Vitamin D Receptors DO Play Role in Hair Loss, Although Effects of Vitamin D Itself Remain Unclear
Science has determined that defective vitamin D receptors in skin cells are responsible for at least one form of hair loss (alopecia), but the actual role of vitamin D itself remains unclear.
Back in February of last year (2011), the Vitamin D3 Blog published an article about Vitamin D Deficiency and Hair Loss, which at the time appeared to be accurate, but that nonetheless spurred quite a bit of controversy among readers. That particular post has been among the most read, and has attracted the most reader comments in the history of this website.
The gist of the post was that while plenty of speculation of a link between vitamin D deficiency/insufficiency and inexplicable and/or premature hair loss could be found online, at the time, we here at the Vitamin D3 Blog had been unable to confirm a scientific link between the nutritional insufficiency and hair loss. The post set off a firestorm of comments (which still arrive at a rate that exceeds our ability to moderate all of them in a timely manner) by readers who believe based on personal experience that such a relationship does in fact exist.
In the time since the previous post on the topic of vitamin D and hair loss went live, a number of studies have been released that appear to validate the reader speculation regarding a possible association between low vitamin D and alopecia, which is a scientific term for baldness and/or hair loss.
According to one study conducted by a group of researchers at the Department of Medicine, Veterans Affairs Medical Center and University of California, both humans with certain mutations in their vitamin D receptors (VDR), and mice lacking in these receptors developed alopecia (baldness). In that study, the mice were born with a full coat of hair, but failed “to initiate normal hair follicle cycling”. The study concluded that the lack of vitamin D receptors resulted in the disruption of the hair follicle structure, which resulted in subsequent failures of hair follicle cycling. The researchers went on to state that such changes are associated with increased hair loss, suggesting that the mutated VDRs were at least partially responsible for the regulation of the gene that controls hair loss, and hence the hair loss itself. (1)
Another study conducted by scientists at the Department of Dermatology at the University of Texas and the MD Anderson Cancer Center in Houston “sought to evaluate the role that vitamin D and the vitamin D receptor play in the hair cycle and assess how this can be clinically applied to the treatment of hair disorders.” While it was determined that the vitamin D receptor does in fact play a role in hair follicle cycling, this receptor acts independently of vitamin D itself in this regard. The research concluded that treatments that up-regulate the vitamin D receptor may hold potential as a possible future treatment for hair disorders, and that further studies should be conducted on the matter. The researchers were quick to admit however, that the actual role of vitamin D in hair follicle cycling is not well understood, and that no conclusions could be drawn at this time about the role of the actual nutrient itself. (2)
In yet another study, this one conducted by the Endocrine Unit, Massachussetts General Hospital and Harvard Medical School in Boston, researchers found that by genetically tweaking the vitamin D receptor-null mice, alopecia could be prevented. Effectively, what they did was take VDR-null mice and mate them with in mice by mating them with two “highly expressing transgenic lines of mice expressing the human VDR” in order to obtain VDR-null mice expressing the human vitamin D receptor-transgene. Expression of the transgene (the one created by cross-breeding VDR-null mice with genetically-altered mice expressing the human VDR) in the VDR-null mice prevented alopecia (hair loss). Thus, the scientists were able to restore the VDR expression in the VDR null mice, preventing the hair cycle defect that leads to the development of alopecia. (3)
One final study worth mentioned a likelihood that keratinocyte is the actual cell responsible for the defective vitamin D receptors, which are believed to lead to alopecia (hair loss, baldness). This study, conducted by the same group of Boston-based researchers responsible for the latter of the three previous studies mentioned, concluded that keratinocyte, the predominant cell type in the epidermis (skin), is the “origin of the defect”. They went on to suggest that “this form of alopecia is due to absence of ligand-independent receptor function.” (4)
Perhaps the most promising study of all was one conducted by researchers at Cedars-Sinai Medical Center/University of California Los Angeles School of Medicine. The very title of the abstract of their research sounds far more promising and to-the-point than those studies previously mentioned. The title reads: “Vitamin D3 analogs stimulate hair growth in nude mice”. The study determined that “Vitamin D3 analogs dramatically stimulated the hair growth of nude mice,” adding that “Vitamin D3 analogs seem to act on keratinocytes to initiate hair follicle cycling and stimulate hair growth in mice that otherwise do not grow hair.” (5)
To conclude, science has determined that a genetic defect in the vitamin D receptors found in skin cells is responsible for at least one form of premature hair loss/baldness/alopecia, or whatever other term one wishes to assign to describe the condition. However, the relationship of the actual vitamin D levels of a person suffering from alopecia has not been established relative to the development of the condition. It may well be that the mutated vitamin D receptors prevent proper absorption of the nutrient, resulting in vitamin D deficiency, which could factor into the loss of hair. Or, it’s entirely possible that new research will determine conclusively that vitamin D itself has nothing whatsoever to do with the condition.
So, for those of you reading this in hopes of discovering how to re-grow your hair, vitamin D3 supplementation may help, but there is no direct scientific evidence to support any claim that it would. The Vitamin D3 Blog is neither suggesting or denying a relationship between an balding individual’s vitamin D levels and the condition of his or her hairline and scalp, nor are we encouraging those suffering from hair loss to go out and purchase supplements in hope of regrowing hair.
That said, if anyone suffering from premature hair loss or balding does decide based entirely upon his or her own rationale to purchase supplements for the purpose of attempting to reverse a receding hair line, we here at the Vitamin D3 Blog would most definitely like to be notified of the results. So if anyone reading this does decide to try vitamin D supplementation (hopefully using vitamin D3 as opposed to D2) in an effort to regrow hair, please fill out the contact form located on the Contact Us page of the site and share your story with us regardless of the end-result. If we receive enough responses, we may do a follow-up post on the subject comparing the results of the readers of this blog who tried D3 supplementation as a means of slowing and/or reversing hair loss or premature balding.