Which Collagen Is Best for You?

Collagen is the body’s main structural protein vital for skin, joints, tendons, and bone strength. This guide breaks down the three primary collagen types (I, II, and III), where they come from, and what they actually do. Learn the difference between marine and bovine collagen, why athletes focus on Types I and III, why Type II supports cartilage, and why true collagen only comes from animal sources. Includes evidence-based insights, dosage guidelines, and the truth behind “vegan collagen” marketing.

Collagen 101: The Basics You Need to Know
Understanding the different types of collagen, their functions, and how to choose the right one for your body and goals.

What Type I, II, and III do

Type I is the body’s tension cable. It provides tensile strength to skin, tendons, ligaments, bone, and scar tissue [1][2].
Type III sits alongside Type I, adding elasticity in skin and blood vessels and helping soft tissues expand and recoil [2].
Type II is the cartilage specialist. It forms the framework of articular cartilage in joints and is not the main collagen in skin or tendons [1].

Where supplement collagens come from

Bovine or porcine hide/skin: mostly Type I with some Type III. These are the usual “collagen peptides” for skin, tendon, bone, and general support [6].
Chicken sternum cartilage: source of Type II (including undenatured Type II used at very small daily doses) for joint comfort/function [11][12].
Marine (fish skin, scales, bones): predominantly Type I with occasional Type III. Great for skin and general support. It is not typically Type II [3][4][6].

Common myth: marine collagen is not the same as Type II. Marine is overwhelmingly Type I [3][4][6].

Peptides vs undenatured collagen

Hydrolyzed collagen peptides are pre-digested chains for easy absorption. They are taken in grams per day to support skin, tendon, ligament, and bone. Effects are dose-dependent and pair well with training [6][9][10].
Undenatured Type II (UC-II and similar) is native cartilage collagen taken in milligrams per day (about 40 mg). It works mainly via an oral tolerance mechanism and is studied for joint comfort and function [11][12].

Why Types I and III matter most for people who train

Tendons and ligaments limit performance and often cause time off. These tissues are dominated by Type I with support from Type III. Several labs show that taking about 15 g gelatine or collagen plus ~50 mg vitamin C, 45–60 minutes before loading or rehab, increases markers of collagen synthesis and may support tissue quality over time [7][8].
So athletes often use daily Type I/III peptides for structure and optionally add undenatured Type II for cartilage comfort.

Doses that map to the research

Skin, tendon, bone, general support: 5–15 g/day of hydrolyzed collagen peptides. Many athlete protocols use ~15 g near training with vitamin C [6][9][7].
Cartilage comfort: 40 mg/day of undenatured Type II for at least 8–12 weeks [11][12].

Powder vs capsules

Collagen peptide studies use grams per day. A typical capsule holds ~500 mg.

5 g/day ≈ 10 capsules
10 g/day ≈ 20 capsules
15 g/day ≈ 30 capsules
This is impractical and costly. Powders mix easily into drinks and support adherence. Capsules do make sense for undenatured Type II because the dose is only ~40 mg/day.

Marine vs bovine

Both are effective Type I sources. Differences are mostly taste, allergen profile, dietary preference, and price. There is no consistent head-to-head evidence that marine outperforms bovine when doses are matched for skin or tendon outcomes. Marine is Type I, not a replacement for Type II cartilage support [3][4][6].

“Vegan collagen” claims

Plants do not contain collagen. Most “vegan collagen” products are collagen builders (vitamin C, glycine, proline, copper, botanicals) that support your body’s own collagen production but do not supply collagen protein.
A newer category uses recombinant technology to make animal-free human collagen (for cosmetics or specialty uses). These are not the bulk powders used in most nutrition supplements yet, so labels can be confusing [14][15].

Practical takeaways

For tendons, ligaments, skin, bone: use hydrolyzed collagen peptides (bovine or marine) 5–15 g/day. If training, consider ~15 g + ~50 mg vitamin C about 45–60 minutes pre-loading [6][7][9].
For cartilage comfort: add undenatured Type II collagen 40 mg/day [11][12].
Marine is Type I. It does not replace Type II. Use the right tool for the job [3][6].
Prefer powders for peptide dosing. Use capsules for Type II micro-dosing.

References

Gelse K, Pöschl E, Aigner T. Collagens—structure, function, and biosynthesis. Adv Drug Deliv Rev. 2003. https://pubmed.ncbi.nlm.nih.gov/14623400/
Singh D, et al. Regulation of Collagen I and Collagen III in Tissue Injury and Repair. Int J Mol Sci. 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC9912297/
Jafari H, et al. Fish Collagen: Extraction, Characterization, and Applications for Biomaterials. Polymers. 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC7601392/
Coppola D, et al. Marine Collagen from Alternative and Sustainable Sources. Mar Drugs. 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC7230273/
Amirrah IN, et al. A Comprehensive Review on Collagen Type I… Polymers. 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9496548/
Wang H, et al. A Review of the Effects of Collagen Treatment in Clinical Studies. Polymers. 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8620403/
Shaw G, et al. Vitamin C–enriched gelatin before intermittent activity augments collagen synthesis. Am J Clin Nutr. 2017. https://pubmed.ncbi.nlm.nih.gov/27852613/ and https://pmc.ncbi.nlm.nih.gov/articles/PMC5183725/
Baar K. Stress Relaxation and Targeted Nutrition to Treat Patellar Tendinopathy. Int J Sport Nutr Exerc Metab. 2019. https://journals.humankinetics.com/view/journals/ijsnem/29/4/article-p453.xml
Paul C, et al. Functional Collagen Peptides… Effective Amounts 2.5–15 g daily. Nutrients. 2019. https://pmc.ncbi.nlm.nih.gov/articles/PMC6566836/
Khatri M, et al. Effects of Collagen Peptides on Body Composition and Performance: Systematic Review. Amino Acids. 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8521576/
Lugo JP, et al. Efficacy and tolerability of undenatured type II collagen (UC-II) in knee osteoarthritis. Nutrition Journal. 2016. https://nutritionj.biomedcentral.com/articles/10.1186/s12937-016-0130-8
Lugo JP, et al. Undenatured type II collagen (UC-II®) for joint support. J Int Soc Sports Nutr. 2013. https://pubmed.ncbi.nlm.nih.gov/24153020/
Gupta A, et al. Undenatured type II collagen for knee osteoarthritis: review. 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12010644/
WebMD. What Is Vegan Collagen? Updated 2025. https://www.webmd.com/beauty/vegan-collagen-what-to-know
Bioprocess International. Plant-Based Recombinant Human Collagen. 2025. https://www.bioprocessintl.com/emerging-therapeutics-manufacturing/recombinant-human-collagen-plant-based-production-addresses-growing-demand-for-a-vegan-option

Disclaimer
Information on this site is general and for education only, based on research sources and our opinions, with references for further reading. It is not medical, nutritional, or fitness advice; consult a qualified healthcare practitioner before starting any exercise, diet, supplement, or medication. We make no claims, guarantees, or warranties, and use is at your own risk. Products and supplements mentioned are not intended to diagnose, treat, cure, or prevent any disease.