Ascorbic Acid vs Sodium Ascorbate
How ascorbic acid and sodium ascorbate differ in potency, absorption, tolerance, and cost.
This page contains affiliate links. Titrate earns a small commission when you purchase through them, at no cost to you. This does not affect our recommendations.
Side by Side
| Ascorbic Acid | Sodium Ascorbate | |
|---|---|---|
| Active content | 100% ascorbic acid | 88.9% ascorbic acid |
| Absorption | High | High |
| How it is absorbed | Absorbed by sodium-dependent vitamin C transporters (SVCT1). Absorption is 70-90% at 30-180 mg/day and falls below 50% above 1 g/day as transporters saturate. | Mineral salt of ascorbic acid; less acidic, same transporter-limited absorption. |
| Typical dose | 75-500 mg daily | 75-500 mg daily |
| Common uses | general supplementation, enhancing non-heme iron absorption | acid-sensitive stomachs |
| Side effects | Diarrhea and GI upset above about 2 g/day. May raise kidney stone risk in susceptible people. | Adds about 116 mg sodium per gram of compound; relevant for sodium-restricted diets. |
| Cost | Low | Low |
| Also called | L-ascorbic acid | buffered vitamin C |
| Labels in index | 2,104 | 243 |
When to Choose Ascorbic Acid
Choose ascorbic acid when you want the reference form at the lowest cost. The reference form. The NIH ODS fact sheet notes that natural and synthetic ascorbic acid are chemically identical.
Ascorbic Acid
All the vitamin C most people can use, at the lowest cost.
What to look for: 100-250 mg tablets. Split larger daily amounts into two doses.
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, 2,104 labels named as vitamin C products list ascorbic acid 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.