About Ester-C

Ester-C is vitamin C made as calcium ascorbate, a buffered form, with its naturally occurring metabolites. It has been on store shelves since 1989.

What Ester-C is

Most vitamin C in supplements is ascorbic acid. Ester-C takes a different route: the vitamin C is bound to calcium as calcium ascorbate, and it keeps the metabolites that form along the way. NIH describes Ester-C as calcium ascorbate with dehydroascorbate, calcium threonate, xylonate and lyxonate, and our panels list them as naturally occurring vitamin C metabolites.

You will see two promises on our packs: "Gentle and Non-Acidic" on the bottles and "Stomach friendly" on the boxes. They describe the buffered form. If plain ascorbic acid bothers your stomach, a buffered form is the usual next thing to try. Our directions ask you to take it with a meal either way.

What we make

Every Ester-C serving gives you 1,000 mg of vitamin C. We make it in two families. The yellow box holds coated tablets: Ester-C 1000 mg, one a day, and Ester-C 500 mg 24 Hour, two a day, both with our C-Sorb citrus bioflavonoid complex. The amber bottle with the orange cap holds Ester-C with Citrus Bioflavonoids, sold under our American Health label, as capsules and vegetarian tablets at 500 mg and 1000 mg.

Bottle sizes run from 45 tablets to 450. A bigger bottle lowers the price of a serving. A smaller one is easier to finish before its date. The comparison page sets all 6 formulas and their 18 sizes side by side.

What vitamin C does for you

Vitamin C is an antioxidant and helps maintain the normal function of your immune system.* Your body does not make it, so it comes from food or a supplement. NIH puts the adult need at 75 mg a day for women and 90 mg for men, and the upper limit at 2,000 mg from all sources.

The research on Ester-C itself is small and specific. A 2006 trial of 50 people sensitive to acidic foods counted fewer stomach complaints after Ester-C than after ascorbic acid. A 2016 trial of 36 adults, funded by the then owner of Ester-C, measured more vitamin C in white blood cells at 8 and 24 hours. NIH, looking across all forms, concludes that none has been shown better than the others. All three sit side by side in our article on buffered vitamin C.

Ester-C at 37 years

The Ester-C name has been on store shelves since 1989. Today the range covers coated tablets, capsules and vegetarian tablets at two strengths, and the people who take it have left 52,616 ratings at an average of 4.7 out of 5.

This site is where the whole range stands together, with the full Supplement Facts of every product, the directions from the pack and the sources behind our health statements. You buy through our retail partner, who handles payment, shipping and returns.

Ester-C boxes and a bottle with an orange and a flask on a marigold table — The Ester-C boxes and the gummy jar on our marigold, the color of every pack.

The Ester-C formulas

The Ester-C formulas side by side
Formula	Form	Serving	Bioflavonoids	Calcium	Vegetarian	Bottle sizes	Per serving, from
Vitamin C 1000 mg Coated Tablets	Coated tablet	1 × 1000 mg	102 mg	110 mg	Yes	90, 120, 2 × 120	13¢
500 mg 24 Hour Tablets	Coated tablet	2 × 500 mg	204 mg	110 mg	Yes	90, 4 × 90	15¢
500 mg with Citrus Bioflavonoids Capsules	Capsule	2 × 500 mg	400 mg	110 mg	No	60, 120, 240, 300	19¢
1000 mg with Citrus Bioflavonoids Capsules	Capsule	1 × 1000 mg	200 mg	108 mg	No	90, 105, 3 × 90	21¢
1000 mg with Citrus Bioflavonoids Vegetarian Tablets	Vegetarian tablet	1 × 1000 mg	200 mg	110 mg	Yes	45, 120, 180, 2 × 180	17¢
500 mg with Citrus Bioflavonoids Vegetarian Tablets	Vegetarian tablet	2 × 500 mg	400 mg	110 mg	Yes	90, 450	16¢

Questions about Ester-C

What is Ester-C?

Ester-C is a vitamin C supplement made with calcium ascorbate, a buffered form of vitamin C, together with naturally occurring vitamin C metabolites. Every Ester-C serving gives 1,000 mg of vitamin C.

How long has Ester-C been around?

Ester-C has been on store shelves since 1989, 37 years.

What does Ester-C make today?

Coated tablets in the yellow box (1000 mg and 500 mg 24 Hour) and, in the amber bottle, capsules and vegetarian tablets with citrus bioflavonoids at 500 mg and 1000 mg.

Is Ester-C the same as ascorbic acid?

No. Ascorbic acid is vitamin C as an acid. Ester-C is vitamin C as calcium ascorbate with its metabolites. Both supply vitamin C, and NIH notes no form has been shown better than the others.