Vitamin D is a fat-soluble vitamin, known for maintaining bone health by increasing blood concentrations of calcium and phosphorus. It also contributes to an effective immune system and normal muscle contraction.
But its blood concentration would be insufficient in more than 50% of French people, according to INSERM data.
In addition to the problems such a deficiency can cause to general health, scientific studies have shown that a vitamin D deficiency could negatively impact hair growth and the regulation of the hair cycle.
What link is there between vitamin D and hair? I answer your questions.
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What role does vitamin D play in the hair shaft?
Regulation of the anagen phase
To promote normal hair shaft growth and ensure healthy hair, the hair follicles at the base of the scalp need certain nutrients.
Vitamin D is among them and may play a role in regulating the anagen phase of the hair (or growth phase). This is indicated by this study.
Aid in the regeneration of the hair follicle
According to this study, certain vitamin D receptors are expressed in keratinocytes of the hair. Once activated, they allow cell differentiation and proliferation, as well as hair follicle regeneration.
A factor in hair growth
If your vitamin D intake is insufficient, the growth cycle of your hair could be disrupted.
Among other things, hair follicles would enter the resting phase prematurely, which can cause rapid hair loss and a reduction in hair density.
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Vitamin D deficiency, what impact on hair?
A vitamin D deficiency leads to hair loss
According to a review from 2021, the majority of scientific studies on the subject show a clear inverse relationship between vitamin D levels and the presence of various non-scarring alopecias (telogen effluvium, androgenetic alopecia, alopecia areata) or scarring alopecia.
A scientific study also showed that a vitamin D deficiency could also be involved in alopecia areata, an autoimmune form of hair loss.
But it is not the only cause
Warning: even if a vitamin D deficiency can lead to hair loss greater than normal, it is not the only potential cause.
Hormonal imbalances, nutritional deficiencies in iron, protein or zinc, medical conditions, genetic predispositions or even a period of intense stress can disrupt the hair cycle and increase shedding.
To improve your issue, I recommend getting a complete assessment from healthcare professionals to determine the true cause of your hair loss.
Should you supplement with vitamin D for healthier hair ?
If a vitamin D deficiency disrupts hair growth and plays a role in premature hair loss, one might assume that increasing intake through supplementation could be beneficial. For example, to strengthen hair, prevent shedding, and support growth.
However, the scientific research appears to be contradictory and does not show sufficiently significant results demonstrating the benefits of vitamin D supplementation on hair health, even in deficient individuals.
Further studies on the subject could be of interest.
How can you maintain a good vitamin D level?
If you want to sport a beautiful head of hair, sufficient serum vitamin D levels are essential. For this, I recommend:
- a sun exposure of 15 to 30 minutes per day, depending on your skin type. Remember to wear sunscreen and avoid the hottest hours of the day.
- to consume fatty fish several times a week as well as eggs, or fortified dairy products.
- to take supplements during the autumn and winter months, when sunlight tends to be lacking, my recommendation? Vitamin D3 (cholecalciferol) supplements, which are better absorbed than those based on vitamin D2. Before starting any regimen, consult your doctor to assess your vitamin D level and needs.
Sources and scientists
- Demay MB et al., 2007, Role of the vitamin D receptor in hair follicle biology
- Cianferotti L et al., 2007, Vitamin D receptor is essential for normal keratinocyte stem cell function.
- Saini K et al., 2021, Role of vitamin D in hair loss: A short review.
- Thompson JM et al., 2017, The Role of Micronutrients in Alopecia Areata: A Review.
- Klein EJ et al., 2022, Supplementation and hair growth: A retrospective chart review of patients with alopecia and laboratory abnormalities.
