How many centimetres does your hair grow each month?

3 misconceptions about the speed of hair growth

1 "Hair grows one centimetre a month": TRUE and FALSE

It is generally accepted that Caucasian hair grows at a rate of one centimetre per month (i.e. 12 cm per year), that frizzy or mixed-race hair grows at a slightly slower rate (0.8 cm per month, i.e. 10 cm per year) and that Asian hair grows at a slightly faster rate (1.25 cm per month, i.e. 15 cm per year).

However, a study published in 2009 in the European Journal of Dermatology ( suggests that Caucasian hair grows from 1.3 cm per month.

So there's no absolute certainty about the reliability of these hair growth rate figures to the nearest millimetre. These figures are still estimates. However, these estimates seem to be backed up by experience, so are probably fairly close to reality, even if there are probably differences of + or - 20 % or even a little more.

Please note do not confuse sprouting of hair per week or per month (anagen phaseand lifespan hair. Even if hair grows slowly, the most important thing is to delay hair loss as long as possible: taking care of it right down to the ends, with the right products and our expert advice, is the ideal hair routine!

2. Oils such as castor oil or coconut oil accelerate hair growth: quite FALSE

To stimulate hair growth Some people recommend applying these oils (castor and coconut alone or combined with other oils such as olive oil) directly to the scalp, then massaging the scalp and leaving on as you would with a hair mask. Of course, you can't keep this mask, which should be rinsed off thoroughly with a mild shampoo.

Two shampoos are recommended, as these oils are very greasy and therefore very difficult to rinse off.

Of particular note important: no reliable scientific study has validated the effectiveness of applying these oils in accelerating hair growth.

From a strictly scientific point of view, these recipes are more a matter of belief than proven reality.

It should be noted, however, that the components of these oils and the massages which we suggest you combine with it, obviously stimulate local micro-circulation and therefore provide the roots with the nutrients they need for hair growth. So on the face of it, the solution may seem interesting.

That said, and this is what we see almost every day at the Centre Clauderer, the 'dose-response' effect is crucial. This 'dose-response' (or 'dose-effect') principle is well known for all active ingredients, whether they be drugs, ingredients incorporated into cosmetic products or ingredients applied directly, as in the case of oils applied to the scalp.

What is it all about? It's very simple. Each active ingredient is associated with its optimum dose to produce a positive effect on health, in this case on the speed of hair growth. This optimal dose is very rigorously sought for the active ingredients incorporated into Clauderer care.

If the active ingredient is under-dosed (or not applied often enough), it will produce little or no effect. On the other hand, if the same active ingredient (in this case, the oils) is applied in too large a quantity (or too often), it will not produce any effect either, and may even produce the exact opposite effect to that expected. In this case, as is often the case, "the best is the enemy of the good" according to the well-known adage.

That's exactly what we're seeing at the Centre Clauderer. We are regularly consulted by customers who assiduously apply these oils (castor and coconut, often combined with other lighter oils) to their scalp. These customers describe a positive effect after the first few applications. Naturally, they are encouraged to continue by the initial beneficial effects. Over time, however, problems appear: they describe hair that grows less quickly, and problems of hair starting to break and hair that becomes drier and drier, with ends that are more and more damaged and dehydrated.

We verify this by microscopically analysing our customers' hair: these oils (castor, coconut or others) end up seeping into the scalp and stagnating inside the hair. hair follicles As a result, these oils end up coating the hair roots, preventing them from being properly nourished. In the end, these oils prevent hair from growing properly, because surrounded by oily residue, the roots can no longer be properly irrigated and nourished by blood micro-circulation. So it's easy to understand why these customers are worried that their hair is growing less quickly: the cause is simple: their hair roots are asphyxiated!

As for the hair becoming brittle as reported by these customers, here too we can understand it through microscopic examination. Difficult to rinse out, these oils (castor or coconut) end up forming a barrier around the hair that stiffens it like a carapace and ultimately makes it dry and brittle in the same way as a treatment containing silicones.

Applying these oils may be beneficial to hair growth, provided that they are not abused.

In conclusion, as our grandmothers used to say, "you need a variety of poisons"!

3. Hair treatments can double or triple the rate of hair growth: FALSE

At Centre Clauderer , we are frequently consulted by customers who want their hair to grow faster and therefore seek our expertise and advice on how to achieve this objective: What vitamins should they use? What diet should they follow? What treatments should they use?

As we have seen, hair has its own growth rate, its "intrinsic" rate, which is, on average, 1 cm per month. Clinical studies have even shown that this rate remains absolutely constant and is even perfectly independent of our general state of health, our diet or even our possible deficiencies,.

In other words, no matter how much we care for it, our hair grows. And it grows at a constant rate. That's pretty good news.

Slow-growing hair is not necessarily unhealthy hair: it follows its genetically programmed growth rhythm (anagen phase).

The belief that there are "miracle" solutions that can change this biological clock is therefore false.

Having said that, many of us are finding it increasingly difficult to grow our hair longer, that we'd like to create hairstyles but can't, that our hair is "growing slower". Some even feel that their hair has stopped growing altogether.

So it's a real question, a real problem.

In reality, the explanation is not at all linked to the speed of hair growth, which tends to decrease. As we have seen, the rate of hair growth remains more or less constant.

So where does this problem come from?

The explanation is that hair doesn't grow long enough, so it falls out before it reaches its 'normal' length.

We get impatient when we don't see our hair getting longer any faster. We attribute this to the speed of hair growth, which is normal and understandable. But the reality is that our hair falls out before it has completed its growth cycle.

The hair that falls out is therefore shorter and shorter and, overall, we get the impression that it's not growing fast enough, when in reality it's not growing long enough.

Your questions :

How many centimetres a month does your hair grow?

We usually say that hair grows 1 centimetre per month. This is probably a generally reliable estimate of Caucasian hair growth, although studies show that there are variations of around + to - 20% from this estimate. It should be added that frizzy hair growth is on average a little slower and that Asian hair growth is slightly faster.

Do masks containing castor or coconut oil speed up hair growth?

Often presented as a miracle solution, these rituals have never produced any real effect in the medium or long term. Quite the opposite, in fact. Over time, these oils impregnate the scalp, surround the hair roots and ultimately prevent the roots from being irrigated normally, thus slowing down the production of keratin and hair growth. If these treatments are applied too often, they can damage hair growth.

Why doesn't our hair grow fast enough?

A real question! Our hair is 'programmed' to grow at a certain rate (around 1 cm per month). Nothing, whether it's diet, hair care or vitamin supplements, can significantly alter this genetically determined rate, either by speeding it up or slowing it down.

When we feel that our hair isn't growing fast enough, that it's slow to gain mass or length, it's actually because it's not growing long enough, that it doesn't have time to become longer: it falls out before it has finished its growth phase.

Jean-François Cabos

Jean-François Cabos is the creator of a unique hair care method based on the research he coordinated, which led to the publication of the book "Cheveux, Racines de Vie" with Hélène Clauderer by Robert Laffont (Collection "Réponses/ Santé").

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