Transcranial photobiomodulation (tPBM) has emerged as a promising economical point-of-care tool to enhance mitochondrial dynamics, mitigate neuroinflammation, improve sleep and cognitive functions in various CNS disorders. Its propensity to modulate cerebrovascular tone can potentially alter cerebral hemodynamics. We set out to investigate whether tPBM can influence the brain oxygenation as assessed by fNIRS in healthy subjects with a body positional challenge.