FAQ · collagen
Collagen supplements FAQ
UK answers to the questions most readers ask before buying collagen. Marked up with FAQPage schema for AI search.
Does collagen actually work?
The evidence is mixed. Industry-funded RCTs (Choi 2019, Bolke 2019) show modest skin elasticity and hydration improvements with 5 to 10g per day over 3 to 6 months. The 2025 American Journal of Medicine meta-analysis of high-quality independent trials did not find a significant skin-aging effect. Take collagen because the cost is low and downside is negligible, not because the evidence is settled.
Marine vs bovine vs vegan collagen, which is best?
Marine collagen is mostly Type I, smallest molecular weight, best for skin. Bovine is Type I + III combined, cheapest per gram, best for skin and gut. "Vegan collagen" does not actually contain collagen; it is a precursor blend (lysine, proline, glycine, vitamin C).
How many grams of collagen per day?
For skin and tendons: 10 to 15g hydrolysed Type I per day. For joints: 40mg undenatured Type II (UC-II), dosed in milligrams not grams. See the collagen dose calculator.
When should I take collagen?
For skin: any time of day. For tendons (Shaw 2017 protocol): 60 minutes before exercise with 50mg vitamin C. With food or fasted, both work for absorption.
How long until I see collagen results?
Plan for 12 weeks of consistent daily use before judging skin or hair changes. Joint effects from UC-II Type II typically take 60 to 90 days.
Can I take collagen during pregnancy?
Most marine and bovine collagen products are considered low risk in pregnancy as they are food-grade hydrolysed protein. Speak with your midwife or doctor before taking any new supplement.
Can I take collagen while on Mounjaro or Wegovy?
Yes. Collagen supplements do not interact with GLP-1 medications. They count toward your daily protein target while on a GLP-1.
Why is my collagen powder fishy or beefy tasting?
Marine collagen tastes mildly fishy unless flavoured. Bovine is mostly tasteless. Liquid formats hide the taste better than powders.
Does collagen help joint pain?
For osteoarthritis, undenatured Type II collagen (UC-II, 40mg/day) has the strongest evidence (Lugo 2016 RCT, 180 days). Type I hydrolysed has weaker evidence for joint pain specifically.
Can I get collagen from food instead of a supplement?
Bone broth contains collagen but at variable concentrations. To match a 10g supplement serving, you would need a large daily portion of bone broth. Supplements are more practical for protocol-level dosing.