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  • Kelin M

Vitamin A for Hair Growth - Does it Work?

Updated: Nov 8, 2022

Want to grow longer, thicker hair? Consuming the right amount of vitamins and minerals can make all the difference in hair growth.

Long, thick hair is a sign of good health and for many people, firmly connected to their self-esteem. We'll show you how you can use Vitamin A properly to improve your hair growth, the best sources of vitamin A for hair growth, and how much vitamin A to take each day.

Our recommended vitamin A supplement is Why Not Natural's liquid vitamin A, found here.

Does Vitamin A Really Help Hair Growth?

If you're wondering, "does vitamin A really help hair growth?", the answer is: yes, but only if you take the right amount. It's critical for cell and tissue growth, and hair is the fastest-growing tissue in the body.

You can use vitamin A for hair growth, and it also keeps your hair healthy. It's necessary for proper functioning of the sebaceous glands, which produce sebum, the oil that keeps your hair moisturized so it can grow to its long, thick, and full potential.

In studies on rats, the rats fed a diet low in vitamin A experienced alopecia, an autoimmune disease that can cause your hair to come out in clumps.

It's important to note that in the case of vitamin A, there can be too much of a good thing. Consuming vitamin A from plant foods in your diet poses no threat to your health, but you should take a supplement with a maximum of 10,000 IU per day as higher doses can actually be toxic and lead to hair loss or thinning.

What is the Best Form of Vitamin A?

There are two forms of vitamin A: preformed and provitamin A carotenoids. Preformed typically come from animal sources, and provitamin A from plants.

The only vitamin A your body can use is preformed, or retinoids (like retinol). Your body must first convert carotenoids (from plants) to retinoids, and not everyone's body is able to do that.

The ability to absorb carotenoids ranges from 5% to 65% and depends on diet, genetics, and gut health. This means that not everyone will be able to meet his or her vitamin A needs from eating plant foods alone.

There's no maximum dose of carotenoids, but it's important to avoid taking more than 10,000 IU per day of retinoids).

What are the Best Sources of Vitamin A?

The best type vitamin A for hair growth is preformed vitamin A, which is found mostly in animal products:

  • Liver (the best source, consume in moderation if pregnant)

  • Cheese (especially cheddar, camembert, and blue cheese)

  • Eggs

  • Oily fish (especially liver and liver oils)

  • Dairy (milk and yogurt)

Colorful vegetables, especially those that are orange, yellow, and red, are rich in carotenoids. Leafy green vegetables are also good sources. Here are some of the best:

  • Mango and papaya

  • Squash (like butternut)

  • Carrots

  • Sweet Potatoes

  • Spinach

As mentioned in the "What is the Best Form of Vitamin A?" section, some people cannot easily convert carotenoids to vitamin A.

Check out this article for a list of our top 10 plant-based and animal-based vitamin A sources.

A good supplement can make up for a lack of vitamin A in the diet. Why Not Natural has a great vegan retinol vitamin A!

How Much Vitamin A Do You Need for Hair Growth?

Figuring out how much vitamin A for hair growth and hair health can be confusing because there's no one-size-fits-all recommendation, but we'll walk you through it so you can make sure you take the perfect amount of vitamin A for beautiful hair.

You should ensure your daily vitamin A consumption meets the current guidelines set by the U.S. Food and Drug Administration.

It's important to note that the RAE, or "retinal activity equivalents", are not the same for all sources for vitamin A and provitamin A (such as carotenoids). It can be a little confusing, but not all vitamin A is created equal (see the "What is the Best Form of Vitamin A?" section above).

The charts below have the recommended amount in IU for retinol, the bioavailable form of vitamin A. Other forms will use the following conversions:

1 mcg RAE = 1 mcg retinol

1 mcg RAE = 2 mcg supplemental beta-carotene

1 mcg RAE = 12 mcg beta-carotene

1 mcg RAE = 24 mcg alpha-carotene

1 mcg RAE = 24 mcg beta-cryptoxanthin

What this means is that if you are supplementing with a retinol (such as retinyl palmitate) or eating it in meat, fish, or dairy, you can use the charts below directly.

If, for example, you're consuming beta-carotene from plant foods, you should multiple the recommended values in both mcg and IU by 12 to find your required daily consumption.

The recommendations are below:

Life Stage

Recommended Amount (mcg RAE)

Recommended Amount (IU)

Birth to 6 months

400 mcg RAE

1333 IU

​Infants 7–12 months

​500 mcg RAE

1667 IU

​Children 1–3 years

300 mg RAE

1000 IU

​Children 4-8 years

400 mg RAE

1333 IU

Children 9-13 years

600 mg RAE

2000 IU

Teen Boys 14-18 years

900 mg RAE

3000 IU

Teen Girls 14-18 years

700 mg RAE

2333 IU

Adult men

900 mg RAE

3000 IU

Adult women

700 mg RAE

2333 IU

Pregnant teens

750 mg RAE

2500 IU

Pregnant women

770 mg RAE

2565 IU

Breastfeeding teens

1200 mg RAE

4000 IU

Breastfeeding women

1300 mg RAE

4333 IU

Be sure to keep your intake below the maximum recommended doses, which are as follows:


Upper Limit (mcg)

Upper Limit (IU)

Birth to 12 months

600 mcg RAE

2000 IU

Children 1-3 years

600 mcg RAE

2000 IU

Children 4-8 years

900 mcg RAE

3000 IU

Children 9-13 years

1700 mcg RAE

5100 IU

Teens 14-18 years

2800 mcg RAE

8400 IU

Adults 19 years and older

3000 mcg RAE

9,000 IU

Other sources recommend a dose lower than 10,000 IU per day.

Why Does Vitamin A Cause Hair Loss?

Vitamin A can cause hair loss at too high a dose. Do not take a supplement with more than 10,000 IU per day.

If you eat liver every week or are pregnant, you should not take a vitamin A supplement.

Vitamin A is fat-soluble and stored in the liver. It is transported to the tissues (including your hair follicles that helps your hair grow longer and sebaceous glands that make your hair moisturized and healthy!) by a process involving a specific protein (retinol-binding protein, or RBP) that's produced by the liver and binds with vitamin A.

When too much vitamin A is consumed over a long period of time, this transport system is overloaded and the excess retinol spills into your bloodstream. This causes vitamin A toxicity, which impacts your hair growth in a negative way.


Vitamin A is a vital component of hair growth. Without enough of it, your hair will not meet its full potential in terms of growth or health!

The best sources of vitamin A for hair growth are animal sources, as these are bioavailable for everyone. However, there are some plant-based retinol forms that can be taken in a supplement.

It's important that you don't take too much vitamin A. The best way to use vitamin A for hair growth is to follow the Goldilocks principle: not too little, not too much, but just enough. For most adult women, between 2,000 IU and 10,000 IU per day of vitamin A is a healthy dose.

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