(PDF) A review of cannabis tea

By Dr. Arno Hazekamp, Cannabis researcher, Leiden University, The

Netherlands

1) The chemistry of cannabis tea.

How did I get involved in the chemistry of cannabis tea? Well, it all started in

2001. Not long after finishing my Master’s degree in phytochemistry (the

chemistry of medicinal plants), my professor one day suddenly asked me how I

would feel about doing a PhD on the medicinal use of cannabis. I am sure you

can imagine my surprise. That year, without me noticing it, the Dutch government

had decided that there was enough reason to consider cannabis, under certain

conditions, a medicine. Because many patients already used street cannabis in

the form of dried flowers (buds) this was chosen as the starting point for the

Dutch medicinal cannabis program as well: dried flowers, also known under their

official pharmaceutical name, cannabis Flos, but of pharmaceutical quality and

with always the same chemical composition. An experienced plant grower

(Bedrocan BV) was contracted for production, and the program became a fact in

2001. Figure 1 shows an example of the product that is currently available in the

Netherlands.

As a scientist, my task would be to help develop this herbal material into

something ‘better’, something more advanced, so that cannabis could be fully

introduced into the world of modern medicine. After all, the fact that cannabis

may have a positive effect in some patients was not enough. What about the

administration form, the dose, the variety of cannabis needed for which medical

condition? Those are issues that need to be resolved for any medicine on the

market, and the Dutch government certainly did not want to make exceptions for

this unconventional herbal product called cannabis. The directive of the Health

Ministry therefore was clear: The Netherlands, as the first country in the world,

would make herbal cannabis available to patients on prescription, if the

pharmaceutical industry and academic researchers would work on developing

modern cannabis-based drugs. Herbal cannabis was simply a temporary and

practical solution in order to help chronically ill patients until the job was done,

and the cannabis-pill was developed. In any other country, medical users were

not as fortunate as they had to wait until such cannabis medicine would have

been developed. Something most of them are still waiting for today.

Some people may believe that herbal cannabis does not have a future in modern

medicine, simply because it is too ‘rough’. After all, real medicines look different:

they come in precise doses, have a fixed composition, and the administration

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form is clear: take 2 of the blue pills a day, and come see the doctor in a few

weeks. Indeed, there is a lot to be desired with the current way cannabis is used

as a medicine. When you ask for your favorite cannabis strain, are you certain

you always get the same product in terms of its chemical composition? My own

research among Dutch coffeeshops clearly indicates this is not the case. And

what about contaminations such as pesticides, growth-enhancers, heavy metals,

microbes? As a patient, can you really afford to be exposed to such risks, when

the only thing you want to do is get better? These are obvious reasons to further

develop medicinal cannabis into a more safe and reliable product.

Of course, the idea of the Dutch program was that the active ingredients of the

cannabis plant would be identified, isolated, and put into nice little pills. Just like it

has happened with so many other medicinal plants in the past: opiates from the

poppy plant, aspirin from willow bark, or anti-malaria drugs from a variety of plant

species such as Artemisia. However, what if such a product would be based

directly on the herbal cannabis that many patients prefer to use today? Is that a

real possibility? I believe it certainly may be, but only if we can come up with a

method of administration that is reliable, reproducible and safe. After all, not

many doctors feel comfortable with just sending patients home with some bud,

and let them decide themselves whether to smoke it, bake it, or even juice it raw.

During my ten years of cannabis research, I have mainly focused on helping to

answer such questions, related to quality control, administration forms and

dosing. Besides studying tea, I have also focused on vaporizing, smoking,

extracts and edibles. According to my studies, cannabis tea is an easy and

reliable way to use medicinal cannabis in its herbal form, if a few simple

guidelines are followed. Please follow me through this chapter as I will introduce

you to the exciting chemistry of cannabis tea.

2) Cannabinoids and terpenes: the active ingredients of cannabis

The cannabis plant has a long history as herbal medicine, and contains a large

variety of pharmacologically interesting ingredients. With more than 500 known

constituents, Cannabis sativa is chemically one of the best studied plants in

science. But because most of these constituents have not yet been properly

characterized for their therapeutic activity, the cannabis plant could be called a

“neglected pharmacological treasure trove” [Mechoulam 2005].

The most interesting among the cannabis constituents are found in the

secretions of glandular hairs, which are also called trichomes or ‘crystals’,

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because of their sparkly appearance. Such trichomes (see figure 2) can be found

all over the male and female plants, but they are particularly concentrated around

the female flowers. The dried resin obtained from the flowers is generally known

as hash, or hashish. This is the source of the most important bioactive

components of the cannabis plant; the ‘cannabinoids’.

Cannabinoids are generally considered to be the main biologically active

constituents of the Cannabis plant, and they are unique to the cannabis plant;

they are found nowhere else in nature. The most famous of all cannabinoid of

course is delta-9-tetrahydrocannabinol, or THC, which is responsible for the

psychedelic effect of the cannabis plant. But there are many more: already 70

different cannabinoids have been identified by researchers, and the number is

still growing. The many cannabinoids are chemically very closely related to each

other, but nonetheless have very different biological and medicinal properties.

THC is the only one of them with significant psychoactive properties.

Although many cannabinoids are known, not all of them are found in all cannabis

products. After all, they were identified over several decades of cannabis

research, studying many different cannabis products, and different and

sometimes rare types of cannabis plants from a variety of origins and qualities.

Not surprisingly, there can be an enormous variation in the relative content of

cannabinoids, and this is part of the reason so many different varieties of

cannabis exist. There is however a handful that you will most likely encounter to

some degree in most cannabis varieties: THC, CBD (cannabidiol), CBN

(cannabinol), CBG (cannabigerol) and CBC (cannabichromene). See figure 3 for

the chemical structures of these compounds.

Traditionally, there has been a dominant focus on THC because cannabis was

mainly used and studied as a psychoactive drug. The main question we asked

ourselves was simply: how high does it get me? But now cannabis is increasingly

embraced as a medicine again, it is time to change that focus and to broaden our

scope. A better understanding of the non-psychedelic components of cannabis

clearly is a step in the right direction. For example, CBD is studied for its anti-

psychotic and anti-tumor properties, while THC-acid (see below) is a potent

regulator of the immune system.

So now we discussed the cannabinoids as an important group of therapeutic

compounds. But have you ever wondered what gives cannabis its distinct smell?

The answer is not the cannabinoids, because they have no smell at all. In fact,

the smell, taste, and perhaps some of the medicinal properties of cannabis come

from another class of compounds called the ‘terpenes’. Together with the

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cannabinoids, they are found in high concentrations in the resin excreted by

cannabis flowers. Terpenes are not only found in cannabis, but in many fragrant

plants all over the world. Terpenes have a lot of different medicinal effects,

including anti-bacterial, anti-inflammatory, anti-asthmatic, and relaxing properties.

Examples of such terpenes are: pinene, humulene, myrcene and beta-

caryophyllene.

Because of centuries of breeding and selection, a large range of cannabis

varieties has been developed, which are commonly distinguished through the

use of popular names such as ‘White Widow’, ‘Northern Lights’, ‘Amnesia’ or

‘Haze’. Already, over 700 different cultivars have been described [Snoeijer, 2001]

and many more are thought to exist. However, it is unclear whether or not these

names reflect any relevant differences in chemical composition. There is a lot of

scientific interest in understanding why varieties are different, and what

constituents are responsible for this. The cannabinoids and terpenes are the

most likely candidates.

3) How cannabinoids work

Now you know that the cannabinoids are widely considered as the main

therapeutic ingredients of cannabis, doing most of the important work. The

terpenes are generally seen as having an additional supporting role. According to

many medical users, this is synergy or holistic medicine at its best. But an

important question remains; how do cannabinoids exert their therapeutic effects,

and under what conditions?

Until quite recently, the biochemical mode of action of cannabinoids was

unknown. Initially it was assumed that cannabinoids such as THC simply dissolve

in cell membranes in the brain, thereby disrupting the function of brain cells,

similar to the way alcohol makes you feel drunk. Then something revolutionary

happened; around the 1990’s, the human endocannabinoid system was

discovered, and we learned that many of our own bodily functions are controlled

by cannabis-like substances in our brain, immune system and other organs. It

was also shown that this combination of cannabis-like substances

(endocannabinoids) and its natural binding sites in the body (cannabinoid-

receptors) was present in every imaginable animal life form, from cats and mice

down to puffer fish and even sea urchins. This clearly showed the evolutionary

importance of such a system for basic survival (and thriving?) of species.

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Currently two types of cannabinoids receptors are known: The CB-1 receptor is

predominantly present in the central nervous system, mainly in those brain

regions that correspond with well-known effects of cannabis consumption: sleep,

appetite, time perception, etc. Overstimulation of CB-1 results in feeling high or

stoned. A second cannabinoid receptor (CB-2) is present mainly in the immune

system where it can influence pain, inflammation and tissue damage.

Based on what we have learned so far, the endocannabinoid system is involved

in many physiological functions and might be related to a general stress-recovery

system. This variety of effects was concisely summarized by the Italian scientist

DiMarzo, who stated that endocannabinoids help you 'feel less pain, control your

movement, relax, eat, forget (posttraumatic), sleep, and protect your neurons'.

Scientific studies clearly show that endocannabinoids play an important role in

keeping our bodies balanced, especially during a state of illness. External

cannabinoids, present in the cannabis plant, are able to interact with our

endocannabinoid system in multiple ways. But is that always a good thing? In

some cases (depending on e.g. cannabis variety, dose, and administration form),

the effects may be therapeutic, but when too much is consumed a state of

intoxication will occur. In some way you could say that recreational users of

cannabis are purposely overdosing a medicinal substance. By looking at the

issue in this way, it may be easy to see the difference between medicinal use

and drug use.

4) The chemistry of cannabis tea

So now you think you know something about cannabis chemistry, right? But what

if I told you the cannabis plant does not produce a single molecule of THC? And

yes, that includes your favorite strain, too! The cannabis plant does produce a

group of chemicals known as cannabinoids, which have truly unique medicinal

properties. What I did not mention yet is that those cannabinoids are not actually

produced in the form we commonly assume. THC and CBD are the most obvious

examples of this; also known as neutral cannabinoids, those are the chemicals

scientists have most closely studied, and users have learned to appreciate for

reasons both medicinal and recreational. However, the cannabis plant actually

produces all of its cannabinoids in the form of so-called acidic cannabinoids,

which are chemically distinct versions of the neutral cannabinoids with straight-

forward names like THC-acid and CBD-acid. Sounds complicated, but it is crucial

for understanding the unique properties of cannabis tea.

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Let me explain. If sufficient heat is applied, the acidic cannabinoids will turn into

their neutral counterparts. So when cannabis is burned for smoking, baked for

edibles, or boiled for tea, non-psychoactive THC-acid turns into THC, CBD-acid

turns into CBD, and so on for all other cannabinoids. This process, called

decarboxylation, is visualized in figure 4. It also spontaneously takes place in

aging cannabis samples as a result of storage and exposure to light, but at a

much slower rate. Until recently, acidic cannabinoids were generally considered

the ‘inactive’ forms of cannabinoids. After all, they can’t get you high, and there is

almost no trace of them in cannabis smoke. Since both consumers and

researchers have focused mainly on smoking as a method of delivery, most of us

were hardly aware that the acidic cannabinoids even existed. But smoking is not

the only way - or the best way - to ingest your medicine. During my studies I

discovered that an average cup of cannabis tea contains about 5 times more

THC-acid than THC, even after 15 minutes of boiling. The reason is that boiling

water is not nearly as hot as the heat applied for baking brownies, or

smoking/vaporizing of cannabis. Cannabis tea should therefore not just be

considered as a weak administration form of THC (which it is), but rather as an

entirely different medicine, because of the presence of high amounts of acidic

cannabinoids.

So what can these ‘acids’ do for you? Well, potentially a lot, because an

increasing number of studies show that they may have important medicinal

properties. For example, CBD-acid has a potent antimicrobial activity, and shows

promising anti-inflammatory effects. THC-acid was found to have a potent effect

on the human immune system (Verhoeckx 2006), and may be studied in clinical

trials soon. And perhaps most interestingly, some acidic cannabinoids may slow

the growth of certain cancers, at least in laboratory tests.

Now you know the whole story of the chemistry behind medicinal cannabis,

promised!

5) The therapeutic potential of cannabis

Almost no plant has been studied as much as the cannabis plant; more than

10.000 papers have been published describing various aspects of Cannabis as a

biologically active plant. Nonetheless, it is hard to think of a medical topic that

can so strongly divide the research community as the medicinal use of Cannabis.

It may even be stated that Cannabis is the most controversial plant in the history

of mankind. But imagine Cannabis sativa would be discovered today, growing in

some remote spot of the world, it would be hailed as a wonder of nature; a new

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miracle plant with the potential to treat anything ranging from headaches to

neurological disorders to cancer.

Although herbal cannabis is currently classified by international regulations as a

“dangerous narcotic with no accepted medicinal value”, that is not exactly true for

some of the major components of the cannabis plant. In fact, there are several

components derived from the cannabis plant that have an accepted and very

interesting potential as a medicine. Marinol® is an oral capsule that contains a

synthetically produced version of the natural THC. It has been approved for

treating nausea and vomiting in related to cancer and AIDS, and for stimulation

of appetite in severely underweight patients. Another product, called Sativex®,

makes use of the combined effects of THC and CBD extracted from cannabis

plants. It is mainly targeted at pain and spasticity in MS. Some other medication

is based on compounds that are modeled after plant cannabinoids, but have a

slightly different chemical structure. An interesting example is ajulemic acid, a

very strong pain killer based on THC, but without the psychotropic effects.

Herbal cannabis itself, in its native plant form, would be hard to patent, which is

the main reason that pharmaceutical companies have not spent too much effort

on this. Nonetheless, the experiences of (large groups of) patients have been

important for the development of cannabis-based medicines. Clinical studies with

single cannabinoids or whole plant preparations have often been inspired by

positive anecdotal experiences of patients using crude cannabis products for

self-treatment. The antiemetic, appetite enhancing, analgesic and muscle

relaxant effects, and the therapeutic use in Tourette’s syndrome were all

discovered or rediscovered in this manner. If herbal cannabis wants to become a

real and legitimate medicine some day, it needs to be studied in much more

detail. But for the time being edibles, tea, and vaporizers may very well be able to

fill the void.

6) Cannabis tea and an introduction to its history.

In Jamaica, which is sometimes quoted as the country with the highest

consumption of cannabis, the different uses of cannabis have been thoroughly

studied [Rubin and Comitas, 1975]. Although cannabis, which is locally known as

ganja, is mostly consumed by smoking, drinking of ganja tea is common among

non-smokers and is consumed even by young children and the elderly. The tea is

attributed various therapeutic and prophylactic qualities and is used as a remedy

for i.e. fever, cold and stress.

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Also around Europe, hemp containing foods, including leaves for tea preparation,

are widely available. Often these products are associated with health. Although it

is legally not permitted, herbal hemp leaves used for tea have been found to

contain relatively high THC levels (up to 5000 mg/kg) and significant

concentrations were determined in the corresponding tea infusions. Potentially,

any health claims based on the consumption of such teas might therefore be

attributable to its (unintended) content of THC or other cannabinoids.

Until recently, virtually no standardized studies had been performed with tea

preparations of cannabis. The single large scale field study which includes the

use of cannabis tea [Jamaica, mentioned above] did not focus on analytical data,

such as chemical composition and potency of cannabis used, making it difficult to

understand the effects or reliability of this administration form. Fortunately, the

introduction of high grade cannabis for medicinal use in The Netherlands (in

2003) has provided a good opportunity to study the composition of cannabis tea.

Under the Dutch regime, patients essentially are able to freely choose their

manner of cannabis consumption. Based primarily on health implications, the

Dutch Health Office advices to consume medicinal cannabis preferably by

vaporizing or in the form of a tea, and not by smoking. Indeed, polls under

medicinal cannabis users in The Netherlands have indicated tea preparation to

be a popular way of consuming cannabis. Also in a more recent survey,

conducted by the International Association for Cannabinoid Medicines (IACM),

cannabis tea was found to be popular; among the 953 participants of the online

survey, about 25% had tried tea as a way to consume medicinal cannabis. The

main advantages cited were the long duration of effects, and the low occurrence

of unwanted side-effects.

Considering these developments, a systematic study on the composition of

cannabis tea would clearly be interesting. As part of my own research, we

performed this study on the preparation and handling of cannabis tea, in

particular on the parameters that can have an effect on the composition of the

tea, such as boiling time, volume of tea prepared, and duration of storage. By

performing a series of experiments, we systematically discovered the effect of

different parameters on the cannabinoid composition of medicinal cannabis tea.

In simple words: what happens when I accidentally use too much cannabis, or

when the phone rings and I boil my tea too long? How long can I store tea, and

will the composition be the same each time I prepare it? For a medicine, such

things obviously may be handy to know.

A major concern with the medicinal use of cannabis is the risk of (accidental)

overdosing of THC, which could lead to psychotropic effects. However, our tea

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study showed that moderate changes in the standard preparation protocol for

cannabis tea (discussed below) do not result in dramatic changes in the

composition of the tea. Cannabis tea has a unique composition compared to

other forms of administration, where heating of the material is typically performed

at much higher temperatures (e.g. smoking, vaporizing or baking), resulting in a

virtual complete conversion of acidic into neutral cannabinoids. But when

cannabis tea is prepared, with temperatures not exceeding the boiling

temperature of water, a significant proportion of THCA can be found. The

recently described effects of THCA on the immune system (Verhoeckx, 2006)

may contribute to the effects that certain groups of medical users claim after

consumption of cannabis tea.

Also other acidic cannabinoids, such as the acids of CBG and CBC (i mentioned

them above) could be detected in tea, but not in cannabis smoke or in vaporized

cannabis. Although the biological activities of these acidic cannabinoids have

hardly been explored yet, their presence makes cannabis tea a unique

administration form that should not be considered as simply a vehicle for THC. In

conclusion, cannabis tea is already consumed by a large number of patients on a

daily base, and their medical claims may certainly be compatible with the unique

composition of the tea.

7) How to make cannabis tea

After reading all the above, you may have become interested in using medicinal

cannabis in the form of a tea? Then now is a good time to discuss how to actually

prepare it. Clearly there are many ways to prepare a tea, and this book is full of

examples. I will only focus on the method that is advised by the Dutch medicinal

cannabis program, simply because that is the method I have a lot of experience

with. You are free to change the recipe if you like, but please be aware that the

composition of the tea may significantly change when you do. The main

advantage of sticking to a standard protocol for making tea, is that you will get

the same dose of medicine every day.

For starters, you need your favorite type of cannabis. You can use cannabis buds

that are fresh or dried, as long as they are not so old that the terpenes have

evaporated, or the cannabinoids have degraded. A good strong smell (terpenes)

may be a good indicator for freshness. Grind the material to homogenize it,

otherwise the different cups of tea may have a significantly different composition.

Now bring water to a rolling boil, and add cannabis. For each liter (quart) of

water, 1 gram of cannabis should be used. Bring back the boiling to a simmer,

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and cover the pan with a lid to prevent evaporation (and to keep more terpenes

in the tea).

A boiling time of 15 minutes was found to be optimal in lab studies. Boiling for a

shorter period leads to a much less potent product, because the acidic

cannabinoids do not have sufficient time to convert to their more potent

counterparts. On the other hand, boiling longer did not much change the

composition of the tea. It seems that after about 15 minutes the composition of

the tea stabilizes, because the water can not take up any more cannabinoids; a

saturated solution forms, because of the limited solubility of cannabinoids in

water.

After 15 minutes of boiling, strain out the solid plant parts by using a strainer or a

sieve. The left over plant material looks very soggy but does still contain active

ingredients. Although I have personally never tried it, you may be able to find a

purpose for it (perhaps dry it in the oven and use it for baking?). The tea you just

produced may taste a little harsh and ‘green’, depending on the cannabis variety

you used. At this point, you may add some honey, milk, or perhaps flavored tea

like peppermint. Brew your own favorite and see what works for you.

I don’t need to tell you that the fresher the tea, the tastier. But that is a lot of work

when you need multiple cups of tea per day. A liter (1 quart) of tea would supply

you with 3-5 cups of tea and therefore seems to be a proper volume to prepare

each day. Storage of cannabis tea, for one day or longer, is of particular

importance, and will be discussed in the next section of this chapter.

If you wonder how cannabis tea compares to smoking a similar amount of

cannabis, consider this: One daily volume of tea (1 liter) contains 1 gram of

cannabis, and will yield on average 4 doses (cups) of tea, to be consumed

throughout the day. By comparison, the same 1 gram of cannabis could be used

to roll about 2 cannabis cigarettes, each containing half a gram of cannabis. This

would translate to 4 doses per day, when smoking half a cigarette per dosing.

Please remember that the tea preparation may feel less potent, because it has

less THC in it, and therefore a lower potential to make you high. However, the

composition of tea is very different from cannabis smoke (think THCA), and its

medicinal effect may be just what you need.

One final warning would be in place here. When using cannabis orally (by

ingesting it), all the active components present will be absorbed by the intestines,

and will be sent straight to the liver. There, a large part of the cannabinoids are

converted in slightly different compounds (e.g.: 11-hydroxy-THC), which have a

stronger psychoactive potential than the original THC. That is the reason that

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edibles and tea may make you feel more high than you are used to. Always be

careful when using cannabis orally, because once you have swallowed it, there is

not much more you can do than sit down and ‘enjoy’ the ride. After each dose, it

is advisable to wait for a few hours before you decide to take another one. Of

course, the advantage of a standard tea preparation is that you will be better able

to predict the effects of your medicine.

8) Solubility of cannabinoids, and implications for storage.

An interesting characteristic of THC, and the many other cannabinoids

mentioned here, is that they are absolutely not soluble in water. When using

boiling water, during the preparation of tea, the cannabinoids will make some

effort to dissolve, but as soon as the tea cools off, you will see the liquid become

turbid. This indicated that the cannabinoids are starting to stick together in large

droplets, which end up as a sticky layer on the inside of your storage container.

Basically, after one day in the fridge, your tea is starting to turn into water again,

and the medicinal effects are quickly lost. This has been visualized in figure 5.

The problem is easily fixed: just add something fatty, like a little milk or coffee

creamer (powder) after preparing the tea, in order to keep the cannabinoids in

solution. Adding butter has been suggested too, but it doesn’t sound particularly

appetizing to me! In this way you can keep tea for up to 5 days, but store it in the

fridge to prevent it from spoiling. Just shake the liquid before pouring yourself a

cup. You can then heat it in a little pan, or by microwave.

When making tea for one day use only, you can also keep the tea in a thermos

so that the tea stays warm and the cannabinoids remain in solution. Always

shake well before you take a cup.

9) Conclusion

Cannabis tea is a widely used, but poorly understood herbal medicine. It is (yet)

too complicated for modern pharmacology, but also too potent to simply be

considered as alternative medicine. Whether we like it or not, right now we are

stuck in the middle. Cannabis tea, with its low potential for psychoactive effects,

and a unique cannabinoid composition, is an interesting administration form for

herbal cannabis. I hope that the information I presented here will contribute to a

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better understanding of cannabis tea, resulting in more appreciation of this

popular form of cannabis administration.

Although it seems clear that the Cannabis plant still has a highly relevant

potential for medicine, it is also clear that the medicinal use of cannabis is not a

panacea. Cannabis, as any other medicine, can have its side effects, especially

when consumed in high amounts. A widely expressed opinion on the unwanted

actions of cannabis and THC has been formulated in a 1999 report of the US

Institute of Medicine on the medical use of cannabis: ”Marijuana is not a

completely benign substance. It is a powerful drug with a variety of effects.

However, except for the harms associated with smoking, the adverse effects of

marijuana use are within the range of effects tolerated for other medication” [Joy,

1999].

With these wise words this chapter has come to an end. I hope you will enjoy the

benefits that cannabis, consumed in the form of a tea, has to offer you. I am

certain that we will see the birth of many cannabis-based medicines in the near

future. But for now: Cheers.

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A review of cannabis tea

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