Calcium Ascorbate vs Sodium Ascorbate
How calcium ascorbate and sodium ascorbate differ in potency, absorption, tolerance, and cost.
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Side by Side
| Calcium Ascorbate | Sodium Ascorbate | |
|---|---|---|
| Active content | Varies by product | 88.9% ascorbic acid |
| Absorption | High | High |
| How it is absorbed | Mineral salt; same transporter-limited absorption as ascorbic acid. Studies of branded calcium ascorbate with metabolites have not shown consistent advantages. | Mineral salt of ascorbic acid; less acidic, same transporter-limited absorption. |
| Typical dose | 75-500 mg daily | 75-500 mg daily |
| Common uses | acid-sensitive stomachs, sodium-restricted diets | acid-sensitive stomachs |
| Side effects | Contributes about 9-10% calcium by weight. | Adds about 116 mg sodium per gram of compound; relevant for sodium-restricted diets. |
| Cost | Moderate | Low |
| Also called | Ester-C (with metabolites), buffered vitamin C | buffered vitamin C |
| Labels in index | 254 | 243 |
When to Choose Calcium Ascorbate
Choose calcium ascorbate when you want buffered vitamin C without added sodium. Roughly 83-90% ascorbic acid depending on hydration state.
Calcium Ascorbate
Buffered forms only matter for stomach comfort.
What to look for: Count the mineral: about 90-100 mg calcium per gram, which adds to other calcium sources.
Find on iHerb Affiliate linkWhen to Choose Sodium Ascorbate
Choose sodium ascorbate when ascorbic acid irritates your stomach and sodium is not a concern. Common in powdered and buffered products.
Sodium Ascorbate
Choose sodium ascorbate when ascorbic acid irritates your stomach and sodium is not a concern.
What to look for: Sodium Ascorbate named on the Supplement Facts panel, with the amount per serving stated.
Find on iHerb Affiliate linkProducts on Titrate
In Titrate's index of NIH label data, 254 labels named as vitamin C products list calcium ascorbate and 243 list sodium ascorbate.
Vitamin C does not have its own search category yet. Each product above links to its full label in the NIH database.
Related
References
NIH Office of Dietary Supplements. Vitamin C: Fact Sheet for Health Professionals.
Levine M, et al. Vitamin C pharmacokinetics in healthy volunteers: evidence for a recommended dietary allowance. Proc Natl Acad Sci U S A. 1996;93(8):3704-3709.
Padayatty SJ, et al. Vitamin C pharmacokinetics: implications for oral and intravenous use. Ann Intern Med. 2004;140(7):533-537.
Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013;(1):CD000980.
Thomas LD, et al. Ascorbic acid supplements and kidney stone incidence among men: a prospective study. JAMA Intern Med. 2013;173(5):386-388.
Davis JL, et al. Liposomal-encapsulated Ascorbic Acid: Influence on Vitamin C Bioavailability and Capacity to Protect Against Ischemia-Reperfusion Injury. Nutr Metab Insights. 2016;9:25-30.