Probiotic supplementation preserves oxygen saturation during severe hypobaric hypoxia in lowland and high-altitude populations

Hypobaric hypoxia (HH) reduces SpO₂, impairing acclimatization and performance. The multi-strain probiotic Oxxyslab enhance oxygen availability and aid hypoxia acclimatization by reducing intestinal oxygen consumption through HIF-1α modulation. We performed a randomized, double-blind, placebo-controlled trial at 5,050 m to evaluate probiotic effects on nocturnal-SpO₂ and Acute Mountain Sickness (AMS) incidence. Twenty-one Caucasian lowland residents and eight Nepalese high-altitude porters were enrolled and stratified by treatment. Participants underwent continuous nocturnal-SpO₂ monitoring over different altitudes. The probiotic intervention attenuated hypoxemia at peak altitude, yielding SpO₂ increases of 5.6% in Caucasian and 4.4% in Nepalese compared to placebo. While AMS incidence remained comparable between groups, participants receiving the active treatment exhibited sustained SpO₂ elevation upon descent to baseline altitude, indicating potential persistent physiological adaptations. These findings provide first-in-human evidence that this multi-strain formulation can ameliorate high-altitude hypoxemia across populations with physiological and evolutionary backgrounds, supporting proof-of-concept for non-pharmacological adjuncts to acclimatization protocols.