SAN FRANCISCO – Dozens of weight-loss and immune system supplements on the market are illegally labeled and lack the recommended type of scientific evidence to back up their purported health claims, government investigators warn in a new review of the $20 billion supplement industry.

The report, released Wednesday by the Department of Health and Human Services’ inspector general, found that 20 percent of the 127 weight-loss and immune-boosting supplements investigators purchased online and in retail stores across the country carried labels that made illegal claims to cure or treat disease.

In addition, many of those and other supplements lacked the scientific studies recommended to support their suggested uses.