Experts say there's no single answer to how often people should shampoo. You may not need to do it as often as you think. It usually comes down to personal preference. For guidance, take a look at your hair type and styling choices.
“I have always said, ‘It’s fine to go a few days without shampooing,’” says Alli Webb, professional hair stylist and founder of Drybar. “For hair that’s normal in terms of oiliness and medium weight, I sometimes tell my clients to go as long as they can without shampooing.”
The idea behind this? Shampooing too often may lead to hair that’s less than lush.
How Shampoo Works
First off, the basics: what does shampoo do?
Shampoo traps oils, so if you do it too frequently, you may dry your hair out, leaving it prone to breakage, says Angela Lamb, MD, an assistant professor of dermatology at the Icahn School of Medicine at Mount Sinai in New York City.
“Hair produces natural oil called sebum, and shampoo is an emulsifier that captures and traps excess oil, dirt, and product residue, which you then rinse out to clean the hair,” Lamb says.
For the most part, some dirt is OK and natural -- and you definitely want some oils to remain in your hair.
“They provide moisturizing and a protection barrier for the skin and hair,” says Carolyn Goh, MD, assistant clinical professor of medicine at the David Geffen School of Medicine at UCLA.
Who Should Shampoo Daily?
The experts agree: Only a small group needs to shampoo daily, like those with very fine hair, someone who exercises a lot (and sweats), or someone living in very humid place, Goh says.
“If you have oily scalp, then daily washing is needed,” she explains. “Sometimes, people think they have dry scalp because they have dandruff, but in those situations, more frequent washing is also helpful.”
Who Can Go a Few Days Without Washing?
The thicker your hair and the less oil, the less you need to shampoo.
“Some people with dry hair or curly hair can wash much less frequently without problems,” Goh says.
How Much Should You Wash?
For the average person, every other day, or every 2 to 3 days, without washing is generally fine.
“There is no blanket recommendation. If hair is visibly oily, scalp is itching, or there’s flaking due to dirt,” those are signs it’s time to shampoo, Goh says.
How Long Is Too Long?
If your hair is styled, you may be able to get away with going longer without lathering up.
“If you’re doing a blowout or using heated styling tools on it, the most important thing I tell people is to make sure your hair is super-clean when you start,” Webb says. “Hair will last longer, look better, and you’ll need to use those stressors less often overall.”
Lamb agrees there’s a lot of variation, and you should think about a style’s overall prep work.
“Some of it is cultural, the natural texture and thickness of your hair, how much you sweat and exercise, and how it’s styled,” she says. “If it’s styled with keratin treatment or you have a blow-out, you may not need to or want to wash more than once a week and put more stress on your hair.”
Go with your gut and preference, with one caveat. “Regardless of how your hair feels, though, don’t go longer than 14 days, ever,” Lamb says, who doesn’t buy in to the total ‘no poo’ movement.
From a medical perspective, Goh says some of her patients only wash their hair once a week. She says as long as they don’t have scalp problems that seems OK. She doesn’t advise them to wash more often.
How to Go Longer Between Washes
In recent years, more and more products have become available to extend how long you can go between washes. And people are coming up with different methods to keep hair looking good.
“Powders actually do work to absorb oil, so it doesn’t sit on the scalp as much,” Lamb says.
“If you still need to style, leave-in conditioners can help. You can also re-wet your hair and condition it more often, too,” Lamb says. This is sometimes called "co-poo" for using conditioner to shampoo.
For the most part, it’s somewhat of a personal preference for just how clean they want their strands to be.
“Everyone has a different threshold for how oily or texturized they want their hair to feel,” Webb says. “I tell people, ‘Sweat is like salt, right?’ You’re getting texture, some of which is totally natural and you can get away with it, but that is also the beauty of dry shampoo. It freshens, and gives you a burst of volume at the roots.”
To re-energize your style, Webb says to spray dry shampoo where oil and dirt tend to accumulate: roots only. Spray at the hairline and nape of the neck, and then lift and spritz small sections of hair. “Spray about 3 to 4 inches from your head,” she says.
You can also use dry shampoo as a sort of preventive step. “I’ll have my stylists use it on a perfectly fresh blowout for lift,” she says. “You can also spray before you go to bed, and it will absorb some of the excess oil overnight. It’s like being proactive about preserving your style.”
So how do you know when it’s time to shampoo?
“If it’s Day Five and your style is falling apart, wash,” Webb says. “Otherwise, do something fun to change it up. Part your hair in a different place, go for a side braid, go for a bun. Use dry shampoo. If you can camouflage, great, and often you get the most compliments when you do something different.”
The Trend and the Stigma
In recent years, it has become trendier to let hair go longer without shampooing, with more and more people going a week or more between washes.
“Many of my patients worry about washing their hair too frequently, yet they really need to wash it more often!” Goh says.
But longer can be totally acceptable. Caroline Lynch, an IT consultant from Michigan, feels like she can put the shampoo bottle down most days. “Since I have thick and curly hair, and more hair than most people, I started shampooing less frequently a few years ago,” she says. “I just kept pushing the date off further as I saw that I could.”
She shampoos about once a week. “Less-frequent shampooing has improved the quality of my hair, because I am not damaging it or drying it out with shampoo, and then with styling tools like blow dryers and flat irons and curlers,” she says. “It also saves money, so I can buy higher-quality shampoo and conditioner since I use it less frequently.”
Lynch does likes to keep hush-hush about her once-a-week habit, though.
“I get a lot of compliments on my hair, and stylists are always telling me how healthy it is, so I think I am in good shape,” she says. “But I still am nervous to tell people about the frequency because of the stigma, or people thinking I’m dirty for not shampooing more often.”