Athletes looking for even the slightest edge often turn to a wide variety of supplements—called ergogenic aids—that are supposed to boost performance. Many weekend exercisers, seeking to enhance their workouts, also try such supplements. We’re not talking about anabolic steroids, which enhance strength and performance but are dangerous and thus banned in most sports. Rather, these are ordinary dietary supplements; two of them— caffeine and baking soda—are found in many foods. Just how “ordinary” are these ergogenic aids? Are they safe? Effective? Here’s an update.
Keep in mind that the great majority of studies on ergogenic aids have been small and short and have involved highly trained athletes or at least young fit subjects, usually men. So it’s not known if, or how much, the results apply to casual exercisers and older people as well as to different types of exercise. It’s also not known whether any benefits would persist with longer use or if adverse effects would increase.
Caffeine: can give a boost
Many, but not all, studies have found that caffeine, consumed in a beverage or a pill, can boost endurance, reduce fatigue and/or improve sprint performance. It may allow people to exercise longer by helping the body break down fats for use as energy, thus sparing carbohydrates. Some of caffeine’s chief effects are on the nervous system—it works with various brain chemicals to improve alertness and reduce perceived effort during exercise. That is, it can make a workout feel easier, so you’re able to do it more strenuously or longer.
People respond differently to caffeine, however. For instance, those who regularly consume caffeine build up a tolerance for it and thus may not derive as much benefit from it. On the other hand, in people not used to caffeine, high doses can cause jitteriness that may hurt performance and may boost heart rate and blood pressure excessively.
Creatine: holds promise
Made from three amino acids (building blocks of protein), this compound is found in meat, poultry and fish. It is also made in the body, mostly in the liver, and is stored mostly in muscle, where it helps replenish a compound called adenosine triphosphate (ATP), which supplies quick energy.
Creatine supplementation has been likened to carbohydrate loading, except that the latter boosts performance in endurance (that is, aerobic) events such as marathons, while creatine primarily helps in activities involving repeated bursts of high-intensity exertion that last less than a minute (anaerobic). Most studies have found that it has some benefit for sprinting, jumping, and weightlifting. A 2010 review paper from the International Society of Sports Nutrition concluded that creatine is the most effective nutritional supplement to boost muscle mass and strength and increase capacity for high-intensity exercise. If your creatine stores are already high, however, supplements may not help.
Creatine appears to be safe—up to five grams a day—in healthy people, though there are lingering concerns about its effects on the kidneys, especially in older people and people with kidney problems. It can sometimes cause gastrointestinal upset.
Sodium bicarbonate: probably not worth It
Some athletes consume sodium bicarbonate (baking soda) hoping to neutralize the lactic acid that builds up in blood and muscles during intense exercise, causing fatigue and impairing performance. Researchers have studied these proposed benefits of sodium bicarbonate for decades, mostly for sprint-type exercise but also for endurance events. An analysis published in the Journal of Strength & Conditioning Research in 2012 concluded that the evidence is conflicting. If sodium bicarbonate has a beneficial effect on performance, it’s minimal. Besides being very high in sodium, it can cause severe bloating and abdominal cramps, which can be a problem during a race or any activity. If you have kidney problems, it can be dangerous.
Antioxidant supplements: useless, at best
Vigorous exercise increases the production of cell-damaging free radicals in the body, which may contribute to muscle soreness and inflammation after a workout. That’s why some experts have advised exercisers to take high doses of antioxidants such as vitamins C and E, since these help counter free radicals. But there’s a delicate balance between antioxidants and free radicals, and it’s now known that free radicals also play some beneficial roles in the body. That is, the “good guys” are not always good, and the “bad guys” not always bad.
Studies have yielded conflicting findings about the effect of antioxidant supplements on exercise performance, with more recent ones raising some red flags. In 2009 a widely publicized German study suggested that instead of protecting athletes, high doses of vitamins C (1,000 milligrams) and E (400 IU) can block some of the benefits of exercise, notably its ability to improve insulin sensitivity and boost the body’s natural antioxidant system. Another study found that high doses of C can have a negative impact on mitochondria, which produce energy in cells.
There’s “more robust” evidence for negative effects of antioxidants in exercise than for positive effects, according to a letter by Spanish and German researchers in the American Journal of Physiology, Endocrinology and Metabolism in 2012. It concluded that antioxidant supplements are, at best, useless—for everyone.
Amino acids: not necessary
There’s an endless array of protein supplements, including whey and casein (found in milk) and a variety of isolated amino acids (protein’s building blocks). The so-called branched chain amino acids (leucine, isoleucine and valine) are especially popular with weight lifters. Some studies have found that these or certain other amino acids can boost protein synthesis and thus help build muscle from resistance training and reduce muscle damage and soreness caused by exercise. But other studies have found little or no benefit. In general, excess protein is broken down in the body and burned for energy or turned into fat. What’s more, amino acid supplements often contain an array of questionable ingredients.
Most active people don’t need to consume extra protein, in any case, since the average American diet supplies more than enough protein. Still, research suggests that eating high-protein food after moderately intense strength training can boost muscle synthesis during the next several hours, which can be particularly important for older people. That doesn’t require amino acid supplements, however.
Hormone boosters: definitely no
Also called testosterone boosters, steroid precursors or prohormones, this large ever-changing group of supplements is particularly problematic. The government has banned over-the-counter sale of dozens of these compounds (including androstenedione) because they contain hidden anabolic steroids or steroid-like substances, which are potentially dangerous; they are now regulated as controlled substances. But marketers simply wiggle around the ban to produce other hormone-related “muscle-building” supplements, which may be no safer than the earlier ones. Among the common ingredients still on the market are DHEA (though banned by the World Anti-Doping Agency), the herb Tribulus terrestris, and the flavonoid chrysin.
The supplements are supposed to build muscle and enhance athletic and sexual performance by mimicking testosterone and/or estrogen or affecting their levels in the body. But most have no effect on testosterone. And there’s little or no evidence that supplements that do boost testosterone (or compounds related to it) have any significant effect on athletic performance.
Experimenting with hormones or anything that may affect them is always risky. Among the potential long-term adverse effects of these products are blood-clotting disorders, increased aggression, reduced HDL (“good”) cholesterol and liver or kidney damage. In men, they can also cause breast enlargement, testicle shrinkage, increased body hair and accelerated growth of prostate cancer. In women, they could cause male pattern baldness, excessive facial hair, deepened voice and possibly abnormal menstruation and increased risk of breast cancer.
Bottom line: If you want to build muscle, lose fat or run, swim or cycle faster, you’re better off with a solid training program and healthy diet than with supplements. In any case, the small effect some of these supplements may have would be meaningless for recreational athletes or exercisers, though the risks are just as great. In particular, if you are counseling children or teenagers who want to excel in sports, persuade them to do it through training, not pills.