Vitamin C
Of 19,716 on-market vitamin c products in the January 2026 DSLD dump, the median declared dose is 113 mg, and 92.2% list Ascorbic Acid as the primary form.
Form share
Of 17,528 products with an identifiable primary form, here is the share held by each form of Vitamin C on the market today.
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| Form | Quality tier | n | Share |
|---|---|---|---|
| Ascorbic Acid | Tier 1 | 16,159 | 92.2% |
| Calcium Ascorbate | Tier 2 | 1,153 | 6.6% |
| Sodium Ascorbate | Tier 2 | 216 | 1.2% |
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (mg), among 18,565 products with a disclosed amount, against the RDA of 90 and UL of 2000.
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- 42.6% of products fall below the fairy-dust threshold (100 mg, 20% of the studied low dose).
- 0.5% of products don't disclose an amount because Vitamin C is declared inside a proprietary blend.
Where does your dose rank?
Enter a per-serving dose (mg) to see exactly how it compares to the 18,522 on-market vitamin c products with a disclosed amount. The chart above groups doses into deciles; this looks up the exact percentile for one number.
By dosage form
By target group
Top brands
| Brand | Products |
|---|---|
| Douglas Laboratories | 391 |
| DC | 321 |
| Wonder Laboratories | 286 |
| Source Naturals | 241 |
| Nature's Way | 230 |
| Nature Made | 196 |
| Centrum | 186 |
| Cellucor | 159 |
| NOW | 155 |
| The Vitamin Shoppe | 153 |
| ProCaps Laboratories | 151 |
| MegaFood | 140 |
| Bluebonnet | 139 |
| Puritan's Pride | 134 |
| Higher Nature | 134 |
| Emergen-C | 133 |
| Pure Encapsulations | 132 |
| Life Extension | 128 |
| Metagenics | 120 |
| Country Life | 119 |
| Solgar | 118 |
| Carlson | 117 |
| Vitamin World | 115 |
| Syntrax | 110 |
| XYMOGEN | 107 |
Search interest over time
How often people search for vitamin c on Google, US only, the last 5 years. This is public interest, not DSLD label data — a spike here doesn't necessarily line up with anything on this page, and Google's own index (100 = that term's peak popularity in the chosen window) is relative, not an absolute search-volume count.
Or see this search directly on trends.google.com.
Forms explained
Reference form; a 1994 comparative absorption/excretion study of three commercially available vitamin C sources is cited for no meaningful advantage of other forms over plain ascorbic acid (PubMed has no abstract, so the result was not independently confirmed). L-ascorbic acid is the biologically active stereoisomer "ascorbic acid" refers to on labels.
Source: Johnston CS, Luo B. 1994, J Am Diet Assoc 94(7):779-81, PMID 8021423
Not shown more bioavailable than plain ascorbic acid in the cited comparison (result not independently confirmed); it delivers less vitamin C per mg of ingredient mass (about 83-90% ascorbic acid by mass for the dihydrate/anhydrous salt) due to the bound mineral. A reduced GI/acid-irritation advantage is commonly claimed but is unsourced here.
Source: Johnston CS, Luo B. 1994, PMID 8021423
Same rationale as calcium ascorbate -- a buffered mineral salt not shown more bioavailable than ascorbic acid.
Source: Johnston CS, Luo B. 1994, PMID 8021423
Reference values
- RDA (adult): 90 mg — 90mg (men 19+); 75mg (women 19+); +35mg/day for smokers
- Tolerable Upper Intake Level (adult): 2000 mg — Based on risk of osmotic diarrhea/GI disturbance at higher intakes
- Studied clinical dose range: 500–500 mg
- Sesso HD et al. 2008 (Physicians' Health Study II), JAMA 300(18):2123-33, PMID 18997197 -- 500mg/day ascorbic acid x mean 8yr in 14,641 male physicians; did not reduce major cardiovascular events vs placebo (HR 0.99, 95% CI 0.89-1.11). This is the only dose supported by the cited paper, so low and high are both 500; higher chronic or acute-dose studies exist but are not cited here.
- Note: No IU convention has ever existed for vitamin C.