The £500,000 London-based brand campaign starts at the end of April and will last throughout May.
The first phase of the through-the-line marketing drive will be an outdoor teaser campaign with just the slogan "Water is H2SLOW", launching the idea that water is not the best fluid to hydrate you. Phase two of the campaign will add to the message with the strapline: "Isostar hydrates you faster.
The outdoor campaign will be supported by events, radio and sales promotions.
The ads were art directed by Peter Harle and written by Dave Woods.
Media is being handled by Mediaedge:CIA.
"Research told us that our main rival, water, was lacking in attitude.
To us, in rehydration terms, it was downright lazy. So, we had to have a go at it,
The outdoor will be supported by ambient, events, radio and sales promotions.
"H2SLOW has researched well with consumers, bringing the proposition to life in one simple word. It's a campaign with legs and works across all media
Isostar brand manager, Farina Jabbari, said.
Dan Photi, strategist at Mediaedge:CIA, added: "We want to make it a little more mainstream, more accessible. The test will be in London, if it's successful it will roll out in key conurbations. The reason we chose outdoor is we wanted to get people while in the right frame of mind - when they were jogging - so we bought sites in proximity to parks, gyms or leisure centres."