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UC-II (Undenatured Collagen)

Undenatured type II collagen

Low-dose chicken-cartilage collagen for knee osteoarthritis pain.

Moderate evidence ✨Joint & Skin

✚ Updated · How we grade evidence

Evidence tier
Moderate
Research weight
Citations
7 verified / 7
Classification
Joint & Skin
❝
What the evidence says. Graded moderate: several RCTs at 40 mg/day show real reductions in WOMAC pain and improved knee function over 3-6 months, but trials are small (n=50-190), short, and largely funded by the ingredient maker, and one pooled analysis found no benefit on the Lequesne functional index. (Moderate evidence: Several controlled trials; effects real but modest or context-dependent.)

What is UC-II (Undenatured Collagen)?

UC-II (Undenatured Collagen) (Undenatured type II collagen) is a joint and skin supplement used for ease knee osteoarthritis pain. NutriDex grades the human evidence as Moderate. UC-II is undenatured type II collagen sourced from chicken sternal cartilage, given at a tiny 40 mg dose. Unlike hydrolysed collagen, it is kept intact so its 3-D epitopes survive digestion and are thought to retrain joint-targeting immune cells (oral tolerance), dampening inflammation. In a 180-day, three-arm RCT (n=191) UC-II cut total WOMAC scores significantly more than placebo (p=0.002) and even outperformed glucosamine+chondroitin (p=0.04). A 90-day trial reported roughly a 33% WOMAC and 40% VAS-pain drop, and a study in healthy exercisers showed better knee extension and longer pain-free exertion. A 2023-2025 meta-analyses confirm meaningful WOMAC and VAS improvements, though function-index results were mixed. Limits matter: trials are small, run only 3-6 months, and most are industry-sponsored, so the effect is probably real but modest and not yet proven durable or head-to-head with drugs.

Purported Benefits

✓Ease knee osteoarthritis pain
✓Improve joint function & stiffness
✓Better knee range of motion
✓Exercise-related joint comfort

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Ease knee osteoarthritis painMultiple RCTs and 2023-2025 meta-analyses show WOMAC/VAS pain reduction; trials small, short, mostly industry-funded. Moderate ↑ benefit · moderate 4
Improve joint function & stiffnessWOMAC function improved in RCTs, but pooled Lequesne function-index results were null. Mixed ↔ mixed · small 2
Improve knee range of motion / exercise comfort in healthy peopleSingle 120-day RCT (n=55) in healthy exercisers improved knee extension and pain-free exercise time. Preliminary ↑ benefit · small 1

Dosing & Compounds

Typical Dose
40 mg/day of UC-II (about 10 mg bioactive undenatured type II collagen), taken once daily, ideally on an empty stomach.
Active Compounds
Undenatured (native) type II collagenTriple-helix collagen epitopes

Safety & Cautions

UC-II is well tolerated; trials report side effects no more often than placebo, with occasional mild GI upset or headache. It is derived from chicken cartilage, so avoid it if you have a chicken or egg allergy, and safety in pregnancy, breastfeeding and children is untested. No well-documented drug interactions exist, but because it acts on the immune system its effects are theoretically uncertain in people on immunosuppressants or with autoimmune disease; it is a supplement, not a substitute for prescribed osteoarthritis care. Educational only — always check with your doctor or pharmacist before combining UC-II (Undenatured Collagen) with any medicine.

Key Studies

Meta-analysis Garcia-Coronado 2025 ✓ Full text
Systematic review/meta-analysis (17 studies): UC-II significantly lowered WOMAC pain (-9.24, p=0.004) and VAS in knee OA.
Systematic review Review w/ limited meta-analysis 2023 ✓ PubMed
Pooled RCTs: UC-II improved WOMAC (MD -8.91) and VAS pain (MD -1.65) vs placebo, but no benefit on Lequesne index.
Systematic review Gupta & Maffulli 2025 ✓ Full text
Systematic review (12 studies): 40 mg/day UC-II safe and effective short/mid-term; calls for larger, longer, independent trials.
RCT Lugo 2016 ✓ PubMed
180-day RCT (n=191): 40 mg UC-II cut total WOMAC vs placebo (p=0.002) and beat glucosamine/chondroitin (p=0.04).
RCT Bakilan 2016 ✓ PubMed
3-month RCT (n=39): native type II collagen plus acetaminophen improved symptoms more than acetaminophen alone in knee OA.
RCT Lugo 2013 ✓ PubMed
120-day RCT (n=55) in healthy exercisers: UC-II improved average knee extension (81.0 vs 74.0 deg, p=0.011) and pain-free exercise time.
RCT Crowley 2009 ✓ PubMed
90-day RCT (n=52): UC-II reduced WOMAC ~33%, VAS ~40% and Lequesne ~20% vs smaller changes with glucosamine+chondroitin.
7 sources cited · 7 verified Search all studies on PubMed ↗

Common questions about UC-II (Undenatured Collagen)

What is UC-II (Undenatured Collagen) used for?

UC-II (Undenatured Collagen) is most often taken for Ease knee osteoarthritis pain, Improve joint function & stiffness, Better knee range of motion, Exercise-related joint comfort. Low-dose chicken-cartilage collagen for knee osteoarthritis pain.

Does UC-II (Undenatured Collagen) work — what does the evidence say?

Moderate evidence. Several controlled trials; effects real but modest or context-dependent. UC-II is undenatured type II collagen sourced from chicken sternal cartilage, given at a tiny 40 mg dose. Unlike hydrolysed collagen, it is kept intact so its 3-D epitopes survive digestion and are thought to retrain joint-targeting immune cells (oral tolerance), dampening inflammation. In a 180-day, three-arm RCT (n=191) UC-II cut total WOMAC scores significantly more than placebo (p=0.002) and even outperformed glucosamine+chondroitin (p=0.04). A 90-day trial reported roughly a 33% WOMAC and 40% VAS-pain drop, and a study in healthy exercisers showed better knee extension and longer pain-free exertion. A 2023-2025 meta-analyses confirm meaningful WOMAC and VAS improvements, though function-index results were mixed. Limits matter: trials are small, run only 3-6 months, and most are industry-sponsored, so the effect is probably real but modest and not yet proven durable or head-to-head with drugs.

What is the typical dose of UC-II (Undenatured Collagen)?

40 mg/day of UC-II (about 10 mg bioactive undenatured type II collagen), taken once daily, ideally on an empty stomach.

Is UC-II (Undenatured Collagen) safe? Any cautions or side effects?

UC-II is well tolerated; trials report side effects no more often than placebo, with occasional mild GI upset or headache. It is derived from chicken cartilage, so avoid it if you have a chicken or egg allergy, and safety in pregnancy, breastfeeding and children is untested. No well-documented drug interactions exist, but because it acts on the immune system its effects are theoretically uncertain in people on immunosuppressants or with autoimmune disease; it is a supplement, not a substitute for prescribed osteoarthritis care.

How many studies support UC-II (Undenatured Collagen)?

NutriDex cites 7 sources for UC-II (Undenatured Collagen), graded "Moderate".

Cite this page
APA

Peh, D. (2026). UC-II (Undenatured Collagen) (Undenatured type II collagen): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/uc2-collagen

BibTeX
@misc{nutridex_uc2_collagen,
  author       = {Peh, Daryl},
  title        = {UC-II (Undenatured Collagen) (Undenatured type II collagen): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/uc2-collagen},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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