If you google "vitamins for hair loss," vitamin D is almost always in the top three. And for good reason. A large part of the population in the Netherlands has a deficiency, especially in the winter months. But how big is the role of vitamin D in hair loss, really?
This is an honest answer, without exaggeration.
What does vitamin D do in your body?
Vitamin D is, strictly speaking, not a vitamin but a hormone. Your body produces it when your skin is exposed to UV-B radiation from the sun. You can also get it through food or supplements, but through food alone, you rarely get enough.
A large part of the population in the Netherlands has a deficiency. Research by the RIVM shows that about 50% of Dutch people are below the recommended values in the winter months. This makes it a real concern.
Vitamin D receptors in your hair follicle
Hair follicles contain vitamin D receptors, also known as VDR (Vitamin D Receptor). These receptors play a role in regulating the hair growth cycle, particularly in the transition from the telogen phase to the next growth phase.
A 2023 study in the scientific journal Life Science Alliance showed that hair follicles in mice without a properly functioning vitamin D receptor do not function normally. The hairs, as it were, became stuck in an intermediate phase of the hair growth cycle, disrupting new hair growth. As a result, the hair follicles could not renew themselves properly, and the normal hair growth cycle remained out of balance.
Simply put: without an effective vitamin D receptor, the hair growth cycle does not proceed properly. This is animal research. Translation to humans is not one-to-one.
Connection with hair loss: what the research shows
In humans, several observational studies show a link between low vitamin D levels and various forms of hair loss.
In alopecia areata, the type of baldness where the immune system attacks its own hair follicles, low vitamin D levels are more often found. There are also indications that reduced VDR expression is associated with less activity of the Wnt signaling pathway, which regulates hair follicle growth.
In diffuse hair loss (telogen effluvium), a connection with vitamin D deficiency has also been found. This is the temporary but sometimes severe shedding that occurs after stress, illness, or a nutritional deficiency.
In hereditary hair loss (androgenetic alopecia), the most common form in men, the direct evidence is weaker. Vitamin D does not directly affect DHT levels or the sensitivity of follicles to DHT.
What vitamin D cannot do
If you have hereditary hair loss, where your hair follicles are sensitive to DHT and slowly thin, vitamin D will not stop that process. That is a mechanism that is deeper in the tissue and driven by other factors.
What vitamin D can do: rectify a deficiency that exacerbates the problem. If your hair follicles are already under pressure from DHT, and you also have a vitamin D deficiency, then something extra goes wrong in the growth cycle. Supplementing in that case is useful as a basic step. But it is not a standalone treatment for hair loss.
How do you know if you have a deficiency?
The only way to know for sure is through a blood test. You can have this done through your GP or a commercial laboratory.
Common reference values:
- Below 30 nmol/L: severe deficiency
- 30 to 50 nmol/L: deficiency
- 50 to 75 nmol/L: suboptimal
- Above 75 nmol/L: sufficient according to most guidelines
Symptoms associated with a vitamin D deficiency include fatigue, muscle pain, reduced immunity, and a gloomy feeling. Hair loss alone is not enough reason to assume a deficiency, but if you recognize several of these symptoms and are rarely outdoors, a test is worthwhile.
Supplementing: what works?
Sunlight is the most direct source. But in the Netherlands, the sun from October to April is too low to produce enough UV-B for vitamin D production. Even in clear winter weather, you don't get far.
Nutrition contributes limitedly. Fatty fish (herring, salmon, mackerel), egg yolk, and fortified products provide some, but rarely enough to completely resolve a deficiency.
Supplements are the most practical option if you know you have a deficiency. The Health Council advises 10 micrograms per day (400 IU) for adult men, and 20 micrograms (800 IU) for people at increased risk. Vitamin D3 is better absorbed than D2. Preferably take it with a meal containing some fat, as it is a fat-soluble vitamin.
Vitamin D as part of a broader approach
If you notice your hair thinning or your hairline slowly receding, vitamin D is one of the basic steps you can take. But it is no more than that: a basic step.
Correcting a deficiency gives your hair follicles a better starting position. But if you want to actively do something about hair loss, you need ingredients that work directly on the follicle. Such as Redensyl, which activates the hair follicle stem, or Procapil, which stimulates blood flow to the hair root.
The Hairborn Growth Serum combines several of these active ingredients in one daily product, without side effects. If, in addition to supplementing a deficiency, you also want to directly do something about your hair, that is a logical next step.
Summary
Vitamin D plays a role in hair follicle health. A deficiency is common in the Netherlands and can disrupt the hair growth cycle. The link with vitamin D is strongest in alopecia areata and diffuse hair loss. In hereditary hair loss, supplementing a deficiency has a contributing value, but it is not a solution in itself.
Do you want to know if you have a deficiency? Have it measured. That's the only way to know for sure.
Frequently Asked Questions
Can you get too much vitamin D through supplements?
Yes, although it happens less often than with some other vitamins, prolonged very high intake of vitamin D can lead to an excess, potentially resulting in elevated calcium levels in the blood. Stick to the recommended dosages and consult a doctor if in doubt about high doses.
Does a sunbed help as an alternative to natural sunlight?
No, a sunbed is generally not recommended as a source of vitamin D, because the UV radiation from sunbeds is often differently composed and increases the risk of skin damage and skin cancer without being a reliable or safe way to improve your vitamin D status.
Can you combine vitamin D with a hair serum?
Yes, there is no known interaction between vitamin D supplementation and a topical hair serum. Vitamin D works systemically in the body, while a serum acts locally on the scalp.
Is there a difference between vitamin D2 and D3?
Yes, vitamin D3 is generally better absorbed and more effectively converted into the active form in the body than vitamin D2, which is why most supplements and guidelines recommend D3.
Does a darker skin tone affect how much vitamin D you produce?
Yes, darker skin contains more melanin, which slows down the production of vitamin D through sunlight. People with darker skin therefore often need more sun exposure to produce the same amount of vitamin D as people with lighter skin.
Can you test vitamin D levels yourself at home?
Yes, there are home test kits where you send a blood drop to a laboratory, although the accuracy can sometimes be slightly lower than a test through a GP. For a first indication, this may be sufficient, but if in doubt, a test through a GP is more reliable.
How long does it take to correct a deficiency with supplements?
For a proven deficiency, it usually takes eight to twelve weeks of consistent supplementation before blood levels return to a healthy level, depending on the severity of the deficiency and the dosage used.
Can you continue to take vitamin D all year round?
Yes, you can, especially if you naturally spend little time outdoors or have a darker skin tone, although the need in summer with sufficient sunlight is generally lower than in winter. If in doubt, consult a doctor about whether year-round supplementation is beneficial for you.
Is there a link between vitamin D and vitamin K in supplementation?
Yes, vitamin K2 is often recommended together with vitamin D, because vitamin D promotes calcium absorption and vitamin K2 helps direct that calcium to the correct places in the body, such as bones instead of blood vessels. This is especially relevant with long-term, high doses of vitamin D.
Can overweight affect your vitamin D levels?
Yes, vitamin D is fat-soluble and can accumulate in fatty tissue, which means it is less readily released into the bloodstream in people who are overweight. This means that people with a higher body weight sometimes need a higher dosage to achieve the same blood levels.
