Hydrogen water vs hydrogen tablets (form / exposure)

Regulatory status: OTC dietary supplement / functional beverage (US, DSHEA); food or food supplement (EU, Japan). Not a prescription drug. Not WADA-prohibited. The form is the delivery vessel and the generation method, not a new molecule

• Same dissolved [H₂] (mg/L / ppm / ppb) at the moment of swallowing as a matched tablet-in-water serving.
• Same **mass** of H₂ ingested per day (mg/day), not just the same ppm in a different volume.
• Same duration of H₂ in the glass / can after opening (decay half-life).
• Unopened retail cans and pouches still contain the labelled ppm after shipping and shelf storage.
• Home electrolytic machines and portable SPE/PEM bottles produce the labelled ppm in the cup that is actually drunk.
• A head-to-head human trial shows the same blood / breath H₂ (Cmax, AUC) for can vs tablet vs machine at matched mg.
• Outcome RCTs that used water (can / pouch / machine) reproduce the same endpoints as tablet RCTs at a matched H₂ mass.
• “Hydrogen water from a can or a machine” is interchangeable with “a hydrogen tablet in a glass.”

Dissolved H₂ is the same molecule in a can, a pouch, a machine cup, and a tablet glass. **Form equivalence is a milligram-and-timing problem, not a new-compound problem.** When a product is measured at drink time, the numbers that exist are: good aluminum pouches **~1.0–1.5 ppm** and holding for months if they start high (Sonobe 2019); one assayed retail can **0.89 mg/L** (Ostojic 2024) and another **0.43 ppm** (Sonobe); plastic bottles **empty**; working effervescent tablets/powders **~1.0–1.4 mg/L** in an open beaker (Ostojic) or **~10 mg/L for minutes** then **1.6 mg/L by 30 min** (LeBaron 2019); research PET generators **7–10 ppm** if sealed and then drunk at once (Kurokawa, Ishibashi); one trial can **≥4.66 mg/L** (Wu 2024). After opening, H₂ falls on a 1–2 hour clock in the only peer-reviewed PET series (Kurokawa 2015).