Vitamin A and Hair: Too Little, Too Much & What the Research Shows

Vitamin A is essential for healthy skin and hair, but with vitamin A the problem runs both ways: too little and too much both cause problems. In reviews of hair loss caused by toxic agents, excess vitamin A is among the agents with described incidents, which is why taking extra vitamin A for hair is not a good idea.

Here's what vitamin A does in the hair follicle, what the toxicity reports say, and what to do instead.

I LOVE MY HAIR NOW

FullyVital hair serum and hair vitamins made tremendous improvements in my hair. I truly love my hair now.

Dorit S.,

Shop Hair Products

Key Takeaways

• Vitamin A is necessary for the growth of healthy skin and hair, but both too little and too much have harmful effects.
• Retinoic acid, its active metabolite, regulates hair follicle stem cells in a dose-dependent way.
• A systematic review of toxic agents that cause alopecia lists vitamin A among those with described incidents.
• Reviews say micronutrient deficiencies may be modifiable risk factors for hair loss, but large trials are needed.

What Is Vitamin A?

Vitamin A is a fat-soluble micronutrient. Its main active metabolites are retinoic acid and retinal.

Does More Vitamin A Mean More Hair?

No. The relationship is dose-dependent and can turn harmful at high intakes. If you're worried about hair loss, a doctor can check whether you're short of anything rather than you adding vitamin A on a guess.

Our Best Sellers

3-Month Growth Bundle

$269.00

Shop Hair System

Hair Revival Supplements

$47.20

Shop Vitamins

Using Vitamin A Safely

• Don't megadose. Too much is harmful.
• Be extra careful in pregnancy. Ask your doctor before taking vitamin A supplements.
• Get tested if you suspect a deficiency.

Our Best Sellers

3-Month Growth Bundle

$269.00

Shop Hair System

Hair Revival Serum

$47.20

Shop Hair Serum

What The Research Shows

Vitamin A In Skin And Hair

A review describes vitamin A as necessary for the growth of healthy skin and hair, with both too little and too much deleterious. Retinoic acid dose-dependently regulates hair follicle stem cells, influencing the hair cycle, wound healing and melanocyte stem cells (VanBuren & Everts, 2022).

When Vitamin A Is Too Much

A systematic review of 47 studies on toxic agents that cause alopecia found the strongest evidence for thallium, mercury, selenium and colchicine. Agents with described incidents include boric acid, arsenic, vitamin A, botulinum toxin and others (Yu et al., 2018).

The Wider Micronutrient Picture

A review of vitamins and minerals in hair loss, including vitamins A, B, C, D, E, iron, selenium and zinc, found they play important but not entirely clear roles in hair follicle development and immune function. It said deficiency may be a modifiable risk factor and that large double-blind placebo-controlled trials are required (Almohanna et al., 2019).

Vitamin C is another vitamin people ask about; see vitamin C and hair.

See also: Manganese for Hair: Benefits, Food Sources & How Much You Need · Selenium and Hair: What the Research Shows

To see how this fits with the other nutrients hair needs, read our guide to the best vitamins for hair growth.

Frequently Asked Questions

Does vitamin A help hair growth?

Vitamin A is necessary for hair, but too much is harmful, and we found no evidence that extra vitamin A grows hair.

Can too much vitamin A cause hair loss?

Vitamin A is among agents with described incidents of toxic alopecia.

Should I take vitamin A for my hair?

Ask your doctor first. A deficiency test is a better starting point.

References

1. VanBuren CA, Everts HB. Vitamin A in Skin and Hair: An Update. Nutrients. 2022. PubMed
2. Yu V, Juhász M, Chiang A, et al. Alopecia and Associated Toxic Agents: A Systematic Review. Skin Appendage Disord. 2018. PubMed
3. Almohanna HM, Ahmed AA, Tsatalis JP, et al. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019. PubMed