• Science Fueling Fitness

Pre-Workouts: How do they work? Who really needs them?


It is common place among the ‘lifting community’ to see a bro downing some pre-workout in the gym changing rooms. However, does this bro even know what he's doing? Because if he did, he would have taken his pre-workout roughly 60 minutes earlier for maximum effect! Let’s take a closer look…... The majority of pre-workout supplements will contain the following ‘ingredients’ or supplements – caffeine, creatine, BCAAs (leucine, isoleucine, valine), beta-alanine and citrulline malate (L-Citrulline). So what exactly are these supplements? And how can they impact your workout, and ultimately your body?

Caffeine – provides a stimulant affect by reducing your perceived level of fatigue, leading to increased endurance performance! It also promotes a sense of readiness by stimulating the Central Nervous System. However, caffeine takes 60-90 minutes to peak in the bloodstream (we have a previous post on this) and so having a coffee as you walk in the gym door is not the optimal approach. Instead, have your caffeine (in this instance in your pre-workout) between 60 - 90 minutes’ pre-gym and your caffeine levels will peak as you start your workout!

Creatine - the mechanism by which creatine aids athletic performance is well documented. It is the most researched supplement in the literature, and with that the most proven. An increased total creatine pool in the body results in faster adenosine triphosphate (ATP) regeneration between sets of high-intensity exercise, allowing athletes to maintain a higher training intensity. Studies show that creatine supplementation has the most pronounced effect on short duration (less than 30 seconds), high-intensity, intermittent exercise. For this reason, creatine supplementation is most useful in periods of heavy lifting (when working in lower reps with sets lasting shorter than 30 seconds) and periods of intermittent, high-intensity training. Creatine Monohydrate is the most well-supported form of creatine and our number one recommended supplement. However, some pre-workouts contain different forms of creatine but also smaller doses! Be careful to check how much creatine is in each serving. A common dose of 3g-5g is suggested every day as this form of dosing reduces the chances of bloating and gastric discomfort that are associated with a loading strategy. In terms of timing - as long as creatine is in your system, you will reap the benefits of it and for that reason, taking it as part of your pre-workout is a suitable strategy!


BCAAs (Valine, Leucine, Isoleucine) – Branched Chain Amino Acids. Typically present in a pre-workout supplement in a ratio of 2:1:1 of Leucine: Isoleucine: Valine. BCAAs are a major topic of debate within the ‘health and fitness world’. Whilst many people advocate for them, others have dismissed them as an irrelevant waste of money, mainly due to the fact that people with a balanced diet high in protein are already consuming the necessary amounts of these branched chain amino acids through their diet, and so do not need to supplement with them. However, what is not under debate, is that leucine is a direct stimulant of the mTOR pathway, which in turn (via another downstream molecule P70s6k) stimulates muscle protein synthesis, the holy grail of hypertrophy! Furthermore, it has been shown that ~3g of leucine is the optimal amount for our bodies to begin building muscle, suggesting that it is not so much about the 25g-30g protein hit, but more so the leucine content in each protein serving. The whole 25g-30g protein hit concept centers around the fact that such a hit will typically provide 2.5g-3g of leucine, and therefore stimulate MPS. People who argue against leucine supplementation will point to studies which suggest leucine as no better than a normal high-protein diet, as a stimulant to muscle hypertrophy. Such studies however, typically compare two groups of resistance training individuals, one consuming a ‘normal diet’ vs the other consuming a ‘normal diet plus leucine supplementation’. Results will show no difference in muscle hypertrophy and strength between the two groups after 10-12 weeks of resistance training. However, what is excluded from honourable mention, is that the groups typically consume diets extremely high in protein, with some studies using up to 3g of protein per kg of body mass – 270g of protein for a 90kg individual!! My point is – no wonder there is no extra benefit from leucine supplementation if the ‘normal diet’ groups consume 3g/kg body mass, a mammoth amount which is impractical and unsustainable for most individuals! After all, leucine is a supplement, one which can be consumed naturally in the diet and if you are consuming adequate amounts of it in your diet, then yes amazingly you will not benefit from further supplementation. Now – where leucine supplementation (either on its own or through BCAAs) is a smart choice, is for people who struggle to consistently consume a high amount of protein in their diet (such as vegetarians for example)!


L-Citrulline – is an amino acid which, upon digestion, gets metabolized by the kidneys and converted into arginine. Enter the big baller arginine! Arginine is another amino acid. It is the main amino acid in the body which contributes to producing nitric oxide – and so, acts as a vasodilator by increasing blood flow. So why not supplement with arginine directly? It has been shown that L-Citrulline can increase plasma arginine levels far more effectively than arginine itself. In addition, L-Citrulline has a better absorption rate then arginine which also helps the process. However, here’s the important part. The conversion of citrulline to arginine, producing nitric acid, takes time (roughly 60-90 minutes – sound familiar?) and so a pre-workout containing L-Citrulline should be taken roughly 60 minutes before your session begins in order to optimise its effects. These effects include increased work capacity, increased session volume, reduced levels of fatigue and some skin-popping pumps! The common recommendation is 6g-8g roughly one hour before your workout, but 4g has also been shown to elicit effects in numerous studies!



Beta-Alanine – is a modified version of the amino acid alanine. Upon digestion, beta-alanine (along with histidine which is another amino acid) are synthesized into carnosine by skeletal muscle. Carnosine can act as an acid buffer and impacts muscle pH regulation. It can therefore slow down the rate of increase in acidity levels in the body and decrease lactic acid levels as they increase. This can then impact endurance exercise as preventing or delaying the build-up of lactic acid can help improve endurance performance. In practical terms, this may add 1-2 reps to your sets of 25 reps. So how could that impact gains? A few more reps here and there build up over time to make substantial increases in total session volume, which facilitates increases in muscle endurance performance. Numerous studies have shown consistent (albeit minor) increases in aerobic running capacity, endurance performance and fat-free mass when supplementing with beta-alanine, both in trained and untrained individuals. The recommended does in the literature is 2g-5g and although it isn’t clear whether the timing of beta-alanine is important or not, you are probably best to take it with your other supplements, 60-90 minutes before you train.



Now that you know a little (and I stress little) of the science behind these supplements, the question becomes who should take them? Well, firstly if you are reading this blog (indicating you aren’t clear on what pre-workouts actually do) then you probably do not need them. What you more likely need is to consistently train, consistently follow a structured gym programme with your specific goals as the target outcome, and to consistently adhere to your diet, be it eating at maintenance, in a caloric deficit or in a caloric surplus. Once you achieve these things (consistent diet and training) then you may think about supplementing your diet with something to give you a little extra! Here, we recommend creatine monohydrate (yes, that is our number one recommended supplement – definitely not a pre-workout mix of supplements that will have less of an impact than creatine monohydrate on your performance in the gym!). Now – If you are still looking for an ‘extra boost’ at the start of your session, we recommend you simply drink a coffee roughly 60 minutes before your workout which will adequately raise your blood caffeine levels and reduce your perceived level of fatigue. So there you have it, if you are novice lifter, a recreational gym-goer or even an advanced lifter with a good diet based upon your fitness goals, the first supplement you should reach for is creatine monohydrate, followed closely by a nice dose of caffeine (through a good old fashioned black coffee) and you have yourself a solid ‘foundation’ upon which to grow. As for the BCAAs, beta-alanine and citrulline that also comprise a pre-workout supplement: ask yourself this, do you really need them? Firstly, let’s deal with leucine. It’s very simple really, if you are in need of leucine (meaning your diet is low in protein and needs supplementation) then yes you may benefit from leucine, you also may need better strategies to increase your protein intake naturally in your diet. As for beta-alanine and citrulline. Do you need these supplements? Perhaps. Perhaps if you are so consistent and advanced with your training and diet that you regularly train to failure in higher rep ranges, then yes beta-alanine will enhance your training (the science has shown this to be true). And yes, if blood flow is your goal in your training and you constantly chase skin-popping pumps, then supplementing with citrulline malate 60-90 minutes before your session will aid with this goal (again, the science has shown this to be the case). So what we are really getting at, is that pre-workout supplements are for very advanced lifters who have already ‘mastered’ both their diet and training approach. It may be the thing that gives them that extra 1%! For the rest of you (us) though, think about this – have I really mastered the other 99% yet? Have I consistently been on point with my diet, my macro-nutrient and micro-nutrient intake? Has my training been consistent and optimal for the goals I am chasing? Have I actually trained ‘hard’ enough to make use of the benefits these supplements may bring? If so, have I optimised my recovery strategies outside of the gym to be at my best/most recovered each time I step into the gym? If the answers to these questions are yes, then pre-workout is likely a good option! But for the majority of us, this is not the case. Don’t overlook the big picture (99%) just to see that extra 1% in the background! So for example, does the 18 year old GAA player who’s trying to make his county minor team need a pre-workout? Definitely not. (He needs proper nutritional strategies to compliment his training). Does the 25 year old bro who goes to the gym 2-3 times per week and has an inconsistent diet, need a pre-workout? No! He needs to be more consistent with the two biggest factors that will help him achieve his goal – diet and training! However, the 30 year old gym-goer who trains 6 days per week, eats like an Olympian and has goals of stepping on stage in 8 months’ time, does he need a pre-workout? He doesn’t ‘need’ it, but would likely benefit from it, as the physical and mental fatigue alone of so many gym sessions become so repetitive that he needs that extra little something to get him ‘in the zone’. He also trains extremely hard and so will reap the benefits of some increased blood flow and reduced rate of lactic acid build-up!


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