Caffeine is the most common ingredient in pre-workout and provides the most significant performance enhancing effect. It’s so powerful that you can drink coffee as your pre-workout and see improvements in exercise performance. For example, extensive reviews found that it improves power in sprint performance by 6.5%, increased the number of reps performed in a set by 9.4%, improved endurance performance by 2.2%, and average power output during endurance activity by 2.9%. There aren’t many other supplements on the market that show strong evidence of performance improvements. Hence why it is a staple ingredient in a pre-workout. You often find doses of caffeine between 100-300mg per serving, and how much you need is dependent on your body weight and caffeine tolerance. Current evidence suggests anywhere from 3-6mg per kilogram of body weight is the sweet spot for the above performance improvements. That would be 210-420mg for a 70kg individual. It seems that it doesn’t matter whether you take 210 or 420mg, both result in similar performance enhancements. Suppose you are not a habitual caffeine user. In that case, you can take much less than 3 to 6mg per kilogram of body weight and still reap the benefits. Other ingredients such as taurine (which will be discussed next) will also reduce the dose needed for caffeine. Some pre-workouts will intentionally leave out caffeine, known as stim free pre-workouts. For those that train at night, these are often preferred as you get the benefits of the active ingredients without staying wired into the night, lying in bed with your eyes wide open.
Thyrene is often added to stim free pre-workouts to replace caffeine and traditional pre-workout supplements to work synergistically with caffeine. One study investigating energy drinks found the taurine doses between 71-3105mg reduce the need for higher doses of caffeine. Subjects needed only 40-325mg of caffeine, and the higher the dose of taurine leads to more significant performance increases, regardless of the caffeine dose. Look for pre-workouts that have taurine when possible.
Citrulline is often used as citrulline malate two-to-one. You can’t go wrong with either ingredient, as malate and citrulline work synergistically to potentially increase ATP production, which is the muscle’s energy source and reduce lactic acid buildup, prolonging fatigue. Citrulline malate has been shown to improve the number of reps when lifting, reduce muscle soreness 24 to 48 hours after lifting, improve maximal grip strength, increase time before exhaustion during endurance exercise, and reduce the feelings of muscle fatigue. If you’re wondering how citrulline malate works, it is a precursor to arginine, which converts into nitric oxide. This is more effective than taking arginine, as arginine is poorly absorbed in the gut, resulting in a little nitric oxide. Whereas citrulline is converted to arginine in the kidneys, leaving plenty of it to convert to nitric oxide. Nitric oxide is a vasodilator, meaning it expands the blood vessels. Most pre-workout underutilize this ingredient, however, lower doses when taken regularly also serve as a performance benefit, so a stim-free option taken daily can also be a great choice.
Beta alanine is another powerful pre-workout ingredient. It has been proven to extend high intensity exercise duration within the 1 to 4 minute range. Beta alanine works by increasing carnosine levels. With high intensity exercise, carnosine buffers hydrogen ions that accumulate alongside lactate. If these hydrogen ions are not buffered, they will accumulate within the muscle, making the environment very acidic. An acidic environment reduces the muscles ability to contract, therefore its ability to produce force, leading to fatigue. Essentially, you’ll be able to go harder for longer or rip out performance reps in the gym. Most likely, you’re looking at doses of 30mg per kilogram of body weight which, for a hypothetical 70 kg individual, would be 2.1g. Most pre-workouts have adequate doses of beta alanine to provide benefits. However, its real power is noticeable when taken daily in doses up to 6.4g per day. This will require pure beta alanine, however, not a pre-workout supplement. Be aware that the beta alanine causes a tingling sensation after taking your pre-workout. This is called parastia and is not harmful in any way. It can be uncomfortable if you’re not used to it, but it only lasts 20 to 30 minutes.
More and more pre-workouts are including betaine anhydrous as a main active ingredient. It doesn’t have as much research behind it as the other ingredients. Still, it has some promising benefits, such as increasing the number of reps performed by 6.5% and reducing the rise in lactate and hydrogen ions. Secondly, burdening may reduce the involvement of AMPK pathway, which increases the anabolic processes after exercise. The AMPK pathway inhibits the anaerobic mTOR pathway, so if betaine can down regulate the AMPK pathway, theoretically you can stay anabolic for a longer period. The current research suggests dosages of 2.5g split into two equal amounts each day. However, it seems the minimum effective dose ranges between 1 to 6g per day, where most pre-workouts are dosed.
Theanine in combination with caffeine in pre-workout supplements acts as a nootropic, also known as brain drugs. Generally, a 2:1 dose of theanine to caffeine is the optimal ratio. In addition, tyrosine also acts as a nootropic.
Finally, there’s Ginseng, which is becoming more common in the pre-workout landscape. Being a traditional Chinese medicinal product, it improves attention, mental health and dopamine.
So with all these ingredients how long does a pre-workout last? Caffeine has a half life of 4-6 hours after ingestion, citrulline’s maximum effect occurs 100 minutes after ingestion but may remain in the body up to 8 hours. So a pre-workout should last about 6 hours, but it kicks in 1-2 hours after ingestion.