Cannabis Terpenes May Do More Than Add Aroma

Terpenes are usually discussed as the compounds that give cannabis its distinctive aromas. Myrcene can smell earthy, limonene citrus-like, and pinene reminiscent of a forest. However, their importance may extend beyond scent, flavour, and their proposed contribution to how cannabis products feel.

A recent review published in the Journal of Drug Delivery Science and Technology examined natural bioenhancers capable of improving the movement of cosmetic and therapeutic ingredients through the skin.¹ Terpenes and essential oils were among the most extensively studied classes.

The review was not limited to cannabis, and it did not establish that adding terpenes automatically makes cannabinoid topicals more effective. What it offers is a useful scientific framework for understanding why certain terpenes could influence cannabinoid delivery when matched with the correct active ingredient, concentration, and formulation.

This changes the conversation around cannabis topicals. The important question may not simply be how much CBD or THC a cream contains. It may be how the complete formulation controls where those cannabinoids travel, how long they remain available, and whether they reach the intended layer of skin.

Why Skin Makes Cannabinoid Delivery Difficult

Human skin is designed to keep foreign substances out. Its outermost layer, the stratum corneum, consists of dense cells embedded within a highly organized mixture of ceramides, cholesterol, and fatty acids. The structure is often compared to bricks held together by mortar.

This barrier limits water loss and protects the body from chemicals and microorganisms. It also prevents many potentially useful ingredients from reaching deeper tissue. Hydrophilic compounds struggle to cross the lipid-rich barrier, while highly lipophilic compounds may become trapped within it.

Cannabinoids present a particular formulation challenge because compounds such as CBD are highly lipophilic and poorly soluble in water. As previously explored in MyCannabis coverage of nanotechnology for CBD absorption, increasing the amount of CBD in a product does not guarantee that more of it will reach the intended tissue.

A basic topical and a transdermal product also have different objectives. A topical may be designed to act on or near the skin. A transdermal system is intended to move an active compound across the skin and potentially into systemic circulation. Deeper penetration is therefore not automatically better. The ideal depth depends on the intended use.

How Terpenes Can Change the Skin Barrier

Terpenes are small, often volatile molecules produced by cannabis and many other plants. The review discusses compounds including limonene, menthol, cineole, eucalyptol, and terpineol. Several can enter the lipid regions of the stratum corneum and temporarily alter how tightly those lipids are arranged.

This can increase membrane fluidity and create less resistant pathways for other molecules. Some terpenes may also affect keratin proteins, improve the partitioning of an active ingredient from the formulation into the skin, or change the local chemical environment where the product meets the skin.

The process is more nuanced than simply “opening” the skin. A terpene that works well with one compound may perform poorly with another. Polarity, molecular size, stereochemistry, volatility, and concentration all influence the result. The vehicle carrying the terpene, whether a gel, oil, patch, or nanoemulsion, can be equally important.

Potential enhancement mechanisms include:

• Disorganizing tightly packed skin lipids
• Increasing membrane fluidity
• Changing interactions with keratin
• Improving active-ingredient partitioning
• Increasing hydration within the outer barrier

These mechanisms can overlap. A formulation may improve delivery through several small effects rather than one dramatic change.

What The Review Found About Natural Bioenhancers

The review assessed more than terpenes. It also examined fatty acids, plant oils, alkaloids, polysaccharides, saponins, triterpenoids, polyphenols, and natural deep eutectic solvents. Each class interacts with skin differently, giving formulators multiple ways to influence solubility, stability, hydration, and permeation.

The review also identified examples in which nanoemulsions strengthened the effects of natural enhancers. D-limonene nanoemulsions improved curcumin delivery, while eucalyptus oil in a nanoemulgel increased curcuminoid permeation threefold. A cineole-containing nanoemulsion increased the permeation of GABA by 3.37 times.

These findings do not prove equivalent performance with cannabinoids, but they show why formulation architecture matters. Nano-sized droplets can improve contact with the skin and keep lipophilic compounds dispersed, while terpenes alter the barrier those compounds must cross. The carrier and enhancer can therefore work together.

This wider development is supported by recent research into terpenes and essential oils in advanced delivery systems, which similarly describes their dual roles as biologically active ingredients and penetration enhancers.

What This Means For Cannabis Topicals

The cannabis industry often markets terpenes through strain identity or the proposed entourage effect. Dermal delivery offers a more concrete formulation question: can a defined terpene improve the movement of a defined cannabinoid through a specific skin model?

The attached review includes a study of cannabinoid-loaded patches using Eudragit E100 matrices. The patches produced different cannabinoid flux depending on the enhancer, although ethoxydiglycol outperformed the natural oils tested. This is an important result because it prevents an overly convenient conclusion. Natural does not automatically mean more effective.

Instead, terpenes should be treated as functional formulation ingredients whose performance requires measurement. A successful cannabis topical would need to establish the identity and concentration of its cannabinoids and terpenes, characterize their release from the product, and determine where they accumulate in the skin.

This could lead to products designed around distinct delivery targets. A cosmetic CBD formulation might prioritize retention in superficial layers. A product intended for localized tissue exposure might seek greater epidermal deposition. A pharmaceutical patch would require much stronger evidence of controlled transdermal delivery and systemic exposure.

The opportunity also extends to hemp-derived ingredients. Recent MyCannabis reporting has examined how hemp terpenes could replace synthetic chemicals. Skin-care formulations could become another high-value outlet for terpene-rich hemp extracts, provided manufacturers can achieve adequate purity, stability, and consistency.

Why Formulation Matters More Than Terpene Hype

A terpene cannot be evaluated separately from the product containing it. The same compound may behave differently in an oil, alcohol solution, hydrogel, nanoemulsion, or adhesive patch. It may evaporate, oxidize, interact with another ingredient, or remain trapped in the formulation instead of entering the skin.

Natural materials also vary according to plant genetics, climate, harvest timing, and extraction method. Even hemp essential-oil yield can change substantially with harvesting choices, as shown in research covered by MyCannabis on flower harvesting and hemp essential oils.

This variability creates a commercialization problem. A laboratory can test purified limonene at a precise concentration. A commercial producer using a complex botanical extract must demonstrate that different batches behave consistently. Otherwise, permeation, irritation, aroma, and shelf stability may change from one production run to another.

Safety Is Part Of Delivery Performance

Increasing penetration is only useful if the skin barrier can recover without meaningful irritation or sensitization. Synthetic enhancers can be highly effective, but some disrupt lipids, increase water loss, or irritate skin at useful concentrations. Natural alternatives attract interest partly because many are considered more compatible with repeated use.

However, natural origin does not guarantee safety. Essential oils are chemically complex, and some constituents can irritate sensitive skin, oxidize during storage, or cause sensitization. Higher concentrations may increase permeation while also increasing adverse reactions.

The paper therefore emphasizes reversible barrier modulation. An enhancer should ideally loosen the barrier enough to improve delivery without producing persistent damage. Concentration, exposure time, skin condition, and interactions among ingredients all need evaluation.

The Evidence Remains Mostly Preclinical

The strongest limitation is the shortage of human evidence. Many studies use laboratory membranes, animal skin, or excised human and porcine tissue under carefully controlled conditions. These models are valuable for comparing formulations, but they cannot fully reproduce living skin, long-term use, variable hydration, or differences among consumers.

Researchers also lack fully standardized methods for comparing natural bioenhancers. Results can change according to the skin model, formulation, measured endpoint, and experimental protocol. A twofold improvement in one laboratory may not translate into a meaningful benefit in a finished cannabis product.

Regulation adds another complication. A cosmetic can claim to condition or improve the appearance of skin, but demonstrating delivery into deeper tissue could push a formulation closer to drug-level scrutiny, depending on its claims and jurisdiction. Better performance can therefore create a more demanding regulatory pathway.

Terpenes Could Become Precision Delivery Ingredients

The most interesting implication is not that terpenes make every cannabis topical stronger. It is that they could eventually be selected with greater precision.

Rather than adding a broad terpene blend for aroma, formulators could choose a particular molecule based on the cannabinoid, target skin layer, delivery platform, and desired release profile. Computational modelling and advanced imaging could help predict how each enhancer interacts with skin lipids before expensive clinical testing begins.

This would reposition terpenes from marketing accessories to measurable components of product performance. It could also encourage cannabis companies to report more than total cannabinoid content. Terpene concentration, release kinetics, skin deposition, stability, and irritation could become equally relevant indicators of quality.

The review provides a strong scientific rationale for pursuing that approach, but not permission to skip clinical validation. Terpenes may help cannabinoids cross one of the body’s most effective barriers. The next challenge is proving that they can do so safely, consistently, and at a depth appropriate for the product’s intended purpose.

References:

¹ Habibi, E., Panahi, L., Abdelfattah, G. M. M., Hosseinzadeh, M. H., Kousar, M., Sarker, S. D., & Nahar, L. (2027). Natural bioenhancers for dermal delivery: Mechanisms, formulation design and cosmeceutical applications. Journal of Drug Delivery Science and Technology, 127, 108910. https://doi.org/10.1016/j.jddst.2026.108910