David L. Katz, MD
Photo: Mackenzie Stroh
Q: I'll be taking HCG injections at a weight loss clinic. What do you think about this approach?
— Leanne Wolfinger, Broken Arrow, Oklahoma

A: I am firmly against it. HCG—human chorionic gonadotropin—is a hormone produced in the placenta during pregnancy that helps regulate embryo development and influences the levels of other hormones. Some doctors and weight loss centers make claims that HCG injections will stifle appetite, allowing you to follow a very low-calorie diet while preserving energy. That just hasn't proved true: Tested against a placebo, the hormone hasn't shown any advantages.

Even if it did work, I would be very wary of trying to manipulate just one hormone; that can be like tossing a pebble into a pond and hoping for just one ripple. HCG stimulates the ovaries, for instance, and can cause fluctuations in ovarian hormones—estrogen and progesterone—and lead to the formation of ovarian cysts. Although science hasn't proved it one way or another, cancer may be a concern: I worry that stimulating the ovaries in this way might increase risk.

The people making positive claims about HCG injections tend to be the ones selling the stuff. Ultimately, the best formula for weight control is eating well and burning calories through exercise. If obesity is an imminent threat to your health, bariatric surgery is a proven, effective option for losing a lot of weight fast.