What's Really in Your Aerosol Dry Shampoo?
Dry shampoo is one of the most-used products in almost everyone's routine, and one we get asked about constantly. The powder itself isn't the problem. But the aerosol format, and what can hide behind a short ingredient list, are worth understanding before you reach for the can again.
The benzene problem
Benzene is a known human carcinogen. It isn't something any brand adds on purpose, and it's prohibited as a cosmetic ingredient in Canada. The issue is contamination, and the likely source is the propellant: the petroleum-derived gases, like butane, isobutane and propane, that push the product out of the can.
This moved from theory to headlines quickly. In December 2021, Procter & Gamble recalled aerosol dry shampoos and dry conditioners from brands including Pantene, Herbal Essences and Aussie after detecting benzene. In October 2022, Unilever recalled more than 1.5 million aerosol dry shampoos in Canada, from brands including Dove, TRESemmé and Bed Head, pointing to the propellant as the source.
Shortly after, the independent lab Valisure published tests of 148 batches from 34 dry shampoo brands. About 70% contained measurable benzene, and the highest level was 170 times the limit the U.S. FDA sets for medications.
Not every aerosol is contaminated. But it's a risk that comes with the format, and you're spraying it as a fine mist near your face, often in a small bathroom, several times a week.
Where hormones come in
Benzene is a cancer concern, not a hormone one. The hormone question comes from other ingredients that can turn up in dry shampoo, aerosol or not:
Fragrance. One word on the label, "parfum" or "fragrance," can stand in for dozens of undisclosed ingredients. Fragrance blends may include phthalates, such as diethyl phthalate, which help scent last longer. Some phthalates have been linked in research to endocrine (hormone) disruption, and the EU has banned several from cosmetics altogether.
Parabens. These preservatives are used to keep products shelf-stable. Some, like propylparaben and butylparaben, have shown weak estrogen-like activity in lab studies, and the EU restricts or bans several of them.
Canada's new labelling rules, phasing in since April 2026, require brands to name common fragrance allergens individually on the label. That's a step forward, but phthalates aren't part of that list, so "parfum" can still hide them.
To be clear, the science on everyday cosmetic exposure is still evolving, and no single product is going to upend your hormones on its own. But dry shampoo is a leave-on product many people use several times a week, sprayed as a mist you breathe in. Choosing formulas with fewer unknowns is a reasonable call.
What overusing dry shampoo does to your scalp
Dry shampoo doesn't remove oil. It absorbs it. Use it day after day without washing, and powder, oil and product build up on the scalp. That can leave it itchy or flaky, make hair look dull and flat, and clog hair follicles. It's a great way to stretch a wash by a day or two, not a replacement for one.
Safer ways to stretch your wash
Choose a non-aerosol formula, like a powder or a pump or liquid spray. No propellant means no propellant-related benzene risk.
Look for fragrance-free formulas, or brands that fully disclose their fragrance ingredients and state they're phthalate-free.
Apply it at night. It absorbs oil while you sleep, so you need less of it.
Target only the roots. Section the hair, apply a small amount, then massage and brush it through.
Clarify regularly if you use dry shampoo often. See when a clarifying shampoo makes sense.
Sticking with an aerosol? Spray in a well-ventilated room, away from your face, and check your product against Health Canada's recalls and safety alerts.
Our pick: Pospone Overnight Dry Shampoo
If you're looking for a swap that ticks these boxes, we love Pospone's Overnight Dry Shampoo, and we carry it right here in the studio. It was created by Kim Ng, a hairdresser with more than 20 years behind the chair, who asked women what frustrated them about dry shampoo and worked with a cosmetic chemist to solve it. It's made in Ontario.
Non-aerosol and benzene-free. It's a spray-on liquid, so there's no propellant at all. It's also alcohol-free and pH-balanced for the scalp.
It works while you sleep. Mist it onto the roots of damp hair at night, massage it in, and it absorbs oil overnight. That's exactly the habit we recommend above.
No white cast. Because it's a liquid rather than a powder, it dries down invisibly, which makes it especially good for brunettes and darker hair.
Plant-based and gentle on sensitive scalps. Kaolin clay absorbs oil, witch hazel helps calm the scalp, and awapuhi and aloe add hydration. Its light scent comes from neroli oil and fades by morning, and the full ingredient list is printed on every bottle. If you'd rather skip scent altogether, the brand's Fluffy Dry Shampoo is scent-free.
The price: $48 for a 30 ml bottle that lasts about 35 uses. It costs more than a drugstore can, but it's concentrated, so a little goes a long way. Order it from our online shop and pick it up at the studio, or grab one at your next visit.
A cause close to home: 2.5% of every Pospone order supports The Shoebox Project, a charity founded here in Toronto in 2011 that provides essentials to women in shelters who are experiencing or at risk of homelessness. It now works with shelters across Canada. Choosing Pospone means supporting a Canadian-made product from a fellow hairdresser, and helping women in our own community at the same time.
Not sure which formula would work for your hair? Ask us at your next appointment. We're always happy to recommend a cleaner option.
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POSPONEOvernight Dry Shampoo
POSPONEFluffy Dry Shampoo Powder
POSPONEDay & Night Duo + Free Scalp Massager
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