Many people have heard of the HCG diet, the program that uses the hormone along with a 500-calorie diet to achieve rapid weight loss. Doctors have raised concerns over the use of the hormone in clinic programs. Now, a new worry has emerged as the injectable hormone goes on sale online.

Before patients were regularly monitored by doctors, but people now are on the diet without any supervision.

"It's working. It really has changed my life," said Tracie Omlie.

Omlie is a believer in HCG. She said the hormone, found in pregnant women, transformed her body.

"You see the results immediately. Every morning when I get up, the first thing I would do is stand on the scale and be like, 'Oh my God! I lost a pound and a half,' Omlie said.

Omlie weighed more than 270 pounds when she started the HCG diet. She quickly plunged more than 100 pounds by cycling on and off the mixture of shots and a 500-calorie diet. She was working with a clinic and had weekly visits that included nutrition counseling about cutting calories and controlling her portion sizes and there were people there watching all of her critical numbers, like cholesterol, glucose and sugar levels.

"I needed to know, for my kids, that I was doing something that was being monitored," Omlie said. "I needed to know from a doctor I wasn't making my health worse."

Now anyone can get the shots on the Internet. For $140, right in their own homes, anyone can be shoot up the baby hormone that Omlie and others claim jump-started their metabolism.

"They don't know what they're doing. They don't know how to dose it. They don't know how to draw it up. Not only should it not be done, but especially done just on your own," said Dr. Dian Ginsberg.

For many people, weight is about more than just cranking up the metabolism or even cutting calories. Doctors said buying mail-order hormones on the Internet is dangerous and most likely you aren't dealing with underlining issues behind the initial weight gain.

"No one is educating you when you're done with it. Thirty days are done, you've starved yourself and find yourself back at square one," Ginsberg said.

The danger of shots aside, Ginsberg said the 500-calorie diet sets off bigger warning bells, and it can be deadly without supervision.

"The shots aren't doing anything. You go three days into 500 calories and the central nervous system freaks out. It can give you blood sugar problems. People can blackout if they don't have enough calories for that day. I think you can take someone and really wind up with a medical problem," Ginsberg said.

After KPRC Local 2's original interview, Omlie lost another 50 pounds. After stopping the HCG, she gained a few pounds back and said now she is holding steady at 168 pounds.

"I don't have the bags under my eyes or the loss of hair or flaky skin, the things you find with malnourishment," Omlie said.

Despite the dangers, for the desperate to downsize, these stories make it hard to resist trying it.