The pace of research into brown fat’s special properties promises to pick up speed during coming years, as small biotechnology companies join pharmaceutical giants in the pursuit of a therapeutic drug that can be used to combat obesity and diabetes.

One of the more aggressive players has been Ember Therapeutics. Researchers give mice injections of irisin, a hormone that appears to turn white fat deposits into brown fat. And initial indications are that the animals show increased amounts of brown fat. Ember’s scientists are also intrigued by BMP7, a protein used to augment healing in spinal injuries that also appears to facilitate the growth of brown fat tissue. Yet another target is FoxC2, a molecule that may cause brown fat to convert energy into heat at room temperatures.

Eli Lilly, meanwhile, has been investigating a hormone called FGF21 which, already known to reduce blood glucose levels, also contains the potential to activate brown fat. “Treatment of obese mice with FGF21 can activate brown fat; this appears to be a major component of the mechanism by which FGF21 causes weight loss in animals,” says David Moller, vice president, endocrine and cardiovascular research and clinical investigation for the drug company.

Still another contender, three-year-old Energesis Pharmaceuticals, is focusing on cells found in skeletal muscle that become what appears to be brown fat. The Boston-based company seeks to identify molecules that cause these so-called brown fat stem cells to differentiate into brown fat, and capture them in a drug. A second route is to take a small biopsy from a patient, isolate the brown fat cells in the sample, manipulate those cells so that they proliferate, and then re-inject them. Testing on animals is imminent and expected to last about 18 months.