If you were to flip through a fitness magazine in the checkout aisle of your local grocer, you'd run across a veritable library of supplement ads, but you might not find anything for endurance athletes. The ripped bodies on those glossy pages could easily fool you into thinking that every supplement on the market is geared toward getting you jacked, but—thankfully—you couldn't be more wrong.

Endurance athletes typically spend hours on end doing continuous activity, whether it's tracking 50-60 miles per week of running, putting over 200 miles a week on their road bikes, or swimming hundreds of laps in the pool. This sheer volume of training, added to a couple of resistance-training sessions a week, means that endurance athletes should be paying extremely close attention to their diet and supplementation.

Endurance training puts extreme demands on athletes' bodies from a physical, mental, and energy standpoint. As if the time required to train for endurance activities wasn't enough, throw in the time required to prep and eat nutrient-dense foods to replenish energy and you quickly run out of hours in the day.

Endurance training puts extreme demands on athletes' bodies from a physical, mental, and energy standpoint.

Thankfully, with the right supplement stack, you can shave some time off your prep time, boost your performance and recovery, and get on your way to crushing a new PR. Here's our list of the top seven supplements endurance athletes should consider!

1. Creatine Monohydrate

Creatine supplementation and endurance exercise aren't typically linked in the same sentence. We think of creatine in terms of strength, speed, and power—and for good reason. There are hundreds of published research studies supporting creatine's use as an effective ergogenic aid for improving muscular strength and size. While many will argue creatine has no place in an endurance athlete's supplement stack, we beg to differ.

If you can look past the direct effects of creatine—and increase in phosphocreatine stores, rapid increase in ATP production, and improved anaerobic performance—you'll see that creatine supplementation can offer indirect benefits to runners, cyclists, and triathletes, and help take their training to the next level.

Interval workouts at lactate threshold, speed work, and hill training are common—and often dreaded—techniques used to improve running efficiency and performance times. The higher the quality of these sessions, the faster you'll be crossing the finish line.

Creatine supplementation has been shown to decrease recovery time during repeated intervals, and increase power output at lactate threshold.[1,2] Improvements in speed, power, and running economy during your training sessions translates to better race-day performance!

Recommended Dose: 3-5 grams per day. Skip over the traditional loading phase often used with creatine supplementation. The initial weight gain, which is caused by an increase in total body water, may slow down performance.

2. Caffeine

Caffeine has long been used by endurance athletes to boost performance. Not only does it provide a quick pick-me-up for those early morning training sessions, but caffeine's ability to reduce perception of effort and help delay fatigue can make those longer runs more bearable.

There have been numerous studies highlighting the benefits of caffeine consumption on endurance performance, including improvements in cycling and cross-country skiing performance, 8-kilometer run times, and faster time trials.[3-6] As an added bonus, caffeine can increase fat oxidation, which can help with weight management.

Since caffeine reaches its highest blood concentration in about an hour, we suggest taking it about 60 minutes before a race so it can help you power through a 5K or 10K—or even a marathon! And although caffeine is a diuretic—meaning that it increases urine production—a recent review article from researchers at the University of Connecticut (Storrs) suggested that caffeine consumption doesn't cause water-electrolyte imbalances or reduce exercise-heat tolerance.[7]

Recommended Dose: 1.3-2.7 milligrams per pound of body weight (200-400 milligrams for a 150-pound individual) 60 minutes prior to exercise.

3. Beta-Alanine

We know beta-alanine supplementation has been shown to improve performance and delay fatigue during high-intensity activity, but is this relevant to endurance athletes? Well, just because you're an endurance athlete doesn't mean you train exclusively at low-intensity exercise, right?

Tempo runs, race pace, and even lifting to improve running economy are all aspects of your training that'll benefit from beta-alanine supplementation. In fact, several studies have found positive effects on endurance performance, including cycling performance and rowing times, with beta-alanine supplementation.[8,9]

During highly intense training sessions, your body accumulates hydrogen ions. These hydrogen ions contribute to lowering pH, which ultimately results in fatigue. Beta-alanine, an amino acid derivative, has been shown to increase intramuscular carnosine content, which can increase the body's ability to buffer hydrogen ions. This can potentially delaying fatigue and improve exercise performance, training volume, and reduce perceptions of fatigue.[10-12]

Recommended Dose: 3-6 grams per day, taken in 800 milligram doses throughout the day to reduce the effects of paresthesia, a temporary tingling or numbness akin to when a limb falls asleep.

4. Sodium Phosphate

Commonly used as a preservative for meats and other foods, sodium phosphate can now add "performance booster" to its resume. Sodium phosphate loading has been shown to increase aerobic capacity and time to exhaustion by enhancing the ability of red blood cells to deliver oxygen to active muscles.[13-15] Additionally, several studies have found improvements in endurance performance by means of increases in maximal oxygen uptake and ventilatory threshold.[16,17]

Recommended Dose: 3-5 grams per day, taken in single gram doses for 3-6 days before an endurance event.

Sodium phosphate can now add "performance booster" to its resume.

5. Branched-Chain Amino Acids (BCAAs)

If you're headed out for a long run or bike ride, don't leave behind your BCAAs. One mechanism of central fatigue in exercise is free tryptophan crossing the blood-brain barrier (BBB). One downside of tryptophan is that it aids in the release of certain neurotransmitters—serotonin, in particular—that can affect arousal, sleepiness, mood, and ultimately fatigue.[18]

Since BCAAs and tryptophan compete for the same protein carrier, increasing BCAA concentrations can reduce the amount of tryptophan crossing the BBB, potentially delaying fatigue. And there's more: The metabolism of BCAAs has been shown to decrease lactate production, potentially increasing your endurance exercise capacity.[19,20]

Substantial evidence also suggests BCAAs can reduce skeletal muscle protein breakdown and promote recovery and immune response from exercise.[21,22]

Recommended Dose: 3-6 grams before or during exercise. A ratio of 2:1:1 leucine:isoleucine:valine appears to be most beneficial.

6. Protein

Endurance athletes need protein! We don't care if you're eating gluten-free, low-carb, low-fat, paleo, or whatever the latest diet trend is—you need protein. While it's not uncommon for endurance athletes to place more focus on carbohydrate intake, protein is essential for the repair, construction, and maintenance of your muscle mass.

Additionally, when you exercise for prolonged periods of time, your body turns to protein as an additional source of energy, making it even more important to consume adequate protein so that you don't sacrifice your muscle tissue!

If you want to get the most out of your protein supplement, try consuming it with a carbohydrate, as the combination of macronutrients may lead to superior rates of protein and glycogen synthesis.

Recommended Dose: 0.5-0.7 grams per pound of body weight daily. During periods of high-volume or intense training, consider increasing your protein intake to 0.9 grams per pound of body weight to help with maintenance and repair of lean body mass.[23]

7. Glutamine

Glutamine is the most abundant amino acid found in the body, so why do you need to supplement with it? Intense physical activity can actually drain glutamine stores faster than your body can replenish them, which can unfortunately cause your body to break down its own muscle, leaving you in a catabolic state. Low levels of glutamine can also compromise your immune system, increasing your risk for infections.

Glutamine supplementation has been shown to aid in recovery, in addition to boosting immune function following exhaustive exercise. A study published in the European Journal of Applied Physiology and Occupational Physiology surveyed more than 200 runners and rowers and found that 81 percent of athletes supplementing with glutamine reported no infections after intensive training, compared to only 49 percent in the placebo group.[24] In short, this study suggests that glutamine supplementation may reduce your vulnerability to infections after prolonged exercise, helping you to train hard and recover fast.

Recommended Dose: 20 grams per day

References

1. Cottrell, G. T., Coast, J. R., & Herb, R. A. (2002). Effect of recovery interval on multiple-bout sprint cycling performance after acute creatine supplementation. The Journal of Strength & Conditioning Research, 16(1), 109-116.
2. Oliver, J. M., Joubert, D. P., Martin, S. E., & Crouse, S. F. (2013). Oral Creatine Supplementation’s Decrease of Blood Lactate During Exhaustive, Incremental Cycling. International Journal of Sport Nutrition and Exercise Metabolism, 23(3), 252-258.
3. Desbrow, B., Biddulph, C., Devlin, B., Grant, G. D., Anoopkumar-Dukie, S., & Leveritt, M. D. (2012). The effects of different doses of caffeine on endurance cycling time trial performance. Journal of Sports Sciences, 30(2), 115-120.
4. Glaister, M., Pattison, J. R., Muniz-Pumares, D., Patterson, S. D., & Foley, P. (2015). Effects of Dietary Nitrate, Caffeine, and Their Combination on 20-km Cycling Time Trial Performance. The Journal of Strength & Conditioning Research, 29(1), 165-174.
5. Bridge, C. A., & Jones, M. A. (2006). The effect of caffeine ingestion on 8 km run performance in a field setting. Journal of Sports Sciences, 24(4), 433-439.
6. Stadheim, H., Kvamme, B., Olsen, R., Drevon, C., Ivy, J., & Jensen, J. (2013). Caffeine Increases Performance in Cross-country Double-Poling Time Trial Exercise. Medicine & Science in Sports & Exercise, 45(11), 2175-2183.
7. Armstrong, L. E., Casa, D. J., Maresh, C. M., & Ganio, M. S. (2007). Caffeine, fluid-electrolyte balance, temperature regulation, and exercise-heat tolerance. Exercise and Sport Sciences Reviews, 35(3), 135-140.
8. Van Thienen, R. V., Van Proeyen, K., Vanden Eynde, B., Puype, J., Lefere, T., & Hespel, P. (2009). b-Alanine improves sprint performance in endurance cycling. Medicine and Science in Sports and Exercise, 41(4), 898-903.
9. Baguet, A., Bourgois, J., Vanhee, L., Achten, E., & Derave, W. (2010). Important role of muscle carnosine in rowing performance. Journal of Applied Physiology, 109(4), 1096-1101.
10. Jordan, T., Lukaszuk, J., Misic, M., & Umoren, J. (2010). Effect of beta-alanine supplementation on the onset of blood lactate accumulation (OBLA) during treadmill running: Pre/post 2 treatment experimental design. Journal of the International Society of Sports Nutrition, 7(1), 20.
11. Harris, R. C., Tallon, M. J., Dunnett, M., Boobis, L., Coakley, J., Kim, H. J., ... & Wise, J. A. (2006). The absorption of orally supplied β-alanine and its effect on muscle carnosine synthesis in human vastus lateralis. Amino Acids, 30(3), 279-289.
12. Howe, S. T., Bellinger, P. M., Driller, M. W., Shing, C. M., & Fell, J. W. (2013). The effect of Beta-Alanine supplementation on isokinetic force and cycling performance in highly trained cyclists. International Journal of Sport Nutrition and Exercise Metabolism, 23(6), 562-70.
13. Folland, J. P., Stern, R., & Brickley, G. (2008). Sodium phosphate loading improves laboratory cycling time-trial performance in trained cyclists. Journal of Science and Medicine in Sport, 11(5), 464-468.
14. Kreider, R. B., Miller, G. W., Schenck, D., Cortes, C. W., Miriel, V., Somma, C. T., ... & Hill, D. (1992). Effects of phosphate loading on metabolic and myocardial responses to maximal and endurance exercise. International Journal of Sport Nutrition, 2(1), 20-47.
15. Czuba, M., Zaj?c, A., Poprzecki, S., & Cholewa, J. (2008). [The influence of sodium phosphate supplementation on VO2max, serum 2, 3-diphosphoglycerate level and heart rate in off-road cyclists](The influence of sodium phosphate supplementation on VO2max, serum 2, 3-diphosphoglycerate level and heart rate in off-road cyclists. Journal of Human Kinetics). Journal of Human Kinetics, 19, 149-164.
16. Czuba, M., Zajac, A., Poprzecki, S., Cholewa, J., & Woska, S. (2009). Effects of sodium phosphate loading on aerobic power and capacity in off road cyclists. Journal of Sports Science & Medicine, 8(4), 591.
17. Kreider, R. B., Miller, G. W., Williams, M. H., Somma, C. T., & Nasser, T. A. (1990). Effects of phosphate loading on oxygen uptake, ventilatory anaerobic threshold, and run performance. Medicine and Science in Sports and Exercise, 22(2), 250-256.
18. Blomstrand, E. (2006). A role for branched-chain amino acids in reducing central fatigue. The Journal of Nutrition, 136(2), 544S-547S.
19. Matsumoto, K., Koba, T., Hamada, K., Tsujimoto, H., & Mitsuzono, R. (2009). Branched-chain amino acid supplementation increases the lactate threshold during an incremental exercise test in trained individuals. Journal of Nutritional Science and Vitaminology, 55(1), 52-58.
20. Gualano, A. B., Bozza, T., De Campos, P. L., Roschel, H., Costa, A. D. S., Marquezi, M. L., ... & Junior, A. H. L. (2011). Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. The Journal of Sports Medicine and Physical Fitness, 51(1), 82-8.
21. Matsumoto, K., Mizuno, M., Mizuno, T., Dilling-Hansen, B., Lahoz, A., Bertelsen, V., ... & Hamada, K. (2007). Branched-chain amino acids and arginine supplementation attenuates skeletal muscle proteolysis induced by moderate exercise in young individuals. International Journal of Sports Medicine, 28(6), 531-538.
22. Negro, M., Giardina, S., Marzani, B., & Marzatico, F. (2008). Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system. The Journal of Sports Medicine and Physical Fitness, 48(3), 347-51.
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