Several supplements have strong evidence behind them for improving exercise performance, but the best choice depends on the type of exercise you do. Creatine, caffeine, beta-alanine, dietary nitrates, and a few others each target different energy systems in your body, so they shine in different situations. Here’s what works, how much to take, and when it matters most.
Creatine for Strength and Power
Creatine monohydrate is the most studied performance supplement in existence, and the evidence is overwhelming. It works by replenishing your muscles’ fastest energy source, the one your body burns through during short, explosive efforts like sprinting, jumping, or lifting heavy weights. When your muscles store more creatine, you can sustain high-intensity output for a few extra seconds per set, and those seconds add up over weeks of training.
In a 35-day trial comparing creatine users to a placebo group, participants taking creatine improved their one-rep max strength by about 20%, nearly double the 10% gain seen in the placebo group. That gap is significant for anyone doing resistance training. The standard protocol is 3 to 5 grams per day, taken consistently. Unlike most supplements on this list, creatine doesn’t need precise timing before a workout. It builds up in your muscles over days and weeks, so daily consistency matters more than when you take it.
Creatine is less useful for long, steady-state cardio like a slow jog or easy bike ride. Its benefits are concentrated in efforts lasting roughly 30 seconds or less per burst, which makes it ideal for weight training, sprinting, and interval work.
Caffeine for Nearly Every Type of Exercise
Caffeine is the closest thing to a universal performance booster. It improves strength, power, aerobic endurance, and muscular endurance across a wide range of activities. It works primarily by blocking the receptors in your brain that signal fatigue, which lets you push harder and perceive the same effort as easier.
What’s interesting is how little you actually need. A meta-analysis of 12 studies found that doses as low as 0.9 to 2 mg per kilogram of body weight produced meaningful improvements in muscular strength, muscular endurance, and movement velocity. For a 70 kg (154 lb) person, that’s roughly 60 to 140 mg, or about one small cup of coffee. Higher doses in the range of 3 to 6 mg/kg are commonly used in research, but the lower end still works.
Timing matters with caffeine. Consuming it about 45 minutes before exercise gives blood levels enough time to peak. If you’re a regular coffee drinker, you may need a dose toward the higher end of the range to feel the same effect, since habitual use builds some tolerance.
Beta-Alanine for Sustained High Intensity
Beta-alanine fills a specific niche: exercises that last roughly one to four minutes at near-maximum effort. Think 400- or 800-meter runs, longer swimming races, rowing intervals, or high-rep sets that push you to the brink. During these efforts, your muscles produce large amounts of acid as a byproduct of burning fuel without enough oxygen. That acid buildup is a major reason your muscles burn and eventually give out.
Beta-alanine works by increasing levels of a buffering molecule called carnosine inside your muscle cells. Carnosine soaks up excess acid, keeping muscle pH more stable and delaying that burning sensation. The catch is that beta-alanine, like creatine, needs to be loaded over time. Most protocols call for 3 to 6 grams daily for at least two to four weeks before you’ll notice a difference. A common side effect is a harmless tingling sensation on your skin, especially at higher single doses, which is why many people split it into smaller portions throughout the day.
If your training is purely low intensity or purely short bursts under 30 seconds, beta-alanine won’t offer much. Its sweet spot is that painful middle zone where acid accumulation is the primary limiter.
Dietary Nitrates for Endurance Efficiency
Beetroot juice has become a go-to supplement for endurance athletes, and the reason is nitrate. Your body converts dietary nitrate into nitric oxide, a molecule that widens blood vessels and improves how efficiently your muscles use oxygen. The practical effect is striking: one study published in the Journal of Applied Physiology found that six days of beetroot juice supplementation reduced the oxygen cost of moderate exercise by about 19 to 20%. Participants also lasted significantly longer during high-intensity cycling, extending their time to exhaustion from an average of 583 seconds to 675 seconds.
That roughly 16% improvement in time to exhaustion is a massive margin for an endurance athlete. The study used 500 ml of beetroot juice per day, containing about 11 millimoles of nitrate. Concentrated beetroot shots, which are widely available, deliver a similar dose in a smaller volume. Nitrate-rich foods like spinach, arugula, and celery also contribute, though it’s harder to hit consistent doses through whole foods alone.
Nitrate supplementation appears most beneficial for submaximal, steady-state exercise, the kind of effort involved in distance running, cycling, or swimming. It’s less clear whether it helps during very short sprints.
Citrulline Malate for Resistance Training Volume
Citrulline malate works differently from the supplements above. It’s an amino acid compound that your body converts into arginine and then nitric oxide, improving blood flow to working muscles. It also plays a role in clearing ammonia, a waste product of intense muscular work. The net result is that you can squeeze out a few more reps per set before fatigue sets in.
A systematic review and meta-analysis found that taking 6 to 8 grams of citrulline malate 40 to 60 minutes before resistance training increased total repetitions by an average of about 6.4% compared to placebo. That may sound modest, but extra reps across multiple sets and multiple exercises compound into meaningfully more training volume over a session, which is a key driver of muscle growth over time. Some research also suggests it may reduce post-exercise muscle soreness, though findings on that point are mixed.
Sodium Bicarbonate for Short, Intense Bursts
Sodium bicarbonate, essentially baking soda, acts as a buffer similar to beta-alanine but works outside the muscle cell rather than inside it. It neutralizes acid in the bloodstream, which indirectly helps pull acid out of the muscles during intense efforts. Research has shown that a dose of 0.3 grams per kilogram of body weight, taken about 90 minutes before exercise, improves total work output in repeated sprint protocols and benefits sports that rely heavily on burning fuel anaerobically: sprinting, middle-distance running, combat sports, and similar activities.
The downside is gastrointestinal distress. Many people experience nausea, bloating, or cramping at effective doses. Taking it with a carbohydrate-rich meal and plenty of water helps, and some athletes use smaller doses spread over a longer pre-exercise window. If your stomach can handle it, sodium bicarbonate is one of the most effective legal performance aids for events lasting one to seven minutes.
Electrolytes and Hydration During Prolonged Exercise
Electrolyte supplementation isn’t flashy, but losing too much sodium and fluid during exercise will tank your performance faster than any supplement can rescue it. During prolonged or heat-exposed exercise, your body loses both water and sodium through sweat, and replacing only water without electrolytes can dilute your blood sodium to problematic levels.
A practical guideline is to drink roughly 200 to 300 ml of fluid every 15 minutes during exercise. For sessions lasting over an hour, a sports drink containing about 6% carbohydrate concentration improves both fluid absorption and energy availability. Going above 8% carbohydrate concentration tends to cause stomach problems. If you notice white salt stains on your clothing after workouts, you’re likely a heavy sodium sweater, and adding extra salt to meals or drinks is worth considering. Carbohydrates in your drink actually speed up sodium absorption in the gut, which in turn helps your body hold onto water more effectively.
Matching Supplements to Your Training
The most important thing is matching the supplement to the type of exercise you actually do. Here’s a quick breakdown:
- Weight training and sprints (under 30 seconds): Creatine and caffeine are your strongest options. Citrulline malate adds value for higher-rep training.
- Sustained high-intensity work (1 to 4 minutes): Beta-alanine and sodium bicarbonate target this zone directly. Caffeine still helps.
- Endurance exercise (longer than 10 minutes): Dietary nitrates, caffeine, and proper electrolyte replacement offer the most benefit.
Stacking supplements is common and generally fine when done sensibly. Caffeine pairs well with nearly everything on this list. Creatine and beta-alanine are often taken together since they work through completely separate mechanisms. The key is starting with one, observing whether it makes a noticeable difference, and then adding others if your goals call for it.