How often to wash thinning hair

People whose hair is thinning tend to wash it less. The reasoning is straightforward: hair comes out in the shower, so fewer showers means less hair coming out. The reasoning is also wrong, and it produces a scalp that is worse off than it needed to be.

This article explains why the drain is misleading, what wash frequency actually depends on, and how to choose a frequency for a scalp you are trying to look after.

Why the drain lies to you

About 10 to 15 percent of the hairs on a normal scalp are in the resting phase at any moment. At the end of that phase, the hair is held only loosely in the follicle, waiting to be dislodged. Washing, brushing, and towelling are what dislodge it. The hair was already detached from its blood supply and was going to fall regardless; the wash only decided when.

This is why the amount of hair in the drain scales with the gap since the last wash. Wash daily and you see 50 to 100 hairs each time. Wash twice a week and you see 200 to 300, which is the same hair accumulated over three or four days and released at once. The person who cuts their washing from daily to weekly and is horrified by the result has not started shedding more. They have started counting in bigger batches.

What frequency actually depends on

• Sebum production. Oily scalps need washing more often, and this is the dominant variable. It is set by hormones, age and genetics, and it rises temporarily when the scalp is stripped.
• Hair texture and density. Fine, straight hair shows oil within a day and is washed more often. Coarse, curly or coily hair distributes oil slowly and is often washed weekly or less; over-washing dries it and increases breakage.
• What you put on it. Dry shampoo, styling product and leave-ins accumulate and need to be removed.
• Sweat and environment. Exercise, humidity, pollution and hats all shorten the interval.
• The scalp's condition. A flaky, itchy or seborrhoeic scalp generally does better with more frequent washing, not less, because the yeast involved feeds on sebum.

A starting point by scalp type

The American Academy of Dermatology's guidance puts it simply: wash oily hair more often, dry hair less, and wash when the scalp is oily rather than on a fixed schedule. There is no frequency that is correct for everyone, and there is no evidence that any frequency causes or prevents thinning.

What matters more than frequency

How you wash has a larger effect on the scalp than how often. A daily wash done well is gentler than a weekly wash done badly.

1. Water temperature. Warm, not hot. Hot water increases sebum production and dries the scalp.
2. Where the cleanser goes. On the scalp, worked in with fingertips for 60 to 90 seconds. The lengths are cleaned by the rinse.
3. How long you rinse. Longer than feels necessary. Residual cleanser irritates.
4. Where conditioner goes. Mid-lengths and ends. Not the scalp.
5. How you dry. Squeeze and pat with a towel. Rubbing wet hair is a major source of breakage, and the thinner the hair mass the more each broken strand shows.
6. How you detangle. Wet hair with a wide-tooth comb from the ends up, or dry hair with a brush before the shower. Never a fine comb dragged through wet knots.

If you have been under-washing

A scalp that has been washed once a week for months while thinning has usually developed buildup: accumulated sebum, dead skin and product. Moving to a more frequent schedule can initially make the scalp feel oilier, because the sebaceous glands adjust slowly. Expect two to three weeks of transition. Do not respond to it with a harsher cleanser; respond with patience and a thorough rinse.

And count the drain honestly. On the first few more-frequent washes you will see the backlog release, and it will look like a lot. It is the same hair, on a shorter interval. After a fortnight the per-wash count settles at your real rate, which is the number that tells you something.