Which weight loss drugs really help you shed pounds?

We sweat, we diet -- we try all sorts of things to lose weight -- but the way we think about weight loss may be about to dramatically change.

"The hottest topic right now in weight loss research is actually medications," Dr. Ken Fujioka, a weight loss expert, said.

He says until now medications have usually helped people lose about five percent of their weight.

"With these new medications, now we're getting what we call double digit weight loss -- 10-percent and up. So now you're losing 20, 30, 40 pounds of weight with these new weight loss medications, which really makes the doctor and the patient a lot happier," Dr. Fujioka said.

And most of these medications are being developed in San Diego. One of them was born at Amylin.

CEO Daniel Bradbury thinks the company's injectible medication will have a huge impact, "In the United States 200-million people are overweight or obese. Over a 100-million people are obese. So it's not just about lifestyle, it's not just about people not trying hard. This is a disease that really needs therapies."

Amylin provided this video of its labs where they've been working for years on a medicine to help people lose weight.

"We don't have a brand name at the moment so they still have their scientific names," Bradbury said.

In simple terms, molecules are used to get your own body to decrease how hungry you feel when you eat food.

"These are molecules which actually act like naturally occurring molecules - leptin -- which is a molecule your fat cells produce to control your body weight. And also a molecule called amalin," Bradbury said.

And at Arena Pharmaceuticals, scientists discovered the compound in this lab that led to Lorcaserin, just a month from going to the FDA for final approval.

"As a species we tend to preserve body fat and you need some way to short circuit that process. And lorcaserin does that by modulating brain systems that can prevent food intake. So it decreases your appetite so you take in less food," Dominic Behan, an Arena Co-Founder, said.

Orexigen Therapeutics plans to take contrave to the FDA for approval within months. Orexigen says in clinical trials, its combination drug has helped people resist food cravings and see double digit weight loss.

And the companies say these drugs are not just about people losing weight to look better.

"From a health status standpoint that's hugely profound. Reduce your blood pressure, lowers your cholesterol and overall improves your health status," Bradbury said.

In trials, these new treatments appear to only have mild, minor side effects in some people such as nausea or headache. And Dr. Fujioka says the medications appear to have good safety profiles plus the potential to save lives.

"They've really, really gone toward the future and I think they're gonna make a big difference over the next year," Dr. Fujioka said.