A cancer diagnosis turns life completely upside down. And even when treatment is over, that does not automatically mean someone feels well again. Pain, fatigue, sleep problems, loss of appetite, and mental distress can persist for a long time. For many people, this is when they begin a search for additional options to support their health and quality of life.

Cannabis and cannabinoids are receiving increasing attention in this regard. But what do people actually use when they say they use cannabis? And does it make a difference whether someone takes an isolated cannabinoid or a full plant extract in which various natural components have been preserved?

Peter Vermeul, founder and owner of CBD Spain, delved into an interesting scientific study from 2026. His findings shed new light on cannabis use after cancer and, above all, on why it is important to look beyond the name cannabis alone.

One in three people uses cannabis after a cancer diagnosis

A study by researchers, including those affiliated with the University of California San Diego, investigated how often people use cannabis after a cancer diagnosis and how this relates to their physical and mental health and quality of life. The results were published in the scientific journal Supportive Care in Cancer.

A striking finding: approximately one in three participants reported having used cannabis after their cancer diagnosis.

That is a significant number. It shows that for many people who have been diagnosed with cancer, cannabis is not just a theoretical topic, but has become part of their search for relief and support.

The researchers also found that people who rated their mental health as average, moderate, or poor used cannabis more often than people who felt mentally well.

That is an interesting correlation, but it also requires careful interpretation. It does not mean that cannabis causes poorer mental health, nor does it mean that cannabis has resolved these symptoms.

Peter makes this insight clear with a good comparison: rain and umbrellas. When you see that people with wet shoes often have an umbrella with them, that does not mean the umbrella is the cause of their wet shoes. More likely, people are seeking protection because it is raining.

The same may be true for people who have had cancer. Those who experience a lot of pain, sleep poorly, or do not feel mentally well may be more likely to seek additional support than someone who feels well.

It is therefore important to look not only at cannabis use, but also at the circumstances and symptoms that precede it.

Cannabis is not just cannabis

Here Peter touches on an important point that remains underemphasized in many scientific studies.

In the study, a variety of products were grouped together under the term cannabis. These included THC products, CBD products, concentrates, edibles, oils, lotions, ointments, and pharmaceutical cannabinoids.

But biologically, these are very different products.

An isolated CBD substance is not the same as a full plant extract. A THC product is not comparable to a CBD product. And heated cannabis oil has a different composition than an extract in which the original cannabinoid acids, such as CBDa, CBGa, and THCa, have been largely preserved.

The way a product is prepared and taken also plays a role.

For example, two bottles may both state 10% on the label, while their chemical compositions differ greatly. One extract may consist largely of CBD, while the other contains CBDa, CBGa, THCa, terpenes, flavonoids, and other plant components in addition to CBD.

It is precisely these differences that make it interesting to look beyond percentages and product names.

The power of the full plant matrix

The cannabis plant contains hundreds of different plant compounds. In addition to the well-known cannabinoids CBD and THC, there are cannabinoid acids, terpenes, flavonoids, and other natural components.

Peter compares this to an orchestra. You can study the violin separately and also research the piano on its own. But that does not tell you how the full orchestra sounds when all the instruments play together.

According to him, something similar happens with cannabis. Much research focuses on individual cannabinoids, while the full composition of a plant extract is far more complex.

In a full-spectrum extract, various components of the plant remain present together. These include CBDa, CBD, CBGa, CBG, THCa, other minor cannabinoids, terpenes, and flavonoids.

The relative proportions and presence of these substances partly determine the chemical profile of the extract.

This is also an important starting point in the development of the Full Spectrum CBDa oils from CBD Spain. Here, the focus is not exclusively on one isolated substance, but rather on preserving the plant's original composition.

For Peter, this is a reason to delve further into scientific research. Not only to investigate whether people use cannabis, but especially what they use and how the composition of the product may relate to their experiences.

A unique research question: cannabis via suppositories

In his article, Peter also addresses a route of administration that receives relatively little attention: the suppository.

When people think of cannabis, they usually think of oil, capsules, or vaporization products. Rectal administration is discussed less often, even though suppositories have long been used in medicine.

The mucosa of the rectum is well supplied with blood, and certain substances can be absorbed there. Absorption occurs differently than with oral intake. When a product is swallowed, some of the absorbed substances first pass through the liver, where conversion can take place. With rectal administration, some of this initial liver metabolism can be bypassed.

This does not automatically mean that every cannabis suppository is better absorbed or more effective.

The composition of the suppository, the fat base used, the concentration, and the chemical form of the cannabinoids all play a role. There is still very little good human research available on the absorption of acidic cannabinoids such as CBDa, CBGa, and THCa via this route.

This is precisely why Peter finds this an interesting area of research. There are still many questions for which science needs to find an answer.

When practical experience prompts further research

In addition to the scientific literature, Peter describes in his article a personal practical experience that has stayed with him.

He received a voice message on WhatsApp from a man with advanced cancer and metastases in the lungs and other organs, among others. The man was in a lot of pain, and his daily life was severely limited as a result.

According to Peter's account, this man began using suppositories into which his full plant extract had been incorporated.

What he subsequently told Peter made an impression. He reported that his pain had eased and that he was able to sleep and eat again. Even eating a sandwich with a fried egg and cheese and drinking a cup of coffee became special moments for him again.

Peter describes above all how clear, relieved, and grateful the man sounded.

It is important to put this experience into the right perspective. A personal report does not prove that the extract treated the cancer, that tumors shrank, or that cannabis can cure cancer. Controlled clinical trials and objective medical data are necessary to establish that.

But Peter does ask an interesting question: should we therefore simply dismiss such experiences?

According to him, no.

A practical experience is not scientific evidence, but it can be a reason to conduct more targeted research. When similar observations are recorded in multiple people, along with information about the composition, dosage, and route of administration used, new research questions can arise from them.

Therein lies an important connection between practice and science.

From cannabis use to understanding composition

The 2026 study shows that a significant group of people use cannabis after a cancer diagnosis. But at the same time, the researchers do not know exactly which products these people used.

Which plant was used? Was it an isolated cannabinoid or a full-spectrum extract? How much CBDa, CBD, CBGa, THCa, and other cannabinoids were present? What terpenes and flavonoids did the product contain? And how was it administered?

According to Peter, these are precisely the questions that deserve more attention in future research.

Because when we group different products under one general term, we may miss important differences that could help explain why people have varying experiences.

For CBD & Herb, this is a topic that closely aligns with our daily practice. We work with the Full Spectrum CBDa products from CBD Spain and guide people who want to learn more about the possibilities of cannabinoids and the different extracts.

In this regard, we believe it is important for people to understand that not every CBD oil is the same. The origin of the plant, the extraction method, the preservation of the original cannabinoids, and the full chemical composition are all aspects that deserve attention.

The science of full-spectrum CBDa is not standing still

What Peter makes clear with his article is that we are still far from knowing everything about the cannabis plant and the different applications of its components.

The next step in research lies not only in establishing whether someone uses cannabis, but especially in carefully investigating what they use. The full chemical composition, the extraction method, the ratio of acidic to neutral cannabinoids, and the method of administration all deserve attention.

This requires further research, careful analysis, and the careful recording of practical experiences.

At CBD Spain, much attention is paid to the composition and quality of the extracts. Peter Vermeul has been involved with the cannabis plant, its processing, and research into the different components for many years. We share his insights and research articles on this page because we believe that good information helps people make more conscious choices.

Would you like to read more about the research into cannabis use after cancer, the role of full-spectrum extracts, and the unique practical experience Peter describes?

Then also read Peter Vermeul's full article. In it, he delves deeper into the 2026 scientific study, the differences between cannabis products, and the questions that, according to him, should be central to future research.

• Why more and more people use Cannabis after Cancer - NL pdf
• Why more and more people with Cancer use Cannabis -EN pfd
  

This article is intended for informational purposes. Cannabis products and CBDa oil are not proven treatments for cancer and do not replace regular oncological treatment. The described practical experience is personal and does not constitute evidence of a medical effect.