Medicines & Supplements A to Z > Vitamin A (Supplement)

Vitamin A (Supplement)

Last updated on July 30, 2019.

Overview   |   Dosage   |   Side Effects   |   Where To Buy  

GENERIC NAMES: Retinol / Vitamin A



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 in supplement. 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 increased the 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.

What are the other sources of Vitamin A?

Most people should obtain adequate amounts of Vitamin A from a healthy diet. 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.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

For detailed information about the use of Vitamin A 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.