Podcast: all about pre-workouts With Kurtis Frank

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Pre-workout boosters (PWOs) are the most popular supplements among bodybuilders, after protein and creatine. They are meant to give you ‘something extra’ during your training. But which ingredients should be in a good PWO and in which doses? Supplements expert Kurtis Frank sheds his light on it in a conversation with coach and author Mike Matthews. Frank is co-founder of Examine.com, the online reference when it comes to supplements. We have summarized the most interesting topics from the podcast for you (video below).


A pre-workout is a supplement that you take before your workout with the aim of improving that workout, or improving the results of that workout. Most ingredients either have an effect on strength (maximum strength, so your 1RM) or on strength endurance.


For strength (aerobic energy), these are caffeine, creatine and alpha-GPC. For endurance (anaerobic energy) citrulline malatebeta-alanine and betaine.

Creatine indirectly saves glycogen (the energy in your muscles), so that you can do an extra repetition in the range of 6 to 10 repetitions. With creatine you become a little stronger and you can do a little more repetitions.


That’s right; in theory it is even better to take creatine after training. But for 90 percent of users, the time of intake doesn’t matter, as long as you ingest 5 grams of the stuff at some point each day. But creatine is certainly not a supplement that you should take immediately before training.


Yes, but the stimulating effect on training is only there if your body is not used to caffeine. That while the negative effect on sleep is always there, even if you are a frequent user.

Caffeine can greatly increase your strength performance. We see increases in 1RM on deadlifts and squats of up to 15 percent. But the big disadvantage is the habituation.

Caffeine has a so-called insurmountable tolerance: once your body is used to a certain dose, for example 200 milligrams per day, caffeine will no longer offer you any benefits in terms of strength, even if you take a (much) higher dose.

To benefit from caffeine during strength training, you should only take it once every two weeks. The rest of the time you should therefore not consume coffee or other caffeinated products, at most one cup of green tea per day. The result is one great workout every two weeks, but at the cost of a further caffeine-free existence. The effective dose for that workout is a minimum of 400 milligrams, increasing to 600 milligrams for heavyweights.

So is pre-workout caffeine intake completely useless for coffee drinkers? Not that per se. Even if you are used to it, caffeine will increase your alertness, which can positively influence your exercise performance. And which, as mentioned, is bad for your sleep, why you should not take caffeine late at night, even as an inveterate coffee drinker.


Alpha-GPC (choline alfoscerate) is a natural choline compound found in the brain. It is much less well researched as a supplement than caffeine and its effect also appears to be weaker, but alpha-GPC probably does not induce habituation. As a result, you could take it before any workout to benefit your strength performance.

Alpha-GPC is a precursor of choline, and therefore also acetylcholine. Acetylcholine is a neurotransmitter that is important in the control of muscles by the brain. Alpha-GPC enters the brain relatively quickly after ingestion. The temporary surplus of acetylcholine ensures that you can contract your muscles more powerfully. The temporary is important here: if you have a surplus of acetylcholine throughout the day, your body gets used to it. By taking only a small amount before training, your body uses it for a boost.

Due to the limited research it is still unclear what the most optimal dose of alpha-GPC is. For strength athletes, 600 milligrams seems to be an appropriate amount, to be taken 30-45 minutes before training. Alpha-GPC may be less well absorbed if you also consume dairy with slowly digestible proteins (such as casein) around the time of its intake .

Editor’s Note: alpha-GPC is a relatively expensive supplement and the main study of its effects on strength athletes was supported by US nutrition company ChemNutra, which does not rule out any conflict of interest. 


Supplementation with citrulline malate increases the levels of nitric oxide (NO) in your body. This widens your blood vessels and allows more oxygen and nutrients to be transported to your muscles. This provides slightly more anaerobic energy during strength training, allowing you to do an extra rep in the 5-10 rep range. In principle, all substances that increase nitric oxide have this effect, for example also l-arginine. Only citrulline malate is absorbed much better, so you really notice it.

Another function of nitric oxide is to activate satellite cells, the stem cells of muscle tissue. These can ‘specialize’ into new muscle cell nuclei and thus help with the growth, maintenance and repair of (damaged) muscle tissue. Citrulline malate can therefore indirectly, via NO, stimulate the process of muscle growth.

8 grams is usually recommended as an effective dose, but 6 grams is probably sufficient. Take citrulline malate 30-45 minutes before your workout. However, the effect is only noticeable later in your training, when you are already a bit tired.

Editor’s Note: citrulline Malate is underdosed in most pre-workouts.


Beta-alanine was sometimes referred to as creatine 2.0, but we now know that it doesn’t do much for maximum strength. Supplementation with beta-alanine is an effective way to increase the concentrations of carnosine in the muscles. Carnosine counteracts the so-called acidification in your muscles, the accumulation of lactic acid that the body produces during heavy exertion of medium duration. Specifically, beta-alanine can help you with efforts of 2 to 3 minutes. The effect is therefore only noticeable with more metabolic strength training, such as very long sets (dropsets, supersets, metabolic finishers), circuit training and sets with very short rest breaks (20 seconds, for example), such as with German Volume Training .

During regular strength training, in which you usually do sets of 6-15 repetitions, beta-alanine is not of much use. In addition, it does not work acutely; the maximum effect is often only reached after weeks, regardless of the timing of intake. It’s all the more striking that beta-alanine is so common in pre-workouts for bodybuilders. But beta-alanine may also have a direct effect on muscle growth, in addition to improving exercise performance. However, this is still unclear and little researched.

By the way, beta-alanine is the component of pre-workouts that causes the well-known tingling. Although harmless, this ‘side effect’ is not experienced as pleasant by everyone. You can prevent it by taking beta-alanine in smaller doses, spread over the day. The recommended daily dose is 2-5 grams.


Betaine is an amino acid from an extract of the sugar beet. Just like beta-alanine, supplementation with 3 to 6 grams can improve muscle endurance (slightly). According to some studies, betaine supplementation also has a direct positive effect on muscle growth, for example by increasing the activity of IGF-1 and anabolic signaling molecules in muscle cells. However, all these studies have been funded by a betaine producer, which is why I am very skeptical.


Most importantly, the label of the product gives enough information, especially when it comes to herbs. Simply mentioning the name of an herb usually says too little about the actual active (or inactive) substance. In the past, dubious substances were often hidden behind the name of an herb.

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