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Head-to-head evidence comparison — which supplement is right for you?
Potassium wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Probably helps
6 of 10 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 Potassium and Selenium have evidence — compare verdict strength side-by-side.
99-500mg daily from supplements (food provides more)
With food to reduce GI upset, Spread throughout day, During/after exercise for athletes
Potassium Citrate or Potassium Gluconate
100-200mcg
With food
Selenomethionine (best absorbed)
2-4 weeks
1-2 weeks
Long-term
With excess or kidney issues
4-8 weeks
4-8 weeks
Effect of changes in potassium intake on blood pressure: a dose–response meta-analysis of randomized clinical trials (2000–2024)
Clinical Kidney Journal (2024) · Meta analysis · n=2500
Dose-response analysis of RCTs from 2000-2024
Magnesium and Potassium Supplementation for Systolic Blood Pressure Reduction in the General Normotensive Population: A Systematic Review and Subgroup Meta-Analysis for Optimal Dosage and Treatment Length
Nutrients (2024) · Meta analysis
Both supplements demonstrated greater reductions in SBP for the general population at lower dosages and longer treatment durations.
Sex-specific associations between sodium and potassium intake and overall and cause-specific mortality: a large prospective U.S. cohort study, systematic review, and updated meta-analysis of cohort studies
BMC medicine (2024) · Meta analysis · n=237036
Meta-analysis examining Potassium efficacy
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.
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.
Potassium has a higher evidence score (9/10 vs 9/10) and wins in 1 of 3 categories.
For reduce inflammation, Potassium has a higher relevance score (85 vs 52).
No known interactions between Potassium and Selenium have been documented in our database. However, always consult a healthcare provider before combining supplements.