UT Health San Antonio study finds amino acid supplement may boost exercise benefits for older adults

Feeling tired can make exercise a challenge, especially with age. A new pilot clinical trial at UT Health San Antonio suggests that supplementing with branched-chain amino acids (BCAAs) alongside an exercise program may help reduce fatigue, improve strength, and ease symptoms of depression for older adults.

“We’ve been studying for years how inflammation contributes to functional decline with normal aging or during disease,” said Jason O’Connor, PhD, associate professor in the Department of Pharmacology at The University of Texas at San Antonio and the study’s co-author. “Among the many factors implicated in this process, the metabolism of amino acids appears to play an important role.”

For many people in later life, maintaining an active lifestyle is easier said than done. Physical and mental fatigue can make regular exercise feel out of reach. This new study indicates that adding BCAAs to an exercise routine may help counter both forms of fatigue, enhancing endurance, energy and mood.

Published in the August 2025 issue of Dietetics, the research found that participants who combined a BCAA supplement with an eight-week exercise program experienced notable improvements compared with those who exercised alone. Participants who received BCAAs reported a 45% reduction in fatigue and a 29% decrease in depressive symptoms, along with modest gains in strength and endurance.

BCAAs, which include leucine, isoleucine, and valine, are essential amino acids that support both muscle and brain health. They may reduce mental fatigue, aid in muscle recovery, and activate pathways that prevent muscle breakdown.

The double-blind, placebo-controlled study involved 20 adults with obesity, averaging 70 years of age, who participated in an eight-week regimen of moderate aerobic exercise and strength training. While exercise alone produced modest benefits, combining it with BCAA supplementation led to greater physical performance and improved mood outcomes.

O’Connor and his team plan to expand their research through larger clinical trials, including studies focused on aging veterans. They are also examining the biological connections between BCAA supplementation, inflammation, physical performance and mental health.

While early results are promising, researchers caution additional information is needed before recommending BCAA supplementation more broadly. Individuals should speak with their healthcare provider before starting any new exercise or supplement regimen.

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UT Health San Antonio is the academic health center of The University of Texas at San Antonio (UT San Antonio), offering a comprehensive network of inpatient and outpatient care facilities staffed by medical, dental, nursing and allied health professionals who conduct more than 2.5 million patient visits each year. It is the region’s only academic health center and one of the nation’s leading health sciences institutions, supported by the schools of medicine, nursing, dentistry, health professions, graduate biomedical sciences and public health that are leading change and advancing fields throughout South Texas and the world. To learn about the many ways “We make lives better®,” visit UTHealthSA.org.

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