Social media platforms are increasingly being used as a market place for illicit drugs, according to the first definitive study of the practice.
The Volteface study found that almost half of under-18s questioned were unconcerned by the appearance of illegal drug adverts on their social media sites.
Lizzie McCulloch from Volteface said the relatively recent phenomenon of drug dealers selling their product through social media had almost become normalised.
"The fact that we've only recently heard about it and now one in four young people are reporting seeing drugs advertised for sale, that's absolutely staggering and actually, we suspect the number is far higher because these ads are popping up much more frequently," she said.
"It's hard to find youngsters who are not seeing these adverts and what we found surprising is how unconcerned young people are by them. For them, it's a normal part of day to day life."