Type II Collagen (Undenatured)
Summary
Undenatured type II collagen is chicken-cartilage collagen used in milligram doses, unlike hydrolysed collagen powders. A 180-day trial in knee osteoarthritis found 40 mg/day of UC-II beat placebo on WOMAC scores (grade C), and small trials in active adults reported better knee range of motion. Most trials were industry-sponsored, and a 2025 trial combining half that dose with hydrolysed collagen was null.
Key facts
- Non-hydrolysed (undenatured) type II collagen from chicken sternum cartilage, dosed in milligrams[1][3]
- 40 mg/day of UC-II, which the 2009 trial described as 10 mg of undenatured collagen and the 2016 trial measured at 1.2 mg by ELISA[2][1]
- 40 mg/day lowered total WOMAC scores versus placebo and versus glucosamine plus chondroitin at day 180 (n = 186 analysed)[1]
- 20 mg UC-II plus 480 mg hydrolysed collagen did not beat placebo over 12 weeks in 68 people with knee osteoarthritis[6]
- The pivotal 2016 knee trial was sponsored by the UC-II maker, with two authors employed by it[1]
- 6 graded human outcomes on this page
- October 13, 2026
How it works
ProposedTrial authors propose oral tolerance: small amounts of intact type II collagen meeting gut immune tissue may dampen immune reactions against joint cartilage. This mechanism comes from preclinical work cited by the authors and has not been confirmed in human mechanistic studies.[1][5]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Knee osteoarthritis | Grade C | Improved | RCT · n = 186 · 2016 | 3 rows |
| Joint comfort | Grade C | Improved | RCT · n = 96 · 2022 | 3 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Knee osteoarthritis symptoms (WOMAC) versus placebo and glucosamine plus chondroitin | Improved | Grade C | RCT · n = 186 · 2016 Adults with moderate-to-severe knee osteoarthritis (multicentre, India) Form: UC-II undenatured type II collagen · Dose: 40 mg/day · Duration: 180 days Total WOMAC fell more than with placebo (P = 0.002) and with glucosamine 1,500 mg plus chondroitin 1,200 mg (P = 0.04), with gains in pain, stiffness and function subscales. Adverse events: 13% UC-II, 12% placebo, 31% glucosamine plus chondroitin. | 26822714 (opens PubMed)Source [1] |
| Knee range of motion in healthy adults with activity-related joint discomfort | Improved | Grade C | RCT · n = 96 · 2022 Healthy adults aged 20–55 with activity-related knee discomfort Form: UC-II · Dose: 40 mg/day · Duration: 24 weeks Knee flexion improved more than with placebo (3.23° vs 0.21°, P = 0.025); extension improved within the UC-II group only. | 35377244 (opens PubMed)Source [4] |
| Knee range of motion, knee and lower-back discomfort (NEXT-II) | Improved | Grade C | RCT · n = 58 · 2023 Healthy Japanese adults aged 20 to under 75 Form: NEXT-II undenatured type II collagen · Dose: 3.2 mg/day undenatured type II collagen · Duration: 12 weeks Knee flexion and range improved at weeks 4, 8 and 12 versus placebo, with improvements in JKOM, knee and back discomfort, walking and stair-climbing tests. | 35512781 (opens PubMed)Source [5] |
| Knee extension and exercise-related knee discomfort in healthy adults | Improved | Grade C | RCT · n = 55 · 2013 Healthy adults with knee discomfort after stepmill exercise but no arthritis Form: UC-II · Dose: 40 mg/day · Duration: 120 days Knee extension improved versus placebo (81.0° vs 74.0°, P = 0.011), and the UC-II group exercised longer before discomfort began versus baseline. No product-related adverse events. | 24153020 (opens PubMed)Source [3] |
| Knee osteoarthritis pain and function (UC-II plus hydrolysed collagen) | No effect | Grade D | RCT · n = 68 · 2025 Adults with knee osteoarthritis (Thailand) Form: Tablets with UC-II plus hydrolysed collagen · Dose: 20 mg UC-II plus 480 mg hydrolysed collagen per day (two tablets at bedtime) · Duration: 12 weeks Pain, KOOS function, rescue-medication use and satisfaction improved in both groups with no difference from placebo; no adverse effects were reported. | 40897777 (opens PubMed)Source [6] |
| Knee osteoarthritis symptoms versus glucosamine plus chondroitin | Improved | Grade D | RCT · n = 52 · 2009 Adults with knee osteoarthritis Form: UC-II (20 mg capsules standardized to 5 mg undenatured collagen) · Dose: 40 mg/day UC-II (10 mg undenatured collagen) · Duration: 90 days WOMAC fell 33% with UC-II versus 14% with glucosamine plus chondroitin, with similar differences in pain (VAS) and Lequesne scores. | 19847319 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| UC-II undenatured type II collagen (40 mg capsules) | Varies[1] | No human absorption data; the proposed action is local, in gut immune tissue.[1] | Adverse events at 40 mg/day matched placebo (13% vs 12%) over 180 days.[1] | Knee osteoarthritis and exercise-related knee discomfort |
| NEXT-II undenatured type II collagen | Varies[5] | No human absorption data.[5] | Reported safe in the 12-week trial.[5] | Knee mobility in healthy adults (3.2 mg/day) |
| Hydrolysed collagen (different product) | Varies[6] | No head-to-head human data against undenatured collagen.[6] | No adverse effects in the 2025 combination trial.[6] | Grams-per-day protein product; see its own page |
Studied doses
Doses studied in human trials ranged from 3.2 mg/day of NEXT-II collagen to 40 mg/day of UC-II for 12 weeks up to 180 days. Most trials used 40 mg/day of UC-II.[5][1][3][4]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Chicken allergy
- UC-II and NEXT-II are made from chicken sternum cartilage; the trials cited here do not report allergy testing, so the source animal matters for allergic people.[1][5]
- Pregnancy and breastfeeding
- The cited trials enrolled non-pregnant adults (the 2016 trial ran pregnancy tests), so they give no safety data for these groups.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
- Milligrams, not gramsUndenatured collagen is dosed at 40 mg/day or less. Hydrolysed collagen is a different product: the 2025 tablet paired 20 mg UC-II with 480 mg of it.[1][6]
- What "40 mg" contains40 mg of UC-II was described as 10 mg of undenatured collagen in 2009, but the 2016 trial measured only 1.2 mg with a newer ELISA, so labels may count different things.[2][1]
- Brand-specific evidenceNearly all positive trials tested branded ingredients (UC-II or NEXT-II), several sponsored by their makers.[1][3][4][5]
Cost per studied dose, without the sales pitch
Compare any product you already have by the amount it delivers, not by capsule count or front-of-pack weight.
Cost per studied dose
Enter the price, servings and the amount per serving from your label.
Frequently asked questions
What is the difference between type II collagen and collagen peptides?
Undenatured type II collagen is intact cartilage collagen taken in milligram doses; collagen peptides are a hydrolysed product taken in much larger amounts, and the trials here do not test one against the other.[1][6]
Does UC-II help knee osteoarthritis?
In a 180-day trial of 186 adults, 40 mg/day lowered WOMAC scores more than placebo and glucosamine plus chondroitin. An independent 2025 trial of a lower-dose combination found no benefit.[1][6]
How much undenatured type II collagen was studied?
Most trials used 40 mg/day of UC-II; a Japanese trial used 3.2 mg/day of NEXT-II collagen.[1][5]
How long before effects appeared?
Trials measured outcomes at 90 to 180 days; the NEXT-II trial reported knee flexion changes from week 4.[2][1][5]
Does it help joints in people without arthritis?
Small trials in active adults reported a few degrees more knee extension or flexion versus placebo after 120 days to 24 weeks.[3][4]
Is undenatured type II collagen safe?
Adverse events matched placebo in the 180-day knee trial. Long-term and pregnancy data are lacking.[1]
Sources
- [1]Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study.. Nutr J, 2016. RCT
- [2]Safety and efficacy of undenatured type II collagen in the treatment of osteoarthritis of the knee: a clinical trial.. Int J Med Sci, 2009. RCT
- [3]Undenatured type II collagen (UC-II®) for joint support: a randomized, double-blind, placebo-controlled study in healthy volunteers.. J Int Soc Sports Nutr, 2013. RCT
- [4]UC-II Undenatured Type II Collagen for Knee Joint Flexibility: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Clinical Study.. J Integr Complement Med, 2022. RCT
- [5]Efficacy and Safety of Dietary Undenatured Type II Collagen on Joint and Motor Function in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study.. J Am Nutr Assoc, 2023. RCT
- [6]Efficacy of combined undenatured type II collagen and hydrolysed collagen supplementation in knee osteoarthritis: a randomised controlled trial.. Sci Rep, 2025. RCT
- [7]Dietary supplements for treating osteoarthritis: a systematic review and meta-analysis.. Br J Sports Med, 2018. meta-analysis
What changed
- Strict second-pass self-review (no separate reviewer could be dispatched for this batch): all 7 PMIDs re-verified by NCBI esummary (titles and years match the record) and efetch checked for retraction, expression-of-concern and erratum flags (none flagged); every evidence row, key fact, form, dose, label line, FAQ and insight re-read against its abstract, and against PMC full text where the dose or count lives. Fixes: meta-analysis insight corrected to match the abstract (short-term effect of unclear clinical importance, clinically important at medium term); removed an unsourced grams-of-collagen comparison and a type I claim; dropped "independent" for the 2025 trial; allergy note limited to chicken. Page set indexable.
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year from the record) and abstracts read for each cited row. Doses, arm sizes, ELISA content, adverse-event table and sponsorship from PMC full texts (PMC4731911, PMC2764342, PMC12405528). No NIH ODS or NCCIH fact sheet covers undenatured type II collagen.