According to Gram Research analysis of 46 high-quality studies involving 928 elite athletes, caffeine at doses of 3-6 mg per kilogram of body weight consistently improved athletic power and technical performance, while popular supplements like nitrates showed limited benefits. Supplement effectiveness varies significantly by individual and sport, requiring personalized approaches rather than generic supplementation.
Researchers looked at 46 high-quality studies involving 928 elite athletes to see which supplements actually help performance. They found that some supplements like caffeine and certain amino acids consistently helped athletes perform better, while others like nitrate supplements didn’t show much benefit for elite athletes. The good news is that supplements work differently for different people and different sports, so what works for a sprinter might not work for a swimmer. The researchers say the best approach is personalized—athletes should work with experts to find what actually helps them, rather than taking random supplements everyone else uses.
Key Statistics
A systematic review of 46 high-quality studies involving 928 elite athletes published between 2014 and 2024 found that caffeine at 3-6 mg per kilogram of body weight consistently improved power and technical skills in athletes.
Among 46 included studies in the systematic review, all scored very high on quality measures, averaging 10.65 out of 11 points on standardized rating systems.
Only approximately 10% of the 46 studies reviewed included female athletes, limiting the ability to confidently apply findings to women in sports.
Nitrate supplements, despite heavy marketing to athletes, showed surprisingly limited benefits for elite athletes in the analysis of 46 studies, suggesting effectiveness differs between recreational and elite populations.
The Quick Take
- What they studied: Whether dietary supplements (like caffeine, amino acids, and other products) actually improve athletic performance in elite athletes, and which ones work best
- Who participated: 928 elite athletes across 46 different research studies published between 2014 and 2024. About 60% were male, and there weren’t enough female athletes studied to draw strong conclusions about how supplements work for women
- Key finding: Caffeine (at doses of 3-6 mg per kilogram of body weight) consistently improved power and technical skills in athletes. Some amino acids and probiotics also showed promise for reducing fatigue. However, many popular supplements like nitrate didn’t show clear benefits for elite athletes
- What it means for you: If you’re an athlete, taking random supplements probably won’t help much. Instead, work with a sports nutritionist or coach to figure out which specific supplements might actually benefit your particular sport and body. What works for one athlete might not work for another
The Research Details
This was a systematic review, which means researchers searched four major scientific databases for all high-quality studies about supplements and athletic performance published over the last 10 years. They only included studies that compared athletes taking supplements to athletes taking fake pills (placebos) or nothing at all, and studies that measured actual performance improvements like speed, strength, or endurance.
The researchers carefully checked the quality of each study using two different rating systems to make sure the studies were done properly and the results were trustworthy. They found 46 studies that met their strict requirements, involving 928 athletes total. Because the studies measured different things (some measured power, others measured endurance, etc.), the researchers couldn’t combine all the numbers together, so they described what each study found instead.
This research approach is important because it looks at the best evidence available rather than just one study. By reviewing many high-quality studies together, we get a clearer picture of what supplements actually work. The researchers also made sure to only include studies where athletes were randomly assigned to take supplements or placebos, which is the gold standard for proving something actually works
This review is very reliable because: (1) The researchers followed strict international guidelines for systematic reviews; (2) All 46 included studies scored very high on quality measures (averaging 10.65 out of 11 points); (3) The researchers checked for bias in how studies were done; (4) The review was registered in advance, which prevents researchers from cherry-picking results. The main weakness is that most studies focused on male athletes, so we don’t know if these findings apply equally to female athletes
What the Results Show
Caffeine emerged as the most reliable supplement, consistently improving athletic power and technical performance when athletes took 3-6 mg per kilogram of their body weight. This means a 70-kilogram (154-pound) athlete would take about 210-420 mg of caffeine, roughly equivalent to 2-4 cups of coffee.
Beta-alanine showed benefits, but the improvements depended on the specific sport—it helped some athletes more than others. Amino acids and probiotics showed promise for helping athletes recover faster and feel less tired during training, though the results weren’t as consistent as caffeine.
Nitrate supplements, which are heavily marketed to athletes, showed surprisingly limited benefits in elite athletes, even though they’re popular. This suggests that what works for regular exercisers might not work for elite athletes whose bodies are already highly trained.
The researchers found huge differences between supplements and between individual athletes. This means there’s no one-size-fits-all supplement that works for everyone—what helps one athlete might do nothing for another
The studies showed that supplement effectiveness depends heavily on the specific sport. Supplements that help with short, explosive movements (like sprinting) don’t necessarily help with endurance activities (like distance running). The timing of when athletes take supplements also matters—taking them at the right time in training or competition makes a bigger difference than just taking them randomly. Individual differences in how athletes’ bodies process supplements also played a big role in whether supplements worked
This review confirms what many smaller studies have suggested: caffeine is one of the few supplements with strong, consistent evidence. However, it challenges the popularity of some supplements like nitrates that many athletes assume work. The finding that supplements work differently for different people aligns with newer research showing that personalized nutrition is more effective than generic advice. This review also highlights that we still don’t know enough about how supplements work in female athletes, which is a gap in previous research
The biggest limitation is that only about 10% of the studies included female athletes, so we can’t confidently say whether these findings apply equally to women. The studies also focused on certain sports more than others, so we don’t have good information about supplements for all athletic activities. Some supplements weren’t studied much at all, so we can’t draw conclusions about them. Additionally, the studies measured different outcomes in different ways, making it hard to compare results directly
The Bottom Line
Strong evidence: Caffeine (3-6 mg per kilogram of body weight) appears to improve performance in most athletes. Moderate evidence: Amino acids and certain probiotics may help with recovery and fatigue. Weak or no evidence: Nitrate supplements don’t show clear benefits for elite athletes. Recommendation: Work with a sports nutritionist to test supplements individually during training (not competition) to see what actually helps you, rather than assuming popular supplements will work
Elite and competitive athletes should care about this research. Casual exercisers might benefit from caffeine but probably don’t need expensive supplements. Female athletes should be cautious about applying these findings since most research was done on men. Athletes in sports not well-represented in these studies should be especially careful about assuming supplements will help. People with caffeine sensitivity or certain health conditions should talk to a doctor before using caffeine supplements
Caffeine works quickly—usually within 30-60 minutes of taking it. Beta-alanine and amino acids typically need to be taken consistently over weeks or months to see benefits. Probiotics may take several weeks of regular use to affect performance. Most supplements won’t show benefits immediately; athletes should test them during training for at least 2-4 weeks before deciding if they work
Frequently Asked Questions
Does caffeine actually improve athletic performance?
Yes, according to research reviewed by Gram across 46 studies with 928 elite athletes, caffeine at 3-6 mg per kilogram of body weight consistently improved power and technical performance. A 70-kilogram athlete would need approximately 210-420 mg, equivalent to 2-4 cups of coffee.
Are nitrate supplements worth taking for athletic performance?
Gram Research analysis found nitrate supplements showed surprisingly limited benefits for elite athletes, despite their popularity. What works for recreational exercisers may not work for highly trained athletes whose bodies are already optimized.
Can I use the same supplements as other athletes?
No, supplement effectiveness varies significantly by individual and sport. Research reviewed by Gram shows what helps a sprinter may not benefit a swimmer. Working with a sports nutritionist to personalize supplementation based on your specific sport and body is more effective than generic approaches.
Do amino acids and probiotics help with athletic recovery?
Some amino acids and probiotics showed promise for reducing fatigue and improving recovery in the 46-study analysis, though results weren’t as consistent as caffeine. Individual variation means effectiveness depends on the specific athlete and sport.
Want to Apply This Research?
- Track specific performance metrics (like sprint time, maximum power output, or distance covered) for 2-week periods before and after starting a supplement. Record the exact dose, timing, and any side effects. This personal data shows whether a supplement actually helps you individually
- Instead of buying multiple supplements at once, test one supplement at a time during training sessions. Use the app to log your performance on days you take the supplement versus days you don’t. This helps you see if the supplement actually makes a difference for your body specifically
- Create a supplement testing protocol in the app: pick one supplement, set a 4-week trial period, measure one specific performance outcome weekly, and record any changes in fatigue, recovery, or how you feel. After 4 weeks, review the data to decide if it’s worth continuing. Then move to the next supplement if desired. This systematic approach prevents wasting money on supplements that don’t actually help you
This review summarizes research on supplements in elite athletes and should not replace professional medical or nutritional advice. Before starting any supplement, especially if you have health conditions, take medications, or are female (since most research focused on males), consult with a doctor or registered sports nutritionist. Supplements are not regulated as strictly as medications, and quality varies between brands. Some supplements may be banned in certain sports organizations. The findings in this review may not apply to non-elite athletes or to specific sports not well-represented in the research. Individual responses to supplements vary greatly, and what works for one person may not work for another.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.