Weight Loss & Diet Plans

The Facts on Leptin: FAQ

Q. Can leptin work as an obesity treatment? continued...

"This stuff is made by fat tissue, and as you get fatter, you make more of it. That was quite a shock because everybody thought that obese people were going to be deficient in leptin," he says.

With the more recent understanding of leptin resistance, it makes no sense to give people leptin if they have an impaired response, Lustig says. "The resistance is still there. No amount of leptin is going to overcome that resistance."

Giving leptin only helps in a few extremely rare cases in the world in which people make no leptin at all, which causes them to overeat and become obese. When those people received leptin by injection, they stopped overeating and lost weight. But for the vast majority of people, the treatment won't work, nor is leptin approved as a medical treatment for weight loss.  

"Leptin is still sort of experimental. There's no real need to take leptin now, unless you're one of those very small -- probably 100 people in the world -- who doesn't make leptin," Atkinson says.

Q. What about leptin supplements, such as those sold on the Internet?

Because leptin is a digestible protein that doesn’t enter the bloodstream, it can’t be taken in supplement form, Atkinson says. “If you were to take it as a pill, it’s just like eating chicken or beef. It’s a protein and your body would just break it up, so you wouldn’t absorb it from a pill.”

So those “leptin supplements” sold on the Internet don’t actually contain leptin, even though their name can be misleading. Instead, these supplements contain ingredients that are purported to help improve leptin functioning or feelings of fullness.

“A variety of these supplements may be more aimed at total wellness -- things like helping balance other hormones, thyroid hormones -- just optimizing health so that the body begins to respond to leptin more appropriately and allows the person to feel full,” says Duffy MacKay, ND, a licensed naturopathic doctor who serves as vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, a trade group for the supplements industry.

“Some of what you’re seeing is tried-and-true ingredients that are known to cause satiety, things like soluble fibers that have been known for a long time to help make people full,” MacKay says.

As for supplements’ effects on leptin functioning, the picture is less clear, he says. “The leptin science has only been unraveling since 1994, so there are a lot of unanswered questions.”

“No magic bullets are being discovered,” MacKay says. “[But] we shouldn’t write this pathway off as something that we shouldn’t continue to explore.”   

Rather than taking supplements that haven’t been fully proven to help, overweight people have other options to aid leptin functioning, experts say. Lustig advises them to reduce resistance to insulin (a hormone that controls blood sugar) and to bring down high levels of triglycerides (a blood lipid).