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Head-to-head evidence comparison — which supplement is right for you?
Collagen vs Vitamin K2: Collagen has the stronger overall evidence (6 vs 6/10); they're alternatives for bone health — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Collagen wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
6 of 6 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
10 of 13 studies with measurable effects showed benefit.
Top outcomes
10-15g
Any time of day, With vitamin C for enhanced synthesis
Hydrolyzed collagen peptides (powder)
100-200mcg (MK-7)
With a meal containing fat
MK-7 (menaquinone-7)
8-12 weeks
8-12 weeks
12 weeks
First week
6-12 months
1-3 years
Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
The American Journal of Medicine (2025) · Meta analysis · n=1474
A total of 23 RCTs with 1474 participants were analyzed.
Effect of collagen supplementation on knee osteoarthritis: an updated systematic review and meta-analysis of randomised controlled trials
Clinical and experimental rheumatology (2025) · Meta analysis · n=870
The meta-analysis revealed an overall significant improvement of both function [MD, -6.46 (95% CI -9.52, -3.40); I2=75%; p=0.00001] and pain scores [MD, -13.63 (95% CI -20.67, -6.58); I2=88%; p=0.00001], favouring collagen supplementation.
Impact of Collagen Peptide Supplementation in Combination with Long-Term Physical Training on Strength, Musculotendinous Remodeling, Functional Recovery, and Body Composition in Healthy Adults: A Systematic Review with Meta-analysis
Sports medicine (Auckland, N.Z.) (2024) · Meta analysis · n=768
This systematic review and meta-analysis represents the first comprehensive investigation into the effects of long-term CP supplementation combined with regular physical training on various aspects of musculoskeletal health in adults.
Vitamins K2 and D3 Improve Long COVID, Fungal Translocation, and Inflammation: Randomized Controlled Trial
Nutrients (2025) · Rct · n=151
The median age was 46 years; 71% were female and 29% were non-white.
The effect of vitamin K2 supplementation on bone turnover biochemical markers in postmenopausal osteoporosis patients: a systematic review and meta-analysis
Frontiers in endocrinology (2025) · Meta analysis · n=2570
Vitamin K2 (VK2) increased osteocalcin (OC; MD 1.86, 95% CI 1.17-2.56) and bone-specific alkaline phosphatase (BAP; MD 1.49, 95% CI 0.98-2.00).
Vitamin K2 in Managing Nocturnal Leg Cramps: A Randomized Clinical Trial
JAMA internal medicine (2024) · Rct · n=310
Of the 199 enrolled individuals, 108 (54.3%) were female, and the mean (SD) age was 72.3 (5.5) years.
Meta-analysis of 23 RCTs (n=1474) found collagen significantly improved skin hydration, elasticity, and wrinkles overall, but high-quality and non-industry-funded studies showed no significant effect. Hydrolyzed collagen peptides preferred for bioavailability.
Based on meta-analyses showing 2.17% WMD improvement in lumbar BMD. Effects primarily demonstrated with MK-7 form in postmenopausal women. Combination with vitamin D3 may enhance effects.
AI-estimated from published studies. Interpret as directional guidance.
Collagen has a higher evidence score (6/10 vs 6/10) and wins in 2 of 3 categories.
For bone health, Vitamin K2 has a higher relevance score (88 vs 85).
No known interactions between Collagen and Vitamin K2 have been documented in our database. However, always consult a healthcare provider before combining supplements.
The honest tier list — proven staples vs situational vs mostly marketing. The hub the other guides feed into.
Curcumin, omega-3, UC-II collagen, Boswellia vs the old glucosamine default — and OA vs RA.
Modest-but-real for skin, growing for joints, weak for hair/nails — plus which type to buy.
Which supplements clash with blood thinners, thyroid meds, antibiotics & more — and what to do.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.