Vitamin D and hair loss

Things to remember

At the start of this new century, scientists have observed that a vitamin deficiency D played a notorious role in a wide variety of diseases.
In terms of hair, several studies have shown the involvement of this vitamin in the hair growth and renewal.
An vitamin D deficiency could prove to be a significant aggravating factor in hair loss.
In France, 10% only of the population would have a satisfactory level of vitamin D.
That's why, at our in-depth hair diagnosis we can ask our customers to have their vitamin D levels checked by a blood test.

Discoveries about vitamin D

Once strictly confined to its role as a bone growth factor, vitamin D's field of action has now been considerably broadened, and it is the subject of wide-ranging research. It could be involved in pathological process of a large number of diseases. At the same time, scientists have discovered that only 10% of the French population have satisfactory levels of vitamin D!

Vitamin D, or calciferol, takes its name from Latin and literally means : calcium transporter. It has been known for almost 100 years for its decisive influence on bone development, which is explained by its ability to promote the absorption of calcium by the intestine and its metabolism in the body. In the last century, it was already being imposed on children in the form of a spoonful of cod liver oil to be swallowed ritually every morning. For a long time, this earned it the nickname of the anti-rachitic vitamin. But over the last fifteen years or so, numerous studies have taken it out of its calcium controller, justifying the interest now shown in it by the international scientific community.

First major finding on vitamin D

The vast majority of our organs have specific vitamin D receptors, the VDR (Vitamin D receptor). The active substance in vitamin D (calcitriol) binds to these receptors and, like a guardian angel, exerts a triple positive action on the organ concerned: protective, anti-inflammatory, immunomodulating. The facts are borne out by an abundance of scientific literature published over the last decade.

Vitamin D could therefore have a positive influence on the management of a wide variety of illnesses, provided of course that you are present at all times. a in the body. The range of pathologies concerned is very broad: from the common cold, flu or psoriasis, to a number of serious diseases such as colon and breast cancer, cardiovascular disease, type 1 diabetes, multiple sclerosis, etc. The list is far from exhaustive, and current research should, in all likelihood, add to it in the near future.

The second key fact about vitamin D

Patients suffering from one of these pathologies all have one symptom in common: they present with a vitamin D deficiency. Hence the reasonable hypothesis that this deficiency is one of the risk factors likely to cause the disease, and that a vitamin D-based treatment could have a preventive or even curative effect on it. Investigations are currently underway to confirm this possibility.

Revision of Recommended Dietary Allowances (RDAs)

Until now, RDAs (Recommended Dietary Allowances) have been designed to satisfy the classic role of vitamin D : to ensure that bones grow and remain healthy. At present, they are proving to be highly inadequate for preventing or treating the diseases mentioned above. As a result, vitamin D specialists recommend that you a sharp upward revision From an average of 400 IU per day, they should now be increased to 2,000 IU.

As for the doses at which the vitamin becomes toxic, these have also been reviewed and set back beyond 10,000 IU per day, without any risk of hypercalcaemia (increased levels of calcium in the blood and accumulation in the tissues).

Before revisionAfter revision
400 IU/day = 10 µg/mL2,000 IU/day = 50 µg/mL
Daily vitamin D intake (IU = internaitonal unit)

Main source of vitamin D

Vitamin D is present in some foods such as oily fish, dairy products and certain mushrooms. But its main source comes from 90% from appropriate exposure to the sun, the body being able to synthesise it in the basal layers of the epidermis and pass it directly into the bloodstream. This skin synthesis can only be established under certain conditions:

  1. Firstly, the quantity and quality of ultraviolet light. In France, for example, the body can only build up vitamin D effectively during the 5 warm months from May to September. between 11 a.m. and 2 p.m.This is when the sun's rays are strongest. In other months or at other times of the day, the sun is not strong enough.
  2. Next, you need to at least one third of the body : face, neck, shoulders and arms for around twenty minutes to half an hour, 2 or 3 times a week, without using sunscreen. If your skin is fragile and does not tolerate the sun well, it is possible to expose it for a shorter period of time each day, but for a longer period. greater number of days of course.
  3. The exposure time required varies according to age and skin pigmentation. Elderly people and darker skin types require a longer exposure to the sun. 3 to 5 times stronger because their epidermis does not synthesise vitamin D as quickly. The same applies to overweight people and smokers.

Only 10% of the French population would have a satisfactory levels of vitamin D. How can this deficiency be explained? According to the specialists, it is a recent phenomenon and our close ancestors must have had much higher average rates than us: they lived more outside. Urbanisation is accompanied by increasingly inadequate exposure to the sun. To compensate for this deficiency, systematic supplementation should be proposed by the attending physician after a blood test, bearing in mind that needs vary considerably, depending on age, sex, skin colour and physiological state (pregnancy, for example).

A study on ferritin and vitamin D in female alopecia

In 2013, an in-depth study carried out in Cairo on 120 women showed that women suffering from androgenetic hair loss or telogen effluvium hair loss had much lower than normal levels of vitamin D and ferritin. The study concluded that supplementation with these two elements was necessary and could be an interesting way of complementing local treatment.

The study involved 120 women aged between 18 and 45:

  • 40 suffered from androgenetic alopecia
  • 40 of hair loss known as telogen effluvium
  • 40 did not lose their hair and formed the control sample.

For each participant, the research included a clinical and dermascopic examination, a thricogram and a blood test to determine her ferritin and vitamin D levels. The results were significant: compared with the average levels found in the control sample, those of the women with androgenetic hair loss or with telogen effuvium (the medical term for diffuse and abundant hair loss) were much lower, in percentage terms:

Average ferritin levelAverage vitamin D level
Control sample = 43.5 μg/LControl sample = 48 μg/ml
Androgenetic fall = - 33%Androgenetic fall = - 43%
Telogen effluvium = - 36%Telogen effluvium = - 65%

Vitamin D deficiency and hair loss

Vitamin D has multiple receptors in hair follicles. His involvement in the hair growth and renewal. This is why, since 2002, several researchers in the USA have been studying its possible contribution to the development or atrophy of keratin.


A series of experiments carried out on mice with ablated VDRs (vitamin D receptors). The results to date are as follows:

  • Deprived of VDR receptors, mice do develop an initial coat, but are unable to renew it properly when the first hair cycle comes to an end. This inability leads to progressive loss of all the hair.
  • At cellular level, there is a qualitative and quantitative decrease in keratynocytes, the keratin stem cells. This is to the benefit of sebocytes, which lead to an increase in sebaceous activity.
  • Hair grows back when mice without fur are given synthetic vitamin D.


  1. Vitamin D therefore seems to play a decisive role on normal hair growth (anagen phase) since its absence prematurely ages the hair follicles, rendering them incapable of correctly starting a new cycle of keratinisation.
  2. An vitamin D deficiency could represent a additional risk factor in the development of alopecia and sebum hypersecretion. This factor is thought to interact with the other factors classically associated with hair loss: heredity, stress, iron anaemia, thyroid problems, etc. 
  3. People who are losing their hair should check their vitamin D levels, especially in autumn, when hair tends to fall out more, and in winter. If they are found to be deficient, they should ask their doctor to prescribe a supplement tailored to their needs.
  4. For more information about your hair loss, have an in-depth diagnosis carried out.


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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