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
Head-to-head evidence comparison — which supplement is right for you?
SAMe wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
0 of 2 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
18 of 23 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both SAMe and Selenium have evidence — compare verdict strength side-by-side.
400-1600mg for mood; 600-1200mg for joints
On empty stomach, Morning and/or midday
Enteric-coated tablets (SAMe tosylate or butanedisulfonate)
100-200mcg
With food
Selenomethionine (best absorbed)
2-6 weeks
4-8 weeks
4-8 weeks
4-8 weeks
4-8 weeks
S-Adenosylmethionine for osteoarthritis of the knee or hip
The Cochrane database of systematic reviews (2009) · Meta analysis · n=656
For pain, the analysis indicated a small SMD of -0.17 (95% CI -0.34 to 0.01), corresponding to a difference in pain scores between SAMe and placebo of 0.4 cm on a 10 cm VAS, with no between trial heterogeneity (I(2) = 0).
Efficacy of Pharmacological Interventions in Milder Depression: A Systematic Review and Meta-Analysis
Neuropsychopharmacology reports (2025) · Meta analysis · n=1049
A meta-analysis found no significant difference in response rates between the two treatments (risk ratio [RR] = 0.96, 95% CI: 0.78-1.18) or dropout rates (RR = 1.08, 95% CI: 0.62-1.88).
S-Adenosylmethionine (SAMe) for Liver Health: A Systematic Review
Nutrients (2024) · Systematic review · n=15
The most common doses were SAMe 1000 mg or 1200 mg per day with or without another treatment or natural supplement.
Selenium, antioxidants, cardiovascular disease, and all-cause mortality: a systematic review and meta-analysis of randomized controlled trials
The American journal of clinical nutrition (2020) · Meta analysis · n=9423
However, a decreased risk with antioxidant mixtures was seen for CVD mortality when selenium was part of the mix (RR: 0.77; 95% CI: 0.62, 0.97; P = 0.02), with no association when selenium was absent.
Selenium for preventing cancer
The Cochrane database of systematic reviews (2018) · Meta analysis · n=27232
For analyses of RCTs with low risk of bias, the summary risk ratio (RR) for any cancer incidence was 1.01 (95% confidence interval (CI) 0.93 to 1.10; 3 studies, 19,475 participants; high-certainty evidence).
Selenium and prostate cancer: systematic review and meta-analysis
The American journal of clinical nutrition (2012) · Meta analysis · n=13254
Three high-quality studies included in the meta-analysis of toenail selenium and cancer risk indicated a reduction in prostate cancer risk (estimated RR: 0.29; 95% CI: 0.14, 0.61) with a toenail selenium concentration between 0.85 and 0.94 μg/g.
Meta-analysis of 656 patients showed small effect size (SMD -0.17) corresponding to only 0.4cm improvement on 10cm pain scale. Effect is modest and barely reaches statistical significance threshold.
Based on Cochrane systematic review showing moderate-certainty evidence for TPO antibody reduction. Effects on thyroid hormone levels (TSH, T4, T3) were inconsistent across studies.
AI-estimated from published studies. Interpret as directional guidance.
SAMe has a higher evidence score (9/10 vs 9/10) and wins in 1 of 3 categories.
For support mood, SAMe has a higher relevance score (90 vs 45).
No known interactions between SAMe and Selenium have been documented in our database. However, always consult a healthcare provider before combining supplements.