Abstract: A method for treating or preventing a disease, condition or state in a subject in need thereof by administering to the subject an effective amount of the (?)-enantiomer of perhexyline or a pharmaceutically acceptable salt, prodrug or derivative thereof, substantially free of the (+)-enantiomer, or pharmaceutical composition containing same. The disease, condition or state may be associated with altered tissue energetics, impaired tissue energetics, altered cardiac tissue energetics, impaired cardiac tissue energetics, altered hepatic tissue energetics, impaired hepatic tissue energetics, and diabetes.