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Why Excessive Vitamin A Can Cause Hair Loss
Dr Mir Malkani
Medically reviewed by
Dr Mir Malkani
Updated on February 27, 2023

Vitamin A is an essential nutrient for the body and it has many important implications. Healthy levels of Vitamin A are needed to ensure that the body’s immune and reproductive systems are functioning properly, and it is also vital for good vision. Vitamin A also supports the maintenance of healthy skin, teeth, hair, bones and organs such as the lungs, liver and kidneys.

But excessive Vitamin A can cause a number of problems, including hair loss. Here we’ll explain why too much Vitamin A is bad for you and your hair.

Table of Contents

Vitamin A toxicity

Although Vitamin A is a vital part of a healthy and balanced diet, like anything, it should be consumed in moderation. Just because it’s a vitamin doesn’t mean that too much of it won’t do you any harm. It is possible to overdose on Vitamin A and the results can be very serious.

Vitamin A is a powerful antioxidant and has many great properties that can improve your health. However, the World Health Organization lists “alopecia” as a result of chronic Vitamin A toxicity. That is, it can occur if you overdose supplements containing this nutrient. In fact, multiple studies suggest that excessive vitamin A intake can cause hair loss. [1, 2]

Vitamin A is not a toxin in itself — but that it can behave as such if taken in excessive doses. When this occurs, the medical community calls it Hypervitaminosis A

Doesn’t Vitamin A stimulate hair growth?

Vitamin A is essential for healthy hair. It repairs it and helps to keep the scalp moist. Many hair loss treatments contain Vitamin A as it is thought to stimulate hair growth. 

Moreover, beta-carotene, one of the two forms of Vitamin A, has been found by research to have beneficial anti-inflammatory properties which are particularly  beneficial to patients with Alopecia Areata (an autoimmune condition which produces hair loss in a spotty pattern).

Vitamin A is a fat-soluble vitamin, which means its stores can build up in the liver where it is stored. While vitamin A is vital for your overall health, over time, excessive intake can actually cause vitamin A toxicity. This may lead to vertigo, headaches, and nausea, as well as skin peeling and weight loss [3].

Too much vitamin A takes its toll on your hair, too. If you take too many supplements of the Retinol kind over a prolonged period of time, the hair follicles will go into overdrive. This means that your hair will be reaching the end of the growth phase too quickly and falling out. If your body is unable to make new hair quickly to replace it, you can end up experiencing hair thinning and in severe cases, baldness.


How much is too much?

For an adult over 19 years of age, 4300 International Units (IU) of Vitamin A per day is considered sufficient for the proper functioning of the organism. These are normally ensured by a balanced diet, with little need for supplementation in a healthy person. 

In order to overdose on Vitamin A, you would have to consume around double your recommended daily intake. According to government guidelines, the upper threshold to which excess intake of Vitamin A is tolerated by your body is 10,000 IU. Exceeding this threshold over a prolonged period of time will lead to overdosing and Vitamin A toxicity. This can have severe effects for your health. 

If you are planning on taking any Vitamin A supplements, it is advised that you speak to your doctor first. It is relatively difficult to overdose on Vitamin A purely by eating the foods in which it is found. 

Vitamin A can be ingested (via diet or supplements) in two forms. Retinol is naturally found in liver and dairy, while beta-carotene is naturally found in vegetables such as carrots.  

However, as the same study cited above points out, Vitamin A toxicity does not occur from the ingestion of beta-carotene, regardless of the dosage. It is only reported when overdosing on retinol. This can only happen through supplementation, as the doses normally ingested through diet – even in large portions, are far too small to do real harm. 

What to do if Vitamin A has caused hair loss

If you believe you’ve lost hair as a result of taking too much Vitamin A, you should reduce your intake. Vitamin A stores in the liver, so your body must use up its reserves before you take any more. If you have been taking a supplement, you may need to stop taking this and get your Vitamin A from food while your body uses up its stores. Once your nutrient levels have evened out, your hair should grow back properly.

If there’s another reason for your hair loss, then too much Vitamin A could make the problem worse. In this case you will need to see your doctor to discuss the root cause of your hair loss and find out what the best course of action is.

How to get a healthy intake of Vitamin A

The best way to avoid taking too much Vitamin A is to get it through food, rather than supplements. Red, yellow, orange and dark green vegetables are all great sources of Vitamin A. You can also get it from eggs, liver, fortified milk and cereals. Eat a healthy, balanced diet and you’ll get all the Vitamin A you need. Plus, your body will be able to process it healthily, rather than storing excess amounts which could lead to serious health complications.

Being cautious about hair loss treatments

Many medications can cause hair loss. Some hair loss treatments also contain Vitamin A. It helps to produce healthy sebum, which prevents hair from drying out and breaking off. It is also an antioxidant, which helps to fight free radicals that can damage the hair.

It’s important to be cautious though, as you do not want to end up using a hair loss treatment that contains too much Vitamin A. If you are getting enough in your diet, you could risk overdosing by using a Vitamin A supplement or treatment. Vitamin E for hair can also be toxic if taken in high doses.

If in doubt, it’s recommended that you contact your GP to discuss your health, diet and lifestyle. They can also give you medical advice on whether taking Vitamin A is necessary based on your unique eating habits. They may also be able to suggest other causes of your hair loss if they believe you’re consuming the right amounts of vitamins and minerals.

And it’s not just vitamin A that can endanger your hair. Certain diets like keto or low-carb diets can impact hair loss. Other foods may also contribute to hair loss, such as sugar, fried foods, and mercury-rich fish.

For more information about hair loss and hair loss surgery, please get in touch with the team here at Wimpole Clinic on 020 7935 1861. We are one of the UK’s best hair loss clinics and our experts will be able to find a hair loss solution to suit you in order to bring your head of hair back to its former glory.

Dr Mir Malkani
Medically reviewed by Dr Mir MalkaniUpdated on February 27, 2023
The Wimpole Clinic offers FUE Hair, Beard & Eyebrow Transplants & Trichology.
Talk to a specialist ☎ 020 7935 1861.
Dr Mir Malkani
Medically reviewed by
Dr Mir Malkani
Updated on February 27, 2023

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