The Real History of Molecular Hydrogen

The history of molecular hydrogen does not begin in a laboratory, and it certainly does not begin in a spa. It begins under the Baltic Sea in 1943, with a young Swedish engineer breathing a gas most of us associate with airships and school chemistry lessons. From there it winds through record-breaking commercial divers in the Mediterranean, a curious footnote from 1975, and a short Japanese paper from 2007 that quietly started an entire field of research.

We are retelling that story because it is a genuinely good one, and because it is so often told badly, with the inconvenient parts sanded off. So, one promise before we start: every claim in this article is sourced and can stand up to scrutiny. Where the science is young, we will say so. Where a finding comes from animals rather than people, we will say that too.

Before the labs: why the history of molecular hydrogen starts underwater

Hydrogen's first job inside the human body had nothing to do with health. It was a diving gas, and a wartime improvisation at that.

1943 to 1945: Arne Zetterström and the hydrox dives

By the early 1940s, divers knew that breathing ordinary compressed air at depth clouds the mind — nitrogen narcosis, the notorious "rapture of the deep". Helium was the obvious replacement, but wartime Sweden was cut off from its main sources of supply, which came largely from the United States. A young Swedish engineer named Arne Zetterström, working with the Swedish Navy, proposed something audacious instead: the lightest gas of all.

His mixture, later called hydrox, was 96 per cent hydrogen and just 4 per cent oxygen. Both numbers were forced on him by physics. Add much more than 4 per cent oxygen and the mixture becomes explosive; keep it that low, and there is too little oxygen to sustain a person near the surface. Hydrox only becomes breathable at depth, where pressure raises the amount of oxygen reaching the blood — so Zetterström's divers had to descend on other gases and switch over part-way down.

It worked. Between 1943 and 1945, Zetterström made a series of six hydrox dives, beginning with a test to 111 metres and reaching roughly 160 metres at the deepest — an extraordinary depth for the era, reached without the narcotic fog that compressed air would have produced long before that point.

The series ended in tragedy. On 7 August 1945, during the last of those dives, made from the naval vessel HSwMS Belos, Zetterström's signals were misread by the crew tending his lines, and he was hauled towards the surface far too quickly, without the staged decompression his own procedures demanded. He died of severe decompression sickness and hypoxia, aged 28. It is worth stating plainly, because his death is sometimes retold as a warning about hydrogen itself: the gas did not fail him. The procedure did.

1968 to 1992: the COMEX Hydra programme goes deeper

Hydrogen diving did not die with Zetterström. From 1968, the French commercial diving company COMEX in Marseille picked up the thread with its Hydra programme, looking for a gas light enough to breathe comfortably at extreme depth and a way around the tremors of high-pressure nervous syndrome.

• Hydra 1 (1968): the programme's first open-water attempt at a hydrogen mixture, at 255 metres — defeated by equipment never designed for water that cold, but a beginning.
• Hydra 5 (1985): divers lived in saturation in a hydrogen-based atmosphere for 36 days at a simulated 450 metres — a world first.
• Hydra VIII (1988): COMEX divers carried out pipeline-connection work in the open Mediterranean at 534 metres, breathing a hydrogen–helium–oxygen blend called hydreliox — still cited as the depth record for offshore diving.
• Hydra X (1992): Théo Mavrostomos reached a simulated 701 metres in an onshore hyperbaric chamber — a record that still stands.

Why does any of this matter here? Because it means professional divers breathed very large quantities of hydrogen, for days and weeks at a time, under close medical supervision — decades before anyone thought of hydrogen in health terms at all. That long record of human familiarity with the gas is part of the backdrop against which later researchers worked. It is not evidence about health benefits, and we will not pretend it is. It is simply where the story goes next.

1975: a curious footnote from a pressure chamber

The first suggestion that hydrogen might do something biologically interesting came in October 1975, when the chemist Malcolm Dole and colleagues published a short paper in the journal Science. It described a single small experiment in mice, kept for up to two weeks in a chamber at eight times atmospheric pressure, exploring an idea about hydrogen and damaging free radicals. The conditions bear no resemblance to anything outside a laboratory pressure vessel, the work was not developed further at the time, and it persuaded almost nobody — the idea then sat essentially untouched for three decades. It belongs in this history because it happened, not because it proves anything.

And if it is a serious health condition that has brought you to this history, a blog is not the place to look for answers — please speak to your GP or another qualified healthcare professional.

2007: Ohsawa, Nature Medicine and the hydroxyl radical

The modern field effectively dates from a single paper. In 2007, Ikuroh Ohsawa and colleagues in Japan published "Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals" in Nature Medicine. Working with cultured cells and a rat model of restricted blood flow to the brain, they proposed that molecular hydrogen selectively neutralises the hydroxyl radical — generally considered the most destructive of the reactive oxygen species — while leaving the milder radicals that cells use for everyday signalling largely untouched. In their rat experiments, inhaled hydrogen markedly reduced markers of oxidative injury.

That idea of selectivity is what made hydrogen scientifically interesting, because conventional antioxidants are far less discriminating. But note the careful wording: this was cell and animal work, the mechanism was proposed, and researchers have debated ever since exactly how much of hydrogen's observed effects the hydroxyl-radical explanation really accounts for. The 2007 paper opened a door; it did not settle the room behind it. Anyone searching for "Ohsawa 2007 hydrogen" today will find the paper itself — and, trailing behind it, nearly two decades of argument about what it means.

After 2007: a young science and a noisy marketplace

What followed was a wave. Review papers charting the field — such as Ohta's 2014 review in Pharmacology & Therapeutics and a broader 2017 review in Oncotarget — describe hundreds of publications since 2007, spanning laboratory studies, animal models and early pilot studies in people, in areas ranging from exercise recovery to metabolic markers.

Most retellings of hydrogen therapy history jump straight from the 2007 paper to a product page. The full picture is slower and less convenient:

• Most human studies so far are small — dozens of participants, not thousands.
• Many of the most striking findings come from cells or animals, and results there do not automatically translate to people.
• The mechanisms are still being worked out, and researchers do not all agree.
• Larger, well-controlled human trials are still needed before anyone can make confident claims.

Alongside this young science, an industry grew up fast — hydrogen water, tablets, inhalation machines — and its marketing has often run well ahead of the evidence. Those overreaching claims are ones we have deliberately chosen not to make.

Why a small clinic in Somerset is telling this story

It is fair to ask where we sit in all this. The answer is: nowhere on the timeline above. H2 Clinic is a small family business in Norton Fitzwarren, near Taunton — not a research institution, not a medical facility, and not the next chapter of anyone's science. We simply find this history fascinating, and we think anyone curious about hydrogen therapy — in Somerset or anywhere else — deserves the full story, caveats included.

What we offer is modest, and we describe it that way. A session means sitting in a comfortable chair in a quiet room, breathing hydrogen-enriched air through a soft nasal cannula, and probably reading a book, because there is nothing dramatic to feel. You can read exactly how a session works before deciding whether it interests you.

One thing we want to be clear about, precisely because this article has covered so much research: the mechanisms described above — reduced oxidative stress among them — are findings from laboratory studies, animal models and small early trials. They are not claims about what a session at our clinic will do for you, and we do not make such claims. Our sessions are not a medical treatment and do not diagnose, treat or prevent any condition; if you have a health concern, please speak to your GP or another qualified healthcare professional first. And in case the name suggests otherwise, our guarantee is a satisfaction promise, not a promise of results.

Arne Zetterström never lived to see where his improvised wartime gas would travel: from the Baltic seabed to a saturation chamber in the Mediterranean, to a rat laboratory in Tokyo, to journals still filling with small studies and open questions. That story belongs to the researchers, and it is still being written. Ours is a much smaller one — a quiet room in Somerset, and a family who think a good story deserves to be told properly. If you are ever passing and want to hear the longer version, the kettle is usually on.