Safest Pre-Workout Supplements

No pre-workout supplement is completely safe for everyone because there's the potential for a negative side effect when you add any supplement or food to your routine. Pre-workout supplements are designed to give you a boost so you can power through your workouts with good stamina. Of the common supplements on the market, creatine, citrulline and beta-alanine are relatively safe when taken in typical amounts, according to Jose Antonio, Ph.D., in the book "Sports Nutrition & Performance Enhancing Supplements." Only take performance-enhancing supplements with your doctor's permission.

Avoid taking higher than recommended amounts. (Image: Andersen Ross/Blend Images/Getty Images)

Beta-Alanine

Beta-alanine is a building block of a substance your muscles use called carnosine. Increasing the level of carnosine in your muscles is linked to improved exercise performance, according to researchers of a study that appears in the April 2009 issue of the journal Medicine and Science in Sports and Exercise. They conducted a double-blinded study evaluating the effect of beta-alanine on endurance cycling. Beta-alanine significantly increased sprint performance at the end of high-intensity endurance bouts, according to the results.

Citrulline Malate

When you exercise, substances like ammonia and lactate build up in your muscles and cause soreness, leading to fatigue. Citrulline malate is a byproduct involved in the urea cycle that appears to help circumvent these effects to improve athletic performance. In a double-blinded study, participants who took citrulline before a barbell bench press significantly boosted the number of repetitions they performed compared to those taking a placebo. It also reduced post-exercise muscle soreness, according to the results, which were published in the May 2010 issue of the Journal of Strength and Conditioning Research.

Creatine Monohydrate

Creatine is a staple in the sports performance community. It's a substance that helps your body produce cellular energy in the form of ATP -- a high-energy molecule. Clinical trials have shown positive benefits of using creatine before workouts. In one such study, creatine significantly increased total power output in healthy males performing high-intensity interval training. The results were published in The Journal of Sports Medicine and Physical Fitness in December 2005.

Supplement Safety

The long-term safety of pre-workout supplements remains unproven. While no serious effects have been reported from using beta-alanine, citrulline or creatine as stand-alone ingredients, the risk of adverse events increases when these are used in combination with other substances. To reduce the risk of side effects, avoid formulas that contain multiple active ingredients. Citrulline may cause mild stomach discomfort, while mild tingling sensations have been reported with high doses of beta-alanine. Taking creatine may cause muscle cramps, water weight gain, loose stool and abdominal discomfort. These side effects are typically mild and temporary.