Alcohol ads that tell people to ‘drink responsibly’ don’t explain how to do so, a new study concludes. Instead, the ads tend to glamorize the products they are selling, according to researchers from the Johns Hopkins Bloomberg School of Public Health.

The researchers analyzed all alcohol ads appearing in U.S. magazines from 2008 to 2010. They found 87 percent of the ads included a message to drink responsibly, but none defined responsible drinking, or promoted not drinking in certain situations, Medical Xpress reports.

In 88 percent of cases, responsibility messages reinforced promotion of the advertised product. Many of the messages contradicted scenes shown in the ads. One vodka ad featured a photo of an open pour of alcohol, with a tagline suggesting the person in the ad had been drinking all night. In small type, the ad told readers to enjoy the product responsibly.

The findings appear in Drug and Alcohol Dependence.

Responsible drinking messages are not required under federal law. The alcohol industry’s voluntary guidelines for marketing and promotion do not provide a definition of responsible drinking, the article notes.

Study leader Katherine Clegg Smith, PhD says a more effective way to promote responsible drinking would be to prominently place warning messages in ads that directly address the behaviors depicted, and to not reinforce marketing messages. “We know from experience with tobacco that warning messages on product containers and in advertising can affect consumption of potentially dangerous products,” she said in a news release. “We should apply that knowledge to alcohol ads and provide real warnings about the negative effects of excessive alcohol use.”