Here we show the dependence of the unicellular biosensor S.ambigua lifespan on the water D/H isotopic composition. This dependence is bell-shaped with descents both in case of deficiency or excess of deuterium in water. The influence of the water D/H isotopic composition on the cell culture proliferative potential and colony forming efficiency in vitro was tested on the human dermal fibroblasts. We observed that the deuterium depleted water stimulates cell colony formation at the early passages. The dynamics of the cell doubling index in the deuterium depleted water-based growth medium showed higher proliferation potential compared to the water with normal isotopic composition. Using scratch assay, we have also studied the impact of the growth medium D/H isotopic composition on the cell motility of human cancer cell lines A549 and HT29. We have shown that the deuterium depleted water considerably suppressed cancer cell lines amoeboid movement in vitro. © 2018 Elsevier GmbH