Amsterdam’s Cannabis Scientist – Joost Heeroma from GH Medical

joost heeroma

Joost Heeroma is a scientist and researcher at GH Medical in Amsterdam. Joost shares the important science around cannabis that isn’t often talked about and discusses the future of cannabis technology and science.

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Matthew: Hi, I’m Matthew Kind. Every Monday look for a fresh new episode where I’ll take you behind the scenes and interview the insiders that are shaping the rapidly evolving cannabis industry. Learn more at That’s Are you an accredited investor looking to get access to the best cannabis investing opportunities? Join me at the next ArcView Group event. The ArcView Group is the premier angel investor network focused exclusively on the cannabis industry. There is simply no other place where you can find this quality and diversity of cannabis industry investment opportunities months or even years before the general public. If that’s not enough, you will also be networking with the top investors, entrepreneurs and thought leaders in the cannabis space. I have personally made many of my best connections and lifelong friendships at ArcView events. If you are an accredited investor and would like to join me as an ArcView member, please email me at feedback at to get started. Now here’s your program.

As the perception of cannabis evolves from a back alley drug for society’s misfits to a plant medicine that can help a myriad of conditions the question on the mind of millions of people is how? How can this plant treat so many disparate conditions? Part of the answer lies in how cannabinoids interact with the human endocannabinoid system. I am pleased to welcome Dr. Joost Heeroma, Director of Science at GH Medical in Amsterdam, to better understand the promise of unlocking the many secrets of the endocannabinoid system. Welcome Dr. Joost.

Joost: Thank you Matt. Thanks for having me.

Matthew: Joost before we get started can you tell us your background and how you got into the cannabis research field?

Joost: Yeah sure. I’m a medical biologist by training with 15 years of research experience behind me and that’s mostly in the fields of genetics and neuroscience and in short the central theme of my research has been homeostasis which is basically balance in your body. How it is your body preserve its integrity throughout life. That is, so that will be the central theme and to go slightly deeper into that for instance as a student I was fascinated by diseases like Cancer and Alzheimer’s and how they are essentially flip sides of the same coin if you will. So in Cancer cells sort of forget to stop dividing and in diseases like Alzheimer’s cells forget to do the opposite. They forget to stay alive and I was fascinated by these processes. How this worked and how they govern the integrity of your body if you will and that started my research.

That later turned into does the same thing happen in the brain? Is this homeostasis just balancing things important for your brain? It turns out that it is. In fact all the learning rules are based on these principles. Without going deeper into that I then started studying human genetic mutations and how these mutations disrupt the feedback mechanisms that usually keep you alive and how these mutations can in turn cause diseases like for instance Epilepsy. Then finally I used all that information to devise intelligent ways of curing diseases for instance by common opportune therapy for epilepsy.

Now that was my career in a nut shell and then the economy collapsed and I found myself looking for a job and then basically as an act of serendipity I saw Arjan and Franco on an episode of Strain Hunters and I had my epiphany and well the rest is history. Now we’re talking to each other.

Matthew: Okay. We’ve had Arjan on the show but can you give a little background on what GH Green House and what they do there in Amsterdam with seeds and what GH Medical is so people can kind of have a context of what the operation is there?

Joost: Yeah definitely. So the Green House is one of the most successful if not the most successful cannabis seed selling companies and they also have a string of coffee shops or cannabis cafe’s in Amsterdam in the Netherlands. And what sort of separates the people at Green House from the rest of the industry as I know it is the passion that Arjan and Franco show for keeping the diversity in cannabis strains in tract and in order to do this they have organized these Strain Hunter expeditions basically traveling to the furthest corners of the globe to find the original land races of cannabis that have essentially not been tampered with by 17 of crossing and this crossing was essentially done for one purpose, the recreational purpose. How high can you get out of it?

So in short Arjan and Franco and the Green House have been looking for less chemical cannabinoids in distinct land races of cannabis and I found this hugely interesting because I’m not sure if you know but the cannabinoids are receiving huge amounts of attention in the medical world by now but 99% of this information is based on THC. Now CBD is sort of getting into the game but there are tens if not more other cannabinoids that are virtually unresearched. So this was the point that got me hooked. When I saw the Strain Hunter’s travel the globe finding these new or old untempered cannabis races I thought bingo that’s, that’s the pharmacological gold mine that we’re looking for. So that in short is how it got started.
Matthew: Yeah and land races just for people to understand that’s a plant in this case the cannabis plant that evolved over a period of time to be ideally suited for its environment is that how you would describe it?

Joost: Probably yes. So a land race is nothing more than an original race so it hasn’t been tampered with by us.

Matthew: Okay.

Joost: And to give you an indication in let’s take the West, Europe and America. Since 1937 when the UN imposed its ban on cannabis the only selection criterion for cannabis was of course how stoned do you get and you can really see the results of this. So in the last couple of months I’ve profiled a lot of different strains of cannabis that you can find here in Amsterdam and essentially they’re all the same when you look at cannabinoids. That basically means we have found a way to purify THC and luckily THC has lots of therapeutic potential but all these other cannabinoids that are in there are practically unresearched and that’s what we want to do and for that you actually need these original races.

Matthew: Okay. Now switching gears to the encannabinoid system.

Joost: Yeah.

Matthew: How would you introduce that to someone that still quite doesn’t understand that?

Joost: Yeah and I can understand why it’s difficult to grasp because until about a year ago I didn’t have a clue and that’s strange because I actually found out that this endocannabinoid system is the mother of all feedback systems and therefore I should have known about it. And so what does it do? I would say that the endocannabinoid system is basically what puts; what stands between us and bacteria. If you see humans as successful life forms, we consist of billions upon billions of cells and to me as a biologist is actually surprised that we are not just a pile of, an amorphous pile of cells. Now we’re actually very nicely sculpted human beings and for that to happen you need to have a system that keeps several factors in check.

First of all, all cells in your body need to know whether or not to divide. If this goes wrong, if cells continue to divide when not necessary you get diseases like Cancer. If cells stop dividing where they should be you get degenerative diseases like for instance Alzheimer’s or Huntington’s and many other diseases.

Another thing that is crucial to successful multicellular life is the distribution of energy. Each cell needs to get the right amount of energy not more, not less, etc. Now failure to control the flow of energy in your body can lead to diseases like Obesity on the one hand or anorexia on the other or Diabetes. Anyway all these metabolic diseases sort of indicate that there’s some level of regulation going wrong. Now the other factor that is crucial to successful multicellular life is the immune system. Your cells need to know what is self and recognized as from anything foreign that invades your body. Anything that is self you need to protect. Anything that is foreign you need to viciously attack.

And finally the cells of your body need to be able to communicate to each other. Now the best example of this is the brain. You need brain communication, neurocell communication in order to be successful in your life. Now the four things so cell division, energy, metabolism, self recognition, or immune response and cellular communication or brain activity those four pillars of life are in fact colonized or governed by the endocannabinoid system. Does that answer your question?

Matthew: Yes, yes. And so those are things; those are kind of background operations that are going on in our lives and we really don’t notice it until there’s a problem perhaps.

Joost: Yeah.

Matthew: Is there any way that people can experience their endocannabinoid system without a problem? Is there something they can see in their life where they say hey that’s my endocannabinoid system at work?

Joost: Hmm good question. I think the most noticeable function of your endocannabinoid system may well be the runner’s high. Are you familiar with the runner’s high?

Matthew: Yes.

Joost: Yeah so I think this story started about 20 years ago and it was primarily explained as an endorphin based story. So endorphins are the body’s own opiates where endocannabinoids are the body’s own cannabinoids and it turns out that the happy feeling you get whilst running is endorphin based and the satisfied feeling that you get after running is actually caused by endocannabinoids. So that is an actual thing you can experience yourself where your endocannabinoid system is at work keeping you happy.

Matthew: Now we’re throwing around the word cannabinoid a lot but what exactly is a cannabinoid and how does it fit into the endocannabinoid system?

Joost: Let’s see to put things in a slightly broader perspective. Have you ever heard of the citric acid cycle?

Matthew: No.

Joost: No. Okay well the citric acid cycle is like the sense we’ll have in all our metabolism and whether you’re bacterium, or a horse, or a human it’s all the same and what this citric acid cycle does is it takes everything that you consume, everything that you eat, sort of grinds it down to atoms and from that your entire; every component of your body is constructed again. From the citric acid cycle everything is made and parts, the three major components of products that are made the energy that you need to keep your body up and running. The lipids to produce all your cells or the membranes surrounding your cells and the proteins of DNA which are essentially the machinery that our body’s work on.

And so straight from the citric acid cycle from the central hub of our metabolism all lipids are made and one major subdivision in these lipids is diacylglycerol which will mean nothing to you but it is like the top of the pyramid of all endocannabinoids. So what I’m trying to say by this is straight from everything that you eat lipids are made and from these lipids your endocannabinoids are made which govern pretty much everything in your body so. Cannabinoids are very natural substances if you will.

Matthew: How can the endocannabinoid system become dysfunctional or overpowered? Does that go back to what you were talking about with Cancer and Alzheimer’s?

Joost: Yeah. So I would say a dysfunctional endocannabinoid system is for instance caused by a mutation. A mutation in your genetic information which may lead to I don’t know Cancer or any other disease that is based on ([15:53] unclear) metabolism or cell division or immunity or brain communication. Did that answer your question?

Matthew: Yes.

Joost: Okay. Now.

Matthew: Go ahead.

Joost: One other thing that I wanted to mention is so all the endocannabinoids are made out of diacylglycerol. It very much, very similar to this all plant cannabinoids are made from terpenes. Now terpenes is also something you’ve probably heard before.

Matthew: Yes.

Joost: And know that we’ll be discussing later on but what is crucial to your understanding of cannabinoids and terpenes is that they are essentially the same thing. Terpenes are very basic chemical building units and for instance if you take one unit you get the smell of menthol, take three units stack them together you get the smell of ginger, you take four you get cannabinoids, you take six you get cholesterol, sex hormones that kind of thing. Take eight you get carotene antioxidants in your body. Have you ever heard of Q10?

Matthew: CoQ10 or something like that?

Joost: Yeah exactly so but the stuff that’s in all these creams for your face and etc, etc. Q10 stands for ten units of isoprene, ten of these terpene units.

Matthew: Okay. So you stack these isoprene units and you get different compounds as you stack them?

Joost: Exactly. You get different compounds with completely different properties and to go one step further if you stack thirty of these compounds on top of each other then you’ve got latex. So that’s sort of to show you the, well the background against which all this stuff is happening. The central point here is that terpenes, terpinoids, cannabinoids are really natural compounds and they are involved in every step of multicellular life.

Matthew: Okay. So terpenes, there’s a lot of talk about flavor and fragrance and so forth. What’s happening with terpenes there that gives us that experience? I know you mentioned the stacking but can you tell us anything about how we experience terpenes from fragrance and so forth?

Joost: Yeah. So as I just said and so one isoprene unit gives you the smell of ([18:40] unclear) and two isoprene units gives you the smell of menthol, etc, etc. Basically every odor, every essential oil that we know of is a terpene. That’s, yeah.

Matthew: Okay.

Joost: Every smell is a terpene and is also important to realize how all this works. It’s not for nothing that we can smell something. The only reason we can smell something is because we have a receptor and it’s also not for nothing that it has an effect on us. For instance if you smell Pinene so the smell of pine it has a physical effect on you. It dilates your lungs which is already making the crossover in between the food substances that we know as terpenes and the medicines that we will get to know as terpenes later on.

Matthew: Do terpenes affect our metabolism in any way?

Joost: Well yeah they do but it’s not really easy to give an example of this. But for instance I’m sure you have smelled nice food and all of a sudden got your gastric juices pumping and before you knew it you were hungry.

Matthew: Yeah sure.

Joost: Yeah so the physical process behind all that is it is fueled by terpenes and in the end it primes your body for eating. So does it have an effect on your metabolism yes definitely?

Matthew: And where can cannabis have the biggest impact on fighting illness and disease right now do you think?

Joost: That’s also a difficult one. Well seeing as cannabinoids actually show therapeutic potential in some of the most well prevalent and debilitating diseases in the West. I can think of Cancer, Obesity, Diabetes, Depression, Insomnia. I would say the total potential impact of cannabis and cannabinoids on disease is huge and which one will prove to be the biggest or which one is the biggest right now I actually have no idea. Everything.

Matthew: When you smoke a joint versus taking an edible, an infused product how is that different? How does that affect your endocannabinoid system differently?

Joost: The differences are huge. For starters when you eat cannabinoids they invariably end up in your stomach. Your stomach is full of acid and that acid immediately breaks down like 50% of all cannabinoids. After your stomach the cannabinoids enter your guts and your intestine or through your intestine and end up in your blood and they get metabolized by your liver which again causes a 50% reduction. So basically if you eat cannabinoids you are already at 25% of the total effect that you could’ve had if you would have injected the cannabinoids which of course no one does but that’s the standard against which we weigh it.

So if you want to preserve cannabinoids for their medical function you probably don’t want to eat them and other roots of application are for instance you could use topical application, just rub an ointment on your skin which will for instance work well for Eczema or Psoriasis but if you got Cancer probably there is a better way of getting the cannabinoids unless it’s Skin Cancer. Speaking of Cancer then you probably want to have a really high dose of some particular cannabinoid in a very specific spot so you might be thinking of an injection or you might be thinking of; for instance if you want to reach your brain and you want to reach it very quickly nasal injection or a nasal spray would make more sense.

If you want it to get there more slowly then maybe eating is better. You see that’s, it really depends on the specific condition that you’re looking to treat. It really depends on that for your choice of rules of application.

Matthew: I really haven’t heard of people injecting cannabis as a medical treatment but is seems like it might be a good idea. Is that happening more or are people talking about that more?

Joost: Yeah. To be honest I don’t know of anyone who has injected cannabinoids either but I know this is how for instance the ([24:03] unclear) so the drug lap of the DEA got their data, you need to have a standard measurement of pharmacological products and the standard is pretty much what happens if you inject it. That constitutes 100% biodegradability and it is against this biodegradability that for instance everything that happens when you do a nasal spray or you already consumed cannabinoids everything is weighed against what would theoretically happen if you inject. Does that make sense?

Matthew: Yes, yes.

Joost: And like I said for real, real nasty cases where you need a really high dose of cannabinoids such as for instance Cancer. I can well imagine that the way to treat it in the future will be an injection. At the moment I don’t know any examples.

Matthew: Joost based on what you’ve seen. Let’s say God forbid you develop some sort of Cancer would you be treating it with cannabis?

Joost: A very good question. I think yes. I’ve spent the last year reading everything I could about cannabinoids and their potential to cure diseases and even though I know we’ve only scratched the surface of the therapeutic potential of cannabinoids I would say the promise is huge and especially for Cancer. I mean people have more or less known that cannabinoids can work against the nausea, basically against the side effects that you have from regular Cancer treatments. But now we actually know that THC kills Cancer cells. It actually kills Cancer cells whereas it leaves non Cancer cells alone. That finding in itself is huge.

Of course we need more information, we need more tests but I think a system that can decide whether a cell is Cancerous or not and then eliminate the Cancer cell is just way better than what we have been able to come up with in regular medicine. Which one will prove to be better I don’t know.

Matthew: Okay. Do you see any clinical trials going on that are promising in Europe or elsewhere with cannabis or cannabis oils?

Joost: There are a few clinical trials going on not too many and a lot of these clinical trials are still being done with synthetic cannabinoids and so these are still primarily initiatives from Big Pharma who of course love patents of all drug and for that you need synthetic cannabinoids. For the plant cannabinoids it’s sort of getting started now. We hope to launch as many clinical trials in the next couple of years as possible and we should be thinking about 100 or 130 different types of disease indications for which we could launch a clinical trial. The most important one going on right now I don’t know.

Matthew: Okay. And where do you see GH Medical going over in the years ahead?

Joost: Well basically doing precisely that launching clinical trials. So what we’ve done in the last year is basically nothing else but making an inventory of all the knowledge that is out there. So I have screened or am in the process of screening approximately thirty thousand scientific papers on fifty different disease areas and this is work that has been done in the last forty years or thereabouts by scientists who did it anyway even though they weren’t supposed to and I’m categorizing all this data trying to find the lacks in our knowledge and trying to supplement that.

So now we’ve more or less reached a point where we know the bits of knowledge that are lacking and we can start formulating the research that is necessary to actually go further and because cannabinoids are such a hugely safe, biologically safe class of product I think we can go straight into the clinical trials and forget about most of the pre-chemical research that’s usually done before. Which is like to find out how safe is the compound? How much can we tolerate, etc, etc.? We already know from thousands of years of user experiences that you can tolerate as many cannabinoids as you want to test so we can skip all that straight to the clinical trials and we’ll take it from there.

Matthew: Yeah that would be great if we could get some solutions quickly here. There’s a lot of people suffering and its like why wait years when it’s really a benign influence at worst. So why?

Joost: Exactly.

Matthew: Why can’t we move forward? So.

Joost: Yeah but the problem is as you are probably very well aware of that everyone is waiting. Well they’re the policy makers doing it at the moment.

Matthew: Right.

Joost: And the whole world I mean I would love to start 100 clinical trials tomorrow but if we would do that we would be shutdown the day after tomorrow.

Matthew: Yeah.

Joost: And we are finding ourselves in a very strange situation that we’re actually dealing more with policy makers, with politicians, etc, etc., than with the actual science.

Matthew: Yeah that’s unfortunate. What’s the reaction from the policy makers? Are they becoming? I mean Amsterdam and the Netherlands are historically liberal relative to other countries but are they receptive to the message of cannabis as medicine?

Joost: Not really. I think it was the Dutch Minister of Justice who said A) that he knew people that have died of smoking cannabis which is impossible. But it does show you the level of information that they use and so I don’t expect much out of the Netherlands anytime soon. But what is very interesting is that we are now being contacted by other governments around the world who are actually sick and tired of having to chase old granny’s that have a bottle of cannabis oil because they have Cancer. People are just getting tired of having to incarcerate other people for just that.

And so the interesting development is that we are now being approached by governments who are actually looking for our advice in how to change the rules so that we can do our research and that’s new.

Matthew: Yeah.

Joost: And maybe this will be the way in which we can start our research but we just don’t know. I don’t know what’s going to happen next week. Hopefully what’s going to happen is we’re going to get our license to do our research and then we can start our trials. But who knows?

Matthew: Joost what’s the best way for listeners to learn more about GH Medical Green House Seeds, Arjan’s cannabis cafe’s there in Amsterdam? Where should they go to learn more about these things?

Joost: Yeah. So first of all to learn more about GH Medical you can go to and that website basically contains all the information that you need to see whether cannabinoid based therapy might be something for you. How it works, etc., etc. It also contains a white paper where we explain our backgrounds, disease backgrounds, and the potential of cannabinoids to cure all these diseases and that is probably good background reading material for most people, for patients, for healthcare professionals, for policy makers and what not. Now going to the Green House as the larger company, Green House Seeds. For information you can go to

Matthew: Okay.

Joost: And finally if you want more information about the cannabis cafe’s or coffee shops as we call them over here. You can go to

Matthew: Okay. Yeah and the cafe’s are really well known there in Amsterdam and very kind of classy places and while we have legal retail shops here in Colorado I hope we go to the next level and have cafe’s similar to what you have in Amsterdam there where there’s a social aspect. Because while it’s legal we can go to a retail shop and then everybody goes home. There’s no public forum.

Joost: Yeah.

Matthew: Which would really I think enhance the experience for everybody so I hope we get to that step soon. But again also Arjan and his partner Franco are also a great place to find them is on Strain Hunters too which is a really kind of interesting show where they go all over the world finding these land race cannabis strains which Joost spoke about a little earlier.

Matthew: So Joost thanks so much for being on CannaInsider and educating us. We really appreciate it.

Joost: Thank you. I hope you learned something from it and hopefully meet again.

Matthew: Thank you.

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Key Takeaways:
[1:52] – Dr. Joost’s background
[4:41] – What is GH Medical
[8:42] – Joost talks about the endocannabinoid system
[12:24] – Joost explains the functions of the endocannabinoid system
[13:27] – What is a cannabinoid
[15:28] – How your endocannabinoid system can become dysfunctional
[18:30] – Joost talks about terpenes
[20:32] – Cannabis’s biggest impact on fighting illnesses and disease
[21:27] – How do infused products, edibles and joints affect your system
[23:49] – Joost talks about injecting cannabis
[26:55] – Cannabis clinical trials
[28:04] – Future of GH Medical
[30:54] – Are policy makers receptive of cannabis as medicine
[32:38] – GH Medical Green House Seeds contact details