Vitamin D

At the end of this long article (but I hope not too boring), we have seen the very important functions that vitamin D  performs in our organism and, involving such a wide spectrum, in fact it behaves more like a hormone (and if you remember we have explained that it also has its chemical structure).

It regulates functions ranging from the musculoskeletal system to the immune and endocrine systems . Furthermore, as we have seen, it also plays a fundamental role in the health of our beloved hair .

So, in my view, it is a wise idea to check the levels of this vitamin through a blood test and have the dermatologist who follows you assessed if it is necessary to start integrating it.

Personally, I regularly integrate it in the autumn winter period and then suspend it in spring and summer and in the last 3 years the values ​​have always been normal.


The Vitamin D is known for its importance regarding the mineralization of bones and teeth , but not everyone knows that also has important functions for the optimal health of the hair bulb and thus of our beloved hair

What is Vitamin D

It is one of the fat- soluble vitamins , which means that they need fat to be dissolved and assimilated. It exists in 5 forms but D2 and D3 are the most bioavailable for the human body.

The Vitamin D2 is made from ergocalciferol , it vegetable and comparable only to feed on.

The vitamin D3 or cholecalciferol is the form naturally present in mammals and is up to 100 times more active compared to ergocalciferol.

It is produced directly by the skin which, through exposure to sunlight, transforms the precursor 7-dehydrocholesterol (deriving from cholesterol) into cholecalciferol

Vitamin D is not stored in the liver and the quantity obtainable from food is very limited . Production takes place essentially on the skin through exposure to the sun.

The cholecalciferol has a structure very similar to that of a steroid hormone why many scholars tend to view it more like a hormone than a vitamin classic.

Vitamin D and Hair

If you find yourself reading this page, you are certainly interested above all in what this vitamin can do in the trichological field , so I start immediately with the salient points:

  • Since it is produced through the skin, its receptor (VDR) is also present in the hair follicles and is expressed during the latter stages of anagen and during catagen . The Vitamin D3 would thus have a key role in starting the anagen phase , the active phase of the life cycle of the hair
  • The levels of this element  are certainly not among the causes of androgenetic alopecia , but its presence is very important for the health of the hair follicle and its deficiency can certainly be the cause of strong scents due to alteration of the hair cycle.
  • Even the fact that rickets , which is the main symptom due to low levels of this vitamin, is very often accompanied by alopecia should make us reflect … certainly it is not androgenetics, but in any case it is clear how much vitamin D is related to hair as demonstrated by this study from the University of Cleveland
  • Instead, this other study from the University of Seoul (Korea) is rather complex for the layman, but in other words it demonstrates that the VDR receptor has a decreased expression in the follicles affected by alopecia areata and universal alopecia, demonstrating once again how the Vitamin D is involved in the process of hair growth
  • is one of the most important parameters that are monitored by dermatologists during a trichological examination in case of hair loss.

Other functions of Vitamin D

Now ok that we are mainly interested in hair … but since vitamin D performs other essential tasks in our body, it is correct to make a rundown of the main functions :

  • Regulates the absorption of calcium in the intestine
  • It allows mineralization by deposition of calcium and phosphorus on bone and teeth,  and this is certainly the function for which it is best known.
  • Regulation of the immune response , confirmed by the fact that the presence of the VDR receptor has occurred on practically all types of cells present in our immune system (T lymphocytes, B lymphocytes, macrophages, etc …). If these cells are equipped with the receptor, it is evident that vitamin D is essential for their proper functioning. Obviously we cannot dwell on this topic as it would require several pages to be explored and is not the purpose of this general article. But for those interested in learning more I put the link to the reference study

Vitamin D and Testosterone

Several studies, such as this one on Pubmed , show a correlation between low vitamin D levels and low testosterone levels .

Also interesting is this study by the University of Graz in Austria where by making 54 men take a dosage of 3332 IU per day of cholecalciferol , there was a significant increase in testosterone as well as obviously the restoration of vitamin D levels.

Certainly many of those who will find themselves reading this article will worry about hearing about increases in testosterone since this hormone is involved, albeit indirectly, in the onset of androgenetic alopecia . However, a correct testosterone value is essential for male individuals to feel good from a sexual and muscular point of view .

It should also be remembered that the increase in testosterone induced by any vitamin D supplements is always and in any case within the physiological limits 

Foods that contain it

Dietary vitamin D is of secondary importance since, as we have seen, most of its production occurs through exposure to the sun . However, the foods in which it is present are essentially the following: Liver, fish oils, fatty fish such as salmon, sardines, eggs (in the yolk), milk, fatty cheeses, butter and some varieties of mushrooms (these however contain ergocalciferol as of vegetable origin)

Reference values

The values can be monitored with the simple and economic analysis of blood 25 (OH) D . We can speak of deficiency with values ​​below 20 ng / ml,  insufficiency if the blood values ​​are between 20 and 30 ng / ml, sufficiency above 30 ng / ml of blood.

However, we talk about the optimal dosage from 40 to 60 ng / ml while above 150 ng / ml you reach toxic levels with the possibility of overdose symptoms that you can see below.

The minimum amount the human body needs to stay healthy is 200 IU per day of vitamin D and typically 3-4000 IU per day can be taken through supplements.

It may seem like a lot, but I remember that exposing yourself to the sun in the summer in a costume can produce up to 20,000 IU in just half an hour. Furthermore,  recent studies show that it is possible to safely take up to 10,000 IU per day


Too low levels of vitamin D  lead to a real hypovitaminosis  whose consequences can be quite serious as we can see below:

  • In children, deficiency can lead to Rickets , which is a pathology that affects the skeleton and can lead to problems with bone deformations or weakness
  • In adults it manifests itself in the form of osteomalacia which consists of muscle and bone pain
  • Abdominal pain
  • In the elderly, however, it can lead to osteoporosis problems and reduced bone density
  • There may be alterations in the life cycle of the hair with possible scents as we have seen in the paragraphs above.


Given the scarce presence in food it is definitely unlikely to have problems with excess vitamin D from this source, just as there are no known cases of overdose due to excessive exposure to the sun. On the other hand, it is possible to create imbalances through excessive intake of specific supplements .

Symptoms can range from simple nausea and abdominal pain problems, up to hypercalcemia , nephrocalcinosis (these are common kidney stones) and soft tissue calcification in the most severe cases . To counter these problems related to excess calcium, it may be useful to combine vitamin K2.

How long to stay in the sun?

It is now known that correct sun exposure is essential for the production of vitamin D, but many have asked the question: “how long do I have to stay in the sun?”

To give a rough idea, it can be said that a minimum time of exposure to sunlight in summer equal to 20 minutes a day , with at least 5% of skin exposed , allows to produce a sufficient serum concentration of vitamin D.

On the other hand, a bathing suit exposure of only 15-30 minutes is capable of producing 10,000-20,000 IU .

It should be noted that any excess cholecalciferol produced will not be wasted, but will be stored in the adipose tissue to be used when needed.

Limitations to absorption

Sometimes, even in the case of optimal exposure to the sun and sufficient food intake, it is possible to run into deficiencies due to limited absorption . The causes can be traced back to the following:

  • Climatic : for example, living in latitudes far from the equator where solar radiation is lower involves risks due to reduced solar exposure
  • Areas where the climate is often cloudy
  • High age : In the elderly, absorption is much less and often results from poor sun exposure
  • Use of high protection creams or sunscreens
  • Dark skin color
  • Obesity which, due to the high levels of body fat , binds cholecalciferol to itself (which we remember is fat-soluble) preventing its use .

Integrate Vitamin D

If, following a blood test, a deficiency is detected, your doctor may opt to prescribe a vitamin D supplement in order to restore the correct blood levels.

It is taken orally or, in cases of malabsorption, also intramuscularly by injection .

This article is not intended to be an advertisement for vitamin D supplements, but a guide on the characteristics of this important element with particular attention to the hair side, so I will limit myself to a quick summary. For further information on this type of supplements, however, an article regarding the products I use is scheduled.


It is a vitamin D3 supplement produced by Abiogen Pharma and subject to medical prescription and therefore can be purchased in pharmacies upon presentation of a prescription. It comes in the form of drops to be taken orally or in the form of a solution for injection for cases of more serious deficiency. The image on the side shows the format of 50000UI in oral solution

Its composition consists of cholecalciferol (in variable quantities depending on the dosage) combined with refined olive oil which guarantees maximum absorption of this fat-soluble vitamin.

Since vitamin D is stored by the human body, dibase does not need to be taken daily and usually weekly or even monthly or quarterly intakes are prescribed if using the 300,000 IU injectable format.


Free sale supplements

Without prejudice to the importance of having a doctor ascertain any vitamin D deficiencies, if for any reason you do not want to take Dibase, you are on vacation and you have no way of getting it prescribed, you find it uncomfortable to take it by drops or injection or whatever the reason, you can find both in pharmacies and online different products in capsules that can be right for you.



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