Healthy Hair Again: Why You Might Want To Avoid Vitamin A

Vitamin A has long been considered essential for eye, skin, bone, dental, and intestinal health. But did you know it’s also one of the most commonly found vitamins in hair loss supplements? Given that, is there any conclusive evidence that vitamin A supplementation can help improve hair health or even reverse hair loss?

The ABCs Of Vitamin A

Vitamin A is a fat-soluble vitamin involved in a variety of bodily functions, everything from skin health to immune support to reproductive health. In the skin, one of vitamin A’s main functions is to encourage cell turnover, which is why so many cosmetic products contain vitamin A derivatives.

Vitamin A exists in two forms: beta carotene and retinol.

Beta-Carotene

Beta-carotene, considered an antioxidant, is the precursor to retinol and considered somewhat of an “inactive” form of vitamin A. While beta-carotene is found in both plant and animal-based foods, retinol is only found in animal-based foods. Once ingested, beta-carotene acts more like an antioxidant, whereas retinol acts more like a hormone. In general, beta-carotene helps to fight off free radicals (i.e., inflammation), and retinol helps to change cell behavior, which impacts organ and tissue functionality.

It’s well-known that UV radiation (sunlight exposure) can increase free radical activity in skin tissues, and thereby elicit inflammation, which can occur in the scalp and hair follicles. In high quantities, UV radiation might elicit enough free radical activity to actually impede hair growth. What’s the upshot? Protecting against UV radiation may also protect against free radical-induced hair loss. Antioxidant carotenoids like beta-carotene are known to build resistance to UV radiation in the skin, which means that beta-carotene consumption may protect against UV radiation-induced hair loss.

Retinol

Retinol supports the immune system, fortifies gut health, and may help with metabolism. The most important effect that retinol deficiency might have on hair growth is actually at the superficial level, meaning its impact on the scalp and the hair follicle itself.

Retinol is important for the activation of stem cells, a process essential for hair growth. If retinol depletion is enough to induce stem cell dysfunction on its own, this may lead to impaired hair growth. Retinol also regulates sebum production in the sebaceous gland. One study demonstrated that retinol reduced or normalized sebum production, abrogating one of the factors that can lead to microbial overgrowth that can impeded hair growth.

Excessive skin cell proliferation (hyperkeratosis) can lead to dead skin cell buildup at the follicular opening and; in turn, this can lead to poor follicle oxygenation. Retinol deficiency can potentially bring about excess skin cell proliferation. In addition, because retinol plays a crucial role in the production of antimicrobial peptides, it may also impair the body’s natural defense against microbial overgrowth at the follicular opening.

Vitamin A Can Actually Increase Hair Loss

Vitamin A deficiencies are incredibly rare, which means that for most people, vitamin A supplementation is unnecessary. There are a few case reports of people with widespread nutrient deficiencies – including vitamin A – and hair loss; however, these cases are mostly found the developing world. Not only can’t these studies be applied to the developed world, they also don’t definitively show that vitamin A deficiencies were at the root of thinning hair.

Studies indicate that less than one percent of Americans are deficient in serum retinol, which suggests that the overwhelming majority of people in the developed world are getting enough vitamin A through dietary means. In addition, the only cases linking dietary-driven vitamin A deficiencies to hair loss are based on reports of men who’ve undergone extreme weight loss – and the loss was related to body hair, not scalp hair.

On the contrary, some studies have shown that low-vitamin A diets have delayed the onset of hair loss or partially reversed male pattern hair loss. Moreover, high-dose vitamin A (as accutane) is directly linked to the hair loss disorder telogen effluvium, all of which indicates that vitamin A supplementation can carry a higher risk of hair loss than it does of hair regrowth.