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Vitamin A (Supplement)

Chinese name:

維他命A

Reviewed by

Joseph Blais, Pharmacist

Expert Advisory Board Member

Last Updated: 2022-05-17

What is Vitamin A for?

Vitamin A is a fat-soluble vitamin that is important for normal visual, immune and reproductive function. It can be further divided into preformed Vitamin A and provitamin A (beta-carotene), which come from different sources. The recommended daily dietary intake of Vitamin A for adults is 900 mcg for men and 700 mcg for non-pregnant women.

Vitamin A can appear as retinyl acetate, retinyl palmitate, beta-carotene or preformed vitamin A. You should only take a Vitamin A supplement when you have a Vitamin A deficiency or are unable to take sufficient Vitamin A from your diet. Vitamin A deficiency can cause night blindness, dry scaly skin, and an increased risk of infection.

How to use it?

Vitamin A is available as oral preparations. The usual adult dose of Vitamin A supplement is 2000-35,000 international units (IU) daily and taken with food. For specific dosages, refer to the product label.

The dosage of Vitamin A and beta-carotene can also be described as retinol activity equivalents (RAE).

What are the side effects of Vitamin A?

Vitamin A supplements usually do not have side effects. However, because Vitamin A is a fat soluble vitamin, high dosages can accumulate in your body and cause symptoms such as dry itchy skin, hair loss and abnormal liver function.

Who should not take Vitamin A?

People allergic to Vitamin A or any component of the formulation.

Pharmacist Tips:

It is always highly recommended to get nutrients like Vitamin A from natural sources first. Preformed Vitamin A and provitamin A come from different sources. For preformed Vitamin A, you can get it from liver, fish oils, milk and eggs. For provitamin A, you can get it from carrots, cantaloupe, leafy green vegetables, orange and yellow vegetables, tomatoes and fruits.
Pay attention to the amount of Vitamin A in different products as it can vary. Taking too much Vitamin A may lead to Vitamin A toxicity. You may experience symptoms such as blurred vision, changes in alertness, loss of appetite, and vomiting.
Excessive intake of Vitamin A during pregnancy can cause birth defects. Always consult your doctor or pharmacist before taking any medications or supplements if you are pregnant.
Avoid heavy consumption of alcohol as it can deplete the liver of Vitamin A and may increase the risk of Vitamin A toxicity.

Common dosing schedule:

Take Vitamin A with food or milk.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Vitamin A may interact with:

Alcohol
Orlistat
Retinoic acid derivatives, e.g. Isotretinoin

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Vitamin A in Hong Kong?

Depending on the recommended daily dose of the products, Vitamin A can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. It can also be obtained from doctors.

For pharmaceutical products containing Vitamin A with a recommended daily dose of not less than 10,000 international units (IU), they require a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Vitamin A (Supplement) in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

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