Collagen Peptides and Vitamin C Together

Quick answer

Vitamin C is required for the body to make collagen, and adults need 75 to 90 mg a day, which most people in the United States get from food. A collagen supplement supplies amino acids, not vitamin C. Two small studies of 15 g of vitamin C-enriched gelatin before exercise gave mixed results.^1,2,3,4

Key facts

Vitamin C is required to make collagen, and without enough of it collagen production falls and connective tissue weakens.¹
Adults need 75 mg (women) or 90 mg (men) of vitamin C a day, and most people in the United States get enough from food and drink.²
In 8 men, 15 g of vitamin C-enriched gelatin an hour before 6 minutes of rope skipping doubled a blood marker of collagen building compared with placebo.³
In 10 active men, 15 g of vitamin C-enriched gelatin or collagen before jump rope tended to raise the same kind of marker by about 20%, but the variation was too large to reach significance.⁴
In a controlled study, a single 200 mg dose of vitamin C was fully absorbed, and doses of 500 mg or more were absorbed less completely.⁵

How the two fit together

People ask this because the two are linked in the body. Collagen is built from amino acids, and the enzymes that finish building it need vitamin C to work. A collagen supplement supplies the amino acids, mainly glycine and proline, but it does not supply the vitamin. The sources describe both ingredients and the link between them, and the link runs from vitamin C to the body's own collagen, not from the supplement to anything else.^1,6

The body needs vitamin C to make collagen. Without enough of it, collagen production falls and connective tissue weakens.⁷

Most people in the United States get enough vitamin C from food and drink. People who smoke or breathe secondhand smoke, and people who eat a narrow range of foods, are more likely to fall short.²

What the graded evidence says

Contributes to normal collagen formation for the normal function of skin, gums, teeth, bones, cartilage and blood vessels*^1,8,9

Moderate evidence

A well-established nutrient function. NIH states that vitamin C is required to make collagen, an essential part of connective tissue, and EU regulators permit this wording, as six separate statements, for foods that are at least a source of vitamin C. Normal skin holds high levels of vitamin C. The claim describes what the body needs vitamin C for. It does not show that extra vitamin C changes how skin looks in someone who already gets enough, and how creams and serums compare with getting enough in the diet is poorly understood.

Amount studied: Recommended intake: 75 mg a day for women and 90 mg for men, from food and supplements

May support skin hydration and elasticity*^10,11

Moderate evidence

A 2023 meta-analysis of 26 randomized trials (1,721 people, mostly women) found better skin hydration and elasticity with hydrolyzed collagen, usually 2.5 to 10 g a day for 8 to 12 weeks, though only one trial used bovine collagen like this product. A 2025 meta-analysis of 23 trials (1,474 people) found the benefit only in company-funded trials; trials without company funding, and higher-quality trials, showed no effect.

Amount studied: 2.5 to 10 g a day for 8 to 12 weeks

The two claims are different in kind. Vitamin C's is a nutrient role, which holds for anyone, and the grade itself says it does not show that extra vitamin C changes how skin looks in someone who already gets enough. Collagen's is a result from trials of the supplement, with the funding caveat shown above. Neither claim covers the two taken together.^1,9,11

The two studies that added vitamin C

Studies of vitamin C-enriched gelatin and collagen^3,4
Study	Who	What was given	What it found
Shaw 2017	8 healthy men, crossover design	5 or 15 g of vitamin C-enriched gelatin or placebo, an hour before 6 minutes of rope skipping, 3 times a day for 3 days	15 g doubled a blood marker of collagen building; blood glycine and proline peaked an hour after a dose
Lis and Baar 2019	10 recreationally active men, crossover design	15 g of vitamin C-enriched gelatin or hydrolyzed collagen, or a gummy, an hour before 6 minutes of jump rope	The marker tended to rise about 20% with gelatin and collagen, but variation was too large for significance

Notice what neither study had: a group given the same gelatin or collagen without added vitamin C. Both compared the enriched product with a placebo, so neither can say how much the vitamin C added. Both were small, and both measured a blood marker, not how tendon, skin or joints behaved.^3,4

Vitamin C from food and from supplements

Half a cup of raw sweet red pepper has 95 mg of vitamin C, three quarters of a cup of orange juice 93 mg, a medium orange 70 mg, a medium kiwifruit 64 mg and half a cup of cooked broccoli 51 mg.¹

Because most people in the United States get enough from food, the question is usually whether a supplement is needed at all. In controlled studies, blood levels rose only a little above about 200 mg a day, and the authors of the 1996 study saw no evident value above 400 mg. The adult upper limit is 2,000 mg a day from food and supplements combined.^1,2,5

The best time to take them

No source we read ranks a time of day for collagen with vitamin C. NIH's vitamin C fact sheets give no advice on the time of day, and the collagen trials gave a single daily amount. The one timing finding comes from the exercise studies: gelatin was taken an hour before activity, and collagen amino acids peaked in the blood about an hour after a dose.^1,2,3,12

Readers who also take biotin should note that NIH's biotin sheets give no time of day either. The point to plan around is a blood test: biotin above the recommended intake can make some tests read falsely high or low.^13,14

Cautions and who should ask first

Two things add up here. High vitamin C intakes raise the oxalate and uric acid passed in urine, and in a feeding study 30 g of gelatin raised urinary oxalate 43 percent compared with whey. Studies on vitamin C and kidney stones conflict, but anyone who has had stones should ask first.^1,5,15

In people with hereditary hemochromatosis, high doses taken for a long time could worsen iron overload and damage tissues. NIH says people with this condition should avoid vitamin C supplements.^1,16

Ask your pharmacist or doctor first

Vitamin C taken at the same time as levothyroxine might increase how much of the medicine is absorbed.¹⁷

Reported in studies

Ask your pharmacist or doctor first

Prescribing labels for extended-release mixed amphetamine salts name ascorbic acid, which is vitamin C, as an example of an acidifying agent that lowers blood levels of amphetamine and can make it less effective. Tell your prescriber if you take vitamin C.^18,19

On the medicine's label

Ask first if you have hemochromatosis or another cause of iron overload, kidney disease or kidney stones.^1,16
Ask first if you are having chemotherapy or radiation therapy, use a blood glucose meter, or take a statin.^1,17
Check the animal source on a collagen label if you are allergic to fish, beef, pork or gelatin.²⁰

What is in our products

What’s in ours

Men's Multi: Vitamin C, 150 mg per serving, from the label
Immune Support: Vitamin C, 180 mg per serving, from the label

What’s in ours

Collagen Peptides: Hydrolyzed Collagen Peptides, 20 g per serving, from the label
Collagen Peptides: Hydrolyzed Collagen Peptides, 20 g per serving, from the label

Questions people ask

Do collagen peptides need vitamin C?

The body needs vitamin C to make collagen from the amino acids it has, whatever their source. Collagen peptides supply amino acids, not vitamin C, and the two studies that added vitamin C to gelatin or collagen had no comparison group without it.^1,3,4

What is the best time to take collagen and vitamin C?

No source we read ranks a time of day. NIH's vitamin C sheets give no time advice and collagen trials gave one daily amount. Two small studies gave 15 g of vitamin C-enriched gelatin an hour before exercise.^1,3,12

Do I need a vitamin C supplement if I take collagen?

Adults need 75 mg (women) or 90 mg (men) a day, and most people in the United States get enough from food: half a cup of raw sweet red pepper has 95 mg, and a medium orange 70 mg.^1,2

Can taking both affect kidney stones?

Both can raise the oxalate passed in urine. High vitamin C intakes do, though studies conflict, and 30 g of gelatin raised urinary oxalate 43 percent compared with whey in a feeding study. If you have had kidney stones, ask first.^1,15

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.