How Much Collagen per Day?Amounts Used in Studies

“How many grams of collagen a day?” is a common question. Here are national standards, ordinary diets, amounts used in research and protein recommendations side by side.

The amounts of collagen used in research are much smaller than the recommended amount of protein overall.

In human studies of collagen, the amount depends on the purpose. Absorption studies tend to give a single larger dose, while studies lasting several weeks often use a few grams a day.

A 2023 review by researchers in Taiwan lists the daily amounts used in 26 trials. Counting the trials by amount gives the following.

The most common amount was 2.5–3 g a day, followed by 4–5.5 g. A 2019 paper also describes the amounts used in past studies as 2.5–15 g a day.

This section shows only the amounts used. Trials differed in source (fish, pig, chicken and so on), form (such as peptides), what was measured and whether other ingredients were added, so the amounts alone cannot show that any number of grams is best.

Collagen is one of the proteins that make up the body. Japan’s Dietary Reference Intakes (2025) set a recommended daily amount for protein overall, by age and sex.

Recommended protein intake per day for women, from the protein table of the Dietary Reference Intakes for Japanese (2025), Ministry of Health, Labour and Welfare

For example, 5 g of collagen is one tenth of the 50 g recommended for women.

Collagen alone cannot replace protein

By one method of rating protein quality (PDCAAS), collagen is classed as an incomplete protein because it lacks tryptophan, one of the essential amino acids the body cannot make. So collagen alone cannot cover the recommended amount of protein.

On the other hand, a 2019 paper calculated that, based on a standard American diet, up to 36% of daily protein could be replaced with collagen peptides while still meeting essential amino acid requirements. The amounts used in past studies (2.5–15 g a day) fall within that range.

One author of this 2019 paper provides research services to a maker of supplements containing collagen peptides. The calculation was based on an American diet, not a Japanese one.

Many people search for the “amount needed in your 50s” or “intake in your 60s,” but there are no age-specific standards for collagen. What is set by age is the recommendation for protein overall, shown in the previous section.

Study participants are also skewed. In the 26 trials summarized by the 2023 review, most participants were women. Most participants were in their 30s to 60s; one trial targeted people aged 65 and over (39 men and women, 12 g a day for 8 weeks).

This does not mean the findings apply only to the same age as the participants. But we found no study that shows a best number of grams for each age group.

In a Japanese study where fish-skin collagen peptides were taken at 12.5 g a day for 8 weeks, no changes were seen in blood test values.

For protein overall, Japan’s Dietary Reference Intakes did not set a tolerable upper intake level, because there was not enough clear evidence to set one. Having no upper limit does not mean any amount is fine.

People who should take care

The relationship between fish collagen and allergy is covered in our study guide “Fish Allergy and Collagen.” If you notice any change in how you feel, stop taking it and consult a doctor.

How many grams of collagen should I take a day?
There is no national daily standard for collagen. Past studies have used about 2.5–15 g a day, but we found no study showing that a particular number of grams is best.

How much collagen do we get from ordinary food?
Japanese women are estimated to take in about 2 g of collagen a day from their diet.

Does the amount needed change in your 50s or 60s?
There are no age-specific standards for collagen. What is set by age is the recommendation for protein overall: for women, 50 g a day at every age from 50 up.

Is collagen alone enough protein?
No. Collagen lacks the essential amino acid tryptophan, so it is classed as an incomplete protein.

Is taking a lot safe?
A study of 12.5 g a day for 8 weeks reported no changes in blood test values. People with allergies, and pregnant or breastfeeding women, should take care.