Your brain does grow new cells in adulthood, and there are concrete ways to increase the rate at which that happens. The process, called neurogenesis, occurs primarily in the dentate gyrus, a small region within the hippocampus responsible for learning and memory. From the birth of a new cell to the point where it’s fully functional and indistinguishable from its older neighbors takes about seven weeks. What you do during those weeks, and in the months and years surrounding them, determines how many new neurons survive and integrate into your brain’s circuitry.
Where New Brain Cells Actually Grow
Adult neurogenesis is largely restricted to one area: the hippocampus, specifically a thin band of tissue called the subgranular zone within the dentate gyrus. Stem cells in this zone divide and produce immature neurons that, within days, send out connections toward other parts of the hippocampus. Over the next two to three weeks, these newborn cells go through a maturation phase where they extend branches into surrounding tissue. During a critical window from about one to six weeks after birth, these young neurons are unusually flexible, showing heightened ability to form new connections. After roughly seven weeks, they settle into their permanent roles.
Not every new cell makes it. A significant number of newborn neurons die before reaching maturity. The factors below influence both how many cells are born and how many survive that vulnerable window.
Aerobic Exercise Is the Strongest Trigger
Of everything researchers have tested, aerobic exercise consistently produces the most robust increase in new brain cell production. A 2024 study comparing different exercise types found that high-intensity aerobic exercise significantly increased hippocampal neurogenesis compared to controls, while resistance exercise and low-intensity aerobic exercise showed weaker or no significant effects. Low-intensity aerobic exercise did trend upward, suggesting that even moderate cardio helps, but pushing your heart rate higher appears to be more effective.
Exercise works partly by raising levels of a protein called BDNF (brain-derived neurotrophic factor). BDNF is one of the most important molecules in this whole process. It stimulates the growth of new neurons from stem cells, activates signaling pathways that keep existing neurons alive, and switches on genes involved in brain plasticity, stress resistance, and cell survival. It also blocks signals that would otherwise trigger cell death. Think of BDNF as both fertilizer and a protective shield for your brain cells. Aerobic exercise is the most reliable, well-documented way to boost it.
Sleep Protects the Cells You’ve Built
Growing new neurons is only half the job. Those cells need to survive, and sleep, particularly REM sleep, plays a critical role in that survival. Research published in 2022 found that just 24 hours of REM sleep deprivation after a learning task impaired both memory formation and the burst of new cell production that normally follows learning. Even more telling, 96 hours of REM deprivation altered whether newly generated cells developed into neurons at all, essentially changing the fate of those cells away from becoming functional brain cells.
This means that pulling an all-nighter or chronically cutting your sleep short doesn’t just make you foggy the next day. It can undermine the very process of building new brain tissue. Prioritizing consistent, sufficient sleep (particularly the REM-rich cycles that occur later in the night) gives newly born neurons their best chance of surviving and integrating properly.
Chronic Stress Suppresses New Growth
Cortisol, the body’s primary stress hormone, is one of the most potent inhibitors of neurogenesis. When cortisol levels stay elevated over weeks or months, the number of both dividing stem cells and surviving new neurons drops significantly. This suppressive effect occurs regardless of sex or reproductive status.
Interestingly, the stem cells that give rise to new neurons don’t have many cortisol receptors themselves. This means cortisol likely works indirectly, damaging or altering the mature neurons surrounding the stem cells, disrupting the chemical signals those neighbors provide, or changing the environment in ways that make it hostile to new growth. The practical takeaway: chronic, unmanaged stress doesn’t just feel bad. It physically degrades the brain’s capacity to renew itself. Anything that reliably lowers your stress baseline (regular exercise, meditation, adequate sleep, reducing avoidable stressors) supports neurogenesis by keeping cortisol in check.
Mental Stimulation and Enriched Environments
An “enriched environment” in neuroscience means exposure to novelty, complexity, and social interaction. In research settings, enriched environments increase both the proliferation and the survival of new brain cells. The mechanism involves activation of growth factor receptors on stem cells, which in turn trigger a signaling cascade through a protein called CREB that ramps up neurogenesis. Enrichment works through at least two channels: it increases the number of stem cells that begin dividing, and it improves the survival rate of immature neurons that would otherwise die off.
For humans, this translates to learning new complex skills rather than passively consuming information. Learning a musical instrument, studying a new language, navigating unfamiliar environments, and engaging in challenging problem-solving all qualify. The key ingredient is novelty combined with effort. Repeating activities you’ve already mastered doesn’t provide the same stimulus.
Nutrition That Supports Brain Cell Growth
Omega-3 fatty acids, particularly DHA, are structural components of brain cell membranes and play a role in neuroplasticity. A randomized controlled trial found cognitive and behavioral benefits from supplementation with 600 mg of DHA daily. Higher doses of combined DHA and EPA (around 2,400 mg per day) have shown measurable effects in as little as 35 days. For general brain health, aiming for regular consumption of fatty fish or a supplement providing at least 500 to 600 mg of DHA daily is a reasonable target.
Beyond omega-3s, a diet that supports BDNF production matters. Flavonoid-rich foods (berries, dark chocolate, green tea), adequate protein for neurotransmitter synthesis, and avoiding chronic caloric excess all contribute. There’s no single “neurogenesis superfood,” but a consistently nutrient-dense diet creates the biochemical environment where new brain cells are more likely to thrive.
Lion’s Mane and Nerve Growth Factor
Lion’s mane mushroom has attracted attention for its ability to stimulate production of nerve growth factor (NGF), a protein that promotes the growth and survival of neurons. The active compounds, erinacines found in the mycelium and hericenones found in the fruiting body, work through different mechanisms but both support neuronal health. Erinacine A in particular has been shown to increase NGF levels in the brain and promote both neurogenesis and neuronal survival.
In a randomized, double-blind, placebo-controlled trial, adults aged 50 to 80 with mild cognitive impairment who took lion’s mane extract for 16 weeks showed significant cognitive improvements compared to placebo. A separate trial in patients with early-stage Alzheimer’s found improvements in memory recall and reductions in neuropsychiatric symptoms. These are promising results, though the research is still relatively early-stage compared to the evidence behind exercise and sleep.
Psychedelics and Structural Brain Changes
Psilocybin, the active compound in psychedelic mushrooms, has shown a surprising ability to promote physical growth of neural connections. A study published in Neuron found that a single dose of psilocybin led to roughly 10% increases in both the size and density of dendritic spines (the tiny protrusions on neurons where connections form) in the frontal cortex. These changes appeared within one day, peaked at seven days, and a portion of the new spines (about 34 to 37%) were still present 34 days later.
This isn’t neurogenesis in the strict sense of creating entirely new neurons. It’s neuroplasticity: existing neurons growing more robust connections. But for someone searching how to regenerate brain cells, this structural remodeling is part of the picture. Psilocybin is currently being studied in clinical settings for depression and PTSD, and it remains a controlled substance in most places. It’s worth knowing about as the science develops, but it’s not something to pursue casually.
Putting It All Together
The most effective approach combines multiple factors, because they work through different mechanisms that reinforce each other. Regular high-intensity aerobic exercise increases the birth rate of new neurons and raises BDNF. Consistent, quality sleep (especially REM sleep) protects those new cells during their vulnerable maturation period. Chronic stress management removes the cortisol brake that suppresses the entire process. Mental stimulation through novel, challenging activities improves survival rates of immature neurons. And nutritional support with omega-3s and potentially lion’s mane provides the raw materials and growth signals the process requires.
The seven-week timeline from cell birth to full integration means these aren’t overnight changes. But the hippocampus is generating new neurons throughout your life, and the choices you make consistently over weeks and months determine whether those cells flourish or die before they ever become functional.