How are FT3 and Abnehmen related?

The relationship between FT3 (free triiodothyronine) and weight loss is complex and not fully understood. FT3 is the active thyroid hormone that increases basal metabolic rate. During caloric restriction, FT3 often decreases as an adaptive mechanism (euthyroid sick syndrome), which can slow weight loss. Conversely, elevated FT3 (as in hyperthyroidism) increases metabolism and causes weight loss, but this is pathological. Observational studies suggest that lower FT3 levels may predict difficulty losing weight, but causality is not established. Evidence is human-observational/moderate. FT3 should be interpreted alongside TSH, FT4, and clinical context. Manipulating FT3 for weight loss is not recommended and may be harmful.