How Often Should You Really Wash Your Hair?

*asking for a friend

Remember that rumour that stretching your wash day would “train” your hair to produce less oil? Bcos same.  

For years, we’ve been told that washing our hair too often strips away natural oils, damages the scalp and somehow teaches our hair to become greasy more quickly. The result? Dry shampoo has become a handbag staple, slicked-back buns have become a lifestyle and many of us have spent an extra day (*or three*) wondering whether our hair really needs washing.

But according to hair experts, the answer is far less black and white. There isn’t a magic number. How often you should wash your hair depends on your scalp, your hair type and your lifestyle. 

First, Think About Your Scalp - Not Your Hair

When people talk about washing their hair, they’re usually thinking about the lengths. In reality, shampoo is designed for your scalp. Your scalp is skin, just like the skin on your face. It contains oil glands that produce sebum, a natural oil that helps protect both your scalp and hair. But the amount of oil your scalp produces varies enormously from person to person.

Some people can go five or six days between washes without their hair looking greasy. Others notice oil building up within 24 hours. And caveat - thicker hair will often “hide” the grease more efficiently, too.

Happily (or irritatingly, depending how you look at it), neither is better. It’s simply biology.Can You Really ‘Train’ Your Hair?This is one of the biggest beauty myths on the internet. 

While delaying a wash might make you feel as though your scalp is adjusting, there’s very little evidence that you can permanently train your sebaceous glands to produce less oil. Oil production is largely influenced by factors such as genetics, hormones and age. Washing your hair doesn’t tell your scalp to make more oil, just as skipping shampoo doesn’t persuade it to make less.

If your roots are greasy, it’s because your scalp has produced oil - not because you’ve washed your hair too often.

So, How Often Should You Wash It?

The honest answer is: whenever your scalp needs it. For some people, that’s every day. For others, it might be every three or four days. And for most of us, the washing timeline can fluctuate wildly. 

Say it’s a cardio-heavy week. Or indeed a heat wave. Increasing the amount you’re sweating will directly affect how quickly you feel the need to wash your hair. And the same goes for using styling products: washing more frequently will remove the excess oil, sweat and product build-up.

And while we’re at the myth busting, we wanted to shed some light on the great damage-by-shampoo debate. Because - contrary to popular belief - washing frequently with a gentle shampoo isn’t inherently damaging. What matters more is using products suited to your scalp and hair type and avoiding excessive heat styling afterwards. 

A clean scalp is generally a healthy scalp.

But What Happens If You Leave It Too Long??

Going a little longer between washes isn’t usually a problem. But this isn’t carte blanche for swerving wash-day excessively: leaving hair unwashed for extended periods can cause problems. Oil, sweat, pollution and styling products accumulate on the scalp over time. In some people, this can contribute to irritation, itching, dandruff or inflammation.

If your scalp feels uncomfortable, flaky or persistently itchy, it’s often a sign that it’s asking for a proper cleanse - not another layer of dry shampoo.

What about hair type? 

Fine hair tends to become oily more quickly because sebum travels down the hair shaft more easily, making frequent washing more common.

Curly and coily hair often appears drier because natural oils have a harder time travelling through the twists and bends of the hair, meaning longer gaps between wash days can work well.

Chemically treated, bleached or colour-treated hair may also benefit from more nourishing conditioners and masks, but that doesn’t necessarily mean the scalp itself should be washed less often.

It’s entirely possible to have an oily scalp and dry ends at the same time. 

The Dry Shampoo Dilemma

Dry shampoo is brilliant in a pinch. It absorbs excess oil, adds volume and buys you an extra day before wash day. And the most technical formulas (Living Proof PHD advanced clean et al.) leave zero visible or textured residue. 

But it’s not a replacement for shampoo. Think of it like deodorant. It helps you feel fresher, but it doesn’t actually clean your skin. Relying on dry shampoo for days on end allows sweat, oil and product residue to remain on the scalp, which can eventually lead to irritation or clogged hair follicles. Use it as a temporary fix - not a long-term strategy.

Signs It’s Time to Wash Your Hair

Your scalp often tells you before your mirror does.If your roots feel oily, your hair has lost volume, your scalp feels itchy or you’ve exercised enough to build up sweat, it’s probably time. Forget arbitrary rules about waiting three days or only washing once a week.

Healthy hair starts with a healthy scalp. To sum up, the “perfect” hair-washing schedule doesn’t exist (sorry).  

Your friend’s once-a-week routine isn’t automatically healthier than your every-other-day wash, and TikTok trends rarely take into account your hormones, hair texture or lifestyle.

Rather than chasing someone else’s routine, pay attention to your own scalp.

Wash your hair when it feels dirty. Use products that suit your hair type. Be kind with heat styling. And remember that good hair days aren’t measured by how long you’ve managed to avoid shampoo.

Sometimes, the healthiest thing you can do is simply enjoy the feeling of freshly washed hair.