Liothyronine is a bioidentical form of triiodothyronine (T3), the active thyroid hormone that plays a critical role in metabolism, energy production, and hormonal synergy. In men and women undergoing testosterone or bioidentical hormone replacement therapy, Liothyronine is often used to optimize thyroid function, especially when symptoms like fatigue, brain fog, weight gain, or low body temperature persist despite balanced sex hormones. By supporting a sluggish thyroid, it enhances metabolic rate, improves mood and mental clarity, and helps patients feel fully optimized during their TRT or BHRT journey. When used in low, carefully monitored doses, Liothyronine can be a key piece in restoring total-body balance and vitality.