The Dangers of Preworkout Supplements

Targeted preworkout supplements are a relatively new fitness strategy.
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Preworkout supplements are products taken prior to physical exercise or sports activities and are designed to enhance various areas of fitness conditioning. Some of these areas include increased strength, endurance, alertness and metabolism. While preworkout supplements have purported benefits, as with any dietary/nutritional supplement, there are possible dangerous side effects.


    In fitness conditioning, strength performance centers on your muscles' ability to lift or maneuver varying amounts of weight. One of the supplements used to enhance strength performance is creatine. Your body uses creatine as a type of catalyst to replace a substance within muscles that supports muscle contraction for strength, called adenosine triphosphate, or ATP. By helping your muscles keep ample supplies of ATP, creatine helps maximize strength during workouts. However, the Mayo Clinic reports that even recommended doses of creatine could cause diarrhea, nausea and cramping; and high doses of creatine are linked to damaging heart, kidney and liver function. Weight gain is also a possible side effect, according to the Mayo Clinic.


    While strength refers to your ability to move or lift weight, endurance pertains to how long you can sustain muscle activity and/or general physical activity. Certain amino acids are among the supplement types used to increase endurance. One of these amino acids is beta-alanine. Beta-alanine is supposedly useful for conditioning because of the secondary substance it produces in your body, called carnosine.

    Carnosine's antioxidant properties help increase endurance by ultimately buffering capillaries and offsetting oxidative stress, which delays muscular fatigue. However, the Human Performance Research Center states that potential adverse effects in taking beta-alanine supplements may include varying levels of skin flushing and paresthesia, which is also known as the “pins and needles” sensation.

Alertness and Metabolism

    Mental alertness allows you to focus more efficiently on your fitness-conditioning activities, which ultimately can help to maximize your overall results. Maintaining a healthy body-fat ratio is another important aspect of fitness conditioning. Caffeine is a supplement that's used to address both of these concerns. It's one of the most common supplements, because it can be ingested through everyday beverages such as coffee and tea. Caffeine functions as a central nervous system stimulant. So, in addition to enhancing performance by increasing alertness, caffeine also serves as a fat burner by raising your metabolism.

    However, while small to moderate doses of caffeine may be beneficial, excessive amounts are counterproductive, by actually impairing performance and causing fatigue. Also, as the Australian Sports Commission points out, what's considered small, moderate or high dosing greatly varies among individuals. Additional side effects may include sleep impairment and withdrawal symptoms ranging from headaches to lethargy. The occurrence and intensity of side effects also greatly vary.

Additional Considerations

    Health-care professionals have reported that possible drug interactions and/or pregnancy complications are associated with each of these supplements. These supplements may also have adverse effects on other existing medical conditions, such as heart disease, diabetes and thyroid disorders. Exercisers are advised to consult their physician before taking any preworkout supplement.

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