Collagen peptides explained: types, dose and how they work
Scarlett Gray
BNutrDiet (Hons), APD, SDA
Reviewed by Scarlett Gray · About Scarlett
Accredited Practising Dietitian with Dietitians Australia (APD200526). Accredited Sports Dietitian and Credentialled Eating Disorder Clinician. First Class Honours in Nutrition and Dietetics from the University of Newcastle.
Reviewed by Scarlett Gray, Accredited Practising Dietitian (APD200526), BNutrDiet Hons, Sports Dietitian. @scarlett__redefiningnutrition
Reviewed: 3 November 2026
Collagen peptides explained: types, dose and how they work
Collagen peptides are one of the most-searched supplement terms in the UK, and one of the most poorly explained. Most blog posts about collagen peptides skip past the actual biology and jump straight to product. Here is a clear, practical explainer of what collagen peptides actually are, how hydrolysis works, the five types of collagen and which ones matter, the dose backed by clinical trials, and how to think about marine versus bovine peptides.
What are collagen peptides?
Collagen peptides (sometimes called hydrolysed collagen, collagen hydrolysate or collagen hydrolysed peptides) are short chains of amino acids derived from native collagen protein that has been broken down through a process called hydrolysis. Native collagen is a long, tightly wound triple-helix protein that the human gut struggles to absorb. Hydrolysis uses heat, water and enzymes to break the long protein chains into much shorter di-peptides and tri-peptides, typically 2 to 5 kilodaltons in molecular weight, which the small intestine absorbs intact. Once absorbed, those short peptides circulate in the bloodstream. They also raise blood levels of the three amino acids that dominate collagen structure: glycine, proline and hydroxyproline. Laboratory studies have shown these peptides can stimulate collagen-producing cells (fibroblasts), and human trials of collagen supplements show modest improvements in skin and joint outcomes, though the exact way this works in the body is still being studied.
The five types of collagen and which ones matter
Type I, II and III, the supplements that count
There are at least 28 types of collagen in the human body, but five matter for supplementation. Type I makes up around 90% of human collagen and dominates skin, bone, tendons and dentin. Type II is the dominant collagen in cartilage and the joints. Type III often appears alongside type I in skin, blood vessels and internal organs. Type I plus type III is the typical skin-and-tendon profile, type II is the cartilage profile. Most marine collagen peptides are predominantly type I and type III. Bovine peptides cover type I, II and III depending on source. Our companion piece on marine collagen peptides vs hydrolysed collagen unpacks the source vs processing distinction.
How collagen peptides work in the body
After ingestion, hydrolysed collagen peptides are absorbed across the intestinal wall as small di- and tri-peptides, with hydroxyproline-containing peptides like Pro-Hyp and Hyp-Gly detectable in the bloodstream within an hour of dosing. Once hydrolysed collagen peptides enter the bloodstream, research suggests they may act as bioactive signals that support collagen synthesis rather than simply providing amino acid building blocks. They also raise the amino acid pool the body uses to build new collagen. The complete UK guide to liquid marine collagen covers the absorption picture in more depth.
Marine versus bovine peptides
Marine collagen peptides come from fish skins and scales, are predominantly type I, and tend to have smaller peptide sizes than bovine, which may aid absorption. Bovine peptides come from cattle and cover types I, II and III depending on source. For skin-focused outcomes, marine is the typical preferred source. For joint and cartilage support, type II bovine or chicken-sourced peptides have specific evidence. Browse the Kollo collagen powder collection for marine-based options.
Collagen types compared at a glance
| Type | Where in body | Common source | Best for |
|---|---|---|---|
| Type I | Skin, bone, tendons, dentin | Marine, bovine | Skin elasticity, hair, nails |
| Type II | Cartilage, joints | Chicken, bovine | Joint comfort, cartilage |
| Type III | Skin (with type I), blood vessels | Marine, bovine | Skin firmness, vascular tissue |
| Types IV and V | Basement membranes, hair, placenta | Rarely supplemented | Specialist applications |
How to take collagen peptides for results
- Take 10g of hydrolysed collagen peptides daily. For skin, the clearest evidence sits at around 10g per day (clinical trial, systematic review and meta-analysis). For joint pain, studies used 5g to 15g per day and found collagen supplementation also increased pain-free time to exertion, so 10g is a sensible starting point
- Get enough vitamin C across your day, the cofactor for collagen synthesis. Total daily intake is what matters, it does not need to be taken at the same time as your collagen
- Choose a named peptide source like Naticol with published clinical trials
- Look for independent third-party testing, such as Informed Choice certification
- Prioritise daily consistency rather than splitting doses across the day
- Allow 8 to 12 weeks of consistent daily intake before judging visible results
Collagen peptides are not magic, but human trials of hydrolysed marine peptides show modest improvements in skin elasticity, hydration and joint comfort when the dose, peptide source and consistency are right. Browse the Kollo collagen powder collection for products built around Naticol marine collagen peptides at the 10g daily dose used in the research.
Kollo Health was co-founded by Jenni Falconer - TV presenter, Smooth Radio breakfast host, ten-time London Marathon runner and host of the RunPod podcast.
