Three drugs known to be helpful for people who have weight problems seem to have minimal results, but serious side effects, according to a new research. However, health experts still consider them good in some people cases.

Although most people who had used these drugs remained overweight, experts say that the drug can be useful in minimizing rates of heart disease, diabetes and other health problems.

"Drugs are not the magic cure and are not for everybody. But in specific patients, they have great benefits," said Dr. Raj Padwal, an assistant professor at the University of Alberta in Canada, one of the paper's authors, according to Associated Press.

The paper published in Friday’s British Medical Journal, analyzes three popular weight-loss drugs: orlistat, or Xenical; sibutramine known as Meridia in the U.S. and Reductil in Europe; and rimonabant, or Accomplia.

Researchers discovered that men or women between 45 and 50 years, with a weight of 220 pounds, have lost less than 11 pounds after using the drugs for almost four years.

Orlistat was used on 10,631 patients being known for preventing fat digestion. The drug helped people to lose only 6.6 pounds, but it reduced diabetes and improved people’s cholesterol levels and blood pressure. Thirty percent of patients had digestive problems and intestinal side effect such as incontinence.

Sibutramine used on 2,623 people helped them lose about 9 pounds. The drug improved their cholesterol levels. Twenty percent of the patients had negative side effects such as raised blood pressure, pulse rates, insomnia or nausea.

Rimonabant, administrated on 6,365 participants in the study, helped them lose 11 pounds and improved their blood pressure and cholesterol levels. Six percent of the patients had mood disorders instead.

In another study published Friday in The Lancet, researchers showed that rimonabant caused psychiatric problems such as depression and anxiety.

Sibutramine and rimonabant work by interrupting nerve signal in the brain.

"Modest weight loss brings surprisingly big health gains," said Susan Jebb, head of nutrition and health at Britain's Medical Rese arch Council, who was not involved in the research.

Instead of using these drugs, health specialists recommend a healthy diet and more exercising.

"The first choice has to be a healthier lifestyle, but medication use can be justified because obesity is a serious medical condition,” said Dr Colin Waine, chair of the National Obesity Forum, according to BBC News.

Anti-obesity drug market is a real business worldwide as over a billion people suffer from being overweight or obese.

Drugs helping in losing weight brought nearly $1.2 billion worldwide in 2005.