today's discovery hinges on a specific kind of fatThe drug targets a receptor called the β3-adrenergic receptor. It's expressed in a variety of places, like the bladder — but also on fat cells. That's what led the researchers to wonder if the compound might aid in burning energy. So the scientists gave 12 male volunteers four times the approved dose of Mybetriq. In all 12, the drug boosted metabolic activity, and increased the number of calories they burned while resting by an average of 200 calories at the peak of the drug's effectiveness. Over time, that works out to about an extra pound of fat burned off every two and a half weeks — without any additional effort. That is, assuming there aren't any complicating factors, says study author Aaron Cypess, who conducted the research when he was at the Joslin Diabetes Center and Harvard University (he is now the section head of translational physiology at the National Institutes of Health). He cautioned that his study was more of a snapshot than a movie; it's not clear what the effects of Myrbetriq are over the course of 12 or 24 hours. That research is next on his list; so is figuring out whether it's possible to induce brown fat activation with a lower dose. In other words: don't try this at home.

Image of brown fat activation with Mybetriq (Courtesy Aaron Cypess)

"It's an explosion."A slew of research into brown fat followed that initial meeting. Some researchers have examined ways to convert white fat to brown fat; other research, like today's, has focused on making brown fat more effective at burning off calories. Yesterday, researchers at Scripps announced a novel compound that also targets brown fat efficiency, though its mechanism of action is different; it's only been tested in mice so far, though human trials aren't far off. They actually hadn't expected the effect, says study author Michael Downes.

it's the first way to activate brown fat without cold exposureMybetriq also may not be ready for prime-time as a weight loss drug. But it's the first way to activate brown fat without cold exposure, Cypess says. That'll make it easier for scientists to study brown fat, since setting up the cold-exposure studies is difficult and expensive. He also doesn't think drugs that stimulate brown fat will be enough to spur weight loss on their own; rather, he sees them as a tool to make diet and exercise easier for people who are overweight. Brown fat is very good at absorbing blood sugar, which is helpful for people who are diabetic and pre-diabetic; if it can make it easier for those people to make lifestyle changes, that's a positive thing.