If you're the sensitive type — the always sneezing, quick-to-get-a-rash-from-a-new-detergent guy or gal — someone has probably already told you to avoid fragrance. Ditto if you've ever been pregnant. In fact, it’s come up as a major no-no in every post we’ve done in this series. But how much do you really know about fragrance? Chances are, not a whole lot. Like most things in the self-regulated personal care business, it's shrouded in mystery — but this is an especially thick and stinky smokescreen.

As for the gentlemen who think they’re clear of risk because they haven’t doused in Drakkar Noir since 1997 — not so fast. Fragrance is in your soap, your shampoo, your aftershave, and your deodorant. Let’s not even talk about the crap they spray your car with post-wash. Of course for women it’s also in ... well, everything. It defies logic, but many lipsticks and mascaras are even made with the stuff.

The biggest rub? If you really, really want to know what’s in those scented concoctions used in most of your products — short of taking them to a lab — you can’t. Here’s why:

safe1. Fragrance is protected under trade secret law. That means the industry is not required to reveal what goes into its mixes. In its Cosmetic Labeling Guide, the FDA states that fragrance ingredients “may be declared ... as "fragrance." Now flip any bottle in your bathroom and peruse that list. Somewhere amidst the unpronounceable words is that familiar “fragrance” — but that alone represents an average of 10 to 20 hidden ingredients. The industry will claim that these protective measures are a necessary bulwark against thieving perfumers — but really? Just because I know what’s in the Caramilk bar, doesn’t mean I can duplicate it. These laws represent a significant deterrent, sure, but any hack can have a perfume analyzed in a lab and get the ingredient list that way. So who should get the protection: the fragrance business or the consumers? Read on.

soap, candle, body wash2. Fragrance is everywhere. As already mentioned — from your lipstick, to your body lotion, to your scented candle, from your cat’s collar, to your Tide.  

beaker on fire3. Many of its ingredients haven’t been tested at all. The industry likes to boast about its scientific review panels and its voluntary safety compliance, but a recent lab analysis of 17 perfumes, colognes and body sprays done by the EWG and the Campaign for Safe Cosmetics reveals: “The majority of chemicals found in this report have never been assessed for safety by any publicly accountable agency, or by the cosmetics industry’s self-policing review panels.”

phthalates and hormornes4. Fragrance may be messing with your hormones. Of the ingredients we do know something about, on average, each of the tested products contained four potentially hormone-disrupting chemicals. J-Lo and Halle Berry’s scents were singled out for containing seven. Among most of the products were phthalates (see our previous entry on that subject), that ubiquitous group of chemicals suspected of causing deformed sex organs in baby boys according to this "60 Minutes" report. Despite mounting evidence, the fragrance industry has argued for their safety in the past.

rat with myrcene5. It may also contain carcinogens. As one example (and there were more), the fragrance compound myrcene was detected in 16 of the 17 products. According to a two-year study conducted by the National Toxicology Program, this substance has shown “clear evidence” of carcinogenic activity in rats. Charming.

allergen6. You could be allergic to it. Twenty-four common allergens were found in the lab results. Sensitizations to fragrance are frequent, varied and, as you can imagine, notoriously difficult to diagnose thanks to the business-friendly laws mentioned above. For the book we spoke to a woman who spent eight years trying to track down the very common but “secret” chemical she was reacting to in fragrance.

nose7. It’s designed to linger in the air. Yet another major frustration for the sensitized. By design — and those ever-nifty phthalates help with this — fragrance is meant to stick in the air and on our bodies. So no matter who’s wearing it, everyone gets to breathe it — and we’ve all had some unpleasant, if not allergic, department store or elevator experience to substantiate that. The more extreme anti-fragrance lot feels that perfume in public is akin to secondhand smoke (PDF).

baby8. Moms and babies should avoid it. For obvious reasons already covered (like sons with small penises), expecting mothers should at least avoid using personal care products that contain fragrance on their bodies and in their environment. For starters, read your labels and ditch any cosmetics that feature the f-word. Blacklist nasty air fresheners and the houses of friends who use them.

essential oils9. The best smells come from nature. The upshot is that perfume has been around since the beginning of time, distilled from the incredible smells provided in nature. While some essential oils can also be allergenic, these are generally a much safer bet — and truly clean companies will list them as their fragrance source. If you’re very attached to your synthetic perfume, consider wearing it less often and switching out other products to limit exposure.

perfume in front of a courthouse10. Fragrance is going to the courts. Canadian cities like Halifax had the fragrance industry up in arms back in 2000 over its anti-scent campaign, and Ottawa proposed putting a ban into law in 2006. But it’s a recent lawsuit in Detroit (yep, Detroit) that should really get the fragrance industry nervous. City employee Susan McBride sued Detroit, claiming that she couldn’t work because of a sensitization to a co-worker’s perfume. She won a $100,000 settlement. Are we smelling a precedent?

This is the second installment in a series inspired by "No More Dirty Looks: The Truth About Your Beauty Products and the Ultimate Guide to Safe and Clean Cosmetics," a forthcoming book by GOOD's features editor Siobhan O'Connor and her co-author Alexandra Spunt.

A version of this story originally appeared on GOOD. Read it here.

Related links on GOOD:

MNN homepage photo: Getty Images Photodisc

10 things you should know about fragrance
Before you cover your body in your favorite scent, read this article. It may make you change your mind.