Help to find super donors for Fecal Microbiota Transplants (FMT)! By donating stool for FMT, exceptionally healthy people can earn $180,000/yr with little effort. Simultaneously they can help chronically ill people improve their health with a novel treatment. Apply here


More detailed summary

Fecal Microbiota Transplants (FMTs) is a procedure that transfers the stool of healthy people to the guts of sick people. The mechanism is to replace a dysbiotic gut microbiome with an eubiotic, disease-resistant gut microbiome. 

So far, FMT has only been proven to be very effective in curing patients of C. difficile infections. However, since the gut microbiome impacts and regulates virtually every aspect of human health, function, and development, FMT is a promising treatment for a very wide range of chronic and acute health conditions[1][2]

FMTs can easily & safely be done at home, both for the donor and the recipient - no doctor needed.

A super-donor is a person who yields outstanding positive effects as a stool donor. Only exceptionally healthy & fit people are super-donors. They are very rare and a few people within the FMT movement have been searching for them for years. Most donors, even reasonable healthy ones, only yield modest benefits.

Human Microbes, an organization specialized in finding super-donors and connecting them with recipients, is paying super-donors $500 per stool. This adds up to $180,000/yr if donating a daily stool!


Purpose of this post

  • Spread the news that this opportunity for super donors exists: With little effort, they can help lots of ill people (“make them more effective”) while earning $500/stool. You should check whether you are a super donor. If you know someone who might be, please share this post with them.
  • Give a rough introduction to FMTs & Human Microbes, with the aim to start a rational discussion about FMT’s benefits. FMTs look very promising, but there is by no means a clear scientific consensus. I’d love for more EAs to look into this, to get more certainty about its efficacy!
  • If your health is suboptimal, maybe you could consider using FMTs. Not just for obviously gut health-related issues, but much more broadly than you might think. Potentially even e.g. unspecified subclinical low energy, low mood, or mental sluggishness.
  • At the end, this post provides you with a long list of useful further links on FMTs, the microbiome and its connection to a vast amount of (mental-) health conditions. This is to help you do your own research, both as a potential super donor or as someone who might benefit from FMTs.
  • Finally, this post is also a shameless attempt to find FMT donors for me to treat my severely limiting gut issues. Please contact me at anton.rodenhauser[at] . 


Who might be a super donor?

  • Donors must be in exceptional physical and mental health. Ideally, top young athletes. Though there are non-athletes who qualify as well.
  • Ideally, donors would be under 30 years old. Donors can be under 18 provided they have signed consent from their parents. Many children need FMT and are ideally matched with young donors.
  • Donors should have minimal antibiotic use.
  • Donors should have a "Type 3 stool" as a Bristol Stool Type.

Check out the links at the end of this post for more information and sources. 

As you can imagine, super donors are very rare and thus very high in demand. In fact, Human Microbes has screened over 25,000 donor applicants so far, including hundreds of college and professional athletes, and still hasn’t found that one “perfect” super donor that fully satisfies all their donor criteria! So please reach out to Human Microbes about potential super donor candidates!!


How much good can you do by finding a super donor?

Know an EA whose gut-borne suboptimal health is holding them back from doing the most good they can do? Find them a super donor, or be a super donor for them!

In recent decades, chronic disease has been dramatically rising all over the world. Depending on what standard for “healthy” you choose, the vast majority of people are now significantly unhealthy – both physically and mentally – and the problem continues to worsen.

It is postulated that the gut microbiome plays a major role in this phenomenon – through widespread overuse of antibiotics, c-sections, lack of breastfeeding, and suboptimal diets. And the damage we’re doing accumulates over generations.

Our host-native gut microbiomes have been evolving alongside us for millions of years. If we lose them, we may never get them back. 

Since the gut microbiome has been shown to impact and regulate virtually every aspect of human health, development, and function, a super-donor may be able to cure numerous acute and chronic illnesses - including many with no obvious gut connection at all. 

Beyond that, FMTs from super donors are promising to make people more than “merely not sick”. They can plausibly/probably make many people more energetic and improve their mental health, sleep, and cognitive functioning. There might even be some longevity benefits to doing FMTs from young donors! You could arguably think of FMTs as a form of “biohacking” for optimal performance/health. Check out the “Links to do your own research” section at the end! 

I can picture a future where we identify one super donor among EAs, and then provide FMTs for all EAs who suffer from low mood, anxiety, low energy, some chronic health condition, etc. Imagine the impact of that super donor EA! 


About Human Microbes & Michael Harrop

Human Microbes was started up in 2020 by Michael Harrop in response to the lack of high-quality donors available at other sources – worldwide clinics, hospitals, stool banks, clinical trials, etc. Almost all of the latter ones focus mainly on acute safety, aka “the donor must not have any obvious diseases or illness so he can’t infect or otherwise harm you”. Instead, Human Microbes emphasizes “you don’t want a merely not sick donor - you want a maximally healthy, extraordinarily well-functioning donor - after all, that’s what YOU want to become yourself.”


Virtually all studies use “merely not sick” donors, resulting in poor clinical trial results and putting patients at risk. According to Michael Harrop, this is why FMTs have not yet been recognized by the scientific community as the miracle cure that they might well be. See “Links to do your own research” section.


Harrop still runs Human Microbes alone. From my heuristics and in my experience (ordering stools, having several calls with him, getting help for this article), he is trustworthy and focuses on the science part of things instead of the business part. He writes (and I’m inclined to believe him) that “While many other operations have a primary financial motivation, our motivation is fixing people and fixing society. We aim to find the fewer than 0.1% of people who qualify, and connect them with doctors, researchers, hospitals, clinical trials, and individuals.” I’m a bit less certain about his epistemic standards & humility. Reading his (Maximilian Kohler is his alias), I get the feeling that he is extraordinarily knowledgeable on the topic and really cares for the science, but he may be a bit too excited about FMTs at times. There is an AMA with him in the comments!

Why aren’t scientists more excited about FMTs?

To be clear, many scientists are very excited about FMTs. It’s an active area of research. Still, one has to ask: Why are results in FMT studies often mixed? Why do many reports state FMTs don’t work? Why so much poor anecdotal evidence?

Answer (according to Michael Harrop): Virtually all FMT studies have one of the following major flaws:

  1. Poor donor quality. Donors should be under 30, have very limited lifetime antibiotic exposure (ideally none), athletic & low body fat, and good mental health. Firm stool consistency seems important too. Typical donor criteria you see are severely deficient. Stuff like "no antibiotics in the past 3 months, 18-50 yrs old, no pathogens in stool & blood test".
  2. Insufficient treatment length. Many studies only do a single infusion, but for many people/conditions you might need to do it daily for 2+ months (Eg: ASU autism study).
  3. Too much oxygen exposure. Blending is quite common and this oxygenates the stool sample, killing anaerobes, and thus very likely reducing efficacy.
  4. Colon-only procedures. The small intestine is very important, so completely ignoring it is a likely flaw for some conditions.

The above is mostly copied from here (link provides lots of evidence for above claims). 

Judging by donor criteria, some of the best FMT studies are coming from a Danish hospital. They made great efforts to find a super-donor. Out of 700 applicants, they only accepted the top 4 “healthiest” ones. They did get better results for C. difficile, i.e. a 100% cure rate, vs the usual 80-90%,  yet failed for IBS and UC. Here is a nice article about it. However, Human Microbes was in contact with the top donor mentioned in the article, and not even their donors passed Human Microbes’ criteria. Thus it is not surprising (according to Human Microbes) that their studies for IBS and UC failed. 

The hypothesis (yet to be tested, but strongly implied) is that FMTs with stools from exceptionally healthy donors, according to Human Microbes’ even stricter criteria, combined with using only “correct” procedures (see above), would show much better results than the above or any other existing study out there.


Effective Entrepreneurship opportunity

I believe that Human Microbes is a great effective entrepreneurship opportunity. Michael Harrop would be more than glad to have some savvy EA business people take over his Human Microbes, which is more like an “amateur project” at this point. He has written to me: “I have no knowledge, interest, or expertise in running a business. My own poor health is typically very limiting. I didn't start out with the intention to create a business. But I think it will need to go in that direction. And I would love it if I could find someone able to do a good job at it. My expertise is knowledge & understanding of human health, development, and function, and the gut microbiome & FMT, and thus screening & selecting stool donors.

He also told me he’d be passionate about people helping him do proper scientific studies with very high-quality super donors - something that has apparently not been done so far. At the very minimum, he’d like to do some citizen science with the help of some proper data scientists/study design experts. 

I’ll write a separate blog post about the “effective entrepreneurship” side of FMTs. 


I am an EA who has benefited from FMTs with stools ordered from Human Microbes. Now I’m writing this blog post to help the cause of FMTs. I strongly want to encourage anyone with super donor potential or who knows someone like that to contact Human Microbes. 

Also, my own health is still quite bad, so I would be extremely grateful for any potential super donors to reach out to me as well. 


Aella did FMT with (I think) Nate Soares as her donor. Nate certainly looks like a super donor to me - someone please tell him about this post!

Michael Harrop’s vision is to identify a 10/10 super donor and, via FMT, use their stool to help upgrade the stool of 'very good' donors to a 10/10 as well. This should help to scale and trickle down the superior health benefits to other people. He says it is plausible but not certain that this will work.


Questions? AMA with Michael Harrop in the comments! 

I’ve arranged for Human Microbes’ Michael Harrop to hang around in the comments. Feel free to ask him any questions! Even if your question feels dumb, or if you haven’t read this full post. Michael Harrop is extraordinarily knowledgeable about this topic! I’d be especially curious about your reasons for being skeptical, for “not buying into this”, or for not trusting Human Microbes/Michael Harrop. If your health is suboptimal, what stops you from trying FMTs as a treatment?

Links to do your own research


PubMed: “Fecal Microbiota Transplantation: Current Applications, Effectiveness, and Future Perspectives”:


PubMed: “Fecal microbiota transplantation broadening its application beyond intestinal disorders”:


Review article: ”The Super-Donor Phenomenon in Fecal Microbiota Transplantation”:


Scientific article on the “microbiome crisis & endemic suboptimal health”:


“Preserving microbial diversity: “the loss of our ancestral microbial heritage, to which we were exposed through millions of years of evolution, may be the driving force behind the dramatic increase of chronic disease”


Diet-induced extinction in the gut microbiota compounds over generations

On the same topic:


Article in “Frontiers in Microbiology”:

"It is now clear that the gut microbiota contributes significantly to the traits of humans as much as our genes, especially in the case of atherosclerosis, hypertension, obesity, diabetes, metabolic syndrome, inflammatory bowel disease (IBD), gastrointestinal tract malignancies, hepatic encephalopathy, allergies, behavior, intelligence, autism, neurological diseases, and psychological diseases. It has also been found that alteration of the composition of the gut microbiota in its host affects the behavior, intelligence, mood, autism, psychology, and migraines of its host through the gut-brain axis." (2018):

Keep in mind that a common theme is the lack of high quality donors being used in most studies, due to the difficulty of finding such people. So we should see dramatically better results once we do find people who meet the ideal criteria. 


Diet-induced extinction in the gut microbiota compounds over generations: 


Nice informational website:

by Michael Harrop

Michael Harrop’s in-depth FMT explainer (Maximilian Kohler is his alias): procedure, benefits, science/epistemic status, donor screening, etc.: 

Michael Harrop: scientific review on numerous health conditions that have a connection with the microbiome and can thus potentially/probably be cured with FMTs. Highly recommended!


How well do FMTs work? What evidence do we have?

One issue is that since C. Diff has proven relatively easy to treat with only 1-2 FMTs, that has been the most common approach for other conditions as well. But for harder-to-treat conditions (most of them) we’ll likely need many more FMTs, as well as higher quality donors. 

Michael Harrop explains “Where are Human Microbes super donor criteria coming from”:

Harrop also writes a lot about gut health and other FMT adjacent topics on his  

FMTs for anti-aging, mood, sleep, brain function, and other “hot” topics 

FMTs, Microbiome & (Anti-) Aging: Forget young blood, you want young poop! 

Microbiome and depression & anxiety: Is a suboptimal microbiome making you unhappy and could FMTs change that? 

Microbiome & sleep: 

Microbiome & brain function:

about Human Microbes 

Human Microbes’ website: 

Here is the $500/stool offer & procedure:

FMT super donor criteria & screening questionnaire: 

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28 comments, sorted by Click to highlight new comments since: Today at 3:02 AM

Naively, I would expect that the body of most top athletes is under a lot of stress and thus not the perfect candidates. On the other hand, being a top athlete is a hard-to-fake signal. 

Currently, I have trouble finding the actual criteria on the website. I would expect that there's little evidence for the metrics that are actually used to decide who happens to be a super donor, so it would be valuable to be more open about the assumptions that go into it. donor criteria are listed on the Donors page. The specifics beyond those basic criteria are not listed for a variety of reasons, including, that they may change over time as we experiment and learn more, and that we need people to be honest with their applications. 

Support for athletes as donors is listed here: 

You are definitely correct that many athletes may be doing harm by pushing themselves beyond what their body is naturally capable of. 

I've screened hundreds of college and professional athletes at this point, including gold medalist Olympians. The vast majority of athletes don't qualify or rank high. 

Saying "A specific Bristol Stool Type" and not what stool type you are looking for seems to be the opposite of listing the desired criteria. 

that they may change over time as we experiment and learn more

Generally, in science, it's useful when the process of learning more about what criteria matter, is an open one where arguments about why certain criteria are believed to matter can be openly challenged and discussed. 

In my last reply, I’ve already listed multiple reasons why we don't advertise the precise criteria. Did you see that?

Elsewhere, in more purely scientific settings, I definitely have discussed the exact criteria and the evidence for them. 

Furthermore, these are arguably proprietary business trade secrets, yet I've made them public in order to try to advance this area of science. 

You are right, that wasn't smart. You want "Type 3" stool on the Bristol scala. That's dry, firm stool. I edited the post accordingly.

Please see my response to the person you're replying to. 

I was also surprised on the large emphasis on top athlete, as opposed to simply athletes, and as opposed to generally very healthy people. My main opposition to looking at high athletes only is that I say many high performing people would waste their potential by becoming athletes, and that looking for athletes filters away many very healthy very high performing people. 

For example I know someone who's been high performing all his life, in kinda all domains (sports, socialising, technical skills, computer games...). He'd be top of class, also had strong motivation and work ethic which got him highest place in an entrance exam to the best engineering school of the country (main subjects being math, physics, engineering, algorithmics). He so rarely fell ill (less than once per several years) it was a shock for him when he did, for the 2 days it would last (to be precise, I'm using ill in a 'ill enough to notice' way, not just a runny nose in winter). He went on to cofound a still successful company in a technical sector (drones). 

I dressed this portrait not to pitch that person to you particularly, but to illustrate that actually there're a whole bunch of people with very similar portraits, all you'll find them all concentrated in certain top engineering schools (there might be similar profiles in other similar top school of other domains but I don't know those). Few of these people become top level athletes (often by preference for something else, though there's also a higher percentage of top level athletes in that population) yet many would have the potential too. As long as we're just basing microbiota transplants on the assumption "very healthy high performing people probably have good microbiota", it makes sense to me to test more of these people for effectiveness in transplants. 

Nobody is saying that only athletes are super donors. They are not. But beign a top athlete is a good proxy for being "exceptionally healthy", and there are some studies supporting the claim that athletes are good donors. 


That person you are describing sounds like a potential super donor! Can I get in touch with him? Can he reach out to Human Microbes?

Right, we probably largely agree with each other. I don't dispute looking for super donors amongst top athletes, as that way you can do a unilateral search (ie. you find a list of top athletes and start asking). In the context of directly asking for recommendations, you gain the possibility of listing any criteria, that can be far more personal and less searchable, and you'll gain access to populations you can't through search. For example, if the criteria is "seems to never fall ill, recovers extremely quickly from illness or injury, highly active and motivated", you can't search for that but I can recommend the top people of my network that meet this criteria, and then you could interview them and get their recommendations along those criteria, and you move up those links to finding more and more healthy people. 

I skimmed the one study on top athletes being better than less top athletes (the one with traditional martial arts ie. not martial arts but actually gymnastics) and was not particularly convinced it was a good basis (because of don't trust one study, and because the critera for being a top athlete in an art+gymnastics competition might not be so objective as to strongly relate to gut microbia. I would have been more reassured if it was on powerlifting with a continuously rising correlation between weight lifted and 'gut health'.

For the specific person I gave as example, he'll be approaching mid thirties by now so though I strongly feel he'd be a very strong candidate at 25 (also the peak  of his athletic performance), he seems less particularly appropriate now due to age and not practising sports as much in the last few years. 

I don't want to be a dead end either, I can forward this article to folks in that engineering school currently (who'll be around 25) and see if there's anyone interested enough that I could give you their contact details to continue from.

Wow, that would be fantastic if you forwarded this article to those folks! Thank you :) on "Towards the Use of Fecal Microbiota Transplantation to Rejuvenate the Gut Microbiome":

Who do I talk to if I want to become a recipient?

Well, if you have money, the best option IMHO is Human Microbes: . They currently charge $1000/stool, and you likely need several ones for more complex gut issues. It's probably the best value per buck you get commercially. You can get it cheaper from them ("them" really being just one person, Michael Harrop) if you "significantly contribute to the HM project, e.g. help them find super donors). 

Another option is finding a super donor yourself. Someone who gives you multiple stools for free/cheaper. That's what I've been trying to do. It's very hard. My main motivation for this blog post is finding super donors for me personally.

Let me know if you want to somehow collaborate with gut issues, search for super donrs, etc.

I'm one of those odd "eat anything people", I mean like, chug galons of milk, stop eating for 10 days, eat 5000+ kcal a day, go for months eating street food in poor parts of SEA and India, raw meet of various kinds, any random fruit peal on etc.. with two food poisonings in my life (both raw oysters) and feeling nausea once or twice a year tops, if even.

Granted FMT is about more than food tolerance, but I assume that's a good proxy, and given the fact that I've never been to athletic nor health conscious food wise I have to think there's some "hidden variable" influencing this and it's probably more subtle.

That being said the Danish study looks promising and it's better than nothing, but I'd love to have some stronger theoretical backing for what the secret sauce of microboime actually is, besides poorly fitting but non zero effect proxies.

Can you be a donor while living in Europe?

What are the specific microbes found, and also those that should not be found in the stool of a superdonor? Perhaps just culturing these microbes separately is sufficient to make a good insertible pill?

There are companies trying to identify that, and use it to create "synthetic" FMT capsules, but it's largely not yet known, and in my opinion it will be decades before we can replace whole stool with synthetic FMT. 

After all, you have to find a super-donor first. 

My gut feeling (no pun intended) says the mythical "super-donor" is a very good excuse to keep looking / trying without having to present better results, and may never be found. Doing the search directly in the "microbiome composition space" instead of doing it on people (thereby indirectly sampling the space) feels way more efficient, assuming it is tractable at all.

If some people are already looking into synthesis, is there anything happening in the direction of "extrapolating" towards better samples? (I.e. take several good-but-not-great donors that fall short in different ways, look at what's same / different between their microbiome, then experiment with compositions that ought to be better according the current understanding, and repeat.)

I think your comment ignores the plethora of evidence supporting donor-quality hypotheses. Much of it was presented in the OP, and covered the permanent extinction of our host-native microbiomes, along with the exponential rise in chronic disease. 

Your suggestion seems to be to “try to find a plethora of plant and wildlife species in a forest that has been burned to the ground”. Whether you can piece it back together is unknown, but I don’t think that’s the best approach to take right now. 

Also, one of the major problems is that most people are not even bothering to look for high quality donors, and expecting FMT to get great results with low quality donors. The gut microbiome is incredibly complex, and we are so far from understanding it well enough [1] to be able to replace whole stool with synthetic FMT. Though I’m not discouraging people from trying it, and making headway there. 

I would recommend anything by Martin Blaser. I also have a wiki section here on the permanent damage from antibiotics, that extends even beyond their killing of microbes: 

There is a tremendous amount of antibiotic overuse/abuse in the medical system. The current guidelines are likely far too generous in promoting their use, and there's even 30%+ overuse according to current guidelines. 

I had an extremely depressing related event recently. I had a donor applicant that was seemingly perfect in every way. Their physical condition and ability were amazing/perfect. Their mental condition seems fantastic as well. But someone gave them frequent amounts of antibiotics over their lifetime, which was almost certainly unnecessary. And now they're suffering the consequences of it (in seemingly-subtle ways). 

There are research groups that have largely given up on finding ideal microbiomes in modern society, and have thus resorted to visiting remote tribes, such as the Hadza [1][2]. 

I know from experience (unfortunately only temporary) that such "ideal donors" do exist in modern society. They're just very rare, and it even seems that the people more likely to qualify are less likely to apply. Many of them are blissfully excelling in life and don't need/want to be bothered by some "weird poop thing". Many of them are making millions of dollars, or on their way to make millions of dollars and don't want to jeopardize that opportunity.

There are research groups that have largely given up on finding ideal microbiomes in modern society, and have thus resorted to visiting remote tribes, such as the Hadza [1][2]. 

If I remember right Bruce Sterling wrote in 1998 in his sci-fi novel Distraction about how when a frozen body was found, there was an immediate commercial interest to sequence the gut microbiome. It's interesting how our world evolves into that future ;)

My understanding is that as of now we know waaay too little about the gut microbiome to make this "direct search in microbiome composition" viable. For example, we basically have no clue about bacteriophages in the gut. Yet they probably play an important role in gut health, and in the efficacy of FMTs. 

Also, even if we knew exactly what composition we wanted, we aren't very good yet to "synthesize it"/grow it in the lab.

Sure, "the reason it doesn't work better is because we need better donors" sounds like a nice excuse. But it is at least suggestive that this is indeed the case. The better the donor criteria, the better the study outcomes. If we extrapolate this to even higher criteria...  

Btw. poor donors are not the only (avoidable!) reason FMTs often show poor results. See the post.

If you make an insertable pill with X predefined microbes, the FDA/EMA likely want you to get it approved as a drug. 

HumanMicrobiome sounds like a project that's doable with a million-dollar as capital. I expect that you might need a billion to do a proper job at the synthetic FMT capsule task.

I'm confused. Human Microbes is already being done with hardly any money? Michael Harrop is basically a complete amateur, and he's been doing it for a while now.

What do you mean with Human Microbiome. What project are you talking about?

Sure, the things you mention need FDA approval and are super expensive.

Of sorry, I got the name wrong. I wanted to say that the thing that Michael Harrop does is possible to do with little money because even the FDA seems to understand that it would be crazy to require clinical tests for approving individual donors. 

On the other hand, if you would start a project for synthetic FMT capsules, I doubt that it could be done at that funding level in the current regulatory environment. 

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