Why washing your hair is a science in itself: a doctor’s tips

Split ends, dandruff and bad hair days are just a few hair problems. You can find out what causes them in the guide «Alles klar beim Haar?» (in German) by Dr Alice Martin. The doctor is co-founder of the dermatologist app «Dermanostic», a telemedical consultation service for skin problems. The app can be used throughout the DACH region (Germany, Austria and Switzerland) for dermatological diagnoses.

Guidebooks

Everything okay with the hair?

German, Lucia Schmidt, Alice Martin, 2023

Guidebooks

Everything okay with the hair?

German, Lucia Schmidt, Alice Martin, 2023

In her book, Dr Martin describes all the important facts you need to know about the growth, health and care of your cutaneous appendages aka hair.

That’s why she’s the right person to contact when it comes to the hairy issue of how often we should wash our hair. Galaxus recently found out in a personal hygiene study how often people in the DACH region actually wash their hair. A third of those surveyed in Switzerland and Germany wash their hair with shampoo every day.

Spoiler: this is too often for some of us.

How your hair is structured

You may have learned in this interview carried out by my colleague Natalie that hair is dead material once it’s pushed out of the scalp. It’s made of the same material as horns, more precisely keratin. «Nevertheless,» emphasises Dr Martin, «I have to take care of my hair. You don’t buy a high-quality carpet and just leave it there. It quickly starts to look unkempt.»

Head hair consists of three layers. The outside is the cuticle layer, then there’s the fibre layer and on the inside is the hair pulp. While the cuticle layer consists of colourless skin or keratinised cells and ensures the shine of your hair, the fibre layer is responsible for the hair colour.

Each hair is anchored in the scalp via hair follicles and has a gland that produces an oily, fatty substance: sebum. There’s no reason to be disgusted by it – sebum has an important function. It protects the scalp and hair from external factors and moisturises the hair. Ideally, sebum spreads from root to tip to prevent it drying out and allow it to remain nice and smooth.

Now the theory’s over with, it’s time to get in the shower:

How often should we wash our hair?

When you wash your hair, the cuticle layer – i.e. the outermost layer of your hair – opens. This makes the hair particularly receptive to care products such as conditioners, but also particularly sensitive. It’s therefore better to avoid vigorous brushing or going to bed with damp, loose (long) hair.

As for the frequency of washing your hair, Dr Martin’s advice is: «There’s no one-size-fits-all solution. You should wash your scalp as soon as it becomes greasy, when you feel that the hair is slightly tacky or has minimal shine.» This usually happens after two to three days – but it can also be earlier or later, depending on the hair structure. Frizzy hair tends to be dry and takes longer to get greasy. «Then it’s enough to wash your hair once or twice a week.» If you do a lot of exercise and sweat a lot, you can still wash it every day.

When it comes to children, you don’t have to worry so much about clean hair. «They don’t have active sebaceous glands yet, so they rarely have greasy hair,» Dr Martin explains. This only changes during puberty because their bodies produce more testosterone. The result: «Kids going through puberty tend to experience increased sebum and greasy hair. So, you should wash your hair more often than you did as a child. If you don’t, you could catch scalp fungus,» says the doctor.

Speaking of fungus: everyone naturally has a yeast fungus on their scalp. But it’s more comfortable in oily regions, where it starts to grow and can cause itching and greasy dandruff. Nevertheless, the following also applies to puberty: «Don’t just wash your hair too frequently; only do it when it looks greasy.»

Because washing your skin and hair every day isn’t good for them. Shampoos remove grease from the scalp – that’s their job. But washing off the sebum that’s supposed to protect your scalp from drying out has consequences. «The scalp becomes itchy. And when you scratch it, small flakes of dandruff appear.» In addition, frequent scalp washing can stimulate the sebaceous glands to produce more – and you don’t want that with greasy hair.

What to do about dandruff

«If your scalp is naturally healthy, with the right care you won’t have dandruff,» says Martin. If you do suffer with it, first check the consistency of the annoying skin particles and rub them between your fingers.

Greasy flakes feel greasy when pressed and leave a shine on your fingertips. In this case, more frequent washing is recommended. It’s best to use a shampoo that contains anti-fungal ingredients so that you can remove the basis of the yeast on your scalp. Otherwise, it multiplies, creates eczema, more dandruff and even hair loss in the worst case scenario.

Dry dandruff, on the other hand, indicates a dry scalp. Washing it with shampoo every day would deprive it of even more moisture – and it will react to this with increased dandruff. It’s a vicious cycle. A mild baby shampoo is absolutely sufficient for dry dandruff. A scalp mask that you can apply regularly provides more moisture.

What care does my hair need?

«What many people don’t know is that shampoo is actually only intended for the scalp because of its degreasing function,» says Dr Martin. «Many people do it wrong and lather their entire hair down to the ends. That dries out the hair.» The best thing to do after wetting your hair is to apply conditioner first to the lengths of your hair, then lather just your scalp with shampoo before washing everything out.

For lengths with issues such as split ends, hair breakage or dry ends, you can use care products such as hair oil, hair masks or conditioners. However, again this depends on the individual hair type and scalp. «If your hair is very oily, the sebum from the scalp can protect your hair – all you need to do is brush it more to distribute the sebum down to the lengths of the hair. For oily hair, a hair mask every week or two would be better.»

If you have dull hair, it’s been weakened by chemicals (colouring) or mechanical factors (tight braids). Even then, frequent washing is counterproductive, as more sebum is removed from the hair, which is supposed to make it supple and resilient. This makes it even more difficult for the hair to work against external stimuli.

Curly hair also needs more care because the strands rub against each other more and tend to be too dry. «If you have curls, it’s best to use hair oil and a leave-in conditioner,» says Martin. «If you have thin, fine hair, you don’t need anything heavy. A normal hair conditioner every few hair washes is sufficient.»

By the way, if you have split ends, don’t fall for the promises of the cosmetics industry. «Once split ends are there, they’re there. You can’t put split hairs back together.» Anti-split ends products create maximum preventative effect by placing a protective coating of active ingredients and a light fatty film around the hair. In the worst case scenario, only cutting off split ends at the hairdresser will help.