Myth vs. Fact

Experts spill the dirty little secrets behind the most common shampoo “truths”

"You need lather to know it's really working."
MYTH The more foam a shampoo produces, the cleaner your hair's getting, right? Not exactly. You may love working up a good head on your head, but those suds are mostly created for psychological effect (Oooh, it's cleaning!). Foaming occurs when surfactant molecules in the shampoo mix with air and create tons of tiny bubbles. Ideally, your head should have only enough lather to lubricate the hair and scalp, so a quarter-size blob of shampoo will usually do the trick.

"You should use a clarifying formula to get rid of buildup."
PARTLY FACT Unless you're using heavy-duty styling products, like pomade, mousse, or gel, regular shampooing prevents styling-product residue from collecting on your hair. If you do need a clarifier, don't use it more than once a week. These detergent-heavy cleansers, which do such a great job of removing buildup, will also do a great job of damaging the hair cuticle.

"Washing every day can be bad for your hair."
MOSTLY MYTH "Daily washing is safe and healthy," says Mort Westman, the cosmetics chemist. If you have oily hair, it's fine to suds up every day--but even oily types should use a gentle formula (translation: one with moisturizing ingredients, like silicones, shea butter, or panthenol). People with coarse or dry hair might want to be more conservative and wash every other day, says L'Oréal's Youssef. No matter what kind of hair you have, as long as you stay away from harsh formulas that strip natural oils and treat your strands with conditioner, regular shampooing won't do any harm.

"For best results, follow with a conditioner."
FACT No, this isn't a scam to sell you two products. Chemists can pack only so many ingredients into each bottle. And a shampoo can't clean properly and deposit enough conditioner to moisturize your locks. Using a separate conditioner will coat strands with ingredients that hydrate and protect. BTW: If your hair's super-oily, apply the thick stuff only from the ears to the ends.

"After a while, your hair gets used to your shampoo. That's why you need to switch to a new brand occasionally."
MYTH Honestly, where do people come up with this stuff? Let cosmetics chemist Westman set the record straight: "Hair is dead, period. So it can't 'get used to' anything. It's just your perception of how your hair responds to a new formula." So if you love your brand, there's no reason to switch.