This is the question we get asked more than any other, and it arrives in two very different voices.
One person has a scented bar of soap in the shower, likes it, and has just read something alarming about the word "fragrance." They want to know whether they should be worried, and they'd rather not throw out a bar they enjoy over a headline.
The other person threw out the dryer sheets years ago, doesn't own a plug-in, reads every ingredient list, and hasn't worn perfume since 2015. They aren't asking whether to worry — that decision is made. They want to know something harder: whether the natural products they replaced everything with are actually better, and where the remaining exposure is hiding now that the obvious sources are gone.
Both deserve a straight answer, and it is not the same answer. We make scented soap. We make scented candles. So we have every commercial reason to wave the whole question away — and no honest reason to. Here is the research, all the way down, and where it lands for each of you.
The question is also more precise than it first sounds: a soap is a rinse-off product carrying maybe a teaspoon of scent per bar, on your skin for ninety seconds. Can something that small and that brief really do damage? That instinct — that dose and duration matter — is exactly the right instinct. It is also, as you'll see, only about eighty percent of the story.
First: what is actually inside the word "fragrance"
A fragrance oil is not an ingredient. It's a formula — a blend of anywhere from a handful to over a hundred aroma chemicals, solvents and fixatives, built by a fragrance house and sold to manufacturers as a finished scent. Some components are distilled from plants. Most, in a modern commercial fragrance oil, are made in a reactor.
And here is the part that bothers us most, more than any single molecule: you are not allowed to know what's in it. The FDA states it plainly — under U.S. labeling law, fragrance and flavor components may be listed collectively as "fragrance," because the law that requires ingredient lists was not permitted to force companies to disclose trade secrets. One word on a label can legally stand in for eighty chemicals — and that exemption has stood, essentially unchallenged, since ingredient labeling on cosmetics became mandatory in the 1970s.
Europe went the other way. Under Commission Regulation (EU) 2023/1545, the list of fragrance substances that must be individually named on the label is expanding from 26 to 82, with the first deadline in July 2026. In the U.S., the Modernization of Cosmetics Regulation Act finally gives the FDA authority to require fragrance-allergen disclosure — but even a fully compliant label will still be permitted to hide everything that isn't on the allergen list behind the word "fragrance."
Notice what the European rule assumes, though, because it matters for the soap question. The disclosure thresholds are 0.001% for leave-on products and 0.01% for rinse-off products — a tenfold difference. Regulators looking at the same allergens decided that something you wash off warrants ten times less concern than something you leave on. Keep that number in your pocket.
The dose question — and the study that answers it directly
This is the heart of it, so here is the strongest evidence available, in both directions.
In 2018, a team published a study in Dermatitis that did exactly the calculation you'd want: it modeled daily real-world exposure to fragrance chemicals across personal care products and compared it against the doses known to induce skin sensitization. The finding was clean and, frankly, reassuring for the soap question. Several leave-on products — lipstick, solid antiperspirant, eye shadow, face cream — showed an increased risk of inducing sensitization, especially in heavy users. The rinse-off products — shampoo, conditioner, facial cleanser — did not.
That is the mainstream dermatological picture: for the induction of a new fragrance allergy, wash-off products sit at the low end of the exposure ladder. The instinct about dose and duration was right.
Now the two honest caveats.
Caveat one: "it rinses off" is less true than it sounds. Soap fragrance is deliberately engineered to survive the rinse. Formulators call it substantivity, and there is an entire body of industry work on how to structure surfactant systems so more perfume deposits on skin and hair — including patented bar formulations that lower soluble surfactant specifically to enhance fragrance deposition and longevity. If a soap still smells good on your forearm an hour later, that scent did not rinse off. It was designed not to.
Caveat two: nobody uses one product. Exposure researchers in the Netherlands mapped usage patterns across 32 different personal care products and made the obvious-but-overlooked point: the same aroma chemical shows up in your soap, your shampoo, your deodorant, your lotion, your detergent and your candle, so the relevant number is never the soap alone — it's the aggregate. A single bar is a rounding error. A whole scented life is not.
That second caveat is the hinge of this entire article, and it is why the two readers get different answers. If your life is fully scented, the soap is a small part of a large number. If you have already stripped the rest out, the soap is a large part of a very small number — and the arithmetic changes character completely.
What fragrance actually does to skin, when it does something
The documented harm from fragrance on skin isn't poisoning. It's allergic contact dermatitis — the immune system learning to recognize a molecule, and then reacting every time it meets it again. Fragrance was named Allergen of the Year by the American Contact Dermatitis Society in 2007, and it has stayed near the top of the list ever since.
How common is it? The best general-population figure comes from a five-country European study that patch-tested a random sample of over 3,000 adults — not dermatology patients, ordinary people. Prevalence of clinically relevant fragrance contact allergy: about 1.9%, with 2.6% reacting to Fragrance Mix I. And one detail worth naming: rates in women were roughly double those in men — which is what you'd expect from the group that uses more scented products, more often, on more skin.
So: roughly one to three adults in a hundred. For the other ninety-seven, a scented bar of soap is a non-event. For those one to three, it is a real and permanent problem — because once you are sensitized, there is no comfortable dose. The reaction is immunological, not toxicological. It doesn't care that the amount was small.
Two groups sit at higher risk. People with eczema or any compromised skin barrier, because a damaged barrier lets allergens through and researchers have repeatedly linked barrier dysfunction to higher rates of contact sensitization. And here's the irony that is genuinely underappreciated: soap itself is the thing that opens the door. Surfactants strip lipids and raise skin pH; they impair the barrier on their own. The fragrance is just the passenger that walks through the door the detergent opened. If you have irritated, cracked, or eczema-prone skin, the harshness of the base matters more than the scent on top of it — which is the whole argument behind our herbs for irritated skin piece.
The uncomfortable part: "natural" does not mean "non-allergenic"
This is the section written specifically for the reader who has already switched everything over. It would be easy to stop at the last paragraph and let you assume essential oils solve this. They don't, and you should hear it here rather than find it out from someone with less at stake.
Look at what's actually in Fragrance Mix I, the standard patch-test screen for fragrance allergy: geraniol, cinnamaldehyde, cinnamyl alcohol, hydroxycitronellal, amyl cinnamaldehyde, eugenol, isoeugenol, and oak moss absolute. Most of that list is plant chemistry — rose, cinnamon, clove, lichen. The two strongest sensitizers in the mix are oak moss absolute and isoeugenol. Both botanical.
It gets more specific than that. Linalool (lavender, bergamot, coriander) and limonene (every citrus peel on earth) are harmless as they sit in the bottle. Exposed to air, they oxidize, and the hydroperoxides they form are potent sensitizers. A Swedish analysis of 5,773 patch-tested patients found contact allergy to oxidized linalool in 7.0% and oxidized limonene in 5.1% — higher than the classic fragrance mixes, and rising year over year. DermNet's summary is blunt about it: these two are now among the most common fragrance allergens in the world, and they come from the plants.
We say this out loud because it's the part the natural-products industry skips, and skipping it is how you lose the right to be believed. An essential oil is not a safety claim. It is a transparency claim: you know the plant, you know what's in it, you can look it up, and you can decide. That's a real and meaningful difference — it just isn't the same as "cannot cause a reaction."
What it does change is what a maker can do about it, and what you can do about it at home. Oxidation is a storage and freshness problem, and freshness is controllable: cool, dark storage, sealed bottles, oils that get used instead of sitting for three years, modest scent loads instead of maximum ones, simple blends instead of thirty-component ones, and every botanical named on the label so a sensitized person can avoid theirs. If you keep a shelf of essential oils yourself, the citrus oils are the ones to date and use up first — an old bottle of bergamot is a meaningfully different substance from a new one. None of that is possible with a fragrance oil, because nobody involved knows what's in it either.
The three chemical worries you've read about — and which ones hold up
Phthalates. The concern is real, and the specifics matter. Health Canada researchers analyzed 252 products and found diethyl phthalate (DEP) in nearly every product category, with the highest levels — up to 2.6% by weight — in fragrances, where it works as a solvent and fixative. None of it was on the labels. But honesty cuts both ways: DEP is not the phthalate the toxicology is worried about. The reproductive and anti-androgenic evidence centers on DBP and DEHP; the toxicological review of DEP and the CPSC's own toxicity review both put it in a much lower risk tier. So: the phthalate story is strongest for the class and weakest for the one actually used in perfume. What remains damning is not the toxicity — it's that it was there, at percent-level concentrations, and no label ever mentioned it.
Synthetic musks. This one holds up, and it's the argument we find hardest to answer. Polycyclic musks like galaxolide and tonalide are fat-soluble and persistent, and they don't stay where you put them. Researchers measuring paired maternal blood, umbilical cord blood and breast milk found them in all three — meaning these molecules cross the placenta. They've been documented in human adipose tissue and blood on every continent. Note carefully what this is and isn't: it is strong evidence of body burden, not proof of harm at those levels. But "we found it in cord blood and we're still arguing about what it does" is not a sentence anyone should be willing to build a product on.
The disclosure gap itself. A study of air fresheners in the U.S. — including products marketed as "all-natural" and "unscented" — found that 12 of 14 emitted phthalates, and none listed them. That is the actual hazard in the fragrance industry: not one villain molecule, but a system where the label cannot tell you, and "natural" on the front of the box constrains nothing on the inside. If you have built a chemical-free household on the strength of front-of-package claims, that study is the one to sit with — it is the clearest demonstration that the word does no work.
Candles are a different question, and a more serious one
Everything above concerns skin. A candle isn't a skin exposure — it's combustion in a room you're breathing, with no rinse step at the end. Different physics, different math.
The most thorough measurement to date burned 24 sets of candles across four waxes and five fragrances in a controlled chamber, tracking CO, NOx, formaldehyde, benzene, PAHs, PM2.5 and ultrafine particles, then modeled realistic indoor exposure. Its conclusion: in most cases the calculated indoor concentrations were well below the relevant guidance values — with exceptions, discussed critically by the authors, for nitrogen dioxide, acrolein and benzo[a]pyrene. Read that study with its own disclosure in view: it was designed in collaboration with candle manufacturers and a fragrance house, with a co-author from the European Candle Association. Which makes the exceptions more interesting, not less. An earlier independent chamber study found that benzene and PAH emissions tracked mostly with the wax, while aldehyde emissions tracked with the additives.
Then there's the chemistry that happens after the flame. Terpenes — including the limonene and pinene in perfectly natural citrus and conifer oils — react with ozone drifting in from outdoors to produce formaldehyde and ultrafine secondary organic aerosol. This is worth sitting with if you love natural scent, because it is the one place where natural earns you nothing: an essential-oil candle is not safe smoke. The rules that actually protect you are about the burn, not the label — trimmed wick, adequate room, real ventilation, and don't run it for hours in a closed bedroom. The full breakdown of wax, wicks and soot is in what makes a candle truly natural.
And the human reporting on all of this deserves respect rather than dismissal. In a nationally representative U.S. survey, 34.7% of adults reported health problems from exposure to fragranced products — respiratory difficulty, mucosal irritation, migraine. Among people with asthma the figure was 64.3%. These are self-reports, not clinical diagnoses, and skeptics are right to say so. They are also a third of the population telling you the same thing about the same products, which is the kind of signal traditional medicine has always been willing to take seriously and industrial science is often too proud to.
Which is what our grandmothers were doing all along
Every tradition we draw from scented things — and every one of them scented with the plant, never with an isolate of it. Frankincense and myrrh burned in the temple. Sandalwood and agarwood in Vedic ritual. In Traditional Chinese Medicine the aromatic herbs are a functional category, not a decorative one: agents that "open the orifices" and awaken the spirit, or that dry damp and move stagnant qi in the middle burner. Ayurvedic dhoop, Mediterranean rosemary and bay, the herbs of the sweat lodge. Thousands of years of people arriving independently at the conclusion that aroma acts on a person, and that the material carrying it should be a whole plant.
Modern research doesn't contradict them; it explains the mechanism. Olfaction is the one sense with a direct anatomical shortcut to the limbic system, which is why scent reaches mood and memory before thought gets a vote — covered in how essential oils affect you when you breathe them. The traditions were right about the effect. What they never did was isolate one aroma molecule, multiply it a thousandfold, and market it as an ingredient with no name.
The products that are genuinely worse — and they're right next to your soap
This comparison is the most useful part of the whole piece, because it reorders the worry list. Rank by exposure route, duration, and surface area — not by how alarming the ingredient sounds — and a rinse-off bar of soap drops near the bottom. Here's what outranks it, in an ordinary bathroom and laundry room.
1. Plug-ins, wax melts and room sprays. A soap touches you for ninety seconds. A plug-in emits continuously for weeks, in the smallest and least-ventilated rooms in the house, with a heating element driving the release. Peer-reviewed exposure assessments of sprays and diffusers under realistic indoor conditions exist precisely because the duration is so different, and it's the same category where 12 of 14 products emitted undisclosed phthalates. Worst exposure profile in the house, and the one most people think is harmless.
2. Fabric softener and dryer sheets. This is the one nobody counts, and it may be the sneakiest. Laundry fragrance is engineered to deposit onto fibers and stay there — which means it sits against the entire body, all day and all night, on a shirt, on sheets, on a pillowcase, on children's pajamas. Not ninety seconds. Sixteen hours. Sampling from residential dryer vents during use of fragranced laundry products found more than 25 VOCs emitted, including acetaldehyde and benzene — both classified as hazardous air pollutants. For most households, this is the single highest-value change available, and it costs nothing.
3. Body spray, perfume, and solid antiperspirant. Leave-on, applied to thin skin, often to a freshly shaved armpit, and reapplied daily for decades. This is the exact category the sensitization modeling flagged as carrying real risk while rinse-off products did not. Perfume is also where the phthalate concentrations were highest and where synthetic musks are most heavily used.
4. Scented tampons, pads and panty liners. The most quietly outrageous one on the list. Belgian government researchers tested 10 scented absorbent hygiene products and found eight allergenic fragrances, with five products containing at least one allergen above 10 µg/g — none of it disclosed to the consumer, because in the EU these products fall outside cosmetic law and fragrance can be used freely. Mucosal tissue, prolonged contact, no ingredient list. Related: a national survey of 1,435 Canadian women found that use of intimate washes and gel sanitizers was associated with substantially higher odds of bacterial infection and UTI. If you go fragrance-free on exactly one thing, start here.
5. Antibacterial "germ-killing" soap. Directly comparable, since it's the same product on the same shelf. In 2016 the FDA banned 19 active ingredients, including triclosan and triclocarban, from consumer antiseptic washes — not over a scare, but because manufacturers could not demonstrate they were safe for long-term daily use or any better than plain soap and water. A scented ordinary bar was the better choice all along.
6. And the one with the largest documented signal of all. Chemical hair straighteners — leave-on, on the scalp, absorbed through skin that has often been abraded first. Following 33,497 women for nearly eleven years, the NIH Sister Study found roughly double the rate of uterine cancer among users, and about 2.5 times among frequent users. No association with dyes, bleach, or perms. That's the shape of a serious personal-care exposure, and it looks nothing like a bar of soap.
Same principle applies to anything else that wants to be natural: ask what the exposure actually is. Rinsed off or left on? Skin, lung, or mucosa? Ninety seconds or sixteen hours? Once, or every day for thirty years? That one question sorts the real risks from the frightening-sounding ones faster than any ingredient list.
If you already live fragrance-free: what's actually left
If you read that list and recognized none of it — no plug-ins, no softener, no perfume, no straighteners — then the honest thing to say is this: you already removed the top of the ladder. Everything with a large documented signal in the literature is in the part of the list you've eliminated. What remains for you is a genuinely different set of questions, and most articles on this topic never get to them because they're still busy convincing people to throw out the dryer sheets.
So here is what's left, in the order it deserves attention.
The exposure you don't control is now most of your exposure. Hotel rooms, gym locker rooms, offices, the laundry aisle, the person next to you on the train, the classroom your child sits in for six hours. When your household number drops close to zero, the environmental fraction becomes the dominant term. That isn't cause for despair — it's a reason to put your energy into the places where you spend the most hours rather than into further optimizing a bar of soap that's already clean.
"Unscented" and "fragrance-free" are not the same word. This is the single most useful piece of label literacy in this article. Fragrance-free means no fragrance material was added. Unscented often means a masking fragrance was added to cover the raw smell of the base — so an "unscented" lotion can legally contain undisclosed fragrance chemicals whose entire job is to be undetectable. The air-freshener study above found exactly this: products marketed as "unscented" still emitted phthalates. If you have been buying unscented, check whether the ingredient list ends in "fragrance" or "parfum." Very often it does.
Your diffuser is not exempt from physics. Households that removed plug-ins frequently replaced them with an essential-oil diffuser, and that is a real improvement — no heating element, known botanicals, no undisclosed solvent. But it is still terpenes released continuously into indoor air, and the ozone reaction described in the candle section doesn't check whether the limonene came from a lab or a lemon. Run it in bursts rather than all day, in a room with air movement, and treat it as an aromatic event rather than an ambient condition. That is also, incidentally, how every tradition that used aromatics actually used them.
Freshness is your version of the ingredient list. The oxidized-linalool finding matters more to you than to anyone else in this article, because you are the person with a shelf of oils. A three-year-old bottle of citrus oil that has been opened repeatedly is a more sensitizing material than the same oil bought last month. Date the bottles. Store them cool and dark. Use the citrus first. Buy smaller quantities more often rather than a big bottle you'll finish in four years.
And if the answer for you is nothing at all, that's a legitimate answer. If you are sensitized, pregnant and cautious, buying for a baby, or simply want the number to be zero, the correct product is an unscented true soap — a plain olive or tallow bar with no fragrance material of any kind. We are not going to construct a reason why you need a scented bar from us instead. A person who has thought this through and concluded "none" has reasoned correctly from their own situation, and the whole point of laying out the evidence is that you get to do that.
So can a natural scent actually be amazing? An honest answer
This is the real question underneath the safety question, and it deserves a straight answer instead of marketing. Fragrance oils are extraordinary. A good perfumer with a full synthetic palette can build things nature simply does not make, and pretending otherwise insults your nose.
So here is the honest ledger.
What essential oils genuinely cannot do. There is no such thing as strawberry essential oil. Or melon, cantaloupe, peach, cream, maple sugar, "fresh linen," or musk. Those notes exist only as synthetics — the fruit and the fabric either yield no usable oil at all or yield one that smells nothing like the fruit. Vanilla and jasmine can be captured, but as absolutes and CO2 extracts, not steam-distilled oils, and at a cost that shows up in the price of the bar. This is the cleanest test we know for any product claiming to be naturally scented: read the scent notes. If a "natural" candle or soap promises cantaloupe, sugared berries, fresh linen or musk, there is fragrance oil in it, whatever the front of the label says. Nature does not sell those notes.
Which means we had to apply that test to ourselves, out loud. An article about undisclosed ingredients that quietly exempts its own author is worth nothing. So we ran it against our own shelf while writing this piece, and it cost us. Five of our candles listed notes — cantaloupe, melon, coconut, cream, maple sugar, lychee, lily — that cannot come from a plant. That meant those candles carried fragrance oil while the page they sat on said we never use it. They are no longer for sale. We did not reword them, and we did not quietly leave them up with a footnote; we took them down, including two we had stock sitting on the shelf for.
Our soaps passed and are unchanged: every bar we sell is scented with named botanicals, listed individually, and you can check them against the test above. So did the candles that were always what they said they were. We would rather run a smaller catalogue that survives its own article than a larger one that doesn't. If the test is good enough to hand you, it has to be good enough to fail in public.
What natural scent does better. Complexity. A real lavender oil isn't one lavender molecule — it's hundreds of constituents in a ratio no formulator would think to write down, which is why a single-note natural has a roundness and a slight unevenness that a reconstruction never quite reaches. It smells like a place and a season rather than like an idea of one.
Where it gets technically hard, and what actually fixes it. Essential oils are more volatile than fragrance oils, and cold-process soap is a brutal environment for them — high pH plus the heat of saponification plus weeks of cure will eat delicate top notes. Citrus fades fastest; that isn't a safety issue, it's a craft one. The real fixes are old and unglamorous: anchor with base notes — patchouli, vetiver, cedarwood, benzoin — build a proper top-middle-base structure instead of a single bright note, use generous loads within the IFRA rinse-off limits, cure properly, and lean into the notes that actually last in soap. Which is why the naturally scented soaps that hold their scent for months are herbal, spiced, resinous and woody — and why a natural bar promising crisp cucumber-melon in month four is telling you a story.
The verdict: yes, a natural scent can absolutely be beautiful, distinctive and worth wanting — but only if you give up the fantasy flavors and build with what actually grows. That's a narrower palette and a more expensive one. It's also, in our experience, a more interesting one. It's the whole reason our soaps are what they are: Wild Lavender as a single true note, Patchouli Pure for the deep end, Dawn Awakening built on lemon, eucalyptus, rosemary, cinnamon and clove, and Essential Shield as an eight-oil citronella blend. Every botanical named. Nothing hiding behind one word.
The bottom line: is a soap with fragrance oils dangerous?
Here is the straight answer, undressed in either direction.
For a healthy adult with intact skin, a rinse-off soap containing fragrance oils is at the low end of the risk ladder, and the evidence does not support calling it dangerous. The dose is small, the contact time is short, the regulators' own thresholds treat rinse-off as ten times less concerning than leave-on, and the best available modeling of real-world use found no sensitization risk from rinse-off products while finding it clearly in leave-on ones.
What that conclusion means for you depends entirely on which reader you are.
If most of your household is still conventional — and that is most people — then the scented bar in your shower is not where your exposure lives, and worrying about it is worry spent in the wrong place. The plug-in in the hallway, the dryer sheets in the laundry room and the perfume on your wrist are each an order of magnitude more exposure than the soap, on every axis that matters: duration, surface area, and whether it ever comes off. Fix those in that order and the soap question stops being interesting. Changing the soap first is doing the easiest thing and calling it the important one.
If you have already removed all of that, the same evidence points somewhere else entirely. You are not the person the reassurance was written for, because you weren't asking for reassurance. Your remaining household exposure is genuinely small, which means the marginal gain from any further swap is also small — and the honest advice is to stop optimizing products and start looking at the two things that actually still move your number: the environments you can't control, and the freshness of the botanicals you already own. And take the "natural is non-allergenic" assumption out of the toolkit permanently. It was never true, the oxidized-terpene data has been saying so for a decade, and believing it is how a fragrance-free household ends up with a reaction it can't explain.
The genuine risks are narrower and real, for everyone. One to three adults in a hundred are already fragrance-sensitized — more women than men — and for them there is no small enough dose; a scented bar means an itchy rash. Anyone with eczema, dermatitis or a broken skin barrier is both more likely to react and more likely to be sensitized in the first place, and the detergent base is doing as much of that damage as the perfume. Babies and young children have thinner skin and a lifetime of exposure ahead of them. And the aggregate matters: one bar is nothing, while soap plus shampoo plus deodorant plus lotion plus detergent plus a plug-in, every day for forty years, is not nothing.
And there is one risk that no study can retire, which is the reason we made our choice. You cannot know what is in it. Not because someone is hiding a poison, but because the law never required anyone to tell you, and the ingredient that turned out to be worth worrying about — the musk found in cord blood, the phthalate at 2.6% by weight — was never on a label either time. Every reassuring safety assessment is an assessment of a formula you were not allowed to read.
So we're not going to tell you that the soap in your shower is harming you, because the evidence doesn't say that, and keeping your trust is worth more than winning the argument. What we'll tell you is what we decided for ourselves: we would rather offer a handful of scents we can name, from plants we can point to, than an unlimited palette we're not permitted to describe. Fewer scents. Named plants. Nothing behind a trade secret. That's not a claim about danger — it's a claim about who gets to know what's touching you.
The rest of the Knowledge library works the same way: the evidence first, the inconvenient parts included, and the conclusion left to you.
Sources
U.S. Food & Drug Administration. Fragrances in Cosmetics (fragrance components may be listed collectively as "fragrance"; trade-secret protection).
European Commission. Commission Regulation (EU) 2023/1545 — labelling of fragrance allergens; list expanded to 82 substances; thresholds 0.001% leave-on / 0.01% rinse-off.
Drechsel DA, Towle KM, Fung ES, et al. Skin Sensitization Induction Potential From Daily Exposure to Fragrances in Personal Care Products. Dermatitis, 2018. (Leave-on products carried sensitization risk; rinse-off products did not.)
Diepgen TL, Ofenloch RF, Bruze M, et al. Prevalence of fragrance contact allergy in the general population of five European countries. British Journal of Dermatology, 2015. (≈1.9% clinically relevant; Fragrance Mix I 2.6%; women ≈2× men.)
Sukakul T, Bruze M, Mowitz M, et al. Contact allergy to oxidized linalool and oxidized limonene: patch testing in consecutive patients with dermatitis. Contact Dermatitis, 2022. (7.0% and 5.1% of 5,773 patients; increasing trend.)
DermNet NZ. Contact allergy to hydroperoxides of limonene and linalool.
Contact allergy and skin-barrier dysfunction: Contact Sensitization in Adults With Atopic Dermatitis — a 21-year tertiary-centre experience (PMC).
Biesterbos JWH, Dudzina T, Delmaar CJE, et al. Usage patterns of personal care products: important factors for exposure assessment. Food and Chemical Toxicology, 2013. (Aggregate exposure across 32 product types.)
Koniecki D, Wang R, Moody RP, Zhu J. Phthalates in cosmetic and personal care products: concentrations and possible dermal exposure. Environmental Research, 2011. (DEP up to 2.6% by weight in fragrances; undisclosed on labels.)
Api AM. Toxicological profile of diethyl phthalate: a vehicle for fragrance and cosmetic ingredients. Food and Chemical Toxicology, 2001.
U.S. Consumer Product Safety Commission. Toxicity Review of Diethyl Phthalate (DEP) (PDF).
Wang H, Zhang J, Gao F, et al. Occurrence and transport of synthetic musks in paired maternal blood, umbilical cord blood, and breast milk. International Journal of Hygiene and Environmental Health, 2015.
Steinemann A. Ten questions concerning air fresheners and indoor built environments. Building and Environment, 2017. (12 of 14 air fresheners, including "all-natural" and "unscented" ones, emitted undisclosed phthalates.)
Salthammer T, Gu J, Wientzek S, Harrington R, Thomann S. Measurement and evaluation of gaseous and particulate emissions from burning scented and unscented candles. Environment International, 2021. (Most modeled indoor concentrations below guidance values; exceptions for NO₂, acrolein, benzo[a]pyrene. Study designed with candle manufacturers and a fragrance house; co-author from the European Candle Association.)
Derudi M, Gelosa S, Sliepcevich A, et al. Emissions of air pollutants from scented candles burning in a test chamber. Atmospheric Environment, 2012.
Nazaroff WW, Weschler CJ. Cleaning products and air fresheners: exposure to primary and secondary air pollutants. Atmospheric Environment, 2004. (Terpenes + ozone → formaldehyde and secondary organic aerosol.)
Steinemann A. Fragranced consumer products: exposures and effects from emissions. Air Quality, Atmosphere & Health, 2016. (34.7% of U.S. adults reported adverse effects.)
Steinemann A. Fragranced consumer products: effects on asthmatics. Air Quality, Atmosphere & Health, 2018. (64.3% of asthmatics reported adverse effects.)
Steinemann A, Gallagher LG, Davis AL, MacGregor IC. Chemical emissions from residential dryer vents during use of fragranced laundry products. Air Quality, Atmosphere & Health, 2013. (>25 VOCs including acetaldehyde and benzene.)
Desmedt B, Marcelis Q, Zhilivoda D, Deconinck E. Sensitizing fragrances in absorbent hygiene products. Contact Dermatitis, 2020. (Eight allergenic fragrances found in scented tampons, pads and liners; undisclosed.)
Crann SE, Cunningham S, Albert A, Money DM, O'Doherty KC. Vaginal health and hygiene practices and product use in Canada: a national cross-sectional survey. BMC Women's Health, 2018.
U.S. FDA. Safety and Effectiveness of Consumer Antiseptics (Final Rule, 2016) — 19 active ingredients, including triclosan, barred from consumer antiseptic washes. See also Skip the Antibacterial Soap; Use Plain Soap and Water.
Chang C-J, O'Brien KM, Keil AP, et al. Use of Straighteners and Other Hair Products and Incident Uterine Cancer. Journal of the National Cancer Institute, 2022. (33,497 women; ≈2× risk among users, ≈2.5× with frequent use.)
Fragrance deposition from cleansing bars: US Patent 6,852,681 — cleansing bars with low soluble surfactant for enhanced fragrance deposition/longevity; and Structured Surfactant Systems for Deposition of Perfume on Skin and Hair, Cosmetics & Toiletries.
