Teenagers are among the growing group of people injecting themselves with black market drugs under the promise of health benefits ranging from weight loss to skin care. In May, Medsafe issued a safety alert about the rise in illegal peptides being imported, sold and used without being tested for safety, quality or efficacy. But health advocates say there's been a massive increase in people using them despite no way of knowing if they're getting what they paid for. Tess Brunton reports.
