Triiodothyronine (T3) is a synthetic or naturally occurring thyroid hormone that plays a critical role in regulating metabolism, energy production, and body temperature. It is a highly potent form of thyroid hormone, derived from the conversion of thyroxine (T4) in the body. In medical contexts, T3 is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough hormones, as well as certain cases of goitre and thyroid cancer.
In the fitness and bodybuilding world, T3 is often utilised as a fat-burning agent due to its ability to increase metabolic rate and promote weight loss. It is particularly popular during cutting phases to achieve a lean physique. However, misuse can lead to serious thyroid suppression and long-term health complications.

Benefits
Fat Loss
T3 is highly effective at accelerating fat loss, making it a valuable tool during cutting cycles or contest preparation.
Increased Energy
The stimulation of cellular metabolism can boost energy levels, supporting intense training sessions.
Improved Body Composition
By increasing calorie expenditure, T3 helps reduce fat mass while maintaining or enhancing a lean physique (when combined with anabolic steroids).