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Head-to-head evidence comparison — which supplement is right for you?
Potassium vs Selenium: they're closely matched on evidence (8.5 vs 6.5/10); they're alternatives for reduce inflammation — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Potassium and Selenium are closely matched across evidence, studies, and safety.
Verdict
Probably helps
9 of 14 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
27 of 34 studies with measurable effects showed benefit.
Top outcomes
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 (2025) · 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.
Both Potassium and Selenium are closely matched — the best choice depends on your specific health goals.
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.
Who actually needs electrolytes (and who doesn’t), what matters (sodium), and LMNT vs alternatives.
Selenium helps; iodine can WORSEN Hashimoto’s. The honest take on "thyroid support".
CoQ10, zinc, selenium, carnitine modestly help sperm parameters — but live-birth evidence is weak.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.