Cannabis has a distinctive aroma, combining citrus, pine, pepper, and floral notes. Beneath these fragrances lies complex chemistry that attracts scientific interest, particularly as the medicinal cannabis industry grows. Terpenes are central to safety, consistency, and product performance. Dean Hatt, senior toxicology consultant at Broughton medicinal cannabis testing consultancy. Broughton, explains their importance in risk assessment.

What are terpenes?

Terpenes are naturally occurring aromatic compounds in cannabis, also found in plants such as pine, citrus, lavender, and pepper. In cannabis, they are produced in trichomes—the same resin glands that generate cannabinoids like THC and CBD. Each strain has its own terpene profile, influencing flavour, aroma, and potential therapeutic effects. Over 200 terpenes have been identified, with myrcene, limonene, pinene, linalool, and beta-caryophyllene being the most common.

The entourage effect

Evidence suggests terpenes may interact with cannabinoids in what is called the entourage effect, enhancing or modulating their physiological impact. For example:

• Myrcene may promote relaxation or sedation.
• Limonene could elevate mood.
• Pinene may counteract some cognitive effects of THC.

First proposed in 1998 by Raphael Mechoulam, this hypothesis suggests terpenes and cannabinoids work synergistically for greater therapeutic benefit. A 2021 University of Arizona study found terpenes like beta-caryophyllene and alpha-pinene amplify pain relief when combined with THC or CBD, without increasing side effects. Research in Scientific Reports shows terpenes can activate CB1 receptors, potentially boosting anti-inflammatory and anxiolytic properties. However, a 2024 review in the International Journal of Molecular Sciences notes that direct synergy in humans remains unproven, emphasizing the need for more clinical trials.

Terpenes and product differentiation

For producers, terpenes shape strain identity, consumer targeting, and market positioning. Flavour and experience often drive preference, especially in North America. Product developers may seek distinctive aromas or milder blends, highlighting the need for consistent scientific assessment to formulate safe, effective products. In the UK, where medicinal cannabis has been legal for prescription since 2018, the MHRA emphasises rigorous quality control. Broughton profiles terpene content to ensure compliance, as variability can affect dosing and therapeutic outcomes.

Quality, safety, and stability

Terpenes can degrade during processing or storage, affecting consistency and safety. Key findings include:

• Terpenes like pinene are prone to photodegradation under UV light, producing off-odour compounds.
• Oxidation can reduce THC potency by up to 50% over time.
• Adding exogenous terpenes in packaging reduced cannabinoid degradation by 47.4% in accelerated stability tests.
• Thermal degradation in vaping or dabbing can produce toxicants such as methacrolein and benzene.

UK guidelines require stability data for CBD products to ensure consistent efficacy and safety.

The importance of risk assessment

Risk assessments identify toxicological concerns, quantify exposure, and compare it to safe limits. For example, beta-caryophyllene, which binds to CB2 receptors for anti-inflammatory effects, must be evaluated in multi-terpene blends according to European Food Safety Authority standards. Understanding terpene chemistry ensures formulations are effective and responsibly designed.

Ongoing research explores neuroprotective roles of terpenes, such as alpha-pinene mitigating amyloid-beta toxicity in Alzheimer’s models, but robust risk assessments remain essential.

Broughton combines analytical science, manufacturing expertise, and toxicology insight to provide a complete development pathway, advancing the cannabis sector safely and responsibly.