|You may be looking for the mission with the same name.|
It can be seen on the shelves of a 24/7 shop. The juice comes in two flavors. One is an orange flavor, and the other is apple flavored. The product may be based on the drugs Love Fist acquired in the mission Love Juice which is two parts boomshine, 1 part trumpet, 5 fizz bombs and a litre of petrol. It is more likely, however, that Love Fist simply named their signature cocktail after the juice brand. It can also be seen in both games in the HD Universe, but not under the Love Juice brand name. Instead, it will just be labelled "Juice with Chunky Bits".
The name 'Love Juice' is likely a reference to semen, which is sometimes referred to as such.