At least five Hawaii residents developed acute liver failure in the past month after taking a weight-loss supplement deemed unsafe by U.S. Food and Drug Administration.

Honolulu liver transplant surgeon Linda Wong said the condition in the adults in their 20s and 30s is concerning because more local people may be taking the so-called fat burner known as OxyElite Pro, the original formula of which included the ingredient DMAA, also known as dimethylamylamine, methylhexanamine or geranium extract.

The FDA banned DMAA in dietary supplements last year, citing elevated blood pressure levels and cardiovascular problems including shortness of breath and chest tightening among some users. The agency has received 86 reports of conditions including psychiatric disorders, heart problems, nervous system disorders and death involving DMAA products.

"I have no idea how many people are taking these medications," said Wong, adding that the five cases she’s seen are so severe the patients will likely need liver transplants. "I talk to these patients and they go, ‘Oh yeah, all my friends are taking it.’ Just because the FDA banned it doesn’t mean all the people in the gym are going to be aware of it. As long as stores sell it, they’re going to buy it."

The patients all have yellow jaundice caused by excess bilirubin in the blood as well as abdominal pain, nausea and loss of appetite, she said.

FDA spokeswoman Tamara Ward said consumers should not be taking any supplements that have DMAA in them and that the agency is working to remove the illegal products from the market.

"They are dangerous. We are trying our best to make sure any products that are on the market that are a risk to consumers are destroyed or taken off the shelf," she said, adding that the agency has limited resources to do so. "Some products are already out there, which is why we’re trying to get the word out for consumers not to buy them or consume them. We are aware that some of the products are still out there. We’re very concerned about that."

Drug company USPlabs voluntarily destroyed in July an estimated $8 million worth of DMAA products, OxyElite Pro and Jack3d, at its facility in Dallas. It has, however, continued to market a reformulated product under the same brand name. The FDA said the reformulated version is still under review to ensure it is free of the ingredient.

Wong warns that dietary supplements can be harmful because drug manufacturers’ supplements aren’t regulated the same way as their prescription drugs.

"A lot of (supplements), if you read the label, just say ‘proprietary blend’ and you don’t know exactly what’s in it," she said.

USPlabs previously stood by the safety of its products, telling the New York Times that there was no medical evidence showing any danger when used as directed. Company officials couldn’t be reached for comment on Wednesday.

Managers at both GNC and The Vitamin Shoppe said they have either destroyed the product or didn’t replenish it after selling out. However, the retailers continue to sell the reformulated versions for OxyElite Pro. The original version of the supplement is still being sold on the Internet.

"The only way for consumers to know (the difference) is to ask, because the bottles look exactly the same," said a manager at The Vitamin Shoppe on Kapiolani Boulevard who was not authorized to speak for the company.