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

Hypobaric hypoxia (HH) reduces SpO2, impairing physiological acclimatization responses and performance. The multi-strain probiotic Oxxyslab has been hypothesized to support altitude acclimatization by optimizing systemic oxygen availability. This is theorized to occur through the modulation of the HIF-1α pathway, which may reduce localized intestinal oxygen consumption, potentially mitigating tissue hypoxia. A randomized, double-blind trial at 5,050 m evaluated the 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 4.3% in Nepalese porters of Rai and Tamang ethnicity compared with placebo. AMS incidence remained comparable between groups. These findings show that this multi-strain formulation can ameliorate high-altitude hypoxemia in both investigated cohorts, supporting the proof of concept for non-pharmacological adjuncts to acclimatization protocols.