Loading…
We use essential cookies (authentication, your saved goals/stack) by default. With your permission we’ll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Head-to-head evidence comparison — which supplement is right for you?
Iron vs UC-II: Iron has the stronger overall evidence (9 vs 5/10); the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Iron wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
6 of 8 studies with measurable effects showed benefit.
Top outcomes
Verdict
Too few graded studies
Top outcomes
18-40mg elemental iron for deficiency (varies by severity) (a typical label dose, not the dose used in the cited trials, which used 60 to 120 mg a day)
On empty stomach if tolerated, Away from tea, coffee, dairy
Ferrous bisglycinate (gentle, well-absorbed) or iron protein succinylate
40mg UC-II daily (providing ~10mg undenatured type II collagen)
Any time of day
Undenatured type II collagen (UC-II, 40mg)
and 6 more not shown
2-4 weeks
4-8 weeks
4-12 weeks
8-24 weeks
8-16 weeks
Throughout use
Daily oral iron supplementation during pregnancy
The Cochrane database of systematic reviews (2024) · Meta analysis · n=48971
There is probably little to no difference in maternal death (2 versus 4 events, RR 0.57, 95% CI 0.12 to 2.69; 3 trials, 14,060 women; moderate-certainty evidence).
The Prevalence of Anemia among Pregnant Women in China: A Systematic Review and Meta-Analysis
Nutrients (2024) · Meta analysis · n=1376204
The results showed that the prevalence of anemia, ID, and IDA among pregnant women in China were 30.7% (95% CI: 26.6%, 34.7%), 45.6% (95% CI: 37.0%, 54.2%), and 17.3% (95% CI: 13.9%, 20.7%), respectively.
Treatment for women with postpartum iron deficiency anaemia
The Cochrane database of systematic reviews (2024) · Meta analysis · n=4558
Intravenous iron versus oral iron supplementation The evidence is very uncertain about the effect of intravenous iron on mortality (risk ratio (RR) 2.95, 95% confidence interval (CI) 0.12 to 71.96; P = 0.51; I² = not applicable; 3 RCTs; 1 event; 572 women; very low-certainty evidence).
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 · n=191
Multicentre randomised, double-blind trial in 191 people with knee osteoarthritis: UC-II 40 mg/day, glucosamine 1500 mg plus chondroitin 1200 mg, or placebo for 180 days
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 · n=52
90-day trial comparing UC-II with glucosamine plus chondroitin in knee osteoarthritis, with no placebo group
Undenatured type II collagen (UC-II(R)) for joint support: a randomized, double-blind, placebo-controlled study in healthy volunteers.
J Int Soc Sports Nutr (2013) · Rct · n=55
Randomised, double-blind, placebo-controlled 120-day trial in 55 healthy people with knee discomfort only on exertion: UC-II 40 mg/day (n = 27) or placebo (n = 28)
Iron has a higher evidence score (9/10 vs 5/10) and wins in 2 of 3 categories.
No documented interaction was found in the data searched. This does not establish that this exact combination is safe.
On Ozempic/Wegovy/Mounjaro? What actually helps — muscle preservation, GI relief, nutrient gaps (no upsell).
Tired? Why most "energy" pills only work if they fix a deficit — and how to find yours first.
Selenium helps; iodine can WORSEN Hashimoto’s. The honest take on "thyroid support".
What’s safe while nursing, the truth about milk-supply herbs, and what to avoid (it passes into milk).
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.