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A New Scientific Approach To Describing Cannabis Strains

Leslie kahn

Humans really like to put things into nice, neat categories, including the cannabis plant. Not only are researchers urging cannabis dispenaries and businesses to stop using the indica-sativa-hybrid classification model, but they are also urging them to stop using the term “strain” when referring to varieties or chemovars. In this article I will explain how science is giving us new terminology which is more accurate. I will also list 4 of the 9 studies on minor cannabinoids and terpenes that just received funding through the National Center for Complementary and Integrative Health (NCCIH). 

Why Indica-Sativa-Hybrid No Longer Works

Dispensaries, cannabis companies and patients all across the US seem to have agreed to classify cannabis varieties as an indica, a sativa or a hybrid when describing the therapeutic effects and the experience that different strains deliver.

With the legalization of both medical and recreational cannabis, cultivators are mixing, matching and creating complex varieties which no longer fit into these categories. It is not terribly useful to simply classify indica as couchlock, sativa as energetic and a hybrid as somewhere in between the two. 

As far back as 1973, botanist Dr. Ernest Small and his partner, H.D. Beckstead, came up with the idea of categorizing cannabis varieties based on their cannabinoid content as follows:

Type I
THC-dominant with more than a 0.3% concentration and a CBD content of less than 0.5%

Type I flower accounts for the majority of varieties currently for sale which is being pushed to the limits, exceeding 30% THC levels. These strains are described as “intoxicating” and are mixed with smaller amounts of minor cannabinoids.

Type II or “Mixed Ratio”
A mixture of THC and CBD in varying concentrations of the two cannabinoids, but almost exclusively with CBD dominating. 

An industry standard as an effective starting point, especially for new patients, is a 1:1 THC to CBD ratio. This type provides many therapeutic benefits without the unwanted side effects of psychoactivity that many patients do not enjoy. There are far fewer products available with this ratio, although there seems to be a trend, based on demand, towards this type.

Labeling a product as “mixed ratio” opens the door to developing varieties that use minor cannabinoids.

Type III
CBD-dominant with very little THC that provides little or no psychoactivity

THC content for Type III flower may be as high as 1% content. That allows it to be used both as fiber and as medicine. A sub-category may be necessary for craft hemp which contains terpenes and higher levels of cannabinoids, in order to distinguish it from industrial hemp used for paper, fabric and other commercial products.

Describing Type III as “intoxicating” may seem like a good selling point for those consumers who are “psychoactivity adverse.” However, it may be dangerous to do so, as some sensitive patients may still experience unwanted effects.

Types IV and V
Cultivators are currently seeking out varieties which are rich in other cannabinoids in an effort to distinguish them from Type I, Type II and Type III categories.

Type IV, a CBG-rich variety, was identified by French researchers led by Dr. Genevieve Fournier in 1987. Similar to Type III in its low levels of THC, this chemovar contained significant percentages of CBGA, the parent molecule from which all other cannabinoids are synthesized. When heated, CBG has the potential to provide appetite stimulation, a reduction of neuron inflammation and act as a neuroprotector.

Type V
In 2004, Dr. Giuseppe Mandolino was the first to identify a Type V, a chemovar of cannabis plants that produces little or no cannabinoid content, known as cannabinoid-null or cannabinoid-zero. 

Cannabis researchers are not entirely clear as to the function of Type V cannabis plants. It is thought that they may play a role in stabilizing Type III plants or that their purpose has not yet be identified.

With no lack of minor cannabinoids such as THCV, CBC, CBCV, CBG, CBGV and CBDV, cannabis researchers are already poised to investigate them. In fact, the National Center for Complementary and Integrative Health (NCCIH) has already announced the funding of new studies of minor cannabinoids and terpenes for potential pain-relieving properties.

Here are 4 of the studies:

1. Mechanism and Optimization of CBD-Mediated Analgesic Effects: Conducted by Dr. Zhigang He, B.M., and Dr. Juan Hong Wang at Boston Children’s Hospital. This study examines the regulating effects of potassium-chloride cotransporter 2 (KCC2) on the analgesic performance of CBD and other minor cannabinoids. KCC2 plays a key role in the electrical signaling of neurons. 
2. Neuroimmune Mechanisms of Minor Cannabinoids in Inflammatory and Neuropathic Pain: Conducted by Dr. Judith Hellman and Dr. Mark A. Schumacher at the University of California in San Francisco. This study focuses on the interactions of minor cannabinoids with 2 receptors; TRPV1 and CB1R and the impact this demonstrates on inflammatory and neuropathic pain in live organisms and in test tubes.
3. Identifying the Mechanisms of Action for CBD on Chronic Arthritis Pain: Conducted by Dr. Yu-Shin Ding at New York University School of Medicine in New York City. Using mouse models, this study investigates the effects of CBD on the regulation of osteoarthritis chronic pain by way of neuroimaging devices and behavior assessments.
4. Analgesic Efficacy of Single and Combined Minor Cannabinoids and Terpenes: Conducted by Dr. Sara J. Ward at Temple University in Philadelphia, PA. Using rodent models, this study seeks to evaluate the effects of four active components of cannabis that may work together to inhibit pain development. The project also assesses how morphine impacts these same four compounds.  

And Finally….

Chemovar vs Strain

Actually, in biological terms, plants don’t have strains. Two factors influence the formation of the cannabis plant:
1. Genotype which is the plant’s genetic makeup
2. Phenotype describes the traits such as color, shape, smell and resin production that influence the genetic code and are affected by the environment.
Industry purists believe that “chemovar” is a much better term. It differentiates one variety from another using cannabinoid, flavonoid and terpene profiles. This provides much more information on how a distinctive variety will affect an individual patient.

I hope this article was helpful in making you think differently about how to refer to cannabis chemovars. 

Sources:, Type I, Type II, Type III: How Science is Changing the Way the Industry Describes Cannabis Varieties, Andrea Sparr-Jaswa, Nov. 8, 2019, Cannabis Genotypes and Phenotypes: What Makes A Strain, Bailey Rahn, April 14, 2014, Cultivar vs Chemovar vs Strain: What’s The Difference? Frances Cassidy, Sept. 1, 2019