Can adults grow new brain cells?
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Yes: several studies support new neurons forming in adult humans in the hippocampus, a brain region. But researchers disagree about how much happens. These findings do not establish that growing neurons repairs brain damage.
Checked against: Spalding study, Dumitru study, NIH NCCIH, October 2026.
Why people believe it
There is real research behind the idea, alongside hope. La Rosa and colleagues describe replacing neurons as a research goal. Researcher Jonas Frisén says his team's findings may help develop future regenerative treatments. The NIH's supplement information also describes common worries about forgetfulness among older patients. It also describes products marketed to improve memory. Those hopes deserve a careful answer.
“My brain can change”
Yes, but changing connections between existing neurons does not add or replace neurons. “Brain cells” also includes cells other than neurons. This page is about neuron formation, called neurogenesis.
“Adults make new neurons”
In 2013, Spalding's team measured carbon-14 in hippocampal neuronal DNA from 55 samples. Their mathematical model estimated about 700 new hippocampal neurons per day. That is an estimate, not a direct daily count.
The dentate gyrus is part of the hippocampus. Yet Sorrells's 2018 study detected no young neurons there in its adult samples. The study concluded that formation there was absent or extremely rare. Franjic's 2022 analysis did not find clear molecular patterns of adult neuron formation in its human data. But it found these clear patterns in mouse, pig and macaque data.
Newer findings support formation: Dumitru's 2025 study identified dividing neural progenitors in adult hippocampi. Disouky's 2026 study identified neural stem cells and immature granule neurons using molecular data. The data came from human hippocampi examined after death, from 38 participants. These are different measurements. They do not give a single agreed count of new neurons produced.
How tissue is handled is one possible source of disagreement. Zhao and van Praag discuss this in their methods review. They say how tissue is preserved, delays after death and staining methods may contribute to conflicting results. That is a possible explanation, rather than proof that a negative finding is wrong.
“It continues into old age”
Boldrini's 2018 study included 28 donors aged 14–79 without neurological or psychiatric diagnoses. It found thousands of immature neurons in the dentate gyrus. But the team warned that these cells were counted at death. Those counts cannot easily show how many neurons form over a year. Immature neurons can even have formed before birth.
“More new neurons means a healthier brain”
In mice, a genetic intervention increased the survival of adult-born neurons. It also helped mice distinguish similar settings more rapidly than controls. But increasing hippocampal neurogenesis alone produced no behaviour changes suggesting an antidepressant effect. Kempermann and colleagues warn against assuming animal findings apply to people in a simple one-to-one way. Spalding's team also explicitly says neuron turnover does not mean lost neurons are replaced by others taking over their function.
Thinking tool: which kind of change?
Ask what “growth” means in the experiment: changed connections, dividing precursor cells, or new neurons joining working circuits? Finding dividing neural precursor cells establishes one stage. Neurogenesis runs from stem or progenitor cell division to new neurons joining working circuits. Even when new-cell numbers stay the same, adult-born neurons may mature and join working circuits differently.
For other claims, ask whether the thing measured is the same thing being promised.
Official positions, with dates
NIH NCCIH, July 2022: its digest says direct evidence for natural products preventing cognitive decline or dementia is lacking. This is despite some modest effects in trials. It reports no convincing evidence that omega-3 supplements treat mild-to-moderate Alzheimer's disease.
US FDA, 3 June 2021: its consumer information stated that regenerative medicine therapies had not been approved to treat neurological disorders. That is the dated US statement, not an approval check through October 2026.
What people also ask
Can damaged brain cells regenerate?
The cited turnover finding does not establish that damaged neurons and their functions are replaced. Future regenerative treatments remain a possibility raised by a researcher.
Do 78-year-old brains still generate new neurons?
Positive studies include older donors, but cannot promise a rate for every 78-year-old. Boldrini studied ages up to 79. Karolinska reports large differences between adults in how many neural progenitor cells they have.
Can you grow new neurons as an adult?
Evidence supports new neurons forming in the adult hippocampus. But the studies disagree about how much this happens. Changed connections alone are not evidence of added neurons.
Check it yourself (5 minutes)
- Open La Rosa and colleagues' public review, Brain Structural Plasticity: From Adult Neurogenesis to Immature Neurons (2020).
- Find “multistep biological process” before the heading “Brief Historical Perspective: Revisiting A Never-Ending Story”.
- Does the definition stop at cells dividing, or continue to new neurons joining circuits?
What you should have found
“Neurogenesis (present both in the embryonic and adult brain) is a multistep biological process spanning from the division of stem/progenitor cells to the functional integration of new neurons in neural circuits.”
Before you forward this: does the box at the top say exactly what the sources below say?
Sources
- La Rosa, Parolisi and Bonfanti, Brain Structural Plasticity: From Adult Neurogenesis to Immature Neurons (2020).
- Spalding et al., Dynamics of hippocampal neurogenesis in adult humans (2013).
- Eriksson et al., Neurogenesis in the adult human hippocampus (1998; abstract).
- Sorrells et al., Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults (2018).
- Franjic et al., Transcriptomic Taxonomy and Neurogenic Trajectories of Adult Human, Macaque and Pig Hippocampal and Entorhinal Cells (2022).
- NIH NeuroBioBank, Dumitru et al., Identification of proliferating neural progenitors in the adult human hippocampus (2025; abstract).
- Disouky et al., Human hippocampal neurogenesis in adulthood, ageing and Alzheimer's disease (2026).
- Boldrini et al., Human Hippocampal Neurogenesis Persists throughout Aging (2018).
- Sahay et al., Increasing adult hippocampal neurogenesis is sufficient to improve pattern separation (2011).
- Kempermann et al., Human adult neurogenesis: evidence and remaining questions (2018).
- Zhao and van Praag, Steps towards standardized quantification of adult neurogenesis (2020).
- Karolinska Institutet, New research confirms that neurons form in the adult brain (2025).
- NIH NCCIH, Dietary Supplements and Cognitive Function, Dementia, and Alzheimer's Disease (2022).
- US FDA, Important Patient and Consumer Information About Regenerative Medicine Therapies (2021).