Scientists say they are inching closer to a wonder pill that could help someone shed pounds without missing out on their favorite foods.
Ozempic and Wegovy have taken America by storm in recent years for their ability to help someone lose weight by suppressing appetite, causing them to eat less.
But the drugs have several side effects, including nausea, nutritional deficiencies and muscle loss, which may raise the risk of frailty and falls in later life.
Now, researchers at the University of California, Berkeley, say they have found a compound that appears to cause weight loss via a different route: by boosting metabolism to increase the amount of energy that cells burn.
In a study on mice, researchers found that the compound 5-tetradecyloxy-2-furoic acid, or TOFA, revved up cells and triggered them to burn more energy, causing the rodents to lose 18 percent of their bodyweight in four weeks.
This happened even though the mice did not eat less or start to move more than previously.
Analysis also showed that virtually all the weight loss was from fat. This differed from GLP-1s, where a significant proportion of the weight loss is from muscle mass.
Dr Anders Näär, a metabolism researcher and senior author of the study, said: ‘Body weight responds to two levers: taking in fewer calories, or spending more energy.
Scientists are investigating a drug that they say could cause weight loss by boosting metabolism
‘GLP-1s work almost entirely on the first, so we went after the second.’
He added to ScienceAlert: ‘Food intake was unchanged, physical activity was unchanged, and body temperature did not rise, yet whole-body energy expenditure increased by as much as 18 percent.’
TOFA was first discovered in the 1970s and has been tested previously as a potential treatment for metabolic disease.
But it was not developed as a treatment after scientists found that it raised levels of triglycerides, a type of fat that raises the risk of a heart attack or stroke.
The scientists emphasized that their research was in the early stages and that TOFA had only been tested in mice. It was not clear whether the compound would be safe and effective in humans.
In the study, published in the journal Science Advances, mice were initially fed a high-fat diet until they developed obesity.
Then, the researchers gave them TOFA orally twice a day for four weeks.
Analysis suggested that the compound caused cells to take up more fat and burn more energy – up to 18 percent more than normal.
There was no evidence that the compound caused the mice to move more or stopped them from absorbing calories.
Overall, the mice also had greater insulin sensitivity and blood sugar control.
Almost all the weight loss was from fat tissue, which researchers said may be because the mice were eating the same amount of food as before – helping to maintain their muscle mass and avoid a nutritional deficiency.
The paper did not find evidence that the drug caused a rise in body temperature or elevated triglycerides, potential side effects. It did not say whether it caused vomiting in mice.
In a second arm of the study, researchers took a separate group of obese mice and administered them with TOFA and GLP-1s.
Overall, they recorded greater weight loss and metabolic improvements in this group compared to the other.
The study says that mice in this group lost about 10 percent of their weight compared to mice on only TOFA or a GLP-1 over a shorter period than the main study.
Researchers believe this was likely because mice were both burning more energy and eating less than before.
The scientists now plan to further investigate TOFA for potential use in humans.
Näär and two other authors are co-founders of the company ReRx Therapeutics, which is developing TOFA as a potential treatment, though this process could take several years.
