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When American runner Thomas Hicks won the 1904 Olympic marathon in St. Louis, Mo., he partially attributed the win to his mid-race drink: a concoction of egg whites for protein, a hint of strychnine poison for stimulation and brandy to numb the pain of running.
You would be hard-pressed to find one of today’s top athletes enjoying Hicks’s potent mix halfway through a marathon. They instead are probably sipping on a high-carb or electrolyte-packed drink or gel to remain hydrated.
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Still, the idea that a supplement could improve our health or sport performance continues to tantalize us, regardless of our individual fitness levels. A 2023 study revealed that one in 10 recreational athletes used over-the-counter medication for performance enhancement.
Some people are drawn to pills, plants or magic elixirs because they present an ostensible alternative to spending more hours at the gym or abiding to a healthy diet. In fact, our search for shortcuts has helped the dietary supplements industry grow to a global value of US$44.3-billion – a number expected to nearly double by 2030.
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And yet, despite the stories that companies, influencers and probably that fitness fanatic at your gym with the perpetual protein shake may peddle, not all popular substances will deliver on their promised performance boost.
“It’s important to keep in mind that, while supplements can work, their potential impact is minute compared to proper nutrition, hydration and good sleep,” said Cristina Sutter, a sport dietitian based in Vancouver. “It’s best to consider them the tip of the iceberg of athletic performance.”
Here, we explore the benefits and drawbacks of seven popular dietary supplements to find out if they are worth the hype, and whether or not they might give you an edge on the court, gym or road.
*A note from our experts: The effects of the following substances will depend on individual variability, route of administration and quantity taken. Consult with your doctor about whether adding a new supplement to your training routine is good for you.
Caffeine
Caffeine is so ubiquitous that it sounds silly to consider it a performance-enhancing substance. But the World Anti-Doping Agency had banned it from Olympic competition until 2004 because of its purported benefits to sport. Good news for coffee lovers: The substance was eventually deemed too accessible to regulate.
Still, researchers continue to find evidence that caffeine could lead to performance benefits by boosting endurance and alertness. More specifically, ingesting the equivalent of one medium cup of coffee one hour before exercise has been shown to increase running and cycling performance, reduce perceptions of fatigue and, unsurprisingly, increase attention and vigilance especially in sleep-deprived people.
Here is the kicker: The effects of caffeine vary heavily between people. Daniel Kane, an associate professor in human kinetics at St. Francis Xavier University, said that one’s current relationship with caffeine probably will dictate whether they can expect a rise in performance. Someone who rarely ingests caffeine could see a significant change after drinking brewed coffee or taking a caffeine pill, whereas a seasoned coffee drinker may not enjoy much of a boost.
“Caffeine is so common that many people might just feel like they already need it to get to the start line,” said Kane. “Maybe it enhances performance, but even if all it provides is a placebo effect, there is nothing wrong with that – provided the health risks of coffee remain minimal.”
Creatine
Popular in bodybuilding circles for the past few decades, creatine – a substance we naturally produce and also ingest from meats and fish that helps us convert food into energy – has long been shown to help build muscle and improve performance in explosive activities such as sprinting and weightlifting. Lately, some researchers are also curious about its benefits to recovery and endurance performance.
Several studies have shown that consuming as little as three grams of creatine a day can improve muscle performance and recovery. But evidence that creatine also boosts stamina and aerobic performance is less conclusive. The substance can also increase water retention, which can slow endurance athletes down. For that reason, said Sutter, creatine is probably a better fit for high-intensity athletes such as weightlifters and sprinters.
“Creatine works best if you have low levels of creatine to begin with,” she said. “So, if you are elderly or simply have never experimented with creatine, then you will see an effect.”
Nitrates/beetroot juice
Tart and scarlet-red, beetroot juice is popular in endurance sports in particular because it is high in nitrate: a compound that our bacteria converts to nitric oxide, which dilates blood vessels and potentially improves aerobic performance by delivering more oxygen to the muscles.
A 2021 review of 73 studies that looked at endurance athletes who run, swim or cycle long distances found that supplementation with beetroot (and other vegetables rich in nitrate) improved time to exhaustion by an average of 25 seconds, and distance travelled by 163 metres.
According to Kane, research indicates that recreational athletes might benefit more from beetroot juice than elite ones, but a growing body of evidence suggests that very well-trained individuals might also enjoy a bump in running economy – the efficiency at which your body expends energy when it runs – after consuming it.
Beta-alanine and/or sodium bicarbonate
Anybody who has suffered through a hard mile run or a 400-metre dash remembers the acute, burning muscle pain that inhabited their quads, calves and hamstrings in the final stretch. That awful feeling is a product of metabolic acidosis: a drop in pH in the body, brought on by intense exercise.
In the past few decades, said Kane, substances with the ability to buffer that drop in pH and delay pain are gaining popularity, such as the amino acid beta-alanine, or sodium bicarbonate (you might know it by its street name, baking soda).
Many studies have demonstrated that taking three to six grams of powdered beta-alanine over at least four weeks can delay muscle fatigue in intense exercise that lasts between one and 10 minutes – like a one-mile race or a single tennis set. Similarly, a 2020 study found that supplementing bicarbonate boosted muscle endurance, but found no effect on muscle strength.
According to Kane, the bicarbonate-curious are better off with regulated supplements, as opposed to sneaking a spoonful of baking soda from the cupboard before heading out for a hard workout, which can lead to dehydration, diarrhea and kidney problems when ingested in high concentrations. Timing is also crucial.
“There is a narrow window of effect of a few hours with these buffers,” he said. “If you take it in the morning, you will see no difference in the afternoon because their half-life appears to be short.”
Cannabidiol (CBD)
Although cannabis has been legalized in Canada for five years now, WADA still bans athletes from using it in competition. Top sprinter Sha’Carri Richardson was handed a two-year doping ban when drug testing revealed traces of THC – the psychoactive compound in marijuana – in her bloodstream shortly after she won the 100 m at the 2020 U.S. Olympic trials. But had she tested positive for cannabidiol (or CBD), another popular compound found in cannabis thought to help with recovery, she would have received no sanction.
CBD produces no high, is fair game for use in sport and can be consumed through oils, creams or tablets. Sutter said the potential benefits of CBD on sleep quality and pain management could allow athletes to train harder and better recover between sessions, but a dearth of research around the compound prevents experts from confirming or denying its usefulness in sports.
“It may be helpful in extreme cases where you’re battling gruelling training conditions, pain and inflammation, but it’s not like it would improve performance,” she said.
Ginseng
There is some evidence that ginseng – a plant root used medicinally, predominantly in eastern cultures – could increase exercise performance by boosting energy and delaying fatigue. One study showed that 1.35 g of ginseng ingestion for 30 days helped untrained adults delay exhaustion in a cycling test.
But Sutter is not convinced that the supplement is worth a try, in part because ginseng products on Canadian shelves rarely come in pure form. One analysis found that only nine of 22 ginseng supplements available to consumers passed a quality control test, with eight containing greater-than-allowed pesticide levels.
“It’s extraordinarily difficult to find ginseng that is not tainted with something else,” she said. “In general, when you buy supplements, nobody tests their purity – it’s not like prescription medication – so it’s notoriously inconsistent.”
What’s worse, she said, is that ginseng could potentially alter cardiological or pulmonary function, and interact with a number of medicines.
“For those reasons, I give a hard no to ginseng supplements.”
L-carnitine
L-carnitine, a naturally occurring chemical that helps convert fat into fuel, is a popular ingredient in energy drinks. The idea is that it could help people lose weight and give them extra spunk in the process.
“That’s the theory, but it doesn’t seem to work,” said Sutter. She cites recent research which shows that to see l-carnitine increase in the body, one would have to take a massive amount of carbs with it. That in itself would make you gain weight, so it defeats the purpose.
“No study has shown that l-carnitine supplements lead to fat loss or fat oxidation – all the theories haven’t translated, so I would steer clear.”