The Stamets Stack Explained: Psilocybin + Lion's Mane + Niacin

Paul Stamets believes this three-ingredient combination could represent "the next quantum leap in human consciousness." It's a bold claim — but the man behind it is no crank. Here's what the stack actually is, what the science says, and how to use it.

The Stamets Stack is one of the most talked-about protocols in the microdosing world. Named after renowned mycologist Paul Stamets, it combines a psilocybin microdose with Lion's Mane mushroom and niacin (vitamin B3) in a specific schedule designed to support what Stamets calls "epigenetic neurogenesis" — essentially, helping the brain grow new connections.

Whether you're curious about microdosing, already practising it, or just want to understand the science, this guide covers everything: the theory, the protocol, the evidence, and the practical considerations.

What Is the Stamets Stack?

Paul Stamets first described this combination publicly on the Joe Rogan Experience podcast and later formalised it through a patent application claiming a method for "enhancing neuroregeneration and cognition" using psilocybin mushrooms, Lion's Mane, and niacin together.

The core idea: these three ingredients don't just add up — they synergise. Psilocybin opens the door to new neural pathways. Lion's Mane builds the scaffolding. Niacin carries the benefits to the furthest reaches of the nervous system.

Stamets developed the concept partly in response to the global rise in neurodegenerative conditions like Alzheimer's and Parkinson's — conditions where neurogenesis (the creation of new neurons and connections) could, in theory, slow progression or support recovery.

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The Three Ingredients Explained

Psilocybin — Neuroplasticity and Serotonin

Psilocybin is the psychoactive compound found in "magic" mushrooms and truffles. At full doses, it produces the well-known psychedelic experience. At microdose levels (sub-perceptual, roughly one-tenth of a full dose), it works differently.

Psilocybin is a 5-HT2A receptor agonist — it binds to serotonin receptors that regulate mood, perception, and cognition. At microdose levels, research suggests it promotes neuroplasticity: the brain's capacity to form new synaptic connections and reorganise existing ones. It also appears to increase BDNF (brain-derived neurotrophic factor), a protein sometimes called "Miracle-Gro for neurons."

The working theory for microdosing is that sub-perceptual doses create a low-level opening of neural pathways — a window of increased flexibility and responsiveness — without the disruption of a full psychedelic experience.

Lion's Mane — Nerve Growth Factor

Lion's Mane (Hericium erinaceus) is a functional mushroom with a strong evidence base for neurological support. Its two key bioactive compound groups — hericenones and erinacines — stimulate the production of Nerve Growth Factor (NGF), a protein that supports the survival, maintenance, and growth of neurons.

A landmark 2009 study by Mori et al. showed that Lion's Mane extract improved mild cognitive impairment in a randomised controlled trial, with benefits diminishing after supplementation stopped. Preclinical studies have shown that erinacines can cross the blood-brain barrier, where they promote myelination (the protective coating around nerve fibres) and neuronal repair.

In the Stamets Stack, Lion's Mane acts as the construction crew: while psilocybin opens the neural architecture to change, Lion's Mane provides the raw material and signalling to build new connections.

Niacin — Peripheral Delivery

Niacin (vitamin B3, specifically nicotinic acid — not the "no-flush" variant) is the most debated component of the stack. At doses of 25–200mg, it causes a "flush": a wave of tingling warmth and redness as blood vessels dilate throughout the body.

Stamets' hypothesis is that this vasodilation acts as a delivery mechanism. By expanding peripheral blood vessels and increasing circulation, niacin may help carry both the hericenones/erinacines from Lion's Mane and the psilocybin metabolites to nerve endings in the peripheral nervous system — regions that might otherwise receive limited exposure.

Niacin also contributes independently: it's a precursor to NAD+, plays roles in DNA repair and cellular energy metabolism, and epidemiological research suggests higher niacin intake correlates with lower risk of age-related cognitive decline.

One interesting side effect Stamets notes: the unpleasant niacin flush may act as a natural deterrent against overuse — if someone tries to take too much psilocybin within the stack, the intensified flush becomes uncomfortable enough to discourage excess dosing.

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The Neurogenesis Theory

The stack's central claim is that these three ingredients work synergistically to promote neurogenesis — the growth of new neurons and neural pathways. Here's how Stamets describes the cascade:

1. Psilocybin activates 5-HT2A receptors, promoting neuroplasticity and increasing BDNF — the brain is primed for change
2. Lion's Mane stimulates NGF production, providing the biological signal and building blocks for new neuronal growth and myelin repair
3. Niacin dilates blood vessels, helping distribute both psilocybin's effects and Lion's Mane's neuroactive compounds throughout the central and peripheral nervous system

The theory is mechanistically plausible — each ingredient has independent evidence supporting its contribution. What remains unproven is whether they genuinely synergise in the way Stamets describes, or whether the benefits are simply additive (or just the sum of whichever ingredient is most active).

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The Protocol: Dosage and Schedule

Stamets has refined his recommended dosages over time. His most current guidance (as of 2023) is:

Schedule: 4–5 days on, 2–3 days off. Repeat for 4–6 weeks, followed by a break of 2–4 weeks before resuming.

This is similar to the Fadiman Protocol in structure but differs in that it stacks additional compounds and tends toward slightly more frequent dosing. See our full comparison of Fadiman vs Stamets for a side-by-side breakdown.

About the Niacin Flush

The flush is real and can be intense, especially for first-timers. Your skin turns red, you feel warmth or tingling, and it can last 20–60 minutes. This is a normal physiological response to niacin's vasodilatory action — not an allergic reaction or sign of harm.

To manage it:

• Start at 25mg and work up slowly over 1–2 weeks
• Take niacin with food to reduce intensity
• The flush diminishes with regular use as the body acclimatises
• Avoid the no-flush (niacinamide/inositol hexanicotinate) forms — Stamets specifically requires nicotinic acid

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What Does the Evidence Say?

This is where intellectual honesty matters. The Stamets Stack has not been tested in a randomised, placebo-controlled clinical trial. Most of what we know comes from two sources: the established independent research on each ingredient, and observational studies on microdosers.

The 2022 Rootman et al. Study

The most significant study to date is Rootman et al. (2022), published in Scientific Reports (Nature). This observational study tracked 953 psilocybin microdosers and 180 non-microdosing controls for approximately 30 days via a mobile app.

Key findings:

• Microdosers showed small-to-medium improvements in mood and mental health measures, consistent across age and gender
• Among older adult microdosers, those using the full Stamets Stack (psilocybin + Lion's Mane + niacin) showed significant improvements in psychomotor performance — specifically a finger-tapping test that serves as a validated neurological measure
• The psychomotor benefit was not observed in older adults who microdosed psilocybin alone, suggesting the stack's additional components contributed something beyond psilocybin

Important caveats: this was self-reported, observational data. Participants weren't randomised. Placebo effects cannot be ruled out. Paul Stamets is a co-author and has financial interests in related companies — a conflict of interest the paper discloses, but one worth noting.

Individual Ingredient Evidence

The honest summary: the stack is built on a scientifically coherent theory, its individual components have real evidence, and the one substantial real-world study shows promising signals. But it hasn't been put through the rigour of a double-blind trial. Treat it as promising, not proven.

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Stamets Stack vs Fadiman Protocol

Both are among the most popular microdosing protocols, but they differ in philosophy and structure:

If you're new to microdosing, many experienced practitioners recommend starting with the Fadiman Protocol for a cycle or two before adding the stack's additional compounds. This lets you establish your baseline response to psilocybin alone.

Read our detailed Fadiman vs Stamets comparison for more.

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User Experiences and Common Reports

Across communities of people using the Stamets Stack (including online forums, the Microdose.me data, and anecdotal accounts), several themes emerge consistently:

• Enhanced pattern recognition — making connections between ideas more readily
• Improved verbal fluency — finding words and articulating thoughts more easily
• Mood stability — a more even emotional baseline rather than peaks and troughs
• Long-term cognitive clarity — effects reported to build gradually over weeks rather than feeling acute
• Reduced anxiety — particularly social anxiety and general background stress
• Psychomotor improvement — fine motor speed and coordination, as reflected in the Rootman study

Many users also note that compared to psilocybin alone, the stack feels more grounded — less "psychedelic adjacent" and more like general cognitive support.

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How to Start the Stamets Stack

Step 1: Check legality in your location

In the Netherlands, psilocybin truffles (sclerotia) are fully legal. Mushrooms are not. If you're in NL, psilocybin truffles from a licensed vendor are your legal source for the psilocybin component. In most other European countries, psilocybin remains a controlled substance — check your local laws before proceeding.

Step 2: Source your ingredients

• Psilocybin truffles — available legally in the Netherlands from reputable smartshop vendors. For microdosing specifically, pre-packaged microdosing truffles are the most reliable option for consistent dosing
• Lion's Mane extract — use a standardised extract, not just dried mushroom powder. Look for products specifying hericenone/erinacine content
• Niacin (nicotinic acid) — available at pharmacies and health stores. Confirm you're buying nicotinic acid specifically, not niacinamide or inositol hexanicotinate

Step 3: Start conservative

Begin with the lower end of each range and assess your response:

• Psilocybin: 0.5g fresh truffles
• Lion's Mane: 500mg
• Niacin: 25mg

Increase gradually if well tolerated. Keep a microdosing journal — tracking mood, cognition, sleep, and any side effects gives you real data to work with. See our microdosing journal template for a structured approach.

Step 4: Time your dose

Take the stack in the morning. The niacin flush peaks around 30–60 minutes after taking it and can be distracting — most people prefer to dose before a light activity period rather than immediately before focus work. Lion's Mane is typically taken with the same timing.

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Safety Considerations

Who should avoid or approach with caution:

• SSRI / antidepressant users — psilocybin and SSRIs interact at the serotonin receptor level. SSRIs may blunt psilocybin's effects; combined serotonergic activity at higher doses carries theoretical risk. Consult a doctor
• People with personal or family history of psychosis or schizophrenia — psilocybin at any dose is contraindicated; the risk of precipitating psychotic episodes is real
• Niacin contraindications — avoid niacin if you have liver disease, peptic ulcer, gout, very low blood pressure, significantly impaired kidney function, or diabetes. Always check with a healthcare provider if uncertain
• Pregnant or breastfeeding — insufficient safety data exists for any component of this stack
• Cardiovascular conditions — niacin's vasodilatory effect warrants caution; discuss with a doctor

Niacin flush management: The flush is not dangerous, but it can be uncomfortable. If you experience it intensely, reduce your dose, take it with a larger meal, or switch timing. It typically reduces in intensity within 1–2 weeks of regular use.

Tolerance and breaks: The 4–5 days on / 2–3 days off schedule is designed to prevent psilocybin tolerance buildup. After 4–6 weeks, a longer break (2–4 weeks) is recommended before resuming.

Affiliate disclosure: Smart Supplements may earn a commission on purchases made through partner links. This does not affect our editorial independence.

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Frequently Asked Questions

Is the Stamets Stack legal in the Netherlands?

The psilocybin truffle component is legal in the Netherlands — psilocybin truffles (sclerotia) are not controlled substances there. Lion's Mane and niacin are freely available supplements everywhere. Note that in most other EU countries, psilocybin in any form remains a controlled substance.

Do I have to use niacin, or can I skip it?

Some people use a two-component stack (psilocybin + Lion's Mane only) and omit niacin. Stamets considers niacin essential to the stack's mechanism, but there's no evidence directly comparing the three-component vs two-component approach. If niacin is contraindicated for you, the two-component version is an option.

What does the niacin flush feel like?

Expect warmth, redness, and tingling — usually starting in the face and spreading to the chest and arms. It lasts 20–60 minutes. It can be mildly to moderately uncomfortable, especially the first few times. It diminishes with continued use. It is not an allergic reaction.

How is the Stamets Stack different from just taking Lion's Mane alone?

Lion's Mane alone is a well-supported nootropic for cognitive health. The Stamets Stack adds psilocybin's neuroplasticity effects and niacin's vasodilation. The theory is that psilocybin primes the neural environment for the structural changes Lion's Mane supports — but this synergy has not been directly tested in controlled conditions.

How long before I might notice effects?

Most users report that effects build over 2–4 weeks rather than appearing immediately. The neurogenesis hypothesis implies a longer timeline — neurons don't grow overnight. Short-term mood and clarity changes may be noticed sooner; cognitive and psychomotor changes tend to emerge over a full 4–6 week cycle.

Should I journal while doing the Stamets Stack?

Yes. Given that effects are subtle and cumulative, tracking mood, focus, sleep, and energy day by day provides much more useful insight than relying on general impressions. It also helps you identify any negative patterns and adjust dosing accordingly.

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The Bottom Line

The Stamets Stack is one of the most ambitious and theoretically coherent microdosing protocols available. Its three components each have legitimate scientific foundations, the synergy hypothesis is mechanistically plausible, and the most robust real-world study to date showed meaningful psychomotor improvements in older adults using the full combination.

It is also, to be clear, still largely uncharted territory. No randomised controlled trial has tested the full stack. Observational data has inherent limitations. The claims Stamets makes — neurogenesis, neurodegenerative repair, cognitive leap — go significantly beyond what the current evidence can confirm.

Approach it with genuine curiosity and healthy scepticism. If you're in the Netherlands and legal access to truffles is straightforward, it's a fascinating protocol to explore carefully. If you're in a jurisdiction where psilocybin isn't legal, Lion's Mane + niacin as a standalone nootropic stack still offers real value — with the psilocybin element something to consider if the legal landscape changes.

The science is moving fast. Watch this space.

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This content is for informational purposes only and is not medical advice. Consult a healthcare professional before starting any supplement. Psilocybin is a controlled substance in most countries — always check local law.

Written by Smart Supplements Editorial Team Last updated: March 2026

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