What is neurogenesis?

Neurogenesis is the process by which entirely new neurons are born in the brain. Unlike neuroplasticity (which involves changes to existing neurons and their connections), neurogenesis adds brand new cells to the neural circuitry.

For most of the 20th century, it was believed that the adult brain could not produce new neurons — that you were born with all the neurons you'd ever have. This dogma was overturned in the 1990s when researchers demonstrated that new neurons are indeed generated in specific brain regions throughout adulthood.

Where neurogenesis occurs

Adult neurogenesis has been confirmed in two main brain regions:

1. Hippocampus (subgranular zone)

The hippocampus is critical for:

Memory formation — converting short-term memories to long-term
Spatial navigation — mapping your environment
Emotional regulation — processing and contextualizing emotions
Pattern separation — distinguishing between similar experiences

New hippocampal neurons are thought to help with learning flexibility — the ability to form new associations and update old ones.

2. Olfactory bulb (subventricular zone)

New neurons are generated for the sense of smell processing. This is less directly relevant to microdosing but demonstrates the brain's ongoing regenerative capacity.

Debated: cortical neurogenesis

Whether new neurons are generated in the cerebral cortex of adult humans remains controversial. Some studies suggest low-level cortical neurogenesis, but it's not well established.

Why neurogenesis matters for microdosing

Research on psychedelics and neurogenesis

Several studies have explored the connection:

Catlow et al. (2013) — Found that psilocybin increased hippocampal neurogenesis in mice and facilitated extinction of fear conditioning
Lima da Cruz et al. (2018) — DMT (a component of ayahuasca) promoted hippocampal neurogenesis in mice
Ly et al. (2018) — Multiple psychedelics promoted dendritic growth (neuroplasticity) and potentially support conditions for neurogenesis

Important caveat: These are animal studies. Direct evidence that microdosing promotes neurogenesis in humans is lacking.

The Stamets Stack hypothesis

Mycologist Paul Stamets specifically designed his microdosing stack to target neurogenesis:

Psilocybin — promotes neuroplasticity and potentially neurogenesis
Lion's Mane mushroom — contains compounds shown to promote NGF (nerve growth factor) and support neurogenesis in animal studies
Niacin (vitamin B3) — Stamets theorizes it helps deliver the other compounds across the blood-brain barrier via vasodilation

The scientific evidence for this specific stack's synergistic effect on neurogenesis is preliminary — the theory is plausible but not yet proven in humans.

Neurogenesis and depression

Reduced hippocampal neurogenesis is associated with:

Major depressive disorder
Chronic stress
PTSD

Successful antidepressant treatment (SSRIs, exercise, ketamine) is associated with increased hippocampal neurogenesis. If psychedelics similarly boost neurogenesis, this could be one mechanism behind their antidepressant effects.

Neurogenesis vs. neuroplasticity

	Neurogenesis	Neuroplasticity
What changes	New neurons are born	Existing neurons change
Where	Primarily hippocampus	Throughout the brain
Speed	Weeks to months	Hours to days
Evidence in humans	Established but debated in extent	Well-established
Psychedelic evidence	Animal studies only	Animal + some human
Scale of impact	Adds hundreds of cells	Modifies billions of connections

Both processes likely contribute to the benefits of microdosing, but neuroplasticity is the more established and immediately relevant mechanism.

How to support neurogenesis

Many of the same factors that support neuroplasticity also promote neurogenesis:

Aerobic exercise — the single most potent neurogenesis promoter
Quality sleep — new neurons are consolidated during sleep
Learning and novelty — stimulates demand for new neurons
Caloric moderation — intermittent fasting may promote neurogenesis
Omega-3 fatty acids — DHA supports new neuron survival
Stress reduction — chronic stress is the #1 neurogenesis killer
Social enrichment — social interaction promotes hippocampal health

What impairs neurogenesis:

Chronic stress and elevated cortisol
Sleep deprivation
Alcohol abuse
Sedentary lifestyle
Chronic inflammation
Social isolation

Neurogenesis