The smallest antioxidant
in the universe.
Molecular hydrogen (H₂) is two hydrogen atoms held by a covalent bond. It’s a gas at room temperature, colorless, odorless, and — compared with almost any other therapeutic antioxidant — ridiculously small. That’s what makes it useful.
01The molecule
Formula: H₂. Molecular mass: 2 g/mol. For comparison, vitamin C is 176 and astaxanthin 596. H₂ is roughly 90 to 300 times smaller than the antioxidants you already know.
Because of its size and lack of charge, H₂ crosses cell membranes without transporters. It reaches the cytoplasm. It reaches the mitochondria. It crosses the blood–brain barrier and enters the brain. Few therapeutic molecules do all three.
02Why it’s selective
Free radicals aren’t all alike. Your body uses some as messengers (nitric oxide, superoxide anion). Others are toxic without nuance (hydroxyl radical, peroxynitrite). The difference matters.
H₂ reacts almost exclusively with the most toxic ones. It doesn’t interfere with the signaling species. That is selectivity, and almost no other therapeutic antioxidant has it to this degree.
Ohsawa et al. Nature Medicine, 2007 — the study that put H₂ on the modern therapeutic map.
03What happens when you take it
H₂ enters fast (minutes via inhalation or H₂-rich water) and clears fast (it doesn’t accumulate, it isn’t stored). That’s good: dose doesn’t compound, and adverse effects documented across 18 years of clinical research are essentially zero.
Administration routes: H₂-rich water (most common), gas inhalation, baths, intravenous saline. Each route fits different uses.
04How it’s measured
In water it’s measured in parts per million (ppm) or milligrams per liter (mg/L). 1 mg/L = 1 ppm. Therapeutic concentration starts around 1.0 ppm. Some studies (Ishibashi 2020) use 7 ppm to detect clinical differences.
The other indicator is ORP (oxidation-reduction potential). Water with dissolved H₂ has negative ORP, typically between −200 and −600 mV.
05What it is not
- It’s not alkalinity. The high pH of alkaline water is not what matters. Here’s the difference.
- It’s not "free energy," "living water," or "structured" filters. It’s a gas measurable by chromatography.
- It doesn’t replace your medication. It’s an adjunct studied in RCTs, not a substitute.