Nutrients the Body Uses to Make Collagen: Protein, Vitamin C, Glycine, Proline and Others

Labels used on this page: established nutritional role, preclinical or mechanism only, promising but limited, and Proper evidence not found.

Protein and amino acids: the building blocks

MedlinePlus explains that protein in food is broken down into amino acids during digestion. [1] Some amino acids cannot be made by the body and must come from food, while others are made by the body from those essential ones or from normal protein breakdown. [1] A 2018 review reports that glycine, proline and hydroxyproline together make up 57% of the amino acids in collagen. [2] The same review says mammals, birds and fish can make glycine from other compounds, and that this synthesis was judged inadequate for maximal collagen production in pigs, chickens and fish. [2] That is animal research, and one author is affiliated with an industry association (the National Renderers Association). [2] It does not show that people need extra glycine or proline. Label: mechanism and animal evidence only.

Vitamin C: a helper for collagen-building enzymes

A 2026 review describes vitamin C (ascorbic acid) as a cofactor for the enzymes that modify collagen, the prolyl and lysyl hydroxylases. [3] MedlinePlus says vitamin C is used to form collagen, which is found in skin, tendons, ligaments and blood vessels. [4] The NHS describes it as helping maintain healthy skin, blood vessels, bones and cartilage. [5] Label: established nutritional role. Whether extra vitamin C beyond usual needs adds collagen in well-nourished adults: Proper evidence not found in the sources we read (we read one small gelatin study, below, and official fact pages). See vitamin C for forms, foods and safety.

Copper and zinc

A 1998 review explains that lysyl oxidase is a copper-dependent enzyme essential for cross-linking collagen and elastin. [6] Label: mechanism evidence. The NHS lists zinc as helping with wound healing. [7] A specific role of zinc in making collagen is not described in the sources we read. See copper and zinc.

Glycine and proline in people: what one small study showed

In a randomized, double-blind crossover study of eight healthy men, gelatin supplements raised blood glycine, proline, hydroxyproline and hydroxylysine. [8] After 15 g of vitamin C-enriched gelatin one hour before rope skipping, a blood marker of collagen production doubled. [8] These are study amounts, not advice, in eight men, with a biomarker rather than a health outcome. A separate study found collagen proteins gave higher blood glycine peaks than dairy proteins. [9] More on glycine: glycine and how collagen supplements are digested.

Official intake levels (not collagen targets)

These are general levels for stated groups. They are not amounts "for collagen."

The NHS figures come from UK pages last reviewed in 2020, and US figures differ. We could not read the NIH Office of Dietary Supplements pages (access blocked), so we did not use them.

• Vitamin C: the NHS says more than 1,000 mg a day can cause stomach pain, diarrhea and gas. [5] MedlinePlus says amounts above 2,000 mg a day are not recommended, can rarely contribute to kidney stones, and large supplement doses are not recommended in pregnancy. [4]
• Zinc and copper: the NHS says high zinc doses reduce copper absorption and advises no more than 25 mg of zinc supplements a day unless a doctor advises it. [7]
• Ask a clinician or pharmacist first if you are pregnant, breastfeeding, take medicines, have kidney or liver conditions, or have surgery planned. Check medication interactions and quality testing.