Neurogenesis
Neurogenesis is the generation of new nerve cells (neurons) from dividing precursor cells. Adult hippocampal neurogenesis is this process in the hippocampus, a brain region central to learning and memory. NootropicsWork classes it as a mechanism.
What it means in practice
In 1998, researchers examined brain tissue, after death, from patients who had been given a marker compound (BrdU) that labels dividing cells. They reported that new neurons, as defined by those markers, form from dividing progenitor cells in the dentate gyrus, part of the hippocampus, of adults [1].
Whether this continues through adult life in humans is still debated. In 2018, two prominent reports reached opposite conclusions: one found that neurogenesis in the human dentate gyrus drops to negligible amounts during childhood, and the other reported lifelong neurogenesis [2]. A 2018 review of the field cites carbon-dating evidence that about 700 new neurons are added per day in each dentate gyrus [2]. A 2021 article argued that very few, if any, new neurons are born in the adult human hippocampus [3]. A 2025 study analyzed the hippocampus from birth through adulthood with single-nucleus RNA sequencing and, in adults, used staining for a proliferation marker (Ki67) to report proliferating neural progenitor cells [4].
Part of the disagreement is about methods. A 2025 review traces the diverging conclusions mostly to immunohistochemistry, the staining of tissue for marker proteins, and discusses the limits of both staining and newer sequencing methods [5].
Why it matters when reading nootropics research
NootropicsWork defines an outcome as something measured in people, such as memory, attention or mood. Neurogenesis is not one: it is a mechanism that might help explain an outcome, so it is never graded. When a page mentions it, the sentence says where the finding came from.
In supplement research, neurogenesis findings can come from cells and rodents. For example, a 2025 systematic review of cell and rodent studies reported that erinacines, compounds from lion's mane mushroom, enhanced neurogenesis in those models [6]. A finding of more new neurons in mice does not show that a supplement changes learning or memory in people.
References
- Eriksson PS, Perfilieva E, Björk-Eriksson T, et al. Neurogenesis in the adult human hippocampus. Nat Med. 1998.
- Kempermann G, Gage FH, Aigner L, et al. Human Adult Neurogenesis: Evidence and Remaining Questions. Cell Stem Cell. 2018.
- Sorrells SF, Paredes MF, Zhang Z, et al. Positive Controls in Adults and Children Support That Very Few, If Any, New Neurons Are Born in the Adult Human Hippocampus. J Neurosci. 2021.
- Dumitru I, Paterlini M, Zamboni M, et al. Identification of proliferating neural progenitors in the adult human hippocampus. Science. 2025.
- Simard S, Matosin N, Mechawar N. Adult Hippocampal Neurogenesis in the Human Brain: Updates, Challenges, and Perspectives. Neuroscientist. 2025.
- Spangenberg ET, Moneypenny A, Bozzo GG, et al. Unveiling the role of erinacines in the neuroprotective effects of Hericium erinaceus: a systematic review in preclinical models. Front Pharmacol. 2025.