How much collagen per day, by the evidence

1. 01

   For skin: 2.5-10 g/day of hydrolyzed peptides

   The skin trials, the most common reason people take collagen, used 2.5-10 g/day of hydrolyzed collagen peptides for 8-12 weeks. A 2021 systematic review of 19 randomized trials (Pu et al., n=1,125) reported improvements in skin hydration and elasticity across this range. Lower doses (~2.5 g) appeared in some specific peptide-formulation trials; 5-10 g/day is the more typical and safer-to-replicate target. The effect is real but modest, and it fades if you stop, so the dose is a maintenance dose, not a course.

2. 02

   For joints and tendons: ~10-40 g/day

   Joint and connective-tissue protocols used higher and more variable doses. Osteoarthritis trials of collagen hydrolysate clustered around ~10 g/day (Bello & Oesser 2006 review), while tendon and ligament protocols used ~15 g of collagen taken with vitamin C about an hour before loading exercise (Shaw et al. 2017). Undenatured type II collagen (a different ingredient) is dosed far lower at ~40 mg/day and should not be confused with hydrolyzed peptides. For hydrolyzed peptides aimed at joints, 10-15 g/day is the practical range.

3. 03

   10 g/day is the sensible all-purpose dose

   If you want one number, 10 g/day of hydrolyzed collagen peptides covers the top of the skin range and the bottom of the joint range, which is why most commercial scoops are sized at ~10-20 g. Going above ~15-20 g/day adds cost without clear added benefit for skin, and the joint evidence does not establish a clean dose-response that rewards megadosing. Start at 10 g/day, hold it for at least 8-12 weeks, and judge the result then.

4. 04

   Collagen does not count toward your protein target

   This is the dosing mistake that matters most. Collagen is ~90% protein by weight, so a 10 g scoop looks like 9 g of protein, but it is an incomplete, low-DIAAS protein with no tryptophan and little leucine, so it does almost nothing for muscle protein synthesis. Counting collagen grams toward a 1.6 g/kg/day protein target effectively shorts your real protein intake. Keep collagen out of the protein math and hit your protein target from complete sources; see our protein-per-day guidance for that number.

5. 05

   Timing, vitamin C, and consistency

   Daily timing has little evidence behind it for skin: morning or night, with or without food, the studied outcomes track total daily intake over weeks, not the clock. The one timing signal is for tendon work, where ~15 g taken with ~50 mg vitamin C roughly an hour before loading exercise was the Shaw 2017 protocol, on the logic that collagen synthesis peaks around the loading window. Vitamin C is a cofactor for collagen synthesis, so pairing the two is reasonable, though most powders are taken simply once a day for convenience.

6. 06

   Price the dose, because $/g is what you actually pay

   At 10 g/day, a tub's cost-per-gram of peptides decides the annual bill. Bulk unflavored bovine peptides run about $0.03-0.04/g, while flavored single-serve sticks and marine collagen reach ~$0.12/g for the identical gram count, a 3-4x spread for the same dose. Since the benefit is modest and the dose is daily and indefinite, the cheapest tested unflavored powder is the rational choice. Our best collagen powder ranking sorts tested products by $/g of peptides so the dose does not cost more than it should.

What people ask us next.

Q01

How much collagen should I take per day?

Match the dose to the goal. For skin (elasticity and hydration), positive trials used 2.5-10 g/day of hydrolyzed collagen peptides for 8-12 weeks (Pu et al. 2021, n=1,125). For joints and tendons, studied doses run ~10-40 g/day depending on preparation. A sensible all-purpose dose is 10 g/day. Effects are modest and fade if you stop, so treat it as a daily maintenance dose, not a short course.

Q02

Is 10 grams of collagen a day enough?

Yes, 10 g/day is a reasonable all-purpose dose. It sits at the top of the skin-trial range (2.5-10 g/day) and the bottom of the joint range (~10 g/day and up). Most commercial scoops are sized at 10-20 g for this reason. Going above ~15-20 g/day adds cost without clear added benefit, since the evidence does not show a clean reward for megadosing.

Q03

Does collagen count toward my daily protein intake?

No. Collagen is ~90% protein by weight but is an incomplete, low-DIAAS protein with no tryptophan and little leucine, so it does almost nothing for muscle protein synthesis. Counting a 10 g collagen scoop as 9 g of protein effectively shorts your real intake. Keep collagen separate and hit your protein target from complete sources; see our protein-per-day guidance.

Q04

When is the best time to take collagen?

For skin, timing barely matters: outcomes track total daily intake over 8-12 weeks, not the time of day, so take it whenever you will be consistent. The one timing signal is for tendon work, where ~15 g with ~50 mg vitamin C about an hour before loading exercise was the studied protocol (Shaw et al. 2017), because collagen synthesis peaks around the loading window.

Q05

How long until collagen works, and does it last?

Skin trials ran 8-12 weeks before measuring improvements in hydration and elasticity, so give it at least that long before judging. The effect is maintenance-dependent: it fades after you stop, because you are supplying substrate, not changing the tissue permanently. That is why the dose is framed as a daily ongoing amount rather than a finite course.

Q06

What kind of collagen should I buy for that dose?

For skin and joints, hydrolyzed collagen peptides (Types I and III, bovine or marine) are the studied form, dosed at the grams above. Do not confuse it with undenatured type II collagen, a different ingredient dosed at ~40 mg/day for joints. Unflavored bulk bovine peptides are cheapest at ~$0.03-0.04/g; our best collagen powder ranking sorts tested products by $/g of peptides.