If you're one of the people who have always thought that if you cut your hair it will make it grow faster, you're mistaken. "That's just one of many myths there are about hair. Like if you wash it every day more of it falls out, or if you shave your head the hair grows back stronger," says dermatologist Dr Ángela Hermosa, who is a member of the Trichology Group at the Spanish Academy of Dermatology and Venereology (AEDV). Hair may be blonde, dark, smooth, wavy, long, short, straight, curly, dry, greasy, brittle, plentiful, scarce and sometimes non-existent... there is no doubt that it is one our signs of identity, but most of us know very little about it.
If you cut it, it will grow faster and thicker. FALSE.
Hair growth occurs at the root, not the ends and that is what determines how it grows, by multiplying its cells. "In other words, it is going to grow at the same rate, whether we have just had it cut or we never cut it. What happens is that hair becomes finer at the ends and if we cut it we have the false sensation of it being thicker, but it isn't. As it grows, it becomes finer again," says David Saceda, who is also a dermatologist.
In fact, many people shave their heads because they believe it will make the hair grow back stronger. "It only gives that impression as it starts to grow, but exactly the same thing happens with beards," says Ángela Hermosa.
Cutting our hair is purely cosmetic. It is not going to grow faster or any thicker afterwards. "Now, it's true that if we never use scissors on our hair and we attack it with hairdryers, tongs and very strong products, the cuticle of the hair - the outside layer - is going to lose its shine and can break more easily. If shaving your head resulted in faster-growing and stronger hair, we would have a solution for alopecia," jokes David Saceda.
With regard to how fast hair grows, it doesn't matter what time of year you go to the hairdresser, because it always grows at the rate of about one centimetre a month, whether it's March, June or December. Nor does the colour or type of hair make any difference.
"Everyone's hair grows at the same speed, but what happens is that curly hair always seems slower precisely because it curls up as it grows and looks shorter," says Ángela Hermosa. The only factor which can slow down growth is age.
"As we get older, the metabolism of the cells in the root of the hair gets slower, so it is normal for older people to only have to colour their hair every two or even three months instead of monthly," says Ángela, who is also a member of the AEDV's Healthy Skin Foundation.
Variables such as genetics and our general state of health obviously affect hair growth, but in general it always grows between 12 and 15 centimetres a year. What happens is that it grows at different rates in different parts of the head. For example, the hair at the sides grow a bit more slowly than on the crown.
Other false beliefs about hair say that if you shave a newborn baby's head, it will have more hair and this will be thicker. Well, no. It's exactly the same as with adults. It may seem stronger but that is because the roots are cut and the shaft is wider than the ends.
It's bad for hair to be washed every day. FALSE.
"Hair needs to be washed when it is dirty. Full stop. If you do sport every day and your head perspires you will have to wash your hair every day, and nothing untoward happens. It's not going to fall out because of that," says Ángela Hermosa. We lose between 50 and 100 hairs a day, whether or not we have a shower. So what happens, then? If we wash our hair once a week, the amount of hair we see on the brush or in the plughole will be much more than if we wash it every day, but not because more of it falls out when we wash it, but because we remove what has been loosening in the days beforehand. Every hair on our head has its own life cycle. They go through a phase of growth which lasts for years and are genetically determined, then they go into a resting phase and finally fall out.
"Every hair is where it is meant to be in its life cycle and that's why although we lose hair every day we don't end up bald," says Ángela.
It is important, however, to use the right sort of shampoo for each hair type. "Men's hair, for example, tends to be greasier because the masculine hormones are the ones that stimulate the sebaceous glands. In women with curly hair, on the other hand, it tends to be drier and more brittle, precisely because that sebum that is produced on the scalp has more difficulty in travelling the length of the hair because of its spiral shape".
We lose more hair in the autumn. TRUE.
This one is correct. There is a seasonal type of hair loss and it tends to coincide with the autumn. Experts believe this is because, as in the summer there is a great deal of sunlight, hair grows at a slower rate. And as hair starts to fall a couple of months after being allowed to grow, it could be that this is why we notice "a little more hair loss" in the months of October and November. It is also normal to lose hair after having a very high fever.
"We have been seeing a number of patients who were infected with coronavirus a couple of months ago, and now their hair is falling out massively. The same thing happens after giving birth," says Ángela, who also says we should not rub our hair with a towel to dry it, because it causes damage.
"A lot of people comb their hair when it's wet because it seems easier, too, but that is when the hair is most fragile because it is swollen and it breaks easily. The best thing is to let hair dry naturally in the air or with a hairdryer that isn't too hot and from a certain distance. And if you have long hair, you should start at the ends and work your way up," she says.