Hidden-market sellers promote unlicensed weight-loss drugs through WhatsApp and Telegram giveaways.
They offer injectable medicines like retatrutide as competition prizes.
The Guardian found groups urging users to enter within 24 hours.
Experts warn these promotions pose serious health risks.
None of the advertised drugs hold UK approval.
UK law allows weight-loss injections only with valid prescriptions.
Platforms say they ban illegal drug sales and remove such content.

