What Is Type 2 Collagen? Undenatured vs Hydrolysed for Joints

Type II collagen is the collagen of joint cartilage, and two supplements carry the name. Undenatured type II collagen is a 40 mg a day ingredient from chicken sternum cartilage, kept intact, with its own knee trials over 24 weeks to 180 days. Hydrolysed type II collagen is a gram-dose peptide from the same cartilage. They work by different proposed routes and have never been tested head to head. No health claim for collagen is authorised in Great Britain; the trials below are reported as counts, as a spoke of the Wellgard collagen guide.

What is type 2 collagen, and where is it in the body?

Type II collagen is the main collagen of articular cartilage, the smooth tissue on the bone ends inside a joint. Skin, bone and tendon are built from type I, with type III beside it in skin and vessel walls. So the "2" on a label names the tissue a supplement was made from, cartilage, in practice chicken sternum; whether it still matters after processing depends on which of the two products below you hold. Types of collagen explained covers the full numbering.

What is undenatured type II collagen?

Undenatured (native) type II collagen is cartilage collagen that has not been heated or enzyme-cut, so its triple helix and the antigenic structures on it are intact. The proposed mechanism is oral tolerance: a small daily amount reaching the gut's immune tissue is thought to make the immune system more tolerant of the body's own cartilage collagen, a route that depends on structures hydrolysed collagen does not carry.¹ The dose is 40 mg a day, a capsule, not a scoop.

Its trials, as counts. In 191 people with knee osteoarthritis, 40 mg a day for 180 days lowered the total WOMAC score more than placebo (p = 0.002) and more than glucosamine hydrochloride with chondroitin sulfate (p = 0.04); safety outcomes did not differ.² In 96 adults aged 20 to 55 with activity-related joint discomfort, 24 weeks increased knee flexion range by 3.23 degrees against 0.21 on placebo.³ A 2023 review counted eight randomised trials in early knee osteoarthritis, 243 people on the ingredient over three to six months, with better WOMAC and pain scores than placebo.⁴

What we don't know: the positive trials were run or funded by the ingredient's makers, and powders sold as undenatured type II differ markedly in fibre size and antigenic configuration, so a result belongs to the material tested, not to the words on the label.¹ The one independent trial, in 68 people with knee osteoarthritis, combined undenatured type II with hydrolysed collagen in a tablet for 12 weeks: both groups improved and did not differ from placebo, a non-significant result.⁵

What are hydrolysed type II collagen peptides?

Hydrolysed type II collagen is the same cartilage taken apart by heat and enzymes into short peptides, sold in grams. Hydrolysis removes the triple helix that defines a type, so once cut, "type II" tells you the raw material was cartilage, not that the peptides differ from type I peptides from hide or fish skin; the antigenic structures the undenatured form relies on are gone.¹

Its own trials are few. In 80 people with hip or knee osteoarthritis, 2 g a day of a hydrolysed chicken sternal cartilage extract for 70 days lowered pain and WOMAC scores more than placebo, with comparable tolerability.⁶ The pooled analyses do not separate it: a 2024 analysis of 35 randomised trials in 3,165 people with osteoarthritis pooled "collagen derivatives", hydrolysed and undenatured together, and found small to moderate reductions in pain and improvements in function.⁷ No trial of either form has shown new cartilage forming; in the 180-day peptide trial that measured it, joint-space width was unchanged.⁸

Type 1 vs type 2 collagen: which do the joint trials use?

Mostly type I. In 180 active adults aged 18 to 30, 5 g a day of hydrolysed type I collagen peptides for 12 weeks reduced exercise-induced knee pain by 21.9 mm against 15.6 mm on placebo; in a supplier-funded trial of 80 adults aged 40 to 75 with early knee osteoarthritis, 3 g a day for 180 days lowered WOMAC pain more than placebo.^{8, 9} The best type of collagen for joints compares the two ingredients.

Can you take type 1, 2 and 3 collagen together?

Yes. The one combination tested, undenatured type II with hydrolysed collagen in 68 people over 12 weeks, reported no adverse effects in either group.⁵ A powder listing types I, II, III, V and X is a blend of raw materials hydrolysed together; the figure to compare is grams of collagen per serving. Multi-collagen explains a five-type listing.

Is type 2 collagen good for bones or skin?

No trial has tested undenatured type II on bone or skin; one trial of hydrolysed chicken cartilage, with chondroitin and hyaluronic acid, measured skin in women, and none measured bone density.¹⁴ The bone evidence is 5 g a day of hydrolysed collagen peptides for 12 months in 131 postmenopausal women with age-related low bone density: spine and femoral-neck T-scores rose while the placebo group's fell.¹⁰ The skin trials likewise used hydrolysed collagen peptides at gram doses. Neither result applies to a 40 mg capsule. Collagen for bones covers the bone trial.

Who should not take type 2 collagen, and does it have side effects?

In the trials both forms were well tolerated: the 180-day undenatured trial reported safety outcomes that did not differ between groups, the 2024 pooled analysis found no increase in adverse events or withdrawals across 35 trials, and the 12-week combination trial recorded none.^{2, 5, 7} Both forms are usually made from chicken cartilage and the label states the source, so anyone avoiding poultry reads the ingredients list. No trial has included children, pregnancy or kidney disease, so those groups ask a GP or specialist first. The NHS says to see a GP if "the pain has not improved after treating it at home for 2 weeks" or "your joints are stiff for more than 30 minutes after waking up".¹¹ Is there a downside to taking collagen covers medicines.

What should you check on a type 2 collagen label?

• Undenatured or hydrolysed. "Undenatured" or "native" type II means the intact 40 mg ingredient; "hydrolysed type II" or "collagen peptides" in grams means peptides. A product can contain both.
• The amount per daily portion. Milligrams for undenatured, 40 mg a day in every positive trial; grams for hydrolysed, against 2 g in the one type II trial and 5 to 10 g in most type I knee trials.
• The source. Chicken sternum cartilage for the trial materials; a blend of hide, fish and chicken is a multi-collagen, compared on grams per serving.
• A trademark is a maker's name for its material, not a type. Materials sold as undenatured type II differ markedly in structure, so ask whether the capsule holds the material that was trialled.¹

Collagen capsules covers how many capsules make a gram dose of a hydrolysate.

Frequently asked questions

What is the best type 2 collagen supplement for joints?

There is no ranking to give: the two ingredients that carry the name were never compared. Undenatured type II at 40 mg a day has eight randomised trials in knee osteoarthritis, 243 people on the ingredient; hydrolysed type II has one 70-day trial of 80 people at 2 g.^{4, 6} Check the label points above and allow 12 weeks at the least.

Is undenatured type II collagen better than hydrolysed collagen for joints?

No trial has put them head to head, so neither can be called better; each has its own trials, above, and the one trial that combined them in 68 people did not differ from placebo at 12 weeks.⁵ Collagen and glucosamine covers the other comparison people ask about.

How much type 2 collagen should you take a day?

Follow the form: 40 mg a day for undenatured type II, the dose in every trial above; 2 g a day for hydrolysed type II in its one trial; 5 to 10 g for hydrolysed type I peptides in most knee trials, 3 g in one, within the 2.5 to 15 g a day used across the literature.^{2, 6, 8, 9, 13} All were taken daily for 12 weeks or longer.

Does type 2 collagen help arthritis?

Osteoarthritis, in the NHS's words "the most common type of arthritis in the UK", is the condition the trials recruited: 191 people on undenatured type II for 180 days and 80 on hydrolysed type II for 70 days reported lower WOMAC and pain scores than placebo.^{2, 6, 12} Collagen is a food supplement, not a treatment for arthritis; the NHS lists "a number of treatments" available "to reduce the symptoms", and a diagnosis belongs with your GP.¹²

Sources

1. Harris RB, et al. Functional characterization of undenatured type II collagen supplements: are they interchangeable? Journal of Dietary Supplements, 2022. PubMed 34060435.
2. Lugo JP, Saiyed ZM, Lane NE. Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study. Nutrition Journal, 2016. PubMed 26822714.
3. Schön C, et al. Journal of Integrative and Complementary Medicine, 2022. PubMed 35377244.
4. Kumar P, et al. Efficacy of undenatured collagen in knee osteoarthritis: review of the literature with limited meta-analysis. American Journal of Translational Research, 2023. PubMed 37854210.
5. Yuenyongviwat V, et al. Efficacy of combined undenatured type II collagen and hydrolysed collagen supplementation in knee osteoarthritis: a randomised controlled trial. Scientific Reports, 2025. PubMed 40897777.
6. Schauss AG, et al. Journal of Agricultural and Food Chemistry, 2012. PubMed 22486722.
7. Liang CW, et al. Efficacy and safety of collagen derivatives for osteoarthritis: a trial sequential meta-analysis. Osteoarthritis and Cartilage, 2024. PubMed 38218227.
8. Park SY, et al. Efficacy and safety of low-molecular-weight collagen peptides in knee osteoarthritis: a randomized, double-blind, placebo-controlled trial. Frontiers in Nutrition, 2025. Supplier-funded. PubMed 40977985.
9. Zdzieblik D, et al. Nutrients, 2021. PubMed 33562729.
10. König D, et al. Specific collagen peptides improve bone mineral density and bone markers in postmenopausal women: a randomized controlled study. Nutrients, 2018. PubMed 29337906.
11. NHS. Joint pain. nhs.uk. Page last reviewed 26 February 2026.
12. NHS. Osteoarthritis. nhs.uk. Page last reviewed 20 March 2023, past its March 2026 review date; re-read 12 October 2026.
13. Trč T, Bohmová J. International Orthopaedics, 2011. Randomised trial, 100 adults, 13 weeks. PubMed 20401752.
14. Schwartz SR, et al. Alternative Therapies in Health and Medicine, 2019. Randomised trial, 128 women, 12 weeks. PubMed 31221944.