Summary
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How much vitamin A should I take?
Unless you're deficient in vitamin A or have a condition that can cause deficiency, you probably don't need to take a vitamin A supplement. Americans are more likely to get too much vitamin A from their diets than too little. The daily requirement for vitamin A is 900 mcg (or 3,000 IU in the retinol form) for men, 700 mcg (2,333 IU) for women, and is lower for children. -
Changing vitamin A labels:
Be aware that supplement labels are in the process of being updated to show vitamin A in "mcg" (micrograms) of retinol activity equivalents - RAE. This is more scientifically correct than the older "IU" format. For reference, 900 mcg = 3,000 IU of vitamin A as retinol or 6,000 IU of beta-carotene, since retinol (and related retinyl forms) have greater biological activity than beta-carotene. -
How much vitamin A is too much?
Too much vitamin A (for adults, over 3,000 mcg RAE daily -- or 10,000 IU in the retinol form) can cause problems, and is of particular concern for women who are pregnant. Although safe when consumed from fruits and vegetables, there are some concerns with taking beta-carotene, which is converted, as needed, to vitamin A in the body. 
Is cod liver oil better than synthetic vitamin A?
The vitamin A in fish oil is the same as the synthetic vitamin A in most supplements -- retinyl palmitate, so it doesn't matter which you use. Cod liver oil tends to cost more but can provide significant amounts of vitamins D and E as well as omega-3 fatty acids (EPA and DHA).-
Best choice for vitamin A supplements?
Among the supplements that passed testing, we selected those that provide the best quality and value as our Top Picks, including selections for an overall vitamin A supplement (including optional selections for very high dose vitamin A and fish-free vitamin A), as well as for vitamin A from beta-carotene and from cod liver oil.
