How To Use The Stamets Stack To Optimize Microdosing

By Anahita Anais, Nervous System and Microdosing Expert, and founder of Microdose Guru. This is educational information about a publicly documented protocol, not medical advice.

Last updated: June 2026.

The Stamets Stack is a microdosing formula created by mycologist Paul Stamets that pairs a psilocybin microdose with Lion's Mane mushroom and niacin (vitamin B3). The theory is that the three together support the growth of new neural connections more than psilocybin on its own. The research behind that claim is mixed, which is worth knowing before you try it.

This guide walks through the standard doses and schedule, what each ingredient does, what the current science shows, and the safety and legal points to weigh first, so you can

decide whether it's worth trying.

What Is The Stamets Stack?

The Stamets Stack is named after Paul Stamets, the mycologist credited with popularizing "stacking," the practice of combining a non-psychoactive substance with a microdose of a psychoactive one to change its effect. The stack has three parts:

• Psilocybin, in mushroom or truffle form, at a microdose (a dose small enough that it does not cause a noticeable "trip").

• Lion's Mane (Hericium erinaceus), a functional mushroom studied for its effect on nerve growth.

• Niacin (vitamin B3), included by Stamets as a delivery aid.

Stamets has proposed that pairing psilocybin with Lion's Mane may support the formation of new neural pathways. That is a hypothesis, not a settled finding, and it has not been shown to "repair" neurological damage in humans. The research section below explains where the evidence stands.

The Stamets Stack Dosing Protocol

The standard Stamets Stack, as Stamets describes it, uses these amounts per dose:

The schedule most commonly cited for the stack is 4 days on, 3 days off: four consecutive dosing days, then three days without. People typically run that pattern for four weeks, then take a two-week break before deciding whether to repeat. The off days and the reset week are there to reduce tolerance build-up.

For reference, a microdose of dried Psilocybe cubensis generally falls in the 0.05 to 0.30 g range; the powder amounts above sit within that window, but potency varies widely between batches. If you want a fuller breakdown of how that range is measured and why it varies, see our guide on how much a microdose is. Doses vary by person and by the potency of the mushrooms used, so most people start at the low end and adjust based on how they respond. This is the protocol as Stamets describes it, not a recommendation. If you take any mood-altering medication or have a diagnosed mental-health condition, talk to a professional before starting, as covered below.

Benefits Of Lion's Mane In The Stamets Stack

Lion's Mane is a medicinal mushroom long used as a nerve tonic. It is rich in β-glucan polysaccharides and has been studied for anti-inflammatory, antioxidant, and neuroprotective properties. Most relevant to the stack, it has been shown to increase production of Nerve Growth Factor (NGF), a protein involved in the maintenance of neurons (Kawagishi et al., Tetrahedron Letters, 1991).

In one animal study, researchers found that dietary Lion's Mane supplementation supported hippocampal neurotransmission and recognition memory in mice, including in an Alzheimer's model context. A separate review catalogues a range of properties reported for the mushroom, including anti-microbial, anti-hypertensive, anti-diabetic, and wound-healing effects. These are findings from a review of mostly preclinical work, not proven outcomes in people.

Lion's Mane is also one of the better-studied options for people who want functional-mushroom support without a psychoactive component. If you are deciding what to pair with a microdose, our overview of functional mushrooms that support microdosing walks through the main candidates and what each one is studied for.

Quality varies widely between Lion's Mane brands. After years of testing sources, I recommend Real Mushrooms for its sourcing standards, third-party testing, and transparency. (Microdose Guru earns a small commission from this link, at no extra cost to you.)

Two things to keep in mind: most of this evidence comes from animal or laboratory studies rather than human trials, and it tests Lion's Mane on its own, not as part of the Stamets Stack. It tells us Lion's Mane is biologically active. It does not, by itself, confirm that adding it to a psilocybin microdose changes the outcome.

The Role Of Niacin

Niacin (vitamin B3) is included in the stack as a delivery aid rather than for its own effects. A standard niacin supplement covers the recommended daily intake of roughly 14 to 16 mg; the stack calls for 100 to 200 mg, which is well above that. Stamets has suggested that niacin's ability to widen blood vessels and cross the blood-brain barrier helps carry psilocybin and Lion's Mane further into the nervous system.

At these higher amounts, niacin commonly causes a "flush": a temporary feeling of heat, tingling, and skin redness that usually passes within 10 to 30 minutes. It is uncomfortable but generally harmless. Medical guidance is that anyone taking more than 500 mg of niacin should do so under the care of a healthcare provider.

The Research

This is the part most Stamets Stack guides skip. Here is the honest state of the evidence.

The largest observational study to test the stack's mood outcomes supports microdosing broadly, but not the stack specifically. A 2022 study in Scientific Reports (Rootman et al., Scientific Reports, 2022) followed 953 psilocybin microdosers and 180 non-microdosing comparators for about a month. Microdosers showed small-to-medium improvements in mood and mental health, and older adults showed some improvement in psychomotor performance. The same study tested whether stacking with Lion's Mane and niacin made a difference. It found that the added ingredients did not change the mood and mental-health results. So the current evidence does not show that the stack improves on a psilocybin microdose alone.

For scale, the same Microdose.me research group has reported on a much larger sample elsewhere: an earlier 2021 paper in Scientific Reports (Rootman et al., 2021) described practices and mental health across roughly 4,050 microdosers and 4,653 non-microdosers. That paper documents who microdoses and how, rather than testing the stack's effect on outcomes, so it widens the picture without changing the conclusion above.

A placebo-controlled study found the benefits may be due to expectation. The largest placebo-controlled microdosing study to date (Szigeti et al., eLife, 2021) had 191 participants secretly randomize themselves to a microdose or a placebo. Both groups improved over four weeks, with no reliable difference between them. The authors concluded that the placebo effect likely accounts for much of the reported benefit.

What's changed since. Microdosing research has kept moving. A 2024 paper in the Journal of Psychoactive Drugs (Syed et al., 2024) mapped global microdosing demographics, substance-testing behavior, and use patterns across a large international sample, confirming how widespread the practice has become while still relying on self-report. And the first dedicated placebo-controlled clinical trial of psilocybin microdosing for major depressive disorder is now underway, with its protocol published in early 2026 (BJPsych Open, 2026).

Until that kind of controlled trial reports, the human evidence stays where it was: early, mostly self-reported, and not yet strong enough to claim the stack outperforms a microdose on its own.

Neither earlier result means microdosing or the Stamets Stack "doesn't work." They mean the human evidence is early, mostly self-reported, and not yet strong enough to claim the stack outperforms a microdose on its own. Knowing that lets you set realistic expectations and pay attention to your own tracked results rather than the hype. This is educational, not medical advice.

Risks, Legal Status, And Limitations

Legal status (current as of June 2026). In the United States, psilocybin is a federally Schedule I substance, meaning it is illegal under federal law. A small number of states have created their own frameworks. Oregon has run regulated psilocybin service centers since 2023, and

Colorado opened its first licensed healing centers in 2025. New Mexico became the third state to legalize access when Governor Lujan Grisham signed the Medical Psilocybin Act (SB-219) in April 2025, with its program set to be implemented by the end of 2027. Lion's Mane and niacin are legal, widely sold supplements. Check your local law before sourcing or using psilocybin.

Safety and contraindications. The niacin flush is the most common side effect of the stack itself. The larger cautions are about psilocybin: it can interact with psychiatric medications (including SSRIs, SNRIs, and lithium), and microdosing is generally not advised for people with a personal or family history of psychosis or bipolar disorder without professional guidance. If you take an antidepressant, our guide on microdosing while taking antidepressants covers the interactions in more detail. Always consult your doctor before starting any supplement or microdosing routine.

What we still don't know. There are no long-term human safety studies on the Stamets Stack, and dosing is not standardized because mushroom potency varies. If you are weighing the real risks rather than the headlines, our overview of whether microdosing can be dangerous is a grounded place to start. Treat any protocol as a starting point to adjust, not a fixed prescription.

Is The Stamets Stack Right For You?

The Stamets Stack is popular, but popular is not the same as right for everyone. The sensible approach is to start low, track how you respond, and adjust. If you take mood-altering medication or have a diagnosed mental-health condition, a protocol built with a professional is strongly recommended over a one-size-fits-all formula.

If you'd rather design your own protocol with a structured resource instead of a generic stack, the Microdosing Protocol Guide gives you a step-by-step framework to build and adjust your own routine, including dosing, scheduling, and tracking. If you're not ready for that yet, you can start with our free mini-guide to get the fundamentals first.

Always consult your doctor before starting a supplement or microdosing regimen.

Frequently Asked Questions

What Is The Stamets Stack?

The Stamets Stack is a microdosing formula created by mycologist Paul Stamets that combines a psilocybin microdose with Lion's Mane mushroom and niacin (vitamin B3). The theory is that the three together support the growth of new neural connections more than psilocybin alone.

What Is In The Stamets Stack, And How Much?

Per dose: psilocybin mushroom powder 100 to 200 mg, Lion's Mane 50 to 200 mg, and niacin (vitamin B3) 100 to 200 mg. The usual schedule is 4 dosing days followed by 3 days off, run for four weeks, then a two-week break.

Does The Stamets Stack Work?

Observational research shows psilocybin microdosers report small-to-medium improvements in mood and mental health, but the largest such study (Rootman et al., 2022) found that adding Lion's Mane and niacin did not improve outcomes over psilocybin alone.

A placebo-controlled study (Szigeti et al., 2021) found no reliable difference between microdose and placebo groups. The human evidence is early and mostly self-reported, and the first controlled clinical trial of psilocybin microdosing for depression is only now underway.

Why Is Niacin In The Stamets Stack, And What Is The "Flush"?

Niacin is included as a delivery aid rather than for its own effects; Stamets suggests it helps carry the other ingredients across the blood-brain barrier. At the 100 to 200 mg in the stack, far above the 14 to 16 mg daily requirement, niacin commonly causes a temporary "flush" of heat, tingling, and skin redness that usually passes within 10 to 30 minutes. It is uncomfortable but generally harmless. Anyone taking more than 500 mg should do so under medical supervision.

Is The Stamets Stack Legal?

Psilocybin is a Schedule I substance under U.S. federal law. As of June 2026, Oregon, Colorado, and New Mexico have created regulated or decriminalized access frameworks, with New Mexico's Medical Psilocybin Act signed in April 2025. Lion's Mane and niacin are legal supplements. Check your local law before sourcing or using psilocybin.

Is The Stamets Stack Safe?

The most common side effect is the niacin flush, a temporary feeling of heat and skin redness that passes within 10 to 30 minutes. Psilocybin can interact with psychiatric medications such as SSRIs and lithium, and microdosing is generally not advised for people with a personal or family history of psychosis or bipolar disorder without professional guidance. Consult your doctor before starting.

How Long Do You Follow The Stamets Stack Protocol?

The common pattern is four dosing days followed by three days off, repeated for four weeks, then a two-week break before deciding whether to start another round. The off days and reset week help reduce tolerance build-up.

Last updated: June 16th, 2026. This article is educational and does not constitute medical advice. Microdose Guru does not sell, supply, or source psychedelic substances. This page contains affiliate links; Microdose Guru may earn a small commission, at no extra cost to you.