Supplement Evidence Explorer for Athletes

Supplements fall into different categories: a few improve performance directly, some only help when you are deficient, and many have little evidence at all.4 This explorer sorts common supplements by what the research reviewed in my articles actually shows, with my own clinical observations next to each.

Evidence at a glance
SupplementVerdict
Show details

Three different questions

Performance supplements, population-level prevention such as low-dose vitamin D in a northern winter, and treating an individual deficiency are different situations.4 When iron or vitamin B12 deficiency is suspected, or before higher-dose vitamin D, testing is better than guessing, because both too little and too much can cause problems.4

How the verdicts work

Performance evidence: trials show a direct performance effect. Supported for its purpose: works for a narrower goal such as overnight protein synthesis. Helps only if deficient: benefit is limited to people with low status. Mixed or limited: results conflict or studies are few. Little or no benefit shown: tested and not found useful for the claimed purpose.

References

Every figure and statement in this tool is linked to a source: the original study where my article cites one, otherwise my own article on the topic. The small numbers in the text refer to this list.

  1. Kazeminasab et al. 2025. The Effects of Creatine Supplementation on Upper- and Lower-Body Strength and Power: A Systematic Review and Meta-Analysis. Nutrients.
  2. Pashayee-Khamene et al. 2024. Creatine supplementation protocols with or without training interventions on body composition: a GRADE-assessed systematic review and dose-response meta-analysis. Journal of the International Society of Sports Nutrition.
  3. Dr. Antti Rintanen: Creatine in Athletes: What the Evidence Actually Says About Performance, Muscle, and Safety
  4. Dr. Antti Rintanen: Which Supplements May Help Athletes? Why Most Answers Should Come From a Blood Test — But Not All
  5. Pengelly et al. 2025. Iron deficiency, supplementation, and sports performance in female athletes: A systematic review. Journal of Sport and Health Science.
  6. Study cited in “Which Supplements May Help Athletes? Why Most Answers Should Come From a Blood Test — But Not All” (reference 11)
  7. Farrokhyar et al. 2015. Prevalence of vitamin D inadequacy in athletes: a systematic-review and meta-analysis. Sports Med.
  8. Wyatt et al. 2024. Effects of Vitamin D Supplementation in Elite Athletes: A Systematic Review. Orthopaedic Journal of Sports Medicine.
  9. Deng et al. 2025. Dietary Supplement Strategies During Conditioning Training in Athletes: A Network Meta-Analysis of Peak and Mean Anaerobic Power, VO(2)max, and Endurance Performance. Food Sci Nutr.
  10. Dr. Antti Rintanen: Protein Before Sleep vs. Fasting: What’s Better for Muscle Preservation During Fat Loss?
  11. Bischof et al. 2024. 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.
  12. Dr. Antti Rintanen: Omega-3 for Athletes: What the Blood Work Actually Tells You
  13. Dr. Antti Rintanen: Magnesium Benefits: What the Evidence Shows and What It Means for Athletes
  14. Zhang et al. 2016. Effects of Magnesium Supplementation on Blood Pressure. Hypertension.
  15. Dr. Antti Rintanen: Zinc in Athletes: What Blood Levels, Diet, and Supplementation Really Tell Us
  16. O’Connor et al. 2022. Vitamin and Mineral Supplements for the Primary Prevention of Cardiovascular Disease and Cancer. JAMA.
  17. Dr. Antti Rintanen: Is Vitamin Water Good for You? What the Research Says About Sugar, Vitamins and Hydration
  18. Vasireddi et al. 2025. Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS Journal®: The Musculoskeletal Journal of Hospital for Special Surgery.
  19. Liu et al. 2008. Systematic Review: The Effects of Growth Hormone on Athletic Performance. Annals of Internal Medicine.
  20. Hermansen et al. 2017. Impact of GH administration on athletic performance in healthy young adults: A systematic review and meta-analysis of placebo-controlled trials. Growth Hormone and IGF Research.
  21. Dr. Antti Rintanen: Peptides for Muscle Growth: What the Evidence Actually Shows

Sources

This tool is based on the articles below and the studies cited in them:

This tool is for general education. It does not diagnose, interpret your own results, give personal recommendations or replace an assessment by your doctor.