Supplements and Running: What Actually Works?

The supplement industry is crowded with products promising speed, endurance, and faster recovery. In reality, very few supplements have strong scientific evidence supporting their use in runners.

This article focuses only on supplements that:

Have consistent, peer-reviewed research support
Apply to endurance running
Improve performance, training quality, or health

Carbohydrates, gels, and electrolytes are intentionally excluded.

1. Caffeine

Best supported supplement for runners

Caffeine is one of the most robustly supported ergogenic aids in endurance sport.

Proven Benefits

Improves endurance performance (2–4% on average)
Lowers perceived exertion at a given pace
Enhances alertness and focus
Improves time-trial performance from 5 km to marathon

Caffeine works primarily through central nervous system stimulation, reducing the brain’s perception of effort rather than changing muscle physiology directly.

Effective Use

Dose: ~3–6 mg per kg body weight
Taken 30–60 minutes pre-run or race
Lower doses can still be effective

Caffeine consistently improves performance across recreational and elite runners (Grgic et al., 2020).

2. Dietary Nitrates (Beetroot Juice)

Improves efficiency, especially in non-elite runners

Dietary nitrates increase nitric oxide availability, improving blood flow and mitochondrial efficiency.

Proven Benefits

Reduced oxygen cost at submaximal paces
Improved time-to-exhaustion
Small but meaningful improvements in time-trial performance

Benefits are strongest in:

Recreational runners
5 km to half marathon distances

Elite runners may see smaller effects due to already-optimized physiology, but evidence still supports use in many cases (Jones et al., 2018).

Effective Use

400–800 mg nitrate (~500 ml beetroot juice)
Taken 2–3 hours before running
Can be loaded over several days

3. Creatine (Training Support, Not Race-Day Speed)

Indirect but well-supported

Creatine does not reliably improve long-distance race times—but it does improve training quality.

Proven Benefits for Runners

Improves sprint ability and finishing kick
Enhances interval training quality
Supports strength training adaptations
May reduce neuromuscular fatigue

Creatine is especially useful for:

Sprinters and middle-distance runners
Runners doing regular strength training
Masters runners preserving muscle mass

The evidence base for creatine’s safety and efficacy is exceptionally strong (Kreider et al., 2017).

Effective Use

3–5 g creatine monohydrate daily
No loading phase required
Best used during training blocks, not peak race phase

4. Beta-Alanine (Event-Specific)

Useful for shorter, high-intensity events

Beta-alanine increases muscle carnosine, improving buffering capacity during high-intensity efforts.

Proven Benefits

Improved performance in efforts lasting ~1–4 minutes
Better tolerance of high-intensity intervals

This makes beta-alanine relevant for:

400 m to 1500 m runners
Some 3–5 km runners with heavy anaerobic demands

It has little value for marathon performance.

Effective Use

3–6 g per day
Requires 4–8 weeks of loading
Tingling sensation is common but harmless

5. Iron (Only When Deficient)

Performance-critical, but not optional supplementation

Iron is essential for oxygen transport. Low iron levels—common in runners—directly impair endurance performance.

Proven Benefits (When Deficient)

Improved VO₂max
Reduced fatigue
Improved training tolerance

Supplementing iron only benefits runners with deficiency or low ferritin. Unnecessary supplementation offers no performance gain and carries risk.

Iron status should always be assessed via blood testing before supplementation (Peeling et al., 2014).

6. Vitamin D (Health and Injury Risk)

Indirect performance support

Vitamin D is not a performance enhancer, but deficiency is associated with:

Increased injury risk
Impaired muscle function
Reduced immune resilience

Supplementation improves outcomes only when baseline levels are low, which is common in winter or indoor-based athletes.

Supplements with Weak or Inconsistent Evidence

The following are often marketed to runners but lack strong support:

BCAAs (when protein intake is adequate)
Antioxidants in high doses (may impair adaptation)
“Recovery blends” without clear dosing

These are not reliably performance-enhancing.

How to Think About Supplements as a Runner

Supplements should:

Address a specific limitation
Support training consistency
Be safe, legal, and evidence-based

They should never replace:

Adequate energy intake
Sleep
Smart training design

Practical Takeaway

Very few supplements truly help runners—but a handful do.

The strongest evidence supports:

Caffeine – direct performance boost
Beetroot juice (nitrates) – improved efficiency
Creatine – better training quality
Iron & Vitamin D – only if deficient

If a supplement doesn’t help you train better, race better, or stay healthy—it probably isn’t worth taking.

References

Grgic, J., et al. (2020). Effects of caffeine intake on endurance exercise performance: a systematic review and meta-analysis. British Journal of Sports Medicine, 54(11), 681–688.
Jones, A. M., Thompson, C., Wylie, L. J., & Vanhatalo, A. (2018). Dietary nitrate and physical performance. Annual Review of Nutrition, 38, 303–328.
Kreider, R. B., et al. (2017). International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation. Journal of the International Society of Sports Nutrition, 14, 18.
Hobson, R. M., et al. (2012). Effects of beta-alanine supplementation on exercise performance. Amino Acids, 43(1), 25–37.
Peeling, P., et al. (2014). Iron status and the acute post-exercise hepcidin response in athletes. PLOS ONE, 9(3), e93002.
Owens, D. J., et al. (2015). Vitamin D and the athlete: current perspectives and new challenges. Sports Medicine, 45(3), 213–229.