What Are CBD, THC and Cannabis Oil? Health Effects of Cannabis-Derived Substances

Introduction

• Scientific name: Cannabis sativa
• English: Cannabis plant
• Turkish: Kenevir bitkisi
• Psychoactive (intoxicating) product derived from cannabis: marijuana/cannabis
• The 2 most studied biologically active cannabis compounds: CBD and THC

CBD is a nonpsychoactive component used for various conditions. THC is the psychoactive (intoxicating, euphoric) component and has other uses.

Cannabidiol (CBD) and delta-9-tetrahydrocanabidiol (THC) are two very different cannabinoids in cannabis. They interact with cannabinoid receptors in the body.

Cannabinoids are substances in the plant known as cannabis or Cannabis sativa . Besides CBD and THC, researchers have identified more than 100 other cannabinoids that can affect the human body. Potential uses of these cannabinoids include treatment of:

• Pain
• Nausea
• Appetite loss and eating disorders
• Spinal cord injury
• Glaucoma
• Multiple sclerosis
• Tourette syndrome
• Anxiety
• Post-traumatic stress disorder
• Irritable bowel syndrome
• Sleep problems

Although CBD and THC interact with the endocannabinoid system, they differ importantly. Unlike THC, CBD lacks the psychoactive effects many associate with cannabis’s characteristic high.

What Is the Endocannabinoid System?

The endocannabinoid system (ECS) is a complex cell signaling system and an important biological system in the body. It was discovered in the 1990s while studying THC, a major psychoactive cannabis substance. Extensive research is investigating how it could be used to treat disease.

“Endocannabinoid” combines endo (internal) and cannabinoid (cannabis). This means the body naturally produces very small quantities of some substances found in cannabis and uses them in bodily functions; a similar system exists for nicotine. The endocannabinoid system has 3 components:

1. Endocannabinoids: similar to cannabinoids in cannabis but produced by the body. Two important ones identified so far are anandamide (AEA) and 2-arachidonoylglycerol (2-AG).
2. Receptors in the nervous system and throughout the body to which endocannabinoids and cannabinoids bind
3. Enzymes helping break down endocannabinoids and cannabinoids

The ECS is present and active even if you do not use marijuana or its derivatives. Although research into its workings is still at an early stage, it is known to help regulate sleep, mood, appetite, memory, reproduction and fertility.

Do CBD and THC Produce a High?

Both are cannabinoids, but CBD and THC interact with somewhat different cannabinoid receptors in the brain.

THC can bind major cannabinoid receptors because its structure resembles anandamide, an endogenous cannabinoid the body produces naturally. This similarity enables receptor interactions and drives recreational cannabis use.

Unlike THC, CBD does not produce the high associated with cannabis. Scientists are not entirely sure how it interacts with cannabinoid receptors but believe it binds differently. It may enhance other cannabinoids’ effects or bind receptors not yet discovered.

How Are CBD and THC Obtained?

Both occur naturally in cannabis plants. Different varieties, such as hemp, can contain different cannabinoid levels.

The main difference between hemp and other cannabis plants is THC content. Plants containing less than 3% THC belonging to Cannabis sativa are considered hemp. Other varieties generally contain more THC and less CBD and are used to make marijuana. A 2016 analysis reported average THC content rising from roughly 4% in 1995 to 12% in 2014. From 2001-2014, average CBD levels fell from 0.28% to below 0.15%.

What Are Their Chemical Structures?

Despite different pharmacological effects, CBD and THC have similar chemical structures. Each contains 21 carbon atoms, 30 hydrogen atoms and 2 oxygen atoms. A slight difference in their arrangement accounts for the substances’ differences.

For Which Medical Conditions Are CBD and THC Being Investigated?

CBD and THC have similar effects in treating medical conditions, but their uses differ in some respects.

People commonly use CBD to help treat:

• Inflammatory bowel disease
• Seizures
• Depression
• Inflammation
• Psychosis or mental disorders
• Migraine

THC also has potential uses for:

• Glaucoma
• Muscle spasticity
• Appetite loss
• Insomnia

 Both CBD and THC may help treat:

• Pain
• Anxiety
• Nausea

Are CBD and THC Legal?

 Many US states have approved medical cannabis for certain patients, with differing definitions and regulation of legal use, prescribing and sale. No federal law permits medical cannabis use. Consequently, use or prescribing is illegal in any state without a law allowing it.

Some states have approved recreational cannabis. Like medical cannabis, recreational use is not federally legal.

In Turkey, a new regulation adopted by Parliament on July 3, 2025 and entering into force after July 2024 established a legal basis for medical cannabis. Under this regulation:

• Prescription Access: Medicinal and supplementary products containing CBD are available only by specialist prescription and only from pharmacies.

• Online Sales Prohibition: Products sold as “CBD oil” outside pharmacies, including social media and websites, are still considered unregulated and illegal.

• Ministry Oversight: Product safety, composition and THC levels are monitored through the Ministry of Health’s electronic tracking system.

Before obtaining medical cannabis, people should investigate their country’s laws. Unless the government explicitly permits it, obtaining or using cannabis for medical or other purposes can lead to legal problems. Medical and recreational cannabis laws also change continually, so local rules should be kept up to date.

What Are the Side Effects of CBD and THC?

Both have been associated with adverse effects. According to the World Health Organization (WHO), CBD is generally safe and does not appear to have abuse potential or harmful properties. The US Food and Drug Administration (FDA) says potential side effects are likely to result from interactions with other medications. Effects on the liver and male fertility are also considered possible.

THC may cause temporary effects including:

• Dry mouth
• Red eyes
• Slower-than-average reaction time
• A general sense of euphoria
• Memory loss
• Coordination problems
• Increased heart rate

Young people in particular may experience adverse psychiatric effects, such as psychotic episodes, with recreational use, possibly because their brains are still developing. Some research suggests regular or high-dose THC may increase schizophrenia risk in certain people.

CBD does not appear addictive and is increasingly used medically in the West. THC appears to be used for recreational/euphoric purposes with a low addiction risk.

What Is Cannabis/CBD Oil? Does It Have a Role in Cancer Treatment?

Oil derived from cannabis, often called “cannabis oil” or “CBD oil,” is frequently claimed to destroy or shrink cancer. It is low in THC and therefore has low addictive effects. It can be used in several forms with differing potential effects: as cooking oil, sprayed under the tongue, or vaporized and inhaled.

Distorted evidence: although some cannabis-derived medicines have FDA approval to reduce cancer treatment-related nausea and vomiting and improve appetite, there is no evidence or clinical trial result showing that cannabis products treat cancer.

Claims that cannabis oil cures cancer rely on limited laboratory research with conflicting results even in laboratory settings. Adverse effects include memory and attention impairment. Perhaps most importantly, cannabis compounds can alter patients’ metabolism of other cancer drugs, increasing adverse effects or reducing efficacy.

Summary

CBD and THC are cannabinoids found in cannabis. Their structures and potential therapeutic uses are similar, but the key difference is that THC produces a high while CBD does not.

Local laws should be understood before obtaining or using CBD and THC. In Turkey, both are illegal substances and recreational use is prohibited. Possession as well as use carries legal penalties.

No human research so far shows that cannabis oil can be used as a cancer treatment. Patients using it or any cannabis form should tell their doctor because of potential adverse effects and interactions with cancer drugs.