Hydrogen-producing tablets: Tablets designed to dissolve in water and release molecular hydrogen gas, creating hydrogen-rich water that can be consumed to potentially provide antioxidant and anti-inflammatory benefits.

Non-hydrogen-producing tablets, identical in appearance and taste to the active supplement

Participants in this arm will consume a single 250 mL dose of hydrogen-rich water containing approximately 1.6-2.0 ppm of dissolved molecular hydrogen (H₂), The HRW will be ingested following an overnight fast, and resting metabolism will be measured approximately 30-60 minutes post-consumption using indirect calorimetry.

The measurements will be obtained during each study visit. Since this is an interventional study assessing the acute effects of molecular hydrogen, measurements will be collected three times:

At baseline, without any intervention (pre-familiarization),

After a single dose of molecular hydrogen, and

After placebo administration.

The period between each intervention will be seven days, serving as a washout period to prevent carry-over effects. All participants will be instructed to maintain their regular diet and to avoid alcohol, caffeine-containing beverages, and strenuous physical activity for at least 24 hours prior to each visit.

Measure Type: Continuous (kcal/day)

Method: Indirect calorimetry

Description: To assess the effect of acute ingestion of hydrogen-rich water versus placebo on resting energy expenditure in healthy young adults.