Endurance & Stamina Supplements Guide

Supplement Science Editorial Team·Evidence-Based Supplement Research

Published May 25, 2026

This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

For endurance, the best-supported aids are caffeine, beetroot nitrate (efficiency), and beta-alanine, plus electrolytes...

Endurance performance rewards smart fueling and training, with a few supplements offering a real edge. This guide covers the ergogenic aids with evidence for endurance — caffeine, beetroot nitrate, beta-alanine — alongside electrolytes and the under-appreciated role of iron, which can quietly make or break stamina.

Who this guide is for

Runners, cyclists, and endurance athletes wanting evidence-aware support. It assumes a training and fueling plan; iron concerns and any health symptoms warrant a clinician, and tested athletes should use certified products.

Key Takeaways

Carbohydrate fueling and training dominate endurance; supplements fine-tune.
Caffeine and beetroot nitrate are the best-supported endurance aids; beta-alanine helps surges.
Low iron quietly tanks stamina — check status (especially women, vegetarians) and correct under guidance.
Electrolytes matter for long, hot, sweaty sessions, not routine training.
Address persistent fatigue or breathlessness medically; tested athletes need certified products.

Fueling comes first

For endurance, carbohydrate availability and training dominate performance. Supplements fine-tune; they don't replace fueling, pacing, and consistent training ^[2].

The endurance edge

Caffeine is one of the most reliable endurance aids, improving perceived effort and performance; dose is individual and tolerance builds.
Beetroot (dietary nitrate) can modestly improve exercise efficiency and time-to-exhaustion.
Beta-alanine helps high-intensity efforts and repeated surges.
Citrulline malate may support blood flow and work capacity.

The iron factor

This is the quiet one: iron deficiency — common in endurance athletes, especially women and vegetarians — impairs oxygen transport and tanks stamina. Correcting a confirmed deficiency can markedly help, but iron should be guided by testing, since excess is harmful ^[1].

Hydration and electrolytes

Electrolytes matter for long, hot, or very sweaty sessions to replace sodium and support hydration; for shorter efforts, water and a normal diet usually suffice. CoQ10 and L-carnitine are sometimes used with limited endurance evidence ^[3].

Safety and the bigger picture

Total your caffeine, don't over-rely on electrolytes for routine training, and address fatigue or breathlessness medically (it can signal iron deficiency or other issues). Tested athletes should choose certified products.

Practical guidance

Dial in carbohydrate fueling and training; use caffeine and beetroot nitrate for race-day efficiency; add beta-alanine for high-intensity work; use electrolytes for long/hot sessions; and check iron status if stamina drops, correcting deficiency under guidance.

Supplements in this guide

7 researched options — tap any for our full evidence profile.

Beetroot / Dietary Nitrate

Strong

Sports Nutrition / Vasodilator

Beetroot juice providing 6-8 mmol (400-500 mg) dietary nitrate taken 2-3 hours before exercise reduces oxygen cost of submaximal exercise by 3-5% and improves time trial performance by 1-3% (Jones, 2014). Effects are strongest in recreational athletes and high-altitude or hypoxic conditions.

Electrolytes

Strong

Mineral / Hydration

Electrolyte replacement during exercise lasting >60 minutes significantly improves performance and prevents hyponatremia. Sodium is the primary electrolyte lost in sweat (0.5-2 g/L). ACSM recommends 300-600 mg sodium per hour during prolonged exercise. Modern electrolyte formulas typically combine sodium, potassium, magnesium, and calcium.

Beta-Alanine

Strong

Amino Acid

Beta-alanine at 3.2-6.4 g/day increases muscle carnosine by 40-80%, improving exercise capacity during 1-4 minute efforts. A 2012 meta-analysis confirmed significant performance improvement with a median effect of 2.85%. The characteristic tingling sensation (paresthesia) is harmless.

Iron

Strong

Essential Trace Mineral

Iron is essential for oxygen transport and energy production. Only supplement if deficient — excess iron is harmful. Ferrous bisglycinate is the best-tolerated form with high absorption. Typical therapeutic dose is 18-65mg elemental iron daily for deficiency.

Coenzyme Q10 (CoQ10)

Moderate

Antioxidant / Energy Metabolism

CoQ10 (100-300 mg/day) is essential for mitochondrial ATP production and is a powerful antioxidant. The Q-SYMBIO trial (2014) showed 100 mg three times daily reduced cardiovascular mortality by 43% in heart failure patients. For exercise, benefits are modest and mainly observed in older or untrained individuals. Ubiquinol is the preferred form for supplementation due to superior absorption.

L-Carnitine

Moderate

Amino Acid

L-Carnitine shuttles fatty acids into mitochondria for energy production. Its strongest evidence is in cardiovascular health — a meta-analysis showed 27% reduced mortality post-heart attack at 2-3 g/day. Fat-burning claims are not well supported in healthy, well-nourished individuals.

Citrulline Malate

Strong

Amino Acid / Performance

Citrulline malate at 6-8 g (taken 40-60 minutes pre-workout) has been shown to increase repetitions to failure by 19-53% in resistance training (Pérez-Guisado & Jakeman, 2010) and reduce muscle soreness by 40% at 24-48 hours post-exercise. It raises plasma arginine more effectively than arginine supplementation itself.

Product Reviews

Best Nitric Oxide Supplements

See our ranked picks →

Frequently Asked Questions

What supplements help endurance?

Caffeine and beetroot nitrate have the best evidence for endurance, with beta-alanine helping high-intensity surges and electrolytes supporting long or hot sessions. Carbohydrate fueling and training do the most, so supplements fine-tune rather than replace the fundamentals.

Why does iron matter for stamina?

Iron carries oxygen, so deficiency — common in endurance athletes, especially women and vegetarians — impairs oxygen transport and quietly tanks stamina. Correcting a confirmed deficiency can markedly help, but iron should be guided by testing since excess is harmful.

Do I need electrolyte supplements for every workout?

No — electrolytes mainly matter for long, hot, or very sweaty sessions where significant sodium is lost. For shorter efforts, water and a normal diet usually suffice, so routine electrolyte products aren't necessary for most training.

Is beetroot juice worth it for racing?

Beetroot (dietary nitrate) can modestly improve exercise efficiency and time-to-exhaustion, making it a reasonable race-day tool. Effects are small and individual, so it's worth trialing in training first, and whole-food beets and leafy greens are a reliable nitrate source.

References

National Institutes of Health, Office of Dietary Supplements (2025). Iron: Health Professional Fact Sheet. NIH Office of Dietary Supplements.
U.S. National Library of Medicine, MedlinePlus (2025). Dietary Supplements. MedlinePlus (U.S. National Library of Medicine).
National Institutes of Health, Office of Dietary Supplements (2023). Dietary Supplements: What You Need to Know. NIH Office of Dietary Supplements.