How much vitamin C should I take per day?

For general health, 200-1000mg per day is plenty. Your blood plasma becomes saturated around 200-400mg per day, and beyond that most extra vitamin C is simply excreted in urine, so megadoses are largely wasted. The tolerable upper limit is 2000mg per day; above that, GI upset is common and the risk of kidney stones rises in susceptible people. The RDA is only 75-90mg, so even 500mg comfortably covers needs with margin.

Is liposomal vitamin C better than regular?

Liposomal vitamin C does achieve higher blood levels per dose than standard ascorbic acid, which matters mainly for high-dose protocols. For everyday immune support at 500-1000mg, regular ascorbic acid already saturates your tissues, so the practical benefit of liposomal is small for most people — and it costs several times more. Liposomal is worth it if you specifically want high plasma levels or have a sensitive stomach; otherwise standard vitamin C is the better value.

Do bioflavonoids make vitamin C work better?

Bioflavonoids are plant compounds often added to vitamin C and marketed as boosting its absorption. The evidence that they meaningfully increase vitamin C absorption or effectiveness in humans is weak and inconsistent. They are not harmful and may have their own minor antioxidant value, but they are not a reason to pay a premium. A plain, well-dosed ascorbic acid does the job.

Best Vitamin C Supplement (2026): Form, Dose & Cost Compared

Q: What is the best vitamin C supplement?

For most people the best vitamin C is plain ascorbic acid at around 500-1000mg per day, ideally third-party tested. Best value is Nature Made Vitamin C 1000mg (USP Verified) at about $0.10/day. For a clean, certified option, Thorne Vitamin C with Flavonoids (NSF Certified for Sport). Vitamin C is cheap and the standard form is well-absorbed at these doses, so there is rarely a reason to pay a premium unless you have a sensitive stomach (buffered) or want high-dose delivery (liposomal).

By Verified Supplement Data · Updated May 30, 2026 · Methodology · About Us

Vitamin C is the easy one: cheap, and the plain form works. Buy ascorbic acid at 500-1000mg/day. Your plasma saturates around 200-400mg/day — beyond that you mostly pee it out (Levine 1996, PMID: 8623000), so megadoses are wasted money.

Best value: Nature Made Vitamin C 1000mg — USP Verified, ~$0.10/day. Cleanest label: Thorne Vitamin C (NSF Certified for Sport).

Pay extra only for a reason: buffered if 1000mg upsets your stomach, liposomal if you want high-dose plasma levels. Otherwise plain wins. Forms compared.

How much you actually need

Vitamin C is where the supplement industry's "more is better" instinct breaks down hardest. The RDA is just 75-90mg. Classic pharmacokinetic work showed plasma vitamin C saturates at around 200-400mg/day — past that, absorption efficiency drops and the kidneys excrete the surplus (Levine 1996, PMID: 8623000). So a 1000mg tablet already gives you comfortable headroom, and a 5000mg "immune megadose" mostly produces expensive urine.

The ceiling matters too: the tolerable upper limit is 2000mg/day. Above that, diarrhea and GI upset are common, and in people prone to kidney stones the risk rises. For nearly everyone, 500-1000mg/day is the sweet spot.

Best vitamin C, ranked

Vitamin C supplements ranked by cost per day
Product	Form	Dose	Servings	Price	Cost/Day	Certification	Buy
NOW Foods Vitamin C-1000 with Bioflavonoids Budget Pick	Ascorbic acid + bioflavonoids	1000mg	250	$18.50	$0.07	None	Buy
Nature Made Vitamin C 1000 mg Extra Strength Best Value	Ascorbic acid	1000mg	100	$9.50	$0.09	USP Verified	Buy
Nature's Bounty Vitamin C 1000 mg Caplets	Ascorbic acid	1000mg	100	$9.75	$0.10	None	Buy
Thorne Vitamin C with Flavonoids Quality Pick	Ascorbic acid + flavonoids	500mg	90	$23.00	$0.51	NSF Certified for Sport	Buy

Which to pick

Best value: Nature Made Vitamin C 1000mg

Nature Made is USP Verified (independently checked for potency and purity), 1000mg ascorbic acid, at about a dime a day. For the overwhelming majority of people, this is all the vitamin C you need.

Cleanest label: Thorne Vitamin C with Flavonoids

Thorne carries NSF Certified for Sport — the strictest third-party tier — for those who want maximum certainty or compete in tested sport. Costs more, and the flavonoids are a minor extra rather than a meaningful upgrade.

Budget: NOW C-1000

NOW C-1000 with Bioflavonoids is the cheapest per day. Fine product; just know the bioflavonoids aren't a proven absorption booster.

What vitamin C is (and isn't) good for

Vitamin C genuinely supports immune cell function and is an essential antioxidant — true deficiency (scurvy) wrecks immunity and collagen synthesis (Carr 2017, PMID: 29099763). But "supports immunity" is not the same as "prevents colds." Routine supplementation doesn't stop healthy people from catching colds; it modestly shortens them. We cover that honestly on vitamin C for immune support.

Frequently asked questions

What is the best vitamin C supplement?

Plain ascorbic acid at 500-1000mg/day, third-party tested. Best value: Nature Made 1000mg (USP Verified, ~$0.10/day). Cleanest: Thorne (NSF Certified for Sport). Pay extra only for buffered (sensitive stomach) or liposomal (high-dose).

How much per day?

200-1000mg is plenty. Plasma saturates at 200-400mg/day; beyond that you excrete the excess. Upper limit 2000mg (GI upset, kidney-stone risk higher). RDA is only 75-90mg.

Is liposomal better?

It reaches higher blood levels per dose — useful for high-dose protocols. At everyday 500-1000mg doses the practical benefit is small and it costs several times more. Worth it for high-dose or sensitive stomachs only.

Do bioflavonoids help?

Evidence they boost vitamin C absorption is weak and inconsistent. Not harmful, but not worth a premium. Plain ascorbic acid does the job.

Related guides

Sources

Levine M, et al. "Vitamin C pharmacokinetics in healthy volunteers: evidence for a recommended dietary allowance." Proc Natl Acad Sci USA. 1996;93(8):3704-3709. PMID: 8623000
Carr AC, Maggini S. "Vitamin C and Immune Function." Nutrients. 2017;9(11):1211. PMID: 29099763
Hemilä H, Chalker E. "Vitamin C for preventing and treating the common cold." Cochrane Database Syst Rev. 2013;(1):CD000980. PMID: 23440782