Intra-workout sports supplements: What to know

Nutritional OutlookNutritional Outlook Vol. 26 No. 3
Volume 26
Issue 3

Help consumers work out longer and recover faster with intra-workout products.

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Intra-workout products taken during exercise are a great way to support recovery between workouts and can complement preworkout products athletes consume ahead of exercise. As diverse as sports nutrition consumers can be, intra-workout products can be formulated and marketed to target multiple subsets of sports supplement users. For example, products with a focus on recovery may be best marketed to weightlifters, while runners and bikers might be more enticed by products that support endurance and recovery.

“The original intention of intra-workout products was to provide amino acids during exercise to fight the catabolic effect of long workouts,” explains Dustin Elliott, senior brand manager, sports nutrition, at The Vitamin Shoppe. “Popular products even included amino acids to promote nitric oxide and exercise endurance as well.” Branched-chain amino acids (BCAAs) became most popular, “as they were seen as the group of essential amino acids most responsible for anabolic signaling,” he says.

BCAAs include leucine, isoleucine, and valine, which stimulate the building of protein in muscle. For the purpose of intra-workout, they may also reduce muscle breakdown.1 This is the catabolic effect Elliot is referring to. Catabolism can be thought of as digestion, breaking down larger structures like protein, fat, and tissue into smaller units such as cells and fatty acids. Anabolism is when smaller units like nutrients, cells, and amino acids are bonded to create bigger structures, in this case resulting in muscle growth and recovery.2

Depending on the exercise, your body needs different things. Anabolic exercises (also known as anaerobic exercises) such as weightlifting help build muscle and increase strength. While strenuous, this form of exercise requires relatively little oxygen and energy use during the exercise itself, with the body expending more energy afterward to repair and strengthen the muscles.2 Hence, the need to promote recovery. Catabolic exercise (also known as aerobic exercise), on the other hand, such as running, biking, or swimming, demands a great deal of oxygen and energy during the workout, which makes it great for burning fat and glucose but also strains muscles over long periods of time. In this case, intra-workout products are meant to slow down muscle fatigue, bolstering endurance.

In either case, fatigue is a real problem, and amino acids may play an important role in how much fatigue we experience. For example, many are aware of the mental health benefits of exercise, improving mood and reducing stress. This is because of the metabolism of tryptophan, which is a precursor to the neurotransmitter serotonin, which modulates mood, among other things.3 It is, therefore, not unusual to find L-tryptophan in an intra-workout product because some research suggests that the essential amino acid may help increase endurance by decreasing the perception of fatigue, possibly even tolerance to pain.3,4 And after all, motivation is a huge factor in fitness, whether you’re trying to get in that next rep on a bench press or biking up a steep hill.

Conversely, too much serotonin production during exercise may cause fatigue, particularly during prolonged aerobic exercise. This is where a healthy balance of BCAAs and other essential amino acids, such as tryptophan, comes into play. This is because during prolonged aerobic exercise, muscle glycogen depletes, increasing the muscles’ reliance on BCAAs for fuel.3 This decreases the ratio of plasma BCAAs to free tryptophan, and because these amino acids compete for entry to the brain, less BCAAs means more tryptophan gets to the brain and more serotonin is produced. Having enough BCAAs to reduce the amount of serotonin production may therefore delay fatigue and enhance performance during exercise.

In fact, the more essential amino acids, the merrier. For example, one small study found that combining the essential amino acids arginine and citrulline with BCAAs may improve the performance of BCAAs to support endurance.5 This is because the metabolism of BCAAs is accompanied by excess hyperammonemia (accumulation of ammonia in the blood), which could induce fatigue. The addition of arginine and citrulline could reduce exercise-related accumulation of ammonia because they increase the urea cycle and nitric oxide biosynthesis.5 Results showed that the combination significantly reduced the ratio of tryptophan to BCAA as well as ammonia content after exercise.

Recovery following exercise is just as important to athletes as reducing fatigue during a workout because it means they can exercise more frequently while reducing their risk of injury. Research has shown that the consumption of BCAAs has been associated with the reduction of muscle soreness, based on a lower presence of muscle damage indicators such as creatine kinase and lactate dehydrogenase. This is particularly true after resistance training, like weightlifting.6

How manufacturers formulate an intra-workout product depends on how they want to market it. For example, citrulline was mentioned before as a complementary amino acid to BCAAs. You may recognize citrulline as a popular ingredient in preworkout products because of its ability to support nitric oxide production. If you want to create a series of products for pre-, intra-, and post-workout purposes, you may want to put citrulline in the preworkout product. Assuming consumers take the products in series, the BCAAs in the intra-workout product would still benefit from the citrulline consumed in the preworkout product. That is, in fact, a popular strategy, and most manufacturers like to delineate between these products so that consumers see the value of buying each one, making it beneficial to avoid too much ingredient overlap between these products.

“Preworkouts focus on ingredients that promote energy, cognitive function, nitric oxide, and endurance, whereas the intra- and post-workout categories focus on muscle recovery, which mostly means using amino acids that don’t have much association with performance benefits,” explains Elliot. “Also, many companies that make preworkouts also play in the intra- or post-workout categories; as a result, they create products that can be taken together, hence the lack of overlap.”

Interestingly, Elliot points out that marketing products as “post-workout” may not have as much value as it did in the past. “The idea of a true ‘post-workout’ product has become a thing of the past for the mainstream sports nutrition audience as this role today is filled solely by protein powders,” he explains. Indeed, protein powders are the accepted way to build muscle following exercise. In fact, you’ll find a number of products on the market labeled “intra/post-workout,” giving consumers opportunity to use the product as they see fit.

That said, a different segment of consumer athletes might want a more comprehensive intra-workout product that supports endurance in addition to recovery. Runners and cyclists, for example, may be more interested in an intra-workout product that helps them run or bike for longer while also supporting recovery. This brings us to another important consideration for
intra-workout products: hydration.

When it comes to sports, hydration is paramount, with replenishing electrolytes being the main goal. Think Gatorade. Now, that idea has evolved way beyond neon green and blue sports drinks.

“Hydration is the fastest growing category in sports nutrition as a result of the performance and lifestyle products in the space. From the performance side, brands are creating what can be considered the evolution of Gatorade as powder or stick packs with higher amounts of electrolytes like sodium. As a result, there are ‘premium’ hydration products for serious endurance athletes now available,” Elliot explains. While these products have immense value in the sports nutrition space, according to Elliot, the draw is not limited to athletes, making standalone hydration products a great prospect.

“The greatest amount of growth, however, has come on the lifestyle side of the hydration trend,” says Elliot. “The idea that hydration supports overall wellness and feelings of well-being started several years ago with the rise in popularity of coconut water. It continues until this day with the idea of hydration not being something that’s just for athletes but an important aspect of everyone’s daily lives. Many brands even promote their products as hangover remedies as well.”

Electrolytes are minerals found in blood and other bodily fluids that carry an electrical charge and help regulate a variety of functions, including how much water is in your body, the acidity of your blood (pH), as well as muscle function.7 Common electrolytes include sodium, potassium, and magnesium. The body loses electrolytes when we sweat, and with enough depletion, dehydration can occur. During exercise, poor electrolyte content can also manifest itself in the form of cramping and spasms.8 Electrolytes are therefore a great complement to an intra-workout formulation, while also viable standalone products.

According to Elliot, sodium and potassium are the electrolytes with the most consumer recognition and are therefore the most popular. And while ready-to-drink (RTD) beverages are the most popular dosage format for hydration and electrolyte products, powder stick packs still remain relevant. “Although stick packs have become a thing of the past for most categories, they are still a popular delivery form for electrolytes,” says Elliot. “They are easy to carry around and throw in bottle of water. You can carry multiple stick packs easily when you travel versus trying to carry multiple bottles. So, while RTDs still dominate the sales in mass for this category, it is the strongest sports category for stick pack sales.”


  1. Branched-Chain Amino Acids (BCAA) – Uses, Side Effects, and More. WebMD. Accessed March 14, 2023.
  2. Anabolism vs. Catabolism: The Role They Play in Your Metabolism. Cleveland Clinic. Accessed March 14, 2023.
  3. Williams, M. Dietary Supplements and Sports Performance: Amino Acids. J Int Soc Sports Nutr. 2005, 2: 63. DOI: 10.1186/1550-2783-2-2-63
  4. Javierre, C.; Segura, R.; Ventura, J.L.; Suarez, A.; Roses, J.M. L-tryptophan Supplementation Can Decrease Fatigue Perception During an Aerobic Exercise with Supramaximal Intercalated Anaerobic Bouts in Young Healthy Men. Int J Neurosci. 2010, 120 (5): 319-327. DOI: 10.3109/00207450903389404
  5. Cheng, I.S.; Wang, Y.W.; Chen, I.F.; Hsu, G.S.; Hsueh, C.F.; Chang, C.K. The Supplementation of Branched-Chain Amino Acids, Arginine, and Citrulline Improves Endurance Exercise Performance in Two Consecutive Days. J Sports Sci Med. 2016, 15 (3): 309-515. PMID: 27803630
  6. Martinho, D.V.; Nobari, H.; Faria, A.; Field, A.; Duarte, D.; Sarmento, H. Oral Branched-Chain Amino Acids Supplementation in Athletes: A Systematic Review. Nutrients. 2022, 14: 4002. DOI: 10.3390/nu14194002
  7. Electrolytes. MedlinePlus. Accessed March 16, 2023.,acidity%20of%20your%20blood%20(pH)
  8. Electrolyte Drinks: Beneficial or Not? Cleveland Clinic. Accessed March 16, 2023.
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