How to Use Dry Shampoo: The Two-Use Cap, and the Can Called Bare That Is Not

Clean hair, the can says. The American Academy of Dermatology's page on dry shampoo, written with two dermatologists, takes those two words apart in its first answer: the product absorbs oil and does not clean anything. From that it builds the rest of how to use dry shampoo: a small amount on the scalp where the hair is greasy, the wait the directions give, a brush-out, and a cap of one or two uses before the hair is washed with water. Past the cap, the page names two consequences. And its one product instruction, fragrance-free if the scalp feels parched, rules out the best-selling can's "Bare" variant on the evidence of that can's own page.

The two-use cap, and what happens past it

The AAD's two dermatologists set the limit together: Drs. Draelos and Mirmirani agree that it's best to wash your hair after one or two dry shampoos. The page says there is no fixed number of uses before a wash, and then gives that one as the answer both doctors land on. How often can you use dry shampoo is therefore not "until it stops working"; it is once or twice, then water.

Two things are named as what happens when the product stays on. The first is to the hair: If dry shampoo stays on your hair or scalp, it can cause problems like hair breakage and hair shedding. That sentence is quoted here as the AAD's and is the whole of what this page says on the subject; anything beyond ordinary breakage from product build-up is a dermatologist's question, not a shampoo aisle's. The second is to the scalp, in Dr. Draelos's words: if you use only dry shampoo and skip shampooing with water, you could develop a condition called seborrheic dermatitis. The verb is "could", and the condition is the one whose milder scalp form is dandruff, which dandruff shampoo covers and which a scalp that has stopped being washed can bring on.

The reason water matters is stated by Dr. Mirmirani: Washing your hair (and scalp) with regular shampoo and water removes dead skin cells, oil, and microorganisms that build up and can cause dandruff, and washing also removes the dry shampoo itself. The stop rule is short: If you develop itching, burning, or another sign of irritation on your scalp, stop using dry shampoo.

What it does, in one word

Absorbs. Dr. Mirmirani's answer to whether dry shampoo cleans hair: No, it just absorbs the oil. Dry shampoo shouldn't replace regular shampooing. Dr. Draelos's: Dry shampoo contains little particles that absorb oil, but it doesn't clean hair. Does dry shampoo clean your hair has one answer from both. The particles are a starch, rice starch on every label read for this page, and what they do is soak up sebum so the hair looks less flat. Nothing is removed until the brush comes through, and nothing on the scalp is cleaned until water does.

How to apply it, per the AAD

The AAD's instructions are a short list, and the first one is about what not to buy.

Store-bought, not homemade. Use store-bought dry shampoo rather than a homemade version. Two reasons, one from each doctor. Dr. Mirmirani: Homemade products can clump, which can make the dry shampoo visible and clog pores in your scalp. Dr. Draelos, on the usual kitchen ingredient: If you use cornstarch in your dry shampoo, bacteria can easily digest it. When that happens, your scalp can develop an unpleasant odor.

A small amount, where the hair is greasy. Apply a small amount only where you need it, starting at the scalp and adding rather than starting heavy, because If you use too much, your hair can become dry, stiff, and gritty.

Wait, then brush. Spread the product evenly over your scalp, let it sit on your scalp for the amount of time it says in the directions, and brush (or comb) it out. The brush is the step that removes the oil the powder absorbed. On waiting longer than the can says: Nothing bad will happen if you leave dry shampoo on for longer than directed. You just won't get the best results.

Fragrance-free if the scalp objects. If your hair or scalp feels parched instead of fresh, Dr. Mirmirani recommends finding a dry shampoo that's fragrance free. That is the only product-selection instruction on the page, and it is the one the product section below is built around.

The 2022 recall, from the FDA-hosted record

Dry shampoo benzene recall is the phrase most people have half-remembered, and the record is a company announcement hosted on the FDA's site. Its first sentence: Unilever United States today issued a voluntary product recall to the consumer level of select lot codes of dry shampoo aerosol products produced prior to October 2021 from Dove, Nexxus, Suave, TIGI (Rockaholic and Bed Head), and TRESemmé due to potentially elevated levels of benzene. The date on the announcement is October 18, 2022.

Three more sentences from it carry the rest. On where the benzene came from: An internal investigation identified the propellant as the source. On what the levels meant: Based on an independent health hazard evaluation, daily exposure to benzene in the recalled products at the levels detected in testing would not be expected to cause adverse health consequences. And on outcomes: Unilever has received no reports of adverse events to date relating to this recall.

That is the whole of what the record says, and this page does not add to it. It names five Unilever brands and lots made before October 2021; it does not name Batiste, Not Your Mother's, or any other maker, and nothing here implies anything about them. It identifies a propellant, which is a component aerosols have and powders do not; what a reader makes of that is a judgment, and the record does not make it. The announcement's own evaluation is that the detected levels were not expected to cause harm, which belongs in the same paragraph as the word benzene rather than in a footnote.

The three products, by what the label says

The card near the top lists three products on the same six points: form and propellants, fragrance on the list and the maker's own scent statement, the absorbent, the maker's directions, whether the brand appears in the recall record, and what was not checked. None was in the recall record. None was used on a head.

Batiste Original. Aerosol. The manufacturer's list opens Butane, Isobutane, Propane, Oryza Sativa (rice) Starch, Alcohol Denat., Parfum (fragrance), so three propellants, then the starch, then the fragrance. Its directions match the AAD's shape: shake, spray at the roots, wait, brush. Not checked: residue, feel, price.

Batiste Bare. Aerosol, same propellants and starch on the page. The name suggests the fragrance-free product the AAD points to, and the page says otherwise: Just a few sprays of this barely-there scent will leave you noticing your clean hair and nothing else. Fragrance appears on its ingredient list. A barely-there scent is a scent, and a scalp that is reacting to fragrance does not read the label the way marketing does. This can is on the card so that "Bare" can be held against its own list, and it does not answer the AAD's instruction. Not checked: the same three.

Not Your Mother's Clean Freak Dry Shampoo Powder, unscented. Non-aerosol. The complete ingredient list on the manufacturer's page is Oryza Sativa (Rice) Starch, Tapioca Starch, Magnesium Stearate, Silica Dimethyl Silylate, Ethylhexylglycerin, Phenoxyethanol, six items, no propellant and no fragrance, and the page carries fragrance-free and talc-free badges that the list bears out. Its directions: section dry hair, dispense onto the roots, massage in, brush through. This is the fragrance free dry shampoo shape the AAD's line describes. The Amazon listing found is a two-pack of 1 oz; a single did not surface. Not checked: the same three.

No ranking follows. One of the three meets the AAD's fragrance-free instruction and two do not, which is a fact about labels rather than a verdict on cans.

When this is a dermatologist's question

Irritation that does not clear a few weeks after stopping, which is the AAD's own threshold on this page. Shedding that continues after the product is out of the routine, since the AAD names shedding as a consequence of build-up and anything beyond that is not a product question. An itchy, scaly rash on the scalp, which is the condition the AAD warns can follow skipping water. When to see a dermatologist covers how to get there.

The AAD's method beside the cans' directions

FAQ

How do you use dry shampoo? The AAD's method: a small amount on the scalp where the hair is greasy, spread evenly, left for the time the directions give, then brushed or combed out. Store-bought rather than homemade. And wash with water after one or two uses.

Does dry shampoo clean your hair? No. Both AAD dermatologists say it absorbs oil and does not clean; water and regular shampoo do that.

How often can you use dry shampoo? The AAD's two dermatologists agree it is best to wash with water after one or two uses. Past that, the page names hair breakage and shedding from product left on, and a scalp condition, seborrheic dermatitis, that can develop if dry shampoo replaces washing altogether.

Does dry shampoo cause hair loss? The AAD's sentence is that product left on the hair and scalp can cause breakage and shedding. That is what this page says on it; hair loss beyond that is a dermatologist's question.

What was the dry shampoo benzene recall? In October 2022 Unilever recalled certain lots, made before October 2021, of aerosol dry shampoos from Dove, Nexxus, Suave, TIGI and TRESemmé for potentially elevated benzene. The announcement identifies the propellant as the source, states that an independent evaluation did not expect harm at the levels found, and reports no adverse events. It names no other brands.

Is there a fragrance-free dry shampoo? Yes, and the AAD's advice for a parched scalp is to find one. Of the three products read here, the non-aerosol powder lists no fragrance; both Batiste cans do, including the one named Bare.

Two words on the can, two dermatologists taking them apart. Dry shampoo absorbs, it does not clean, and how to use dry shampoo is mostly a matter of stopping at the second use and reaching for water. The can that calls itself bare lists a fragrance; the powder with six ingredients does not; and the recall that made the category famous is a propellant story with its own conclusion attached. The other product that stays on the hair between washes, leave-in conditioner, has its own week limit and its own placement rule from the same two dermatologists, in leave-in conditioner.

Sources

• Dry shampoo: Dermatologists' tips for getting your best results, American Academy of Dermatology, last updated March 2024
• Unilever issues voluntary U.S. recall of select dry shampoos due to potential presence of benzene, company announcement hosted by the FDA, October 18, 2022
• Batiste Original and Batiste Bare, manufacturer pages
• Clean Freak Dry Shampoo Powder, Not Your Mother's, manufacturer page