When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Everyone wants to get the most out of the time they spend exercising, and "preworkout" supplements claim to help you do exactly that. It might be tempting to try one of these supplements before hitting the gym or heading out for a run, in hopes of increasing your energy levels, muscle power or endurance during your workout. Preworkout supplements often contain a mystery blend of ingredients ranging from caffeine to guarana to creatine. But do these supplements work, and are they safe to take? It turns out that these supplements may just change the way you feel while you're working out. Moon told Live Science. But those physical effects don't make people bigger, stronger or www.PrimeBoosts.com faster, Moon said. And although some of these supplements' ingredients - such as caffeine, creatine and beta-alanine - have been shown to modestly enhance performance in extreme athletes and bodybuilders, they only give people an edge if they are pushing themselves to the limit, Moon said.

And some supplements on the market may contain illegal and dangerous additives, such as amphetaminelike stimulants. Even supplements that contain only legal ingredients can include high levels of caffeine, which can have a negative effect on the heart, recent testing by one independent lab found. Get the world’s most fascinating discoveries delivered straight to your inbox. Several studies have shown that taking caffeine can provide a physical boost before a workout. For instance, a 2012 study in the Journal of Strength Conditioning and Resistance found that men who took caffeine supplements could deadlift, bench-press and do other heavy lifting at greater weights compared with men who took a placebo. Other studies have suggested that runners and rowers can increase their aerobic capacity with a dose of caffeine, although the studies noted that the benefits of caffeine tend to wane as people develop a tolerance to it. However, too much caffeine can pose a health risk, and supplements can contain much more than is found in food or drinks.

A person could guzzle gallons of coffee and not suffer from a true caffeine overdose. But even at much lower levels, caffeine can worsen underlying conditions such as a heart arrhythmia, leading to cardiac arrest. In recent testing, the supplement testing company LabDoor michaelgreis.org looked at 45 popular preworkout supplements and found that many contained extremely high doses of caffeine. One supplement contained 435 milligrams of caffeine - almost as much as four cups of coffee. The research has not been published in a peer-reviewed journal, meaning it has not gone through the standard process used to vet scientific findings. Although the lab found that none of the s may be misleading because there's no good research on what dose may be effective for many of the supplement ingredients, some of which act synergistically. And consumers should know that supplement makers often tweak their products' formulations every four or five months, so testing from companies like LabDoor will always be "playing catch-up" with these products, Moon added. Other common preworkout ingredients include the B vitamin niacin, which can cause sweatiness and blood flow to the skin called a "niacin flush," and vasodilators, such as citrulline, which widen blood vessels.