Online sellers promote unlicensed weight-loss drugs through WhatsApp and Telegram competitions.
They offer injectable medicines like retatrutide as prizes.
The Guardian found posts urging users to enter within 24 hours.
Experts warn these promotions pose serious health risks.
Retatrutide remains experimental and lacks approval anywhere in the world.
Other prizes include unapproved peptides and tanning drugs.
UK law restricts weight-loss injections to prescription-only supply.
Unlicensed sellers bypass safety checks and medical oversight.
Researchers say these giveaways normalise dangerous drug use.
