Californian-based Penta, named after the patented process that was said to produce a five-sided H2O molecule, has re-emerged with a $4m (€2.61m) advertising spend aimed at health-conscious women and a new emphasis on the supposed health benefits of the functional beverage. Penta is citing an in-vitro clinical study that showed human skin cells cultured in Penta water suffered less damage from ultraviolet radiation than skin cells cultured in plain water. The study was conducted by the dermatologist Dr. Jean Krutmann at the Environmental Health Research Institute which is attached to the University of Dusseldorf. Further studies have been commissioned at the University of California to study hydration, antioxidant and anti-aging characteristics, Penta said. Functional waters If any proof were needed of the validity and interest in the functional water segment, Coke's purchase of Glaceau VitaminWater, a start-up only established in 1996, for $4.1bn last year, provided plenty. The US market is growing at more than 30 percent with Glaceau taking about one third of the total market. Penta's consumer-friendly re-launch is being spearheaded by a new chief executive officer in Dennis O'Brien, formerly of ConAgra and Procter & Gamble. "Who cares how many sides are on the molecule? Let's keep it focused on consumer benefits," O'Brien said. The new Penta packaging claims its drinkers feel more energized, alert and healthier and it invites consumers to gulp three bottles a day. If not satisfied, a money back guarantee is in place. Backlash Oxygen waters suffered a negative media backlash in their first incarnation after consumer advocacy groups like the Washington DC-based Center for Science in the Public Interest (CSPI) and others took issue with the water's claims that it could be more rapidly absorbed into the body because it had been infused with "added oxygen". A 2005 review of studies in the area found little credibility among them. The Journal of the American Medical Association compared five brands to tap water and cited research that showed drinking oxygenated water before exercise did not improve performance. "It's a difficult claim to prove," international beverage market researcher, Zenith International said at the time. "To move into the bottled water mainstream, research supporting the benefits needs to convince both the industry and consumers." Sales plummeted even as interest in functional waters took off and Penta will be hoping it can take a more permanent place among the likes of Glaceau VitaminWater that have done so much to establish the functional water category in North America. "The scrutiny will come," said O'Brien, "but we're better equipped to handle it."