At a glance:
- Creatine (3–5 g/day), whey protein and caffeine are the sports supplements with the strongest scientific evidence.
- The optimal protein intake for strength sports is at least 1.6 g per kilogram of body weight per day.
- Caffeine (3–6 mg/kg, 45–60 min before training) improves both endurance and strength performance.
- Most fat burners and testosterone boosters lack sufficient scientific evidence.
The scientific evidence for sports supplements is growing rapidly, but marketing claims often outstrip their actual effectiveness. This guide aims to give you a clear, research-based overview of which supplements really work, at what doses and for whom. We draw on position stands from the International Society of Sports Nutrition (ISSN) and randomized controlled trials indexed in PubMed.
Which sports supplements are backed by scientific evidence?
The ISSN divides sports supplements into three categories according to their effectiveness: those with strong evidence, those with moderate evidence and those with insufficient evidence. Creatine, caffeine, whey protein and beta-alanine fall into the category with strong evidence.
Creatine is the most extensively studied supplement for strength and power sports. In the ISSN position stand, Kreider et al. (2017) recommend 3–5 g of creatine monohydrate per day for long-term use. Creatine increases phosphocreatine stores in your muscles, improving explosive strength during short bursts of activity — particularly important in sports that require maximum strength for one repetition, such as competitive bench press, covered in the 16th Estonian Bench Press Championships – guidelines.
Beta-alanine increases muscle carnosine levels, which buffer the lactic acid produced during training. A meta-analysis of 22 studies by Hobson et al. (2012) showed that taking 4–6 g of beta-alanine per day for at least 4 weeks significantly improves performance in efforts lasting 60–240 seconds (Hobson et al., 2012). Temporary tingling of the skin (paresthesia) is a harmless side effect, not a warning sign.
How much protein should an athlete consume per day?
Adequate protein intake is the foundation of muscle growth and recovery. A systematic review and meta-analysis of 49 randomized controlled trials (n ≈ 1,800) by Morton et al. (2018) found that the optimal protein intake for strength training is at least 1.6 g/kg of body weight per day (Morton et al., 2018). Older adults (over 40 years of age) may need 1.8–2.2 g/kg per day for muscle protein synthesis, as the anabolic response to amino acids declines with age.
In the ISSN position stand, Jäger et al. (2017) recommend spreading your protein intake across 3–4 meals, each containing 20–40 g of high-quality protein (Jäger et al., 2017). Whey protein is an excellent choice immediately after training because it is absorbed quickly; casein is the best choice before bed. You can find answers to common questions in our Questions and answers: supplements article.
Does caffeine improve athletic performance?
Caffeine is one of the few supplements with well-established benefits in both endurance and strength sports. The ISSN position stand by Goldstein et al. (2010) recommends a dose of 3–6 mg/kg of body mass 45–60 minutes before training (Goldstein et al., 2010). Caffeine works primarily by blocking adenosine receptors, reducing feelings of fatigue and improving concentration.
Caffeine is well suited to athletes in sports that combine strength and endurance — for example, those practicing the disciplines described in Kettlebell biathlon – guidelines, which require both explosive strength and sustained endurance. Its stimulant effect may diminish in regular caffeine users; a 1–2-week break before an important competition helps restore sensitivity.
Which supplements should beginner athletes avoid?
Many supplements on the market lack reliable scientific evidence. The NIH Office of Dietary Supplements warns that the actual clinical benefits of many fat burners, testosterone boosters and exotic herbal blends are minimal or unproven — some may even harm your health through interactions.
If you are a beginner, we recommend starting with three basic supplements backed by strong evidence: protein, creatine and, if needed, caffeine. More complex formulations require a clear understanding of your training goals and health status — for an example of a structured approach to training, see the Alfa 2010 guidelines.
References
- Kreider et al. (2017). International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. PMID: 28642676
- Jäger et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. PMID: 28642428
- Goldstein et al. (2010). International society of sports nutrition position stand: caffeine and performance. J Int Soc Sports Nutr. PMID: 20205813
- Morton et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. PMID: 28698222
- Hobson et al. (2012). Effects of β-alanine supplementation on exercise performance: a meta-analysis. Amino Acids. PMID: 22090168
Frequently asked questions
What is the best way to take creatine?
The most effective and extensively studied form is creatine monohydrate at a dose of 3–5 g per day. A loading phase (20 g per day for 5–7 days) speeds up muscle saturation but is not essential — consistently taking 3–5 g per day achieves the same result within a few weeks (Kreider et al., 2017).
When is the best time to consume protein?
The optimal time to consume whey protein is within 1–2 hours after training. However, research shows that your total daily protein intake (1.6–2.2 g/kg) matters more than the exact timing (Jäger et al., 2017). Casein before bed supports overnight muscle recovery.
Is caffeine suitable for all athletes?
Caffeine is suitable for most athletes. Exceptions include people with heart rhythm disorders, anxiety disorders or uncontrolled high blood pressure, who should consult a doctor first. Individual tolerance varies considerably due to genetic differences — some people experience little stimulant effect from caffeine.
Is the tingling caused by beta-alanine harmful?
No, paresthesia, or tingling of the skin, is a harmless, temporary side effect. To reduce it, split your daily dose into several smaller doses (e.g. 2 × 2 g) or choose a sustained-release formulation.
Can supplements replace a healthy diet?
No. Supplements complement a varied, balanced diet, but they cannot replace the nutrients, dietary fiber and phytonutrients found in natural foods. Your regular diet should meet your needs for both macronutrients and micronutrients; supplements are intended to fill specific gaps.
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