke—eliminating the source altogether rather than trying to ventilate it away. When a clinic asks visitors to come “fragrance free,” it is protecting the microscopic beginnings of life from airborne toxins measured in parts per billion.
Case studies & consumer products
Dry shampoos & spray deodorants (Unilever, Batiste, Secret, Old Spice): recalled after benzene detection; litigation cites elevated leukemia risk. fda.gov lawsuit-information-center.com topclassactions.com
“Fresh‑scent” laundry detergents & dryer sheets: laboratory vent studies found >25 hazardous air pollutants, including acetaldehyde and styrene, vented outdoors each load. washington.edu
Plug‑in air fresheners & scented cleaners: indoor air sampling detects VOC bursts that exceed chronic‑reference exposure levels for irritants like ethanol and terpenes. sciencedirect.com lung.org
Galaxolide in major cleaning brands: activists forced phase‑outs after evidence of bioaccumulation and persistence similar to legacy POPs. womensvoices.org
Regulatory & disclosure gaps
In the U.S., fragrance formulas are trade secrets; neither the FDA (cosmetics) nor CPSC (household cleaners) requires full ingredient lists, hampering consumer choice and physician diagnosis.
Only California, the EU, and a handful of retailers mandate limited disclosure of 26‑31 “allergenic” fragrance substances—out of the thousands that are regularly being used.
The EPA acknowledges that most fragrance chemicals have never undergone endocrine‑screening assays, leaving large data gaps. epa.gov niehs.nih.gov
What about essential oils?
Many people swap plug‑in fresheners for diffused or topically applied essential oils (EOs) because they are marketed as being “natural.” But EOs are still concentrated mixtures of volatile organic compounds (VOCs) (mostly terpenes such as limonene, linalool, and α‑pinene). Room and field tests show that running a single EO diffuser can push indoor VOC levels into the hundreds to low‑thousands µg m‑3 range, comparable to synthetic air fresheners.
Once those terpenes mix with background ozone they quickly oxidise into secondary pollutants (formaldehyde, acetaldehyde, and ultrafine particles) just as synthetic fragrance terpenes do. The newest full‑scale diffuser study found that terpene‑derived particles and carbonyls climbed well above precautionary indoor‑air limits within the first hour of use, especially in small or poorly ventilated rooms.
Endocrine‑disrupting evidence
Lavender and tea‑tree oils. A 2007 New England Journal of Medicine case series linked regular topical use of products containing these EOs to pre‑pubertal gynecomastia—abnormal breast growth—in three boys; in‑vitro assays showed both oils were estrogenic and anti‑androgenic. nejm.org pubmed.ncbi.nlm.nih.gov
Mechanistic confirmation. NIEHS researchers isolated eight common constituents of lavender and tea‑tree oils (e.g., eucalyptol, linalool, α‑terpineol) and demonstrated estrogen‑receptor activation and androgen‑receptor blockade in human cell lines, strengthening the causal link. endocrine.org sciencedaily.com pmc.ncbi.nlm.nih.gov
Other oils (e.g., clary sage, peppermint) show weaker or no endocrine activity in similar screens, but systematic safety testing of the 200‑plus commercially popular EOs is sparse.
“Natural” vs. “synthetic”
Better: EOs generally lack phthalate solvents and nitro‑/polycyclic musks that bio‑accumulate, so their body burden may clear faster.
Not better enough: The dose of reactive terpenes released—and therefore secondary formaldehyde and particle formation—can mirror or exceed that of synthetic fragrance products. Routine inhalation, especially in tight, energy‑efficient homes, still carries respiratory‑irritant risks.
Endocrine caveats: While direct hormone‑like effects appear to be limited to a handful of oils, lavender and tea‑tree are among the most widely marketed; long‑term, low‑dose implications for sensitive groups (children, pregnant users, males with low testosterone) remain unknown.
Better Choices — How to Replace Fragranced Products
Source control beats ventilation: fragrance‑free policies in offices, schools, and health‑care settings immediately lower VOCs similarly to how smoke‑free laws did.
Do not buy plug-in air fresheners, diffusers, and other products that spray artificial fragrance throughout your home, they are undoubtedly making you sicker.
Opt for “fragrance‑free,” not merely “unscented.” (“Unscented” can still use masking fragrance.)
Choose products without essential oils added. Essential oils produce a similar amount of VOCs to synthetic fragrance chemicals.
Aerosolized beauty products are highest‑risk because propellant contamination introduces benzene and other petrochemical by‑products. Avoid hairsprays, spray-sunscreens, and other aerosol products.
Support and advocate for full‑label laws and independent testing to close the disclosure gap. We deserve to know what is in the products we use!
How to Keep Your House Smelling Nice Without Fragrance
You may be wondering what I do to keep my house smelling nice with 4 pets. I use vinegar and baking soda to clean and neutralize odors. I have a steam mop that I love, that keeps the floors shiny, and I make my own cleaning spray using isopropyl alcohol and castille soap. I also have a HEPA filter in most high-traffic areas to help out with the dust from our 4 pets. My vacuum also has a built-in HEPA filter.
A few times per week, I open all the windows to get fresh air circulating. Periodically I will also burn organic white sage, which is not great for air quality but I like the scent and view it as less bad than using synthetic fragrance or essential oils. I also bake and cook at home every day and am often infusing herbal concoctions in my kitchen, so my house often smells like the things I’m making.
My Fragrance-Free Cleaning Spray Recipe (makes 16oz)
Fill half the spray bottle with 70% isopropyl alcohol
Add 2 TBS of castille soap
Fill the rest of the way up with distilled water
You can infuse the water with whole herbs like mint or lemon for a nice fresh scent.
I use a glass spray bottle I purchased from amazon. It works really well for pretty much everything except glass, which it does leave a few streaks. For glass cleaning I use the brand Screen Mom, which is a plant-based and fragrance-free cleaner that works just as well as Windex imo.
Final Thoughts
Just as second‑hand smoke shifted from a benign social norm to a recognized indoor toxin, a growing body of toxicology, epidemiology, and product‑recall data argues that routine exposure to synthetic fragrance mixtures carries non‑trivial risks—respiratory, endocrine, and carcinogenic—warranting the same public‑health precautionary approach.
