How do you choose a vitamin C, and is 1,000 mg necessary?

Vitamin C is one of the most crowded categories, running from 500 to 1,000 mg and above, in lozenges, chewables, tablets and powders.

How much is enough?

Recommended intakes set by the US National Academies' Food and Nutrition Board, as published by the NIH Office of Dietary Supplements, are 90 mg a day for adult men and 75 mg for adult women. The tolerable upper intake level is 2,000 mg a day.

Product amounts therefore sit well above the recommended intake. Vitamin C is water-soluble and the excess is excreted, so a very large amount does not mean the body uses all of it.

Is 1,000 mg necessary?

It depends on what the daily diet already supplies. A single guava is very high in vitamin C, so someone eating fruit regularly may not need a large amount from a supplement.

Very large single amounts leave some people feeling uncomfortable; splitting into two occasions a day is usually easier.

How do the chemical forms differ?

Ascorbic acid is the basic form, and it is acidic.

Calcium ascorbate and other mineral-bound forms are less acidic, which some people find sits better. Labels read calcium ascorbate (provides vitamin C X mg); the bracketed figure is the one to compare.

Vitamin C from acerola comes from fruit, and usually provides less per tablet than a synthetic form.

How do you choose a format?

Lozenges suit use during the day. Tablets deliver a large amount in one. Powders suit anyone who dislikes swallowing tablets, but often contain sugar or sweeteners, which the nutrition panel will show.

Which statements are available?

The annex to Thai Ministry of Public Health Notification No. 447 (B.E. 2566) recognises that vitamin C contributes to the normal function of the immune system, to normal collagen formation for the normal function of skin, bones, gums, teeth and cartilage, and that it increases iron absorption.

In what order should you decide?

First, consider what your diet already supplies. Second, pick an amount that fits rather than the largest number. Third, if large amounts have been uncomfortable before, try a less acidic form. Fourth, choose a format you will keep using.

Dietary supplements are not intended to prevent, treat or cure any disease.