Why pre-workout caffeine is overrated and possibly harmful for your gains

Walk into any serious gym with your gym bag void of supplements and you’ll be out of place. You’re even more out of place if you enter the gym without 1,3,7-trimethylxanthine rushing through your veins. I’m talking about everyone’s favorite supplement drug, caffeine. “Fueling up” before a workout with a caffeinated beverage has become as synonymous with training as getting your protein in after a workout. Energy drinks alone were a 50 billion-dollar industry as of 2014 and are expected to exceed 80 billion by 2024.

It has become dogmatic among the bros consuming a caffeinated beverage before a workout is necessary to maximize your performance, and thus, your gains. But is this really the case? Not necessarily. Caffeine can indeed give you the motivational kick in the ass you need to go to the gym and train [2,3] . However, as you will see, the benefits of consuming pre-workout caffeine for the typical trainee trying to look good naked are massively overrated. You’ll also learn why habitual caffeine use may even be detrimental to your gains over the long term, especially for those who train later in the day.

Caffeine & performance

There’s no doubt you’ve heard caffeine can benefit your performance, or even magically turn you into the raging juiced up bro on the label. Despite what you’ve been led to believe, the truth is, the research shows caffeine can potentially benefit your performance. This review examined a collection of meta-analyses (a statistical analysis of multiple scientific studies), and overall, the literature indicates, on average, caffeine improves strength performance and muscle endurance (the ability to perform more reps per set).

Digging deeper into the review, one meta-analysis showed caffeine increased upper body strength but not for the lower body, while another meta-analysis found caffeine didn’t benefit strength at all but did benefit muscular endurance. Some individual studies find almost trivial performance benefits such as performing more reps during a single set of an exercise. I get it, every little bit counts, but the subjects in that study consumed a massive 6 mg/kg dose of caffeine, that’s over 400 mg (one cup of coffee contains 95 mg of caffeine, on average) for a 150 lb person. Some individual studies showed no benefit in performance when consuming caffeine at all, even with high doses.

The disparity is likely or partly due to interindividual responses to the ergogenic effects of caffeine. Just because studies on average show a benefit, doesn’t mean you fall within the area of the statistical bell curve that receives the benefit.

Supplement companies like to cherry-pick specific studies for their products, usually citing only a couple of studies out of the many that exist, especially for caffeine. It’s important to always look at the literature as a whole, only then can you make an objective assessment. Caffeine’s benefits on performance are not as black and white as you may think. Not only that, when specifically looking at the benefits of caffeine on muscular strength and endurance, most research shows you need to consume at least a 3 – 6 g/kg dose. For a 200lb person, that’s 270 – 550 mg of caffeine. For a 150lb person, that’s 200 – 410 mg of caffeine. Ironically, many pre-workouts contain 200 mg or less caffeine per suggested serving size. That doesn’t matter though, as long it feels like you’re gaining a benefit from it, that’s all the company cares about, you’ll keep coming back for more.

You may be thinking, “if the research shows I can benefit from taking caffeine, why not always consume caffeine to cover my bases?” Before you stock up on your favorite pre-workout, there’s much more to consider. The studies in the meta-analyses mentioned above test the performance benefits of caffeine during a single bout. Therefore, this vast amount of research doesn’t check if the performance benefit of caffeine diminishes over time with habitual use, which is very relevant to the recreational trainee consuming the same pre-workout dose of caffeine before every session.

Caffeine tolerance

As mentioned earlier, caffeine can give you a psychological boost. Many can attest to this. However, most habitual caffeine consumers can also tell you this; the wonderful caffeine buzz they get every morning at work or before their training session diminishes over time. Tolerance to the effects of caffeine on heart rate, blood pressure, and adrenaline and noradrenaline levels have been shown to start immediately upon habitual caffeine use. Tolerance development is real and builds quicker than most people realize. Just ask the person that can’t seem to stay awake at their desk despite just slamming down an extra-strength 5-hour energy and a large coffee an hour before that (I have personally seen this happen).

To combat the ever-increasing tolerance to caffeine, you may think continuously increasing your caffeine intake is a viable solution. However, you can’t just keep upping your caffeine dosage to reap its benefits. Eventually, once you are consuming 750 – 1200 mg of caffeine per day, your tolerance will be insurmountable and you will no longer receive the psychological benefits from consuming caffeine. This is when things can get ugly. You may think you’re still receiving some psychological benefit from it, but all you’re likely accomplishing at this point is subsiding caffeine withdrawals (headaches, decrease in subjective well-being and physical energy, irritability, joint/stomach pain). Even abstinence from 100 mg per day can cause withdrawals. Once you are consuming enough coffee throughout the day to feed everyone in the gym, your caffeine addiction may have reached the same level as a serious heroin user; you’ll be feeding your addiction just to feel “right,” so you don’t experience withdrawal symptoms. Ok, maybe you won’t feel sick to your stomach and look for every opportunity, at whatever cost, to get your fix (or perhaps you will), but you get the point.

What about the relationship between habitual caffeine use and its effect on performance over time? Unfortunately, a limited amount of research has studied this relationship. I was able to find three studies that did, all of which test habitual caffeine use and its effect on performance over time on endurance activities. Two of the studies [2] did show participants developed a tolerance to the performance benefits of caffeine.

In the third study, the authors of the study concluded that habitual caffeine use does not result in tolerance to its performance benefits. However, there is bias within this study based on its design. The study had participants assigned to a group based on their level of habitual caffeine consumption. There was a low, moderate, and high intake group. Each group received a 6 mg/kg dose of caffeine. Even though the high intake group performed better with caffeine than without, the participants in the high intake group were still, on average, receiving a larger caffeine dose (about 100 mg) than they were accustomed to. Furthermore, the high intake group saw the lowest relative increase in performance.

Based on the limited research we have, it’s likely the benefit of caffeine on performance diminishes with habitual caffeine use or becomes trivial. I’d like to see more research, specifically research that looks at habitual caffeine use during resistance training.

Aside from building a tolerance to caffeine, suffering from withdrawals, and no longer receiving its ergogenic and psychological benefits, chronic caffeine usage can also cause a significant problem: Sleep deprivation.

Caffeine & Sleep

Sleep deprivation has become a growing concern in the united states. Around one-third of American adults as of 2014 don’t get enough sleep. Sleep deprivation is one reason many rely on caffeine the next day. However, it’s not the best idea to ignore your sleep deficiency and rely on caffeine to make up for your lack of sleep.

Overall, the literature shows that caffeine use decreases your sleep quality, especially when consumed close to bedtime. This is problematic for those of us that like training later in the day. If you like throwing down a pre-workout supplement loaded with caffeine and have trouble sleeping at night, caffeine is likely a primary culprit.

Like its effects on performance, the effects of caffeine on sleep varies per individual and is dependent on tolerance. However, complete tolerance to the adverse effects of caffeine on your sleep may never occur. Even a 200 mg dose of caffeine consumed by habitual users in the early morning hindered their sleep quality at night! Remember, you likely need at least a 3 mg/kg dose of caffeine to gain any benefit. That’s a lot of caffeine, especially if you train later in the day. Just because you are no longer feeling the effects of caffeine doesn’t mean it won’t hinder your sleep. And just because you are sleeping doesn’t mean you’re getting quality sleep. Caffeine disrupts the various stages of sleep and reduces your time in deep sleep.

Sleep deprivation is terrible for your gains

From muscle hypertrophy and recovery standpoint, your body is most anabolic when you’re sleeping. If you don’t sleep well, your gains and recovery suffer. Sleep deprivation can hinder your ability to gain muscle and lose fat by increasing hunger [2], lowering your resting metabolic rate, reducing your testosterone levels, increasing cortisol (a catabolic hormone) levels, and increasing insulin resistance. All of which are also general health concerns. Sleep deprivation can even cause your blood pressure to rise.

And if you’re still not too worried sleep deprivation will hurt your gains, the following studies that examined the impact of sleep restriction on weight loss will be a wake-up call.

The participants in this weight loss study lost 60% more fat-free mass and lost 42% less fat, just from sleeping 2.2 hours less a night (5.23 instead of 7.42 hours) for 14 days! Furthermore, when sleep-deprived, the participants resting metabolic rate lowered by 114 kcal/day, and their hunger increased.

This study also examined the impact of sleep restriction on weight loss and has even more extreme results. Two groups went on an 8-week calorie-restricted diet, but one group was also sleep-restricted. The sleep-restricted group had their sleep restricted five days per week but were free to sleep as much as they wanted the other two days, typical of the modern workweek. In the end, each group averaged the same weight loss and almost the same amount of sleep per day. However, the sleep-restricted group only slept an average of 5.5 hours during the five sleep-restricted days, which resulted in the group losing 85% of their weight as lean mass! The group that did not have sleep restriction only lost 17% of their weight as lean mass. Getting quality sleep is critical for recomposition success. Remember this study the next time you think catching up on sleep over the weekend can make up for sleep lost during the week.

The fallacy of the 6-hour rule

A mainstream rule of thumb goes as follows: If you stop consuming caffeine at least 6 hours before bed, it will have minimal or no effect on your sleep quality. Quite a convenient time for most of the population that trains in the afternoon or after work. The “logic” behind this? Caffeine has a half-life of about 6 hours (in reality, it varies per individual), meaning half of the caffeine will remain in your system after that amount of time. However, not only does this rule of thumb have no scientific basis; it doesn’t even tell you how much caffeine you need to hold yourself to. If it’s only 10 mg, that likely won’t affect your sleep, but if its 300 mg, that means you’ll still have around 150 mg in your system come bedtime. A study from 2013 showed 400 mg of caffeine consumed six hours before bed reduced sleep time and efficiency just as much as consuming that same amount of caffeine at bedtime. We also have the study mentioned above that showed sleep can be disrupted by 200 mg of caffeine taken in the morning.

Anecdotally, I have also found the 6-hour rule to be a poor recommendation for those who are responsive to caffeine and struggle to get good sleep in general. In practice, no exact rule exists; people metabolize and respond to caffeine differently. Trainees not sleeping well has even led to the popular opinion that training late in the day is detrimental to your sleep when in reality, it’s likely the massive amount of caffeine many consume 6 hours or so before their scheduled bedtime. Lifting weights improves sleep quality and won’t hinder it as long as your training session ends at least 1 hour before your scheduled bedtime.

Muscle hypertrophy & pre-workouts

Ironically, the studies that many supplement companies like to flaunt in favor of caffeine on performance don’t even prove what most of us are after; better long-term muscle growth and strength development when we go to the gym jacked up on caffeine like a Belgian blue bull in heat. Just because studies have shown an acute increase in performance during a single session, doesn’t mean you can extrapolate that to more gains over the long run. No way. Unfortunately, there doesn’t seem to be any long-term studies that only tested the relationship of pre-workout caffeine on muscle hypertrophy and strength.

However, there are quite a few studies that have looked at this relationship with pre-workout supplements that contain not only caffeine but a lot of other substances as well. This review from May 2018 included all of the studies on pre-workout supplements up to that point. Out of the 14 studies (four tested a pre-workout that didn’t contain caffeine) in the review that were longer than ten days in duration with subjects resistance training, 13 of them found the pre-workout improved either muscle growth, strength, focus, energy levels or some combination of those performance measures. A couple of the studies did not find any significant difference in any performance measure, but the authors still conveniently concluded that the supplement may enhance performance or cognitive function based on the data.

Now you may be thinking, “ah-ha, so all of that money I’ve spent on my pre-workout is justified, the research on this is quite clear!” Now, before you get too excited, there’s something you need to consider with these studies. If you read through all 14 studies, they were all funded in some way or another by the supplement company whose pre-workout was tested in the study. Yes, every single study. Two of the studies, this one and this one, were performed at the same institute, and self-reported dietary intakes were precisely the same for each study. Coincidence? I think not, more like lazy researchers copying and pasting. Only one study in the review did not find a benefit when taking the pre-workout, nor did the authors even suggest there may be one; I’m going to guess those authors were taken off the Christmas card list that year.

To be fair, a lot of the studies (11 out of the 14) tested a pre-workout that contained creatine, which is as close as it gets to the “magic pill.” Creatine has been shown to increase strength and muscular endurance. However, its effects are still somewhat modest, and not everyone responds to creatine supplementation. Ironically, most people aren’t even impressed with creatine (we’ve all heard “bro, it just fills your muscles with water”). News flash: if you’re not impressed by creatine, no other legal supplement will impress you.  

Research and potential publication bias aside, you still need to think about how a study translates to you, the individual. As you now know, consuming caffeine, especially later in the day, is likely bad for your sleep quality and thus likely bad for your gains. This is especially the case for the person that likes training in the afternoon or early evening. We associate better performance in the gym with better gains, but that is only if your recovery – the stuff you need to right outside of the gym, like sleeping well – remains on par. If you don’t sleep well, your gains suffer.

Pre-workout caffeine is likely less of an issue if you train early in the day, such as before work, or if you like training early on a Saturday morning. Caffeine can even help offset the bio-rhythmic loss of performance from training early in the morning. So, if you train first thing in the morning, a small amount of caffeine (100 mg or so) is probably ok. Remember, though; it’s still possible consuming caffeine in the morning can negatively impact your sleep. It’s also easy to fall into the trap of consuming more and more caffeine as time goes on due to tolerance buildup.

One option is to buy a caffeine-free pre-workout, but even then, there’s still likely substances in it you’re paying for that will not benefit you [2]. Furthermore, most pre-workout supplements underdose on the more promising substances such as creatine, beta-alanine, and citrulline malate anyway. That’s why it’s best to buy supplements like creatine, separately. Finally, the supplement industry as a whole is still poorly regulated and shoddier than people realize. Supplement contamination with dangerous or even banned substances remains an issue, along with manufacturers cutting corners by underdosing in relation to what’s on the nutritional label.

Caffeine as a fat burner

Caffeine is marketed as a fat burner; a means to increase one’s energy expenditure via an increase in metabolic rate, resulting in more fat loss over time. Sounds great in theory, especially to those looking for an easy way to shed fat. However, the increase in energy expenditure from consuming caffeine is modest at best. The increase in energy expenditure is dose-dependent, with high doses resulting in an energy expenditure increase of around 100 kcal. Some research has shown no increase in energy expenditure. The participants in the study were habitual users, so this implies a tolerance to the “fat-burning” effects of caffeine also occurs.

Sadly, many still don’t realize you need to be in a net caloric deficit to lose fat (if only they put that on the label!). Just because caffeine or a fat burner increases your energy expenditure doesn’t mean anything if you’re still consuming more calories than you are burning. 100 or so calories are a drop in the bucket.

Finding a hack or shortcut is not the key to fat loss success, despite what the “experts” say. Often, those who resort to fat burners aren’t taking care of the much more critical core principles behind a sustainable fat loss diet. Fat burners are at the very bottom of the fat loss success hierarchy. What’s key is having an overall satiating and enjoyable diet that you can stick to for the long term. If you’re suffering during a fat loss diet because you’re always starving and regularly eating food you don’t enjoy, you’re almost guaranteed to revert to your old eating habits and eventually put all of the fat you lost back on, regardless of whether or not you’re taking a fat burner. Fat burners are not the answer. Once you are in control of the more essential aspects of a fat loss diet, only then should you consider taking a fat burner. Even then, it’s no magic fat loss pill.

Conclusion

Caffeine is the world’s most used psychoactive drug and is addictive, a lot more than people realize. Combine its addictive properties with the ever-increasing desire of people looking for shortcuts and exaggerated claims made by the supplement industry with fancy marketing ploys, it’s easy to convince the general public they need a pre-workout or energy drink.

As with anything in life, caffeine use comes down to weighing the potential benefits with the costs. The advantage of habitual caffeine use for the typical, motivated trainee trying to get jacked and lean? It’s likely not going to help you reach the end goal faster or make it easier, especially if you’re not doing the many other, more important things right in your program (progressive overload, tracking your workouts, proper nutrition, sleeping well). Many of you out there have probably looked in the mirror recently and stared at more or less the same physique from a year ago, or even longer. Do you think all of those supplements you’re buying are making a difference? You should get your priorities straight.

For a competitive strength athlete, it can be potentially beneficial to use caffeine strategically during a competition to give you an advantage. However, this can backfire as caffeine can cause anxiety. It’s not exactly the best feeling to be extra shaky and nervous when trying to squat your 1RM in front of a crowd.

The cost? Caffeine does cost money. It can also wreak havoc on your sleep (especially if you consume the high dosages recommended based on the performance meta-analyses from earlier), which would likely eliminate any potential benefit, or even hinder long-term progress. Habitual caffeine use that causes sleep deprivation often leads to a pernicious cycle in which you consume more and more caffeine to make up for lack of sleep. Caffeine is easy to abuse, which leads to dependence, withdrawal, and any potential benefits are likely lost due to tolerance buildup. Therefore, it’s best for strength trainees and bodybuilders to avoid caffeine altogether, especially if you train in the evening. Like every drug, it’s best never to start using it in the first place. Be above the influence kids.

Many people cringe at the idea of not consuming their pre-workout caffeine but you’ll be pleasantly surprised even going cold turkey will not affect your training performance (unless you allow it to via the nocebo effect) and it will soon feel normal again not going into the gym all jacked up on caffeine. Humans are creatures at habit; at first, breaking a habit, such as not consuming caffeine before a workout, doesn’t feel right and is uncomfortable, but you eventually get used to it, and that will become the new norm. Believe it or not, we didn’t evolve requiring anything other than the energy from the food we eat to perform at a high enough level in the gym to obtain the adaptive response from our training we’re looking for.

It’s time to stop relying so much on your pre-workout caffeine. It’s nothing more than a psychological crutch, a crutch that can eventually screw you out of gains. Many people have it in their heads they cannot perform in the gym without caffeine because they suffer from withdrawals and have unfortunately given in to the hysteria fabricated by those who sell it. Many are in denial of this, of course. Those who swear by the requirement of consuming pre-workout caffeine to perform well in the gym are addicted (mission accomplished for the supplement industry). No one likes being told this, but the truth often hurts and generally doesn’t sound sexy (not nearly as sexy as the half-naked chick fake smiling, trying to sell you the damn pre-workout). Confirmation bias is real; people will make whatever claim necessary to justify their usage.

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