Symlin, or pramlintide, is synthetic amylin, a natural hormone that slows stomach emptying and leads to a feeling of fullness. Currently Symlin is used to dampen blood sugar rises in people with diabetes, but it's showing potential as a weight loss drug as well, according to a recent study.

The researchers examined 204 obese subjects for sixteen weeks, half of whom received Symlin injections thrice daily before meals and half of whom were given a placebo on the same schedule.

About 31 percent of the Symlin group lost five percent or more of their weight, compared to only two percent of the placebo group. On average, they lost about eight pounds. Furthermore, 72 percent of them said that their appetite control had improved, versus 31 percent of the placebo group, and 52 percent said their wellbeing had improved, versus only 17 percent of the placebo patients.

Symlin has not yet been approved as a weight loss drug. It is approved as an add-on treatment for people with type 1 who fail to reach glucose control on optimal insulin therapy, or for type 2s who fail to reach glucose control on optimal insulin therapy, with or without concurrent use of metformin or a sulfonylurea. It requires a prescription from your doctor, and insurance often doesn't pay for it. The average wholesale price is about $99 to $179 per month.

Sources: Medline Plus; Journal of Clinical Endocrinology and Metabolism, August 2007