A hydrogen water bottle is a portable device that dissolves molecular hydrogen (H₂) gas into drinking water using electrolysis. The H2CAP PLUS is a cap-style unit that fits standard 28 mm and 30 mm bottle threads. It splits water at a solid-polymer membrane and delivers the hydrogen into the water you drink, while venting oxygen separately.

For the chemistry behind it, see how the SPE/PEM technology works.

No batteries. The H2CAP PLUS runs on USB power only, drawing a maximum of 4.5 W. The cap itself weighs just 53 g, which is a fraction of the 400–650 g battery units common in this category.

Full dimensions and materials are on the specifications page.

The main practical differences are weight, power source, and whether the output can be verified. The H2CAP PLUS is battery-free, lighter than typical competitors, and backed by a third-party test report rather than a marketing figure alone.

See the full side-by-side comparison of six devices. Competitor figures shown there are each company's own published values.

This is the most common hydrogen water bottle FAQ question. Dissolved hydrogen (DH) measures 1,000–1,500 ppb and ORP −400 to −800 mV, depending on the water and cycle. A single cycle typically lands in the 1,000 ppb range; running two consecutive cycles, or starting from mineral/alkaline water, can reach the upper end near 1,500 ppb.

In independent testing by the Japan Hydrogen Water Promotion Association (JHPA), the device measured 1,036 ppb (Report No. 218H-221). Details are on the H2 concentration test page.

Because molecular hydrogen escapes quickly, it must be measured right after generation. We use a dissolved-hydrogen meter (hydrogen-reduction method), and the concentration can be cross-checked with a methylene-blue reagent titration. The JHPA report used the same class of instrument on a sample filled and measured immediately after a full cycle.

The measurement methods — and how to verify output yourself — are explained on the test page and in the science section on dissolved hydrogen measurement.

Hydrogen is a small, fast-diffusing molecule, so it is best to drink the water soon after it is made. With the cap kept closed, our retention testing shows concentration holding for an extended period; once the bottle is opened, the dissolved hydrogen falls off within hours. For this reason we recommend drinking promptly rather than storing.

Retention curves for different water types are shown on the H2 concentration test page.

Fill the bottle, attach the H2CAP PLUS, invert it, and connect USB power — generation starts automatically. A cycle runs about 3.5–5 minutes depending on water quality, and an orange LED signals completion. A cleaning cycle is required before first use.

Step-by-step instructions, LED signals, and error codes are on the how-to-use page.

Use clean drinking water — purified, RO, tap, or mineral water below 50 °C. Mineral or alkaline water tends to give the highest readings. Do not add salt or use carbonated, flavored, or sugary liquids, as these can foul the electrode and shorten its life.

It uses a standard USB source. Most power banks and USB adapters work directly. Smartphones require an OTG adapter to supply power, and iPhones do not supply power to it. Keep the USB connector dry — a rapid orange LED blink can indicate moisture at the connector.

Molecular hydrogen is a naturally occurring gas, and hydrogen-infused water has a long track record of use. The H2CAP PLUS wetted parts use STS304 stainless steel, Tritan, and food-grade silicone. We do not make health claims; if you have a medical condition, consult a physician.

A fuller discussion is on the science page: is hydrogen water safe?

Molecular hydrogen has been studied in a large and growing body of scientific literature. We present what that research does and does not show, without overstating it. You can browse indexed studies on PubMed, and read our overview at molecular hydrogen: what the research shows.

The H2CAP PLUS holds CE, RoHS, and KC marks, and was tested by JHPA (third party). Manufacturer patents also apply. Compliance documents are available to verified partners on request.

See the certifications & test reports page.

Warranty terms and coverage are described on the warranty page. We sell wholesale to distributors rather than direct to consumers, so pricing, MOQ, and Incoterms are handled through our partner program.

To start, see the distributor program or contact us.