What is the Stamets Stack?

The Stamets Stack is a microdosing approach named after mycologist Paul Stamets. It combines three ingredients, psilocybin, Lion's Mane, and niacin, taken on a four-days-on, three-days-off schedule. The idea is that the combination does more together than any one part alone.

What is in the Stamets Stack?

Three things: a microdose of psilocybin, Lion's Mane (a culinary and medicinal mushroom), and niacin (vitamin B3). Each is included for a different reason in Stamets' thinking, with the niacin acting as a distribution aid.

What is the Stamets Stack schedule?

The commonly cited rhythm is four days on, then three days off, repeated for several weeks before a longer break. That is more consecutive dose days than the Fadiman protocol's one-on, two-off cycle.

Does the Stamets Stack cause neurogenesis?

That is the hypothesis behind it, not an established fact. The neurogenesis idea is based largely on early and animal research, and it has not been proven in humans. Treat it as an interesting theory, not a settled outcome.

Stamets Stack or Fadiman protocol, which is better?

Neither is better outright. Fadiman is simpler and gives cleaner baseline days, which makes it easier for beginners to read. The Stamets Stack is a more involved approach built around a specific hypothesis. Many people start with Fadiman and explore the Stack later.

June 22, 2026· 6 min read

The Stamets Stack: Microdosing With Lion's Mane and Niacin

If the Fadiman protocol is the bare-bones classic, the Stamets Stack is the more elaborate cousin. It is named after Paul Stamets, the mycologist and author known for his work on fungi, and it is the other schedule almost everyone encounters early on.

Where Fadiman is purely a schedule, the Stamets Stack is a schedule plus a recipe plus a theory. This guide explains all three, plainly, and where the theory is solid versus where it is still just a theory. It is educational only, and it does not give amounts.

What the Stamets Stack actually is

Three ingredients, taken together, on a set rhythm:

A microdose of psilocybin (the same sub-perceptual idea as any microdose).
Lion's Mane (Hericium erinaceus), a mushroom used both in cooking and in traditional medicine.
Niacin (vitamin B3).

The schedule most associated with it is four days on, three days off, repeated over a number of weeks before a longer break. That is a notable contrast with Fadiman's one-on, two-off cycle: more consecutive dose days, fewer rest days in each cycle.

The thinking behind each ingredient

This is where the Stack differs from a plain schedule. Each part is there for a reason, at least in theory.

Psilocybin is the active microdose, the same component people use on other protocols.
Lion's Mane is included because it has been studied for its effect on nerve growth factor, and Stamets' hypothesis is that it and psilocybin together may support neuroplasticity, the brain's ability to form new connections.
Niacin is included as a distribution aid. Niacin causes a "flush", a warming, reddening sensation, and the idea is that it helps carry the other compounds through the body to the extremities. Some also frame it as a deterrent against taking too much, since a larger niacin dose is unpleasant.

It is worth being clear-eyed here: this is a reasoned hypothesis from someone who knows fungi deeply, not a proven mechanism. Which brings us to the important caveat.

The neurogenesis idea, honestly

The headline claim attached to the Stamets Stack is that it may promote neurogenesis, the growth of new neurons. It is a genuinely interesting idea, and there is early research on both psilocybin and Lion's Mane that makes it plausible.

But "plausible" and "early" are the operative words. Much of the supporting work is animal or laboratory research, and the specific claim that this combination grows new neurons in humans, in the amounts used in a microdose, has not been established. Treat the neurogenesis story as the theory the Stack is built on, not as a result you should expect. Anyone telling you it definitely rewires your brain is going beyond what the evidence supports.

How the schedule compares to Fadiman

The four-on, three-off rhythm changes the experience in a couple of ways:

More consecutive dose days. Four in a row, rather than single doses spaced out. Some people find a run of days more useful; others find the tighter spacing harder to read.
Fewer clean baseline days per cycle. The three off days still matter as integration days, but there are proportionally fewer ordinary days to compare against than on Fadiman.

That trade-off is the main reason a lot of people start with Fadiman. Its wide spacing makes the early weeks easier to interpret. The Stamets Stack tends to appeal to people who already have a feel for their own response and want to explore a specific approach.

Who tends to choose it

People are drawn to the Stack for a few reasons: the appeal of the neurogenesis hypothesis, an interest in stacking complementary ingredients rather than a single substance, or simply because Paul Stamets is a trusted name in the mushroom world. None of those are wrong reasons, as long as the theory is held as a theory.

If you are completely new, the simpler path is usually to learn your own baseline on a plain schedule first, then decide whether a more involved stack is worth adding.

Tracking the Stamets Stack with Dose Days

Dose Days supports the Stamets Stack as a built-in protocol, so the four-on, three-off rhythm is laid out for you rather than something you have to count in your head. You log each dose day with an intention, a mood, and a note, and you do the same light check-in on the integration days, so the whole cycle is visible rather than just the dose days.

Because the Stack involves more than one ingredient, having a clean record matters even more. It is free to start, and everything stays on your device.

A note on safety and the law

Microdosing involves substances that are controlled in most places, and the research is still early. This is educational information, not medical advice or a recommendation to use anything.

A specific note on niacin: the flush is normal but can be uncomfortable, and like anything taken regularly it is not free of considerations, especially alongside other medication. As with the psilocybin component, the risks are higher for anyone with a personal or family history of psychosis or bipolar disorder, or anyone on other medication where interactions are not well understood. Understand the law where you live, and speak to a qualified professional about your own situation. There is a fuller note on safety and US legality in the Fadiman protocol guide.