Vitamin D is the sunshine vitamin that many of us never get enough of, especially those of us in the northern hemisphere. It is an important regular of thousands of genes, which affects every aspect of our health from growth to maintaining a healthy body and mind. And there is also a connection between vitamin D deficiency and hair loss.
Summer is coming up shortly for many of us, so I thought this would be a timely article to write.
One of the first things my doctor tested when I was experiencing increased hair shedding was vitamin D. This was because there is good evidence that low levels of Vitamin D can lead to a condition called alopecia.
Aside from hair loss, vitamin D deficiency can lead to several other serious health issues if not corrected.
What is Vitamin D
Vitamin D is quite different from the rest of them. It functioning more similar to way hormones interact with our cells. And almost every one of your cells had a vitamin D receptor (VDR).
Vitamin D is important in regulating calcium and phosphate in the body. It’s super important in helping bones grow strong and properly in early childhood and also maintaining bone density as an adult.
There’s a lot more to Vitamin D however. In recent years, we’ve learned that vitamin D also has important functioning on cell cycle, the immune system, DNA replication and expression of our genes.
Vitamin D deficiency has been linked to a growing number of diseases, and it’s been found that even people in sunny places can still easily become deficient due to lifestyle and work factors.
Recommended daily allowance
We don’t need much vitamin D to stay healthy, some of it can be obtained through diet unless you have a strict diet and are vegetarian or vegan.
- An adult male needs 600 IU per day
- An adult female needs 600 IU per day
- Adults above 70 years of age need 800 IU per day
This is the absolute minimum to stay healthy. But we know from research over the past decade that higher amounts can be protective against many conditions. Some health organizations now recommend adults get between 1000-2000 IU of vitamin D per day.
How are Vitamin D and Hair growth connected?
The hair follicle is just another part of the body that is regulating by Vitamin D. In a paper published in 2012, researchers found that VDR is important in regulating the skin’s biology. Vitamin D was shown to be important for cell proliferation and differentiation in the hair growth cycle. 
Another study in 2016 showed that mice lacking VDR had delayed wound healing due to lack of stem cell activation, and this, in turn, would affect both the interfollicular epidermis and the hair follicles. 
Although there are few double-blind, placebo-controlled studies looking at the effect of Vitamin D on hair loss and hair regrowth, we do have one interesting study from 2014 with 4 Egyptian families who had mutations in their Vitamin D receptor (VDR) gene.
This mutation caused rickets and other health issues. One of the problems they had also experienced was hair loss (alopecia). One of the patients had successful hair regrowth from complete hair loss after receiving vitamin D.
To understand how successful vitamin D could be in hair regrowth, more studies would have to be done and also controlled for many variables. Correcting deficiencies earlier on would likely yield more positive results.
And of course, these were extreme cases. Most people do not have such mutations in the vitamin D receptor gene but become low in vitamin D from lack of sun exposure.
Serum Vitamin D levels and hair fall in women
In a study looked at a student population in South India, researchers investigated the connection between hair loss and serum levels of vitamin D.
44 participants of the study were enrolled and the mean age was 20 years. Among females, those with low serum levels of vitamin D were more likely to have diffuse hair loss.
However, it should be noted that the limitation of this study was that the results were subjected. There was no hair counts done to objectively measure these results.
That being said, given the evidence that vitamin D is important for hair growth, it’s something that should be investigated further.
Vitamin D and alopecia areata
Autoimmune disease is another cause of hair loss. Vitamin D regulates our immune system, it puts the breaks on part of the immune system which could damage the cells and cause the immune system to go after healthy cells.
In a study looking at vitamin D levels and patients with alopecia areata, they discovered that compared to control, they were much more likely to be vitamin D deficient. 91% of the patients with the condition were deficient compared to just 33% of the healthy controls.
To sum it up
Vitamin D can both, directly and indirectly, help prevent and treat hair loss in those who are deficient. There are several ways in which vitamin D can help:
- Vitamin D is important in activating VDR, which then activates stem cells for hair follicle regeneration
- Vitamin D helps block inflammation, a known factor in scarring of hair follicles and hair fall
- Vitamin D boosts the production of antimicrobial peptides (part of your innate immune system) which protects the scalp from bacterial and fungal infections
- Vitamin D helps regulate mood and lower the risk of depression (a known cause of hair fall, mostly in women)
There are many anecdotal reports out there on hair loss forums and other health forums for women that vitamin D was able to stop hair loss and help regrow hair. (see this thread).
The original poster was diagnosed with vitamin D deficiency by her doctor and had been experiencing hair fall in the shower.
After taking 100,000 IU of vitamin D per week for 12 weeks to correct her vitamin D levels, she noticed lots of hair regrowth and bald spots on her head were disappearing.
That amount of Vitamin D is okay to take for the short term, but not long term. It’s always best to consult and get monitored by a doctor if you want to take 100k per week. However, for most people, a maintenance dose of 1000-2000 IU of vitamin D3 is perfectly fine.
How long will it take for vitamin D to reverse hair loss
Hair growth cycle takes months, so even if you start correcting your vitamin D levels, you won’t likely see any significant benefit for at least three months.
However, I generally advise people that they should wait at least 6 months before evaluating whether or not something has worked.
This is because we can go through at least one or two cycles before the hair follicle functions normally again and produces hair that is both visible and strong. And is able to reach terminal length without falling out too early.
The earlier you catch the deficiency, the more chance you have of regrowing your hair.
Where can you get vitamin D?
Vitamin D levels drop in the winter and rise in the summer if you have your body and face exposed to the sun. Of course, I recommend sensible sun exposure and don’t let yourself get burned.
But 20-30 minutes in the sun is plenty for most people and will raise vitamin D levels enough to last a few months.
People are not living in sunny climates will have to get vitamin D either through their diet or by taking supplements.
Foods that contain vitamin D
- Cod Liver Oil
- Mushrroms (D2)
There are many supplements such as hair multivitamins which will already contain vitamin D, but it’s worth checking to see how much. You should aim for at least 1000 IU per day to maintain healthy serum levels.
There are also different types of vitamin D supplements. Some are gel gaps which contain olive oil or another type of oil, and others are powder form.
It’s advised that you take your vitamin D with a meal to help absorption, but either way should be okay in this case.
Remember, if you’re taking vitamin D at higher doses than recommended, it’s important you get blood tests done to check your 25 (OH) D3 levels.
Vitamin D is clearly important for proper hair follicle regeneration and hair growth. Taking steps to prevent a deficiency in the first place is a great idea.
The link between hair loss and hair growth is becoming stronger, and more doctors are aware of it. However, more research should be done to confirm the findings in animals and humans.
We know that a deficiency is bad, but what if levels of vitamin D were increased to high-normal levels. Would that improve hair growth even more? Right now it’s impossible to say.
It appears that hair loss is reversible through taking vitamin D and correcting a deficiency. The earlier you correct the deficiency, the more likely you’ll see quicker results.
1 Mediator1: an important intermediary of vitamin D receptor-regulated epidermal function and hair follicle biology.
2. Vitamin D and calcium regulation of epidermal wound healing.