This post was written by Chioma Oguagha, PharmD, Parkview Health.
Have you ever taken a pre-workout supplement and shortly after, experienced intense itching? This is a common experience and is often caused by beta-alanine, an ingredient often included in pre-workout products. Although the sensation can be uncomfortable, it is usually temporary and is not a sign of an allergic reaction.
What's happening
Beta-alanine is an amino acid often found in sports supplements. It helps increase carnosine in the muscles. During intense exercise, muscles can build up acid, which can make them feel tired. Higher carnosine levels help reduce this buildup, allowing muscles to work longer before getting tired.
The National Institutes of Health (NIH) Office of Dietary Supplements suggests that consuming beta-alanine doses of 800 mg or more can produce moderate-to-severe paresthesia in some people, which can feel like a tingling, itching, burning or prickling sensation. This reaction is most frequently felt on the face, neck, hands and upper body.
Beta-alanine-related paresthesia is caused by activation of sensory nerve pathways. Unlike itchiness from an allergic immune reaction, the body does not release histamine or cause a rash or hives. The response is usually temporary and lasts about 60-90 minutes. Smaller doses or a sustained-release formulation may alleviate the severity of this impact.
Other sources of itching or flushing
Another common supplement found in pre-workout mixes that may cause itching is niacin (vitamin B3). Nicotinic acid, a type of niacin, can cause a brief "flush," which is characterized by warmth, redness, burning and itching as blood vessels near the skin become larger. This effect is more likely to occur when taking higher doses, such as 30 to 50 mg or more. Niacinamide, another form of niacin sometimes found in exercise supplements, does not normally cause flushing.
Although this nutrient is essential for converting food to energy, current research suggests little to no benefit to taking it right before a workout. The flushing effect may make the supplement feel more noticeable, but it doesn't indicate improved performance. Most people without a vitamin B3 deficiency can meet their daily niacin needs through their diet by eating foods like chicken and turkey breast, yellowfin tuna, peanut butter, brown rice and fortified breakfast cereals.
Exercising caution
While beta-alanine and niacin in pre-workout supplements are often non-allergic causes of itching or flushing, it is essential to read the full Supplement Facts panel before consumption, as adverse reactions may also occur if a person is sensitive or allergic to certain ingredients.
Common ingredients in pre-workout supplements, like botanical extracts, flavorings, color additives, caffeine and other substances, may cause a serious allergic response. Stop taking and/or seek medical attention if you experience the following symptoms:
- Hives
- Severe rash
- Swelling of the lips or tongue
- Wheezing
- Difficulty breathing
- Dizziness
- Fainting
Final thoughts
Dietary supplements, including pre-workout, are not approved by the U.S. Food and Drug Administration for safety or effectiveness before they are sold. Always review the supplement's ingredients, and consider talking with a pharmacist or your primary care provider if you experience an undesired reaction. They can help determine what's causing the reaction.
For more information on pharmacy services, contact or visit a location near you.
References
U.S. Food and Drug Administration. (n.d.). How to report a problem with dietary supplements.
