Sports supplements: what really works for performance and recovery
In brief
Very few supplements live up to their promises. For performance, only five have real evidence: creatine, caffeine, nitrate (beetroot), beta-alanine and bicarbonate. For recovery and muscle, it is protein first. The rest mainly serves to correct a deficiency (iron, vitamin D) — or is frankly overrated (BCAAs, glutamine). None of them replaces training, sleep and what is on your plate.
Key facts
Key points
- An international consensus recognises only four families with “good evidence” of a performance gain: caffeine, creatine, buffering agents (bicarbonate, beta-alanine) and nitrate.
- Creatine is the best-studied supplement: it increases strength and power on short efforts, and supports muscle mass.
- For muscle, protein comes before “magic” powders; aim for around 1.6 g/kg/day in total, diet included.
- Iron, vitamin D and magnesium are justified to correct a deficiency or for a normal function, not to “dope yourself”.
- A supplement can be contaminated with a doping substance: quality and certification matter as much as composition.
The sports-supplement aisle promises everything to athletes and fitness enthusiasts: more strength, more energy, lightning-fast recovery. The reality is more sober. When experts from the International Olympic Committee reviewed these products, they kept only a handful with real evidence of a performance gain — the rest ranging from “maybe useful in some cases” to “no demonstrated effect”[1].
This article sorts things out, without indulgence: what works for performance, what really helps recovery and muscle, what only serves to correct a deficiency, and what is simply overrated. Every claim is based on verified studies, with a word of honesty about how strong the evidence is. A dietary supplement neither prevents, treats nor cures any disease: this text informs, it does not replace the advice of a doctor or a sports nutritionist.
Before supplements: the foundation that does 90% of the work
The supplement is the icing — not the cake
No supplement makes up for poorly built training, nights that are too short or a careless diet. Even the best-studied ones add only a few per cent of performance on top of an already solid foundation. If that foundation is missing, the most expensive powder compensates for nothing. This is the first thing to bring into your routine before spending a single franc on supplements.
That foundation comes down to three words: train, sleep, eat. Progress is built during recovery, not during the session — a topic we cover in detail in our guide to the four pillars of sports recovery. Until these foundations are in place, supplements remain a detail.
The plate comes before the shop
Most of an amateur athlete’s needs are covered on the plate: carbohydrates to replenish energy (glycogen) stores, varied protein to repair muscle, fruit and vegetables for micronutrients. A supplement is justified when a specific need is not covered — an intake that is hard to reach, a confirmed deficiency, or a targeted ergogenic effect for competition. Not “just to be safe”, just in case.
The right reflex
Before adding a supplement, ask yourself three questions: is my training consistent? Am I sleeping enough? Am I eating enough and varied? If the answer is “no” to any of them, that is where the real lever is — not in a new tub.
Performance: the 5 supplements that have really proven themselves
Of the hundreds of products sold to athletes, the International Olympic Committee consensus recognises only a small group — the genuinely effective supplements — with solid evidence of a direct improvement in sports performance: caffeine, creatine, buffering agents (bicarbonate and beta-alanine) and nitrate[1]. Here is what each one does, and for what type of effort.
Creatine: the best-supported supplement
No sports supplement is as well studied as creatine — and the evidence is solid. It increases the muscle’s rapid energy stores and reliably improves performance on short, intense efforts: more maximal strength, more power, a few extra reps. Combined with strength training, it also supports muscle mass gains and a leaner body composition[2]. The usual dose is 3 to 5 grams a day of monohydrate, the cheapest and best-tested form.
Two honest caveats. First, creatine does not help pure endurance: a marathon runner will get nothing measurable from it. Second, some people respond little (the “non-responders”), and the weight gain of the first few days is mostly water stored in the muscle, not fat.
Caffeine: the ally of endurance and concentration
Caffeine is the other safe bet. It stimulates the central nervous system, which makes it the star ingredient of pre-workout formulas. Taken about an hour before exercise (3 to 6 milligrams per kilo of body weight), it improves endurance, strength and speed, and above all it reduces the perception of effort: the same intensity feels less hard[3]. Endurance benefits the most. A well-dosed strong coffee already does the job — no need for capsules.
The response varies from one person to another, partly for genetic reasons. Beyond about 9 mg/kg, you gain nothing more and mostly reap the side effects: jitteriness, tremors, disturbed sleep. More is not better.
Beta-alanine: for efforts that “burn”
Beta-alanine raises muscle carnosine, a molecule that helps buffer the acid produced during high-intensity exercise. The result: a modest improvement in exercise capacity and muscle endurance, especially for very hard efforts lasting between one and four minutes — typically a 400 or 800 metres, a long, gruelling set[4][15]. For efforts of less than a minute, it brings nothing. The real effect is small, and it often causes harmless skin tingling.
Nitrate (beetroot juice): an endurance boost
Nitrate, found in beetroot juice, promotes blood flow by relaxing the blood vessels (the mechanism also studied for blood pressure) and helps the body use oxygen more efficiently. Studies associate it with a moderate improvement in endurance, especially in untrained or moderately trained people; in elite athletes, the effect fades[5]. The evidence is more variable than for creatine or caffeine, hence a cautious verb: it may help, but it is not guaranteed.
Sodium bicarbonate: the buffer for intense efforts
An old kitchen remedy, sodium bicarbonate acts as a buffer in the blood and improves intense efforts of one to a few minutes[6]. The effect is small to moderate — and the downside is well known: frequent digestive upsets. It must be tested in training before any competition, never on the day itself for the first time.
| Supplement | For which effort | What science shows | Good to know |
|---|---|---|---|
| Creatine | Strength, power, muscle | Improves short, intense efforts; supports muscle mass. | 3–5 g/day; pointless for pure endurance. |
| Caffeine | Endurance, alertness | Improves performance and reduces the perception of effort. | 3–6 mg/kg, ~1 h before; variable response. |
| Beta-alanine | Intense efforts 1–4 min | Modestly improves exercise capacity. | Small effect; skin tingling common. |
| Nitrate (beetroot) | Endurance | Associated with a moderate gain, especially in the less trained. | Variable effect; less clear in elite athletes. |
| Sodium bicarbonate | Intense efforts 1+ min | Small to moderate buffering effect. | Digestive upsets; test it in training. |
Recovery and muscle: protein first
Protein, the real basis of muscle building
To repair and build muscle, nothing replaces protein. A large analysis pooling 49 trials showed that, combined with strength training, it increases gains in strength and mass — but the benefit plateaus at around 1.6 grams per kilo of body weight per day[7]. Beyond that, taking more brings nothing extra. It is the total daily intake that counts, diet included — not just the powder. Adequate protein supports muscle protein synthesis, the process behind muscle repair and growth.
Whey (milk protein) — and its isolate version, purer and low in lactose — simply remains a convenient way to reach this total when the plate falls short: quick, easy to digest, rich in amino acids. But eggs, fish, meat, dairy or pulses do the same job. The powder is a supplement, not a substitute for a meal.
Omega-3 and tart cherry: a boost to recovery
Two supplements show real, if modest, value for muscle recovery after exercise. Omega-3s (fish oils) reduce muscle soreness and perceived muscle fatigue, ease markers of exercise-induced muscle damage after a gruelling effort, and slightly improve the return of strength[9] — though the data remain heterogeneous. Tart cherry juice (Montmorency) also has a small to moderate effect on soreness and strength recovery after exercise, especially if taken a few days beforehand[10]. Useful around a competition or a big training block, with no miracle to expect.
BCAAs and glutamine: the aisle’s false friends
Here are the marketing stars that disappoint on analysis. BCAAs (branched-chain amino acids) are sold as essential to recovery, but a complete protein — milk, whey, egg — does better: muscle building needs all the essential amino acids, not just three. The literature does not justify taking isolated BCAAs when protein intake is already adequate[8]. The same verdict applies to glutamine: in healthy athletes, no benefit for performance or recovery is demonstrated, and its often-claimed role in immune function is not established for sport either[8]. Better to put that budget into real protein.
Hydration: when water is no longer enough
Under an hour of effort, water does the job
For a short session, plain water is more than enough: no need to bring out the coloured drink. The difference between a sweet-and-salty drink and water only becomes worthwhile on prolonged efforts, beyond about an hour[14]. Below that, an isotonic drink is mostly a matter of comfort or taste.
Beyond an hour: electrolytes and carbohydrates
On long efforts, a drink containing carbohydrates and electrolytes (especially sodium) can bring a real benefit compared with water alone: it maintains energy, encourages you to drink, and helps limit dehydration[14]. The goal is not to lose more than 2% of your body weight in water — the threshold beyond which performance and temperature regulation start to deteriorate.
Water and sodium needs vary enormously from one person to another: there is no universal recipe. And beware of the opposite excess — drinking too much plain water on a very long effort can, rarely, dilute the blood’s sodium dangerously. The sodium in the drink also helps avoid this trap.
Correcting a deficiency, not “doping”: iron, vitamin D, magnesium
Some supplements only help if you are lacking in something. In a person with normal status, they bring nothing measurable — and in excess, they can even be harmful. The right reflex: check before supplementing, ideally with a blood test.
Iron: decisive in case of deficiency, useless otherwise
Iron carries oxygen in the blood: lacking it drags down endurance. In deficient (but not yet anaemic) women, supplementation increased endurance performance[13]. The nuance is crucial: this benefit exists only in deficient people. The most affected populations are women and endurance athletes. Iron “contributes to normal oxygen transport in the body” and “to the reduction of tiredness and fatigue” — but it should not be taken blindly: an excess is toxic. Blood test first.
Vitamin D: watch out especially in winter
Vitamin D deficiency is common in athletes, particularly in winter and at our latitudes, for lack of enough sunlight. It plays a role in bone health and muscle function: vitamin D “contributes to normal muscle function”[12]. Here too, correcting a deficiency is plausibly useful; on the other hand, adding more when the level is already good brings no demonstrated performance gain. A blood test tells you where you stand.
Magnesium: useful for muscle function, not an anti-cramp remedy
Magnesium is often sold as the solution to cramps. But science does not follow: a landmark Cochrane review concludes that it is unlikely that supplementation usefully prevents muscle cramps in adults[11]. So there is no point expecting a reliable anti-cramp effect from it. Magnesium does, however, have genuine recognised functions: it “contributes to normal muscle function”, to “electrolyte balance” and to “the reduction of tiredness and fatigue” — claims authorised in Switzerland and the European Union. It is from this angle, and not as a cramp remedy, that it has its place.
The cramp myth
“Got cramps? Take magnesium”: this very widespread advice is not supported. In adults, magnesium supplementation does not reliably reduce cramps compared with a placebo[11]. Frequent cramps deserve to have their cause investigated (hydration, unusual effort, sometimes medical advice) rather than an automatic “magnesium” reflex.
Choosing well: quality, safety and false friends
The overlooked risk: contamination
A supplement is not just a question of efficacy: it is also a question of safety. Some products on the market contain, through negligence or fraud, undeclared substances — sometimes stimulants or compounds appearing on anti-doping lists. For a tested athlete, a poorly controlled tub can cost a suspension. Favour transparent brands, manufactured within a regulated framework (in Switzerland, compliant with Annex 14 of the Swiss Food Information Ordinance, OIDAl) and, for competition, products tested by an independent third party.
More is not better
Stacking supplements “just in case” does not make you more performant — it mostly weighs on the bill, and sometimes on digestion. This is the case with antioxidants: intense effort produces free radicals — that is oxidative stress — but swallowing high doses of antioxidants (vitamin C, vitamin E) brings no proven performance benefit, and the plate (fruit and vegetables) already covers the essentials. Better a few well-chosen products for a real need than a medicine cabinet. And be wary of promises that are too good: a supplement that swears “instant energy”, a “fat-burner” or a “guaranteed” result overplays what science allows it to say.
- 1Start with the foundation: consistent training, sleep, sufficient and varied diet.
- 2Target a specific need: a proven performance effect (creatine, caffeine…) or a deficiency confirmed by a blood test (iron, vitamin D).
- 3Check quality: origin, brand transparency, a clear ingredient list, anti-doping certification for competition.
- 4In case of doubt, an ongoing treatment or a medical condition, consult a healthcare professional before starting any new supplement (doctor or sports nutritionist).
Frequently asked questions
Which supplements are really worth it for an athlete?
Very few, in reality. For performance, an international consensus recognises only five safe bets: creatine, caffeine, nitrate (beetroot juice), beta-alanine and sodium bicarbonate. For muscle and recovery, it is protein first. Iron, vitamin D or magnesium only serve to correct a deficiency or support a normal function. Everything else — BCAAs, glutamine, various “burners” — is overrated. And none of them replaces training, sleep and diet.
Is creatine dangerous for your health?
No, not at the usual doses in a healthy person. Creatine is the most studied sports supplement, and its safety is established at 3 to 5 grams a day of monohydrate. The weight gain of the first few days is water stored in the muscle, not fat, and the idea that it “damages the kidneys” in a healthy person is not confirmed. If you have kidney disease or are on medication, ask a doctor before taking it.
Do you need BCAAs for strength training?
In most cases, no. BCAAs provide only three amino acids, whereas building muscle requires the full set. A complete protein — whey, milk, egg, meat — does better, and the literature does not justify taking isolated BCAAs when protein intake is already sufficient. If you eat enough protein over the day, BCAAs add nothing: better to keep that budget for real protein.
Does magnesium really help against cramps?
Not reliably. A landmark Cochrane review concludes that it is unlikely magnesium supplementation usefully prevents muscle cramps in adults. Magnesium has other recognised functions — it contributes to normal muscle function, to electrolyte balance and to the reduction of tiredness and fatigue — but it is not an anti-cramp remedy. Frequent cramps deserve to have their cause investigated rather than automatically relying on magnesium.
Is whey essential for building muscle?
No, it is only convenient. What matters is total protein intake over the day — around 1.6 grams per kilo of body weight is enough to maximise gains with strength training. Whey is a simple, quick way to reach this total when your plate falls short, but eggs, fish, dairy or pulses do the same job. It is a supplement, not a must.
When should you drink an isotonic drink rather than water?
Mainly beyond an hour of effort. Below that, plain water is more than enough. On long efforts, a drink with carbohydrates and sodium maintains energy, encourages you to drink and helps limit dehydration — the goal being not to lose more than 2% of your body weight in water. Needs vary a lot from one person to another; and drinking too much plain water on a very long effort can, rarely, become risky.
Is coffee enough to improve performance?
Yes, in many cases. The effect of caffeine on endurance and perception of effort is well demonstrated, and a well-dosed coffee taken about an hour before exercise already does the job — the useful dose is 3 to 6 milligrams per kilo of body weight. There is no point aiming for high doses: beyond that, you gain nothing more and mostly reap jitteriness, tremors and disturbed sleep. The response also varies from one person to another.
Can supplements cause you to fail an anti-doping test?
Yes, it is a real risk. Some supplements contain, through negligence or fraud, undeclared substances that appear on anti-doping lists. For a tested athlete, a poorly controlled product can lead to a suspension, even without any intention to cheat. The safeguard: choose transparent brands, manufactured within a regulated framework, and, for competition, favour products tested by an independent body.
Sources and references (verified on PubMed)
15 sources- Maughan R.J. et al. (2018). IOC consensus statement: dietary supplements and the high-performance athlete.
- Kreider R.B. et al. (2017). ISSN position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine.
- Guest N.S. et al. (2021). ISSN position stand: caffeine and exercise performance.
- Saunders B. et al. (2017). β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis.
- Hoon M.W. et al. (2013). The effect of nitrate supplementation on exercise performance in healthy individuals: a systematic review and meta-analysis.
- Saunders B. et al. (2022). Sodium bicarbonate supplementation and the female athlete: a brief commentary with small scale systematic review and meta-analysis.
- Morton R.W. et al. (2018). Effect of protein supplementation on resistance training-induced gains in muscle mass and strength.
- Master P.B.Z., Macedo R.C.O. (2021). Effects of dietary supplementation in sport and exercise: a review of evidence on milk proteins and amino acids.
- Yaghoobi E. et al. (2026). Effects of LC-ω3 PUFA supplementation on muscle pain, function, and damage markers following exercise: a systematic review and meta-analysis of RCTs.
- Hill J.A. et al. (2021). Tart cherry supplementation and recovery from strenuous exercise: a systematic review and meta-analysis.
- Garrison S.R. et al. (2020). Magnesium for skeletal muscle cramps.
- de la Puente Yagüe M. et al. (2020). Role of vitamin D in athletes and their performance: current concepts and new trends.
- Pompano L.M., Haas J.D. (2019). Increasing iron status through dietary supplementation in iron-depleted, sedentary women increases endurance performance.
- Sawka M.N. et al. (2007). ACSM position stand: exercise and fluid replacement.
- Hobson R.M. et al. (2012). Effects of β-alanine supplementation on exercise performance: a meta-analysis.