Alopecia Areata and Vitamin D: Should You Get Tested?
- Gwen Adey
- May 21
- 3 min read
Updated: 21 hours ago
If you have alopecia areata, I think it is reasonable to have your vitamin D level checked.
A recent systematic review looked at eight studies on vitamin D and alopecia areata. Overall, people with alopecia areata were more likely to have low vitamin D levels than people without it. Several studies also found that lower vitamin D levels were linked with more severe alopecia areata.
You can read the research paper yourself here:
This does not prove vitamin D deficiency causes alopecia areata, and it does not prove vitamin D supplements regrow hair. But the evidence is strong enough that many clinicians consider vitamin D worth checking in people with alopecia areata.
Importantly, this research applies to alopecia areata, which is an autoimmune condition.
It should not automatically be assumed to apply to every type of hair loss (eg this research does not apply to androgenetic alopecia, frontal fibrosing alopecia etc).
Why vitamin D might matter in alopecia areata
Vitamin D is involved in immune regulation, and vitamin D receptors are found in hair follicles themselves.
Alopecia areata happens when the immune system mistakenly attacks hair follicles.
Researchers think vitamin D may play a role in the immune environment around the follicle and in normal hair cycling.
This is one reason many dermatologists and hair specialists will often check vitamin D levels in people with alopecia areata.
How to check your vitamin D level
You can:
Ask your GP about testing
Use a private blood testing service such as:
Medichecks Vitamin D blood test
One Day Tests Vitamin D blood test (you are welcome to use code GROWTHFACTOR)
These tests usually measure 25-hydroxyvitamin D, which is the standard blood marker used to assess vitamin D status.
Should you only test once?
Probably not.
Vitamin D levels can change significantly throughout the year, especially in countries like the UK where sunlight exposure changes with the seasons.
Levels are often lowest at the end of winter and highest at the end of summer. This means a “normal” vitamin D level in August does not necessarily mean levels will still be adequate in February or March.
For people with alopecia areata — especially those previously found to be deficient or borderline — it may be reasonable to consider rechecking vitamin D periodically, including considering seasonal variation.
What if your vitamin D is low?
If your vitamin D level is low, options may include:
Sensible sunlight exposure
Dietary changes
Vitamin D supplements
Treatment-dose vitamin D prescribed by your GP if deficiency is significant
The NHS states that from late March or early April until the end of September, many people in the UK can make enough vitamin D from sunlight on the skin. To be clear, the NHS says you should avoid sunburn (this is DNA damage and increase cancer risk) and you don’t need to tan.
NHS also notes that many adults may benefit from vitamin D supplementation during autumn and winter when sunlight in the UK is not strong enough to maintain vitamin D levels.
You can read the NHS guidance here:
Do not take very high doses of vitamin D long term unless advised by a doctor, as excessive vitamin D can be harmful.
Which supplements are reasonable?
After testing, if you are found to be deficient you have a number of supplement types available.
Options include:
Standard pharmacy vitamin D tablets or capsules
Supplements recommended by your GP, pharmacist or dietician
Bottom line
If you have alopecia areata, I think it is reasonable to have your vitamin D level checked.
The current evidence suggests low vitamin D is more common in alopecia areata and may be linked with more severe disease. It is not a proven cure - but it is a sensible thing to investigate.
Author: Dr Gwen Adey BDS MFDS RCS
First published: 21/05/26
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