Stamets Stack: Protocol, Dosage, Effects & More

The Stamets Stack[i] is essentially a recipe and a set of instructions for a supplement for neuro-health. A “stack,” in this case, means a combination of a psilocybin microdose with some other supplement, the idea being that the ingredients enhance each others’ effectiveness.

As the name implies, the Stamets Stack was developed by Paul Stamets, the well-known mycologist and author. It’s not entirely clear how well the stack works, as it has not been through clinical testing, but some people do report good results, and the treatment appears to be fairly safe when used as directed. And, as they say, absence of evidence is not evidence of absence!

Two caveats are worth noting before we get going. One is that the stack includes a small amount of psilocybin, meaning that the whole thing is illegal in many jurisdictions. Please know what the law in your area is and don’t get sent to prison.

The other issue is that much of the reputation of the stack rests on the reputation of Paul Stamets, a reputation that has been somewhat exaggerated by many writers. He is a mycologist, popular science writer, and businessman. He sells mushroom-based supplements and grow-kits, as well as his books. He is responsible for introducing many people to the fascinating topic of mushrooms. But he is not especially well-regarded by his fellow mycologists, and (branding to the contrary) his scientific work appears to be only tangentially related to his business—his products involve discoveries he claims to have made about mushrooms yet he has never submitted that research for peer review.

It is neither unusual nor unethical for a company to engage in product-development research and then keep the details proprietary, but that is business and not science.

Stamets’ recommendations, including the Stamets Stack, should not be given the cachet of having been developed by a “leading mycologist,” but must instead be evaluated on their own merit.

The Stamets Stack

The Stamets Stack combines a microdose of psilocybin (meaning a dose so low as to not cause any hallucinations) with doses of lion’s mane mushroom and niacin. It is to be taken according to a protocol of dosing days and non-dosing days over a six-to-eight-week cycle. Taking psilocybin every day long-term would be counterproductive, as the body develops a tolerance and doesn’t react strongly to it anymore.

The stack is supposed to help with a wide variety of issues, from reducing irritability and nerve pain to increasing empathy and feelings of connectedness to reducing the effects of aging on the brain[ii]. Essentially, it is supposed to make the user a better person.

Why Psilocybin?

Psilocybin is the primary ingredient in the stack, though there isn’t very much of it by volume. The Stamets Stack is basically a psilocybin-microdosing protocol. The other ingredients in the stack are there to enhance and extend the effects of the psilocybin microdose.

Microdosing psilocybin means taking a dose low enough that it does not cause sensory distortion or irrational thinking. Instead, there is a slight change of mood and often a greater sense of connectedness. Users often report a subtle but definite shift in consciousness that supports personal growth.  It’s possible to carry out ordinary daily activities while microdosing, and people generally do so. It’s common to microdose repeatedly for a period of time in order to work through a particular personal issue or problem. Although research into the therapeutic use of psilocybin is in its infancy, surveys show microdosers generally find the practice valuable.

Psilocybin is found in many different mushroom species, sometimes in combination with other psychoactive substances. The stack can be made with virtually any of these, though the dose will vary depending on the potency of the mushroom (or truffle). To some extent, the character of the experience may also vary.

Why Lion’s Mane?

Lion’s mane mushroom is reputed to support neurological health, including the regeneration of damaged brain tissue. It’s important to recognize that although such effects are supported by scientific research, the relevant studies are still very preliminary and include very few, if any, clinical studies in human patients—that doesn’t mean lion’s mane extracts don’t work, only that we can’t be certain that they work, or how well they work.

Lion’s mane is part of the stack both because of its ability to promote brain and nerve health generally, and because of speculation that it can help the brain grow and change in ways prompted by the psilocybin.

Lion’s mane can simply be eaten—cooked properly, it tastes a little like crab meat—but for medicinal use it is available as an extract. Choosing the right extract is a little challenging.

The first difficulty is that the species, lion’s mane (Hericium erinaceus), is treated by some writers as interchangeable with its several close relatives in the same genus, as though all have the same medicinal potential. Actually, while all members of the group are safe to eat and taste about the same, it wouldn’t be surprising if their biochemistry differs enough that they can’t all be used the same way. We don’t know for sure yet, though. Since it’s likely some manufacturers share the all-Hericiums-are-alike assumption, it’s important to confirm that what you’ve got is indeed the right species.

The second issue is choosing the right Lions Mane. There are a lot of cheap mushroom supplements out there that are made out of mycelium (not real mushrooms). You want a Mushroom Supplement that is made out of fruiting bodies and measured by beta-d-glucans.

Why Niacin?

Niacin[iii], part of the group of substances called B-vitamins, is involved in metabolism, as well as the health of the digestive system, skin, and nervous system. Niacin deficiency is a serious disease called pellagra[iv] and can be caused by a diet deficient in both niacin and tryptophan, or by excessive consumption of either alcohol or corn that has not been properly treated–the Mexican tradition of mixing corn meal with lime or wood-ash prevents pellagra, but when corn became a staple in cultures without that tradition, pellagra became common. It is now rare in industrialized countries except among people who are food-insecure or have eating disorders.

In most cases, if you aren’t deficient in a vitamin, taking extra won’t help anything; if you have enough, you can’t use more. Your cup is full, so to speak. Niacin is an exception; it is used to treat high cholesterol, especially for people who can’t take statins.

Niacin is part of the stack because of its role in nervous system health, and because it is thought to be able to help the other substances in the stack spread through the body and into the brain. The reason niacin is thought to be able to help substances spread is that in high doses it causes blood vessels to dilate, allowing more blood close to the skin—the so-called niacin flush. That doesn’t mean niacin flushes the body out, as though cleaning it; it means that it makes the skin turn red and puffy (of course the redness is only visible in light-skinned people). The niacin flush is harmless, but it’s unpleasant, and is the main reason niacin isn’t used to treat cholesterol more often—patients often refuse to keep taking it. There is a no-flush version of niacin available, but the flush is part of the reason niacin is in the stack in the first place, so no-flush is not recommended.

Stamets Stack Dosages

Although in most cases it’s better to get dosage advice from a healthcare professional, not an article online, the Stamets Stack is a recipe, and recipes include measurements:

  • 100 to 200 mg dried magic mushrooms or equivalent amount of magic truffles
  • 500 to 1000mg of lion’s mane extract powder
  • 50-200mg of niacin

The protocol is based on a cycle of four weeks taking the stack, followed by two to four weeks without taking it. After those weeks off, you have the option of starting another cycle. Within each week of the cycle, four days are dosing days followed by three days without a dose.

It’s OK to eat lion’s mane (the whole mushroom, not the extract) on the non-dosing days, but do not take psilocybin in any form.

The above instructions raise some questions.

Which magic mushroom species is this? Potency varies, so 0.1 gram of one species is very different from 0.1 gram of something else. It’s likely Psilocybe cubensis, but it’s hard to be sure. Fortunately, we know this is supposed to be a microdose, and we know that for any psychoactive mushroom (or truffle), the microdose is one tenth the size of the smallest hallucinogenic dose, so it’s possible to calculate the correct amount of mushroom for whatever species you may end up using.

The other problem is that these recommendations are ranges, and it’s not obvious how one decides whether to take, say, fifty milligrams of niacin or four times that amount—but we do not have an answer to that one at this time.


Since the Stamets Stack has three ingredients chosen to enhance each other, we need to look at safety from four different angles—for each of the ingredients and for the stack as a whole.


As always, the most obvious safety concern is that if you possess psilocybin in a jurisdiction where it’s illegal, you could go to prison.

The chance of psilocybin causing serious problems unrelated to the law is low but not zero, and the long-term health effects of repeated microdosing have not been studied. Be forewarned. However, the risk of psilocybin-related problems is generally linked to the size of the dose, so the risk associated with microdosing is probably very small.

Lion’s Mane

Lion’s mane may be eaten freely. Lion’s mane extract is generally recognized as safe, with a few provisos[v].

There isn’t enough research to be sure it is safe for long-term use or by women who are pregnant or breast-feeding, but that doesn’t mean it isn’t safe, only that we don’t really know. And like many other medicinal mushrooms, it seems to be able to lower blood sugar and reduce blood clotting—either of which could be a good thing in some circumstances, but people who are already on blood thinners or who are being treated for clotting disorders or diabetes might need to avoid lion’s mane. It certainly should not be used immediately prior to surgery.


Curiously, the ingredient with the longest list of possible safety concerns isn’t either of the mushrooms—it’s the niacin[vi]. Taking large doses of niacin for any purpose besides correcting niacin deficiency is risky, and while the recommended dose for the stack is less than a tenth of what typically causes serious problems, it’s also well over ten times the recommended daily allowance. So caution is in order, and some people should not use the Stamets Stack because of the niacin in it.

Large, prescription-strength doses of niacin cause unpleasant flushing and dizziness, as noted. The flush is harmless, but further side-effects might not be. These include diarrhea, nausea and vomiting, itchiness, rapid heartbeat, gout, liver damage, and diabetes. Niacin can also worsen hypotension, peptic ulcers, gallbladder disease, thyroid disorders, and existing cases of diabetes or gout. While the dose recommended for the stack usually doesn’t cause serious problems, users need to be alert for the possibility of something going wrong—and should definitely not take a higher-than-recommended dose.

People who have any of the conditions that extra niacin makes worse simply should not use the Stamets Stack without qualified medical guidance. The same goes for anyone who is pregnant, is taking statins, anticoagulants, blood-pressure medication, chromium, or zinc.

Just be careful.

The Stamets Stack as a Whole

The stack has not been studied enough yet to be sure there are no problematic effects. There could be, we just don’t know. An equally important question is whether the Stamets Stack actually works—and, as pointed out earlier, we don’t know, yet.

It’s also important to note that Paul Stamets’ claims for the mixture are not scientific—that doesn’t mean the stack can’t work, only that it might not work for the reasons he says it does. And it’s good to exercise caution when a person makes their identity as a scientist a central part of their brand and then makes product claims that are not scientific. Frankly, the contrast is not inspiring of trust.

Let’s explore what we mean by “not scientific.”

Paul Stamets’s specific, publicly-stated goal in developing the Stamets Stack is to further users’ development into better, more-enlightened people in order to trigger the next stage in human evolution[vii]. But evolution doesn’t work that way; personal growth, fueled by mushroom use or otherwise, doesn’t change the genome. The idea that characteristics acquired during an individual’s life might somehow be passed down to their descendants is called Lamarkian evolution, and it was discredited in the 1930’s[viii]. There is no known mechanism by which is could happen and no evidence that it ever has happened. And yet Stamets is trying to make it happen with mushrooms (and niacin!) through a method that is based on preliminary scientific research, conjecture, and possibly further research that Stamets may have conducted but won’t show to other scientists for review. None of this is how science works.

With all this being said, there is preliminary (and largely anecdotal) evidence that microdosing psilocybin  does help with a variety of physical and mental issues. And combining psilocybin with lion’s mane and niacin, both of which have some connection to the health of the nervous system, does sound like a reasonable thing to try. Provided reasonable precautions are taken (most especially with the niacin), the stack is probably safe for most users.


[i]       (n.d.). Stamets Stack (Stacking Lion’s Mane). Microdosing Institute

[ii]      Brand, D. S. (2022). The Stamets Stack: Can Microdosing Really Change Your Brain? Double Blind

[iii]     (n.d.). Niacin. Mayo Clinic

[iv]     Redzix, S, Gupta, V. (2021). Niacin Deficiency. Nation Library of Medicine.

[v]      (n.d.). Lion’s Mane Mushroom—Uses, Side Effects, and More. WebMD

[vi]     (n.d.). Niacin. Mayo Clinic

[vii]    Brand, D. S. (2022). The Stamets Stack: Can Microdosing Really Change Your Brain?

[viii]   (n.d.m). Larmarkism. Britanica


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