Japan is going crazy over hydrogen, and it's not just for fueling futuristic cars. A growing number of people think it may be the next fountain of youth. The smallest and most fundamental molecular building block of matter, hydrogen (H2) is a tasteless, odorless, and flammable gas. But ingesting it regularly in quantities as small as four to eight parts per million (0.004-0.008ppm) yields some intriguing effects on human health.

Since 2007, hundreds of peer-reviewed articles have demonstrated that hydrogen has therapeutic potential in nearly every organ of the human body and in dozens of different human disease models, notes the Molecular Hydrogen Foundation, a non-profit scientific organization.

Hydrogen's effectiveness begins with its size (it is composed of just two atoms), which allows for easy diffusion into the body where it scavenges toxic oxygen radicals-key culprits involved in the process of breaking down DNA, RNA and proteins. H2 also appears to trigger the activation of additional antioxidant enzymes such as glutathione, superoxide dismutase, and catalase. Lastly, it may alter "cell signaling," which produces anti-inflammatory, anti-allergic, anti-obesity, and anti-aging effects.

The net result is a more youthful appearance and feeling over time, says Kazushige Kiriyama of Zero Corp., who was busy explaining the virtues of hydrogen therapy to interested onlookers at the recent Caretex Expo held in Tokyo.

"It's really catching fire here in Japan as the field reports as well as the research reports are coming in very positive," he says. "People are drinking it, breathing it, and taking it any way they can in hopes for the elusive 'waka gaeri' ('return to youth') effect.

Based in Aichi Prefecture, about 350km southwest of Tokyo, the company has been aggressively marketing its own brand of hydrogen products for home use for the last two years. The machines work as ionizers, freeing H2 molecules by electrolysis from water, where they are normally combined with oxygen (in H2O). A typical water ionizer can run on tap water, but purified water yields the best results.

At the fair, Zero's staff offered free 10-minute H2 gas sampling sessions. After installing a transparent tube from the hydrogen generator into the nostrils, an HDTV microscope was aimed above the capillaries in volunteers' fingernails. After a few minutes of inhaling the gas rated at about 4.5-5.0ppm, blood flow appears to quicken under 320x magnification.

"It's freakish to see your own blood flowing through your veins!" says one astonished Japanese person trying H2 for the first time. "I hope this is a good thing!"

JPN reporters tried the machine next. The 10-minute session produced a feeling of light-headedness, combined with a sense of relaxation, along with a mild perspiration that lasted for hours. There was no chemical or antiseptic residue. Customers were each allowed to take their breathing apparatus home.

Zero Corp.'s staff estimate that 10 minutes of hydrogen gas is equivalent to drinking five liters of water in terms of the cleansing effect on internal organs. In air, hydrogen is present at a volume fraction of 4-75% and could theoretically reach combustible levels, but this is highly unlikely if the temperature does not exceed 500 C, note chemists.

Other means of consumption include H2-rich drinking water, the injection of saturated salt water, and diffusion through the skin via bathing with reactive magnesium. Hydrogen water is also produced and sold commercially in Japan.

A study conducted by the U.S. National Institutes of Health found a plethora of potentially useful applications for hydrogen-rich water, including retardation of the development and progression of Parkinson's disease, Alzheimer's, glaucoma, the prevention of arteriosclerosis, and the reduction of trauma due to burns, heart attacks, and cancer drugs. And it found that H2 has no cytotoxicity, even at high concentrations.

The implications for diabetics and the obese are just as profound. Researchers at Nippon Medical School in Kawasaki found that long-term consumption of H2 water significantly controlled fat and body weights, despite no increase in consumption of diet and water. "Drinking H2-water decreased levels of plasma glucose, insulin, and triglyceride, the effect of which on hyperglycemia was similar to diet restriction," they said. "The results suggest the potential benefit of H2 in improving obesity, diabetes, and metabolic syndrome."

Zero Corp. markets a range of therapeutic hydrogen products, including two hydrogen generators that retail for 720,000 yen and 540,000 yen, respectively.

The company has also set up a hydrogen bar in Tokyo's tony Ginza district, where customers can take a 10-minute concentrated hydrogen gas break for 1,000 yen. Sales are presently confined to the domestic market, but Mr. Kiriyama says the firm is eyeing overseas customers.

"'Will hydrogen make you live longer?'" he says rhetorically, still very spry and animated for a man in his 70s. He confesses to inhaling hydrogen gas as part of his everyday routine. "The technology has obviously not been around long enough to allow for conclusive research that spans decades. But all the signs are pointing in the right direction."