Almost 11,000 shipments of illegal weight loss drugs have been seized up to the end of May.
Revenue says this is a massive increase compared to last year's total which was about 2,300.
Revenue has urged people to beware of medical products sourced on social media, as they may not be regulated, effective or even safe to use.
The HSE has advice on medical options for obesity listed on its website.
Regular Operations
A spokesperson said Revenue seized 85 shipments in one operation, including products packaged as Ozempic, Wegovy, and Mounjaro.
It says further actions as part of the operation uncovered additional products packaged as Tirzepatide.
A separate operation saw 625 detections made while Revenue officers were examining packages at mail centres in Dublin and the Midlands.
These parcels had a range of illegal medical products packaged as Semaglutide, alongside other previously unknown botox and tanning type products.
Revenue believes these were sourced on social media.
A Trend
Revenue says this is a trend officers have noticed, particularly those stationed at mail centres or courier hubs.
They have seen a "significant increase" in packages containing prescription only medical products.
"The vast majority of packages intercepted contain weight-loss products addressed to private individuals who have purchased these products online."
"Larger consignments are occasionally detected at ports and airports."
Revenue's work is supported by sharing intelligence nationally and internationally with EU and other partners.
"Consumers are reminded that it is important to take care when purchasing medical products online, as they may not be safe or effective."
"Consumers should also be cautious as they may suffer a financial loss if goods they purchase are subsequently seized because they are subject to restrictions," the spokesperson concluded.
