TOFA Burns Mouse Fat Without Muscle Loss
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- TOFA (5-tetradecyloxy-2-furoic acid) increased energy expenditure in obese mice by up to 18% without raising body temperature or physical activity, per a study published August 21 in Science Advances.
- The compound works through a dual mechanism — inhibiting lipid production as an ACC inhibitor while simultaneously activating PPARα and PPARδ receptors that switch on fat-burning genes — distinguishing it from prior ACC inhibitors that raised triglyceride levels.
- Obese mice treated with TOFA lost fat while preserving lean muscle mass and showed improved insulin sensitivity, lower triglycerides, and reduced signs of fatty liver disease, according to the study led by UC Berkeley professor Anders Näär and first author Justin Y. Lee.
- TOFA outperformed a two-drug combination pairing a lipid-suppressing compound with a separate energy-expenditure compound, suggesting the single molecule's integrated mechanism matters more than the sum of its parts.
- Combined with GLP-1 drugs — semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) — TOFA produced larger improvements in body weight, glucose control, insulin, and triglycerides than either treatment alone, with researchers describing the effect as additive or synergistic.
- TOFA was first identified in the 1970s and has never been approved for metabolic disease; the researchers have launched ReRx Therapeutics with backing from Berkeley's Nucleate and SkyDeck programs to advance the compound toward human trials.
Why it matters: GLP-1 drugs like Ozempic and Wegovy risk muscle loss because they work by cutting calories, not burning energy. TOFA takes the opposite lever — raising metabolic rate — and in mice stacks additively with GLP-1s without eroding lean mass. The finding gives the makers of Ozempic and Wegovy a candidate combination partner aimed at the muscle-loss problem in long-term patients.
Ask SkimNews
