Humanin, a naturally occurring peptide, was shown in lab tests to keep human immune cells alive and boost their energy when they’re starved of serum, hinting it might help with conditions where cells have low metabolic activity, like mitochondrial problems or brain injury.

Humanin (HN) has been reported to be an endogenous peptide that exerts highly selective neuroprotection against cell death induced by various types of Alzheimer's disease-related insults. We previously proposed the much broader cytoprotective potential of HN from the result that HN suppressed serum-deprivation-induced death of rat pheochromocytoma cells. In this study, we showed that HN also suppressed death of human lymphocytes cultured under serum-deprived condition. Further, we revealed, by assaying metabolic activity and survival rate, that HN was a potent factor capable of increasing the metabolic activity of individual serum-deprived lymphocytes. To our knowledge, there is no report described about a rescue factor that increases the metabolic activity of individual serum-deprived cells and prolongs their survival. This novel feature of HN may enable us to apply this peptide for the management of diseases involving poor metabolic activity, such as mitochondria-related disorders and brain ischemia.