Cannabigerol (CBG) is a naturally occurring compound found in the cannabis plant, often referred to as the “mother cannabinoid.” It is the precursor molecule from which more abundant compounds, such as cannabidiol (CBD) and tetrahydrocannabinol (THC), are synthesized. Unlike THC, CBG is non-intoxicating, meaning it does not produce a “high,” leading to growing interest in its properties and inclusion in various wellness products.
CBG’s Origin and Synthesis Pathway
CBG concentration begins with Cannabigerolic Acid (CBGA), the acidic form of CBG. This compound is the foundational precursor to nearly all other cannabinoids and is synthesized within the glandular trichomes on the plant’s surface. The biosynthetic process starts with the condensation of two molecules: geranyl diphosphate (GPP) and olivetolic acid. This reaction is catalyzed by the enzyme CBGA synthase, which marks the first committed step in the entire cannabinoid pathway.
Once CBGA is produced, it acts as a centralized branch point for the plant’s subsequent cannabinoid production. Specific enzyme variants, such as THCA synthase and CBDA synthase, then convert the CBGA into the acidic forms of other major cannabinoids, namely THCA and CBDA. In most mature cannabis varieties, these enzymatic conversions are highly efficient, consuming the majority of the available CBGA. This explains why CBG is often considered a minor cannabinoid, typically present at less than 1% concentration by weight in the final harvested material. The neutral form, CBG, is later generated from CBGA through a process called decarboxylation, which involves the removal of a carboxyl group, typically triggered by heat or ultraviolet light exposure.
Factors Influencing CBG Concentration
The final CBG level in a harvested plant or derived product is susceptible to genetic and environmental variables. The single most influential factor is the plant’s genetic makeup, with specialized high-CBG cultivars, sometimes referred to as Type IV chemovars, being bred specifically to express a non-functional or attenuated synthase enzyme. This genetic modification prevents the efficient conversion of CBGA into other cannabinoids, allowing the CBGA to accumulate instead. These specialized strains can yield CBG concentrations significantly higher than the typical 1% found in traditional varieties.
A second major factor is the timing of the plant’s harvest, as CBGA levels are highest in younger plants. As the plant matures and enters the flowering stage, the synthases become increasingly active, rapidly converting CBGA into THCA and CBDA. Harvesting the crop earlier in the flowering cycle, before these conversion enzymes have completed their work, results in a higher concentration of the CBGA precursor. Environmental stressors, such as temperature, also play a role, as the CBGA synthase enzyme operates optimally within a narrow temperature range, with some studies suggesting an ideal window between 28°C and 32°C.
Even after harvest, post-processing techniques like curing and storage influence the final CBG content. The acid form, CBGA, slowly converts to the neutral CBG over time, especially when exposed to light or warmer temperatures. This non-enzymatic conversion, or decarboxylation, can be accelerated by controlled heat application during the extraction or refinement processes.
Quantifying CBG Content
Accurate CBG determination relies on specialized analytical chemistry techniques performed by accredited third-party laboratories. The gold standard method is High-Performance Liquid Chromatography (HPLC). This technique involves dissolving a sample of the plant material or extract in a solvent and then pumping it through a column packed with a stationary phase material.
As the sample passes through the column, different cannabinoids, including CBG and its acidic precursor CBGA, separate based on their chemical properties. A detector then measures the amount of each compound present, allowing for precise quantification. HPLC is suitable for CBG analysis because it performs separation without requiring heat, a crucial distinction from older methods like Gas Chromatography (GC). By avoiding heat, HPLC measures both neutral CBG and acidic CBGA separately, providing a true representation of the sample’s chemical profile.
This distinction is important for calculating the total potential CBG, which represents the maximum amount of neutral CBG that could be present after full decarboxylation. Laboratories use a specific formula to account for the molecular weight difference when the carboxyl group is removed from CBGA: Total CBG is calculated by adding the measured CBG to the CBGA content multiplied by a conversion factor (approximately 0.878). The official record of these results is presented in a Certificate of Analysis (CoA), which details the exact concentrations of CBG, CBGA, and the total potential CBG, providing scientific verification of the product’s claims.
Interpreting CBG Levels in Consumer Products
For the consumer, CBG levels are communicated on product packaging in two primary ways, depending on the product type. Raw or processed flower material typically lists the CBG content as a percentage by dry weight. For instance, a high-CBG strain might be labeled as containing 15% Total CBG, indicating that 150 milligrams of CBG are available per gram of flower.
Conversely, concentrated products like oils, tinctures, and edibles display the CBG concentration in milligrams (mg) per serving or mg per bottle. A tincture might list a total of 1,000 mg of CBG, with a dropper representing a 33 mg serving. The highest CBG concentrations are found in pure CBG isolate, which is a white crystalline powder testing at nearly 100% CBG, or in broad-spectrum extracts derived from high-CBG biomass. Consumers should use the Certificate of Analysis to cross-reference the label claims, ensuring the reported percentages or milligram amounts align with the third-party lab results for the total potential CBG content.