The Real Scoop on Pre-Workout Supplements for Triathletes

Pre-exercise formulas are marketed as being your workout's best friend. But do they live up to the hype? An R.D. breaks down the most common pre-workout supplements for triathletes, from caffeine to BCAAs.

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Now and then, you might be looking for a little boost to help supercharge your workout, so a supplement that promises to enhance performance seems like a no-brainer. The most common pre-workout supplements for triathletes claim to increase athletic performance using several ingredients that deliver a physical and psychological boost. Just swallow it down 30 minutes before you start your workout, and you’re good to go.

These powders and pills have become increasingly more popular among athletes of all stripes, with the global market being valued at $12.6 billion in 2019—with an expected healthy annual growth. This dollar value strongly suggests it’s not just the pros who are partaking.

But what’s exactly in these pre-workout supplements for triathletes? Do they deliver on their lofty promises to take your workouts to the next level? We take a deep dive into the common ingredients in these supplements and try to figure out if they can give triathletes a competitive edge.

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The Pre-Workout Supplement Matrix

Not all formulas are the same, so the ingredients in each product can vary. But here are some of the most common players in the pre-workout supplement game.


The best available evidence points to this being the item in pre-workout supplements that is most likely to help jazz up your workouts. Over the years, research has consistently demonstrated consuming caffeine before working up a sweat can help elevate performance via a few different mechanisms including improving force of muscular contraction and diminishing the perception of discomfort to help you push harder. In a recent investigation in the journal Medicine and Science in Sports and Exercise, 23 well-trained male athletes saw their time to exhaustion increase during an intense treadmill running test when they were provided with 4.5 mg of caffeine per kilogram of body weight 45 minutes before exercise compared to when they were supplied a placebo. This performance benefit was attributed largely to a caffeine-induced increase in VO2max, the maximum rate of oxygen your body can use during exercise.

A couple of important points to keep in mind when using a pre-workout powder for a caffeine buzz. To effectively rev up your workouts and races, you’ll need between 2 to 6 milligrams of caffeine per kilogram of body weight. In other words, 130 to 380 milligrams for a 140-pound runner. Everyday coffee drinkers and/or frequent caffeine supplement users may need the higher end of this dosage range to experience a workout boost than those who are caffeine naïve. A good product should tell you how much caffeine you are getting, which could come from green tea extract or caffeine anhydrous, a dehydrated form of pure caffeine. Be aware that if you are using a pre-workout supplement to power a late-day workout, the caffeine could stick around long enough to disrupt sleep patterns.

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Beta-alanine is a non-essential amino acid that is produced endogenously in the liver and also found in various foods including poultry and beef. Its potential impact on exercise performance stems from the vital role it plays in the production of carnosine within our muscles. (The rate-limiting factor of carnosine synthesis is beta-alanine availability.) Since carnosine serves as a buffer against acid accumulation in working muscles and, thereby, reduces the acidity that can impair muscular functioning, higher levels derived from beta-alanine supplementation, in theory, should allow active bodies to push harder with less burn and fatigue. Supplementing with beta-alanine has been shown to elevate carnosine levels in muscles by up to 80% after 10-weeks of use.

To date, the predominance of the literature suggests that taking beta-alanine can be a viable method for lowering intramuscular acidosis and, in turn, muscular fatigue caused by a build-up of acid, but is more impactful during activities where there are high rates of anaerobic energy delivery such as shorter duration max-effort sprints. So it could be beneficial for helping to increase your work capacity (anaerobic threshold) and the time it takes for exhaustion and perceived fatigue to set in, especially in cases where acidosis is a limiting factor. These scenarios might include taking on shorter inclines lasting 1 to 4 minutes, or when you need to really pick up the pace for a few minutes during a race. But it likely won’t do much for helping improve aspects of lower-intensity endurance (aerobic) exercise such as time to exhaustion during a long steady-state run or bike ride. At lower work rates there is a much lower drop in the pH of blood within muscles so the usefulness of carnosine as an acid buffer is less helpful. But even for hard-charging efforts, beta-alanine is not an ergogenic slam dunk. A recent study in the Journal of the International Society of Sports Nutrition found that swimmers received little benefit from taking 4.8 g of beta-alanine daily for 6-weeks when it came to max efforts in the pool.

We need to keep in mind that the amount of beta-alanine administered in studies (4 – 6 g in divided daily doses) is typically at least twice as much as that found in most pre-workout supplements and participants used it for several consecutive days (loading phase) and not just occasionally before a hard workout. And starting levels of muscle carnosine can vary among people – it’s often lower in vegetarians and vegans who don’t consume it from meats as well as women and older individuals. Athletes with high amounts of fast-twitch muscle fibers such as professional sprinters will have higher levels. So, perhaps people starting with lower baseline levels of carnosine in their muscles would benefit the most from beta-alanine supplementation, a hypothesis that needs some research dollars to investigate.

Photo: Getty Images
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Say hello to one of the most studied sports nutrition supplements ever. By way of the kidney and liver, the human body already produces creatine (a naturally occurring amino acid) on its own and we also consume it when eating meat and fish. Supplementation simply boosts the amount of creatine available in the body. Creatine monohydrate, the most common form in pre-workout supplements, is made of one creatine molecule combined with one molecule of water.You’d need to eat almost inhuman amounts of animal flesh to hit the level of creatine available in most supplements.

There is a bounty of research showing that creatine monohydrate helps increase strength and performance in high-intensity, explosive exercises like HIIT (high-intensity interval training), weight training, and track and cycle sprints. How? Your muscles convert creatine into creatine phosphate, which is then generated into adenosine triphosphate (ATP), which your body uses for explosive exercise. In other words, creatine increases your body’s ability to produce energy rapidly when you need it most. If you’re able to lift more weight in the gym or sprint faster, you’re able to create an environment for increased training adaptations such as muscle strength and size or tolerance to short bursts of max effort. So your finishing kick may benefit from creatine use.

Although creatine supplementation has been positioned to primarily benefit athletes involved in activities involving short bursts of intensity such as sprinting and weight training, there is a growing body of evidence hinting at the idea it may also provide beneficial effects for activities that are more endurance-focused. For example,there is research that individuals supplementing their diet with creatine experienced less muscle damage, inflammation, and muscle soreness in response to a 30km run. A study in Medicine & Science in Sports & Exercise found that highly trained men who supplemented with creatine improved their power output during the 4km homestretch of a 120km cycling trial. Creatine in combination with adequate carb consumption may also have the ability to increase muscle glycogen stores, which is presumed to be due to a creatine induced cell volume increase, allowing for more space for glycogen synthesis. (Glycogen is the most important energy source for higher intensity endurance activities.) Still, if your workouts are primarily casual in nature without much in the way of intense efforts (here’s looking at you everyday jogger) taking creatine supplements isn’t likely to do much for you.

There remains some question as to whether taking creatine before or after a workout is more effective, with this study finding that taking it soon after a workout is best for bolstering strength and lean body mass. And populations who aren’t getting much creatine through their diets, such as vegans and vegetarians, may benefit most from supplementation since their baseline creatine levels are lower.

The best available evidence suggests taking 3 to 5 grams of creatine monohydrate a day will help maintain levels of creatine that can have an ergogenic effect and an amount that is safely consumed. Watch out for pre-workout supplements that contain a lot less as this will diminish any possible benefit.

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Betaine (pronounced “BEET-uh-een”) is naturally derived in the body from the breakdown of choline, and it’s also found in a handful of food sources including wheat germ, spinach, and, you guessed it, beets.

The mechanisms underlying the possible benefits of betaine supplementation for athletes is not fully understood, but could involve increasing both muscle protein and creatine synthesis, both of which can improve muscular strength and power, elevating muscle oxygen consumption, improving insulin signalling and lowering the build-up of lactate.

Some speculate that betaine can increase circulating nitrate concentrations, thereby improving physical performance by boosting nitric oxide production, but science has failed to show that an acute dose before exercise can noticeably raise nitrate levels. Finally, there is some suggestion that increased betaine intake can improve heat tolerance which would be beneficial when exercising in steamy conditions, but much more research is needed before any conclusions about this function can be made.

To date, most of the positive findings for betaine supplementation have been shown for strength training. For instance, this study performed by researchers at Springfield College in Massachusetts showed gains for those who followed a weight-training protocol and supplemented with betaine for six weeks. This included adding more muscle mass, lowering body fat and improving muscle power when lifting weights. A separate investigation in the Journal of Strength and Conditioning Research found that men who took 2.5 grams of betaine daily for 2-weeks were able to complete more bench press reps at a given weight compared to when using a placebo. One study showed there were some strength and body composition gains in those taking part in CrossFit training but not enough to result in significant aerobic and anaerobic performance benefits.

For endurance sports, betaine likely has the biggest impact on all-out efforts such as intervals or when sprinting to the line. This recent study in the Journal of Dietary Supplements found that college-aged women who took 2.4 grams of betaine daily for 2 weeks experienced an increase in mean power output during a cycling test by an average of 3.2% compared to when taking a placebo. Also, ratings of perceived exertion were lower when participants were asked to put out their maximum power for 30 seconds. This investigation in the Journal of the International Society of Sports Nutrition discovered that when male and female cyclists drank a carb-electrolyte beverage infused with 2.5 grams of betaine for a week, their average peak powder during sprints improved by more than 6 percent. Not all studies have found that daily betaine intake can increase performance such as aerobic capacity. Overall, it’s not likely to have much use in improving the performance metrics of long, steady-state types of activity.

To glean any muscle size and power benefits for betaine supplementation, you very likely would need to take it consistently, and at levels of 2 to 5 grams, which could be more than what is found in a pre-workout formula.

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L-Citrulline is a non-essential amino acid that is turned into L-arginine in the kidneys after supplementation.Since arginine is the main substrate for the synthesis of nitric oxide (NO), citrulline ingestion can indirectly increase NO production in the body. In turn, given the role of NO in vasodilation and increasing blood flow the running theory is that citrulline supplementation can increase the transport of oxygen and glucose to working muscles thereby improving muscular functioning and reducing fatigue for better physical performance. As a component of the urea cycle, arginine assists in clearing ammonia from your system, which is a byproduct of muscle breakdown during strenuous exercise and may contribute to fatigue. So by increasing arginine and thereby reducing ammonia levels, this is another mechanism by which citrulline could boost your game. There are very few foods that have notable amounts of citrulline, watermelon being a notable exception.

In supplements, citrulline is frequently bound to malate, an organic salt of malic acid. This is the most researched form of citrulline, and there is speculation about an independent role of malate in producing performance benefits, but there’s a dearth of research to compare citrulline malate to L-citrulline directly. Malate helps regulate enzymes involved in the breakdown of glycogen (the storage form of carbohydrate) into energy, so ATP production for muscular contraction could be increased via greater availability of malate.

To date, the research on the benefits of citrulline malate (CM) concerning improved performance for both aerobic and anaerobic exercise are mixed, with dosing and methodological disparities being the main limitations for being able to lay down any firm conclusions. This recent study in the European Journal of Sports Science determined that active males experienced no benefit in performance metrics such as time to fatigue and watt generation during a cycling trail from an acute 8 gram dose of CM. This is another investigation that determined that consuming 12 grams of CM 1 hour before a fitness test did not result in better performance variables like power output and time to fatigue compared to a placebo. Some data shows that taking CM may improve performance during weight training, including increasing the number of reps a person can pump out before giving up, especially for lower body exercises. It may also help quell muscle soreness after resistance training. However, these resistance training benefits are not universally found.

The amount of CM used in research is typically around 8 grams which can be twice as much found in pre-workout powders. So, like other items in pre-workout supplements, the optimal amount of citrulline in products might not be enough to make much of an impact, if any. There might be an important distinction between acute and chronic supplementation; whereas acute citrulline supplementation doesn’t seem to reliably improve performance, consistently using it over several days before workouts may bring about some sought-after results.

Photo: Getty Images
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Of the nine essential amino acids that we must get from our diets, three are the branched-chain amino acids (BCAAs): leucine, isoleucine and valine.“Branched-chain” refers to their chemical structure.

Branched-chain amino acids are the building blocks of protein. For your body to re-build and grow new muscle, you need these amino acids, especially leucine which activates a certain pathway in the body that stimulates muscle protein synthesis. During exercise, levels of BCAAs can be diminished as they are oxidized by working muscles so adding more into the mix could lower the amount of muscular breakdown and muscle soreness. This report suggests that increased BCAA consumption can lower signs of muscle damage associated with endurance exercise. And a single, acute dose of BCAA at levels of 0.087 g/kg body mass has been shown to improve indicators of recovery from resistance training including a faster return of strength and lower perceived muscle soreness. Also, when BCAAs drop during exercise there might be an increase in levels of tryptophan in your brain, a chemical that converts to serotonin and may cause premature fatigue to set in during exercise; this is a mechanism that warrants more research.

But what we don’t know is if taking BCAAs before a workout is significantly better than simply getting them from foods like eggs, dairy and meats. This study found that while supplementing with BCAAs can reduce muscle soreness after resistance training this benefit was negated if participants simply consumed enough total protein in their diets. In the end, the benefits of BCAA are likely more pronounced for activities like weight training and running where there is more muscular damage incurred, and only if the activity is more intense. Ideally, look for a product that delivers roughly a 2:1:1 ratio of leucine, isoleucine, and valine.

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L-theanine is a unique amino acid common to the leaves of the plant species Camellia sinensis, the leaf used to make green tea. Theanine has been shown to improve a handful of indices of cognitive functioning including lowering mental stress and anxiety responses to challenging tasks, both of which could be useful to an athlete during a challenging workout. Theanine exerts its effects mainly by supporting levels of inhibitory neurotransmitters in the brain and promoting a state of relaxation.

There is some indication that theanine and caffeine (another common compound in pre-workout supplements) provide a one-two punch by working synergistically to improve certain mental tasks like attention, task switching and alertness. This could, in theory, be beneficial to athletes by helping them get a better handle on the task at hand such as a PR pursuit or podium finish.

But we should not be so quick to extrapolate the findings of theanine in non-exercise settings to what may occur during workouts. Save for this recent study in the Journal of the International Society of Sports Nutrition which found that an acute dose of a combination of caffeine, theanine and tyrosine, another amino acid, before exercise may help improve measures of movement accuracy which would be beneficial for sports requiring quick and accurate movements (maybe more applicable to a sport like soccer than triathlon), there isn’t much in the way of research pertaining to theanine supplementation and exercise performance.

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B Vitamins

The various B vitamins like niacin and thiamine play a critical role in energy metabolism so some pre-supplement formulas include them with the promise that they can help your body be more efficient at generating more energy. In the real world, there is no good data to show that taking B vitamins before a workout will do anything to improve performance. The only real chance that supplementing with these nutrients will do anything for elevating your training is if they are helping to overcome a dietary deficiency which, save for vitamin B12 in vegans, is uncommon.

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So, should you take a pre-workout supplement?

It’s hard to say. If fatigue often prevents you from training to your full potential or you don’t mind spending the money to try something that may give your runs, rides, and swims a boost then a pre-workout supplement could be worth exploring. But if you are content with your training and race results, there is nothing to suggest that these products are a game-changer.

There is a slim suit of research to rally around regarding pre-workouts and performance metrics. But a few promising results are out there. Researchers in this small University of Oklahoma study saw a bigger jump in training volume, V02 max and lean body mass in recreational athletes who took a pre-workout supplement containing caffeine, creatine, citrulline and amino acids 30 minutes before completing a HIIT routine three times a week for 3-weeks compared to those who took a placebo. Another study discovered that a pre-workout supplement allowed twelve physically fit men to increase the number of efforts performed and time to exhaustion during a high-intensity interval exercise session involving running bouts of 15 seconds on the treadmill at 120% of the maximum aerobic speed, interspersed with 15 seconds of passive recovery. However, an investigation in the International Journal of Exercise Science found that an acute, one-time does of a multi-ingredient pre-workout supplement was not enough to improve 5k race time or feelings of fatigue during the workout.

You’ll notice that there just isn’t any research conducted on long endurance efforts to wield any conclusions. The ingredients commonly included in pre-workouts to date do not have enough solid evidence to show efficacy for these exercise modalities. And, as we have shown, the quantities of the individual ingredients in supplements may not be enough to bring on significant performance benefits. But, with that said, there could be some synergies among ingredients allowing them to benefit you at lower doses. And since these powders need to be mixed with water, at the very least they will encourage better pre-workout hydration practices.

Degree of fitness also likely plays a role. A highly trained athlete may be awarded with fewer benefits than a weekend warrior simply because they have less possible fitness to gain. And don’t lose sight that it’s likely important to take the supplement regularly (chronic) instead of just occasionally (acute) before getting ready for a big workout. Items like creatine and citrulline need to be consumed over several days to be most impactful. Doing this, you’ll need to be cognizant of the extra caffeine this introduces to your day.

Dietary supplements such as these formulas are not regulated by the U.S. Food and Drug Administration (FDA) in the same way drugs are regulated. This means no dietary supplement can be guaranteed to be 100% safe, or that all ingredients listed on the label are accurate. For some people, some of the ingredients in pre-workouts may end up doing more harm than good by increasing anxiety, restlessness, and insomnia, or blood pressure and heart rate.

And always remember that no amount of pre-workout powder will outperform proper nutrition, smart training and healthy sleep patterns when it comes to taking your performance to new levels. After all, we can’t find any science showing that betaine or citrulline can turn a donkey into a racehorse.