The present invention relates to compositions and kits including a chemical uncoupler, such as tyrphostin 9 or precursor or a salt thereof, and compositions including a chemical uncoupler, such as tyrphostin 9 in combination with one or more therapeutic agents, for example, L-carnitine, which are useful, for example, in treating obesity, preventing weight gain, promoting weight loss/slimming, and/or treating or preventing the development of diabetes.