Some marijuana retailers are promoting their products on social media in ways that appeal to minors, a new study finds.

The researchers evaluated one year of publicly displayed posts on Facebook and Instagram by companies from four states where recreational marijuana use is legal (Alaska, Colorado, Oregon and Washington). They searched for restricted content, such as branded promotions or discounts, youth-focused messaging and health benefits. They also looked for required warnings, such as age minimums, avoiding impaired driving and health risks.

Discounts or promotions were found in about 35% of posts, despite being prohibited by states. Although warnings were required, less than half of posts had them. The study found that messages that promoted marijuana overconsumption were present in 12% of posts, despite being considered restricted content.

“There’s little doubt, based on years of research on tobacco and alcohol advertising and more recent research on marijuana, that advertising and marketing that has youth appeal or that exposes young people to the positive aspects of marijuana have a significant impact on teens’ attitudes and behaviors around marijuana use,” Linda Richter, vice president of prevention research and analysis at Partnership to End Addiction, told HealthDay.