When the average person thinks of the most popular way to consume cannabis, one of their first thoughts is by smoking a joint or bong (or some other form of combusted flower material inhaled into the respiratory system), however there are a variety of other ways to ingest your cannabis medicine without having to spark up a doobie. According to the Canadian Cannabis Survey 2020, 79% of people report smoking as the most common method of cannabis consumption [22]. Despite its popularity, smoking cannabis has many health risks due to the act of inhaling a combusted sticky icky nuggy luscious sweet sweet flower of Momma Mary Jane. It has been shown to have the same effect on the lung tissue as cigarettes, thereby increasing the risk of several chronic health conditions including cancer of the mouth, tongue, throat, and lungs, as well as chronic bronchitis, emphysema and heart disease and stroke [2-7]. Smoking cannabis decreases the effectiveness of the immune system, and increases the susceptibility of infections in immune-suppressed individuals [4-6]. The American Lung Association cautions against the smoking of cannabis due to the risk it poses to the health of the lungs [7]. Thankfully other forms of cannabis have evolved so that consumers and patients have a choice in how they medicate, providing healthier, safer and non-psychoactive options [11]. Such alternatives include vaporizing or dabbing concentrates, infused edibles (example: baked goods, salad dressings, spices, drinks, gummies, chocolate, sugar, maple syrup, freezies, ice cream, candies, etc.), oil and alcohol-based tincture drops and sprays for under the tongue, patches, vaginal and rectal suppositories, and one of the least understood, the topical route of administration [8]. In the following article I will discuss how the topical cannabis interacts with the largest organ in the body and the health benefits associated with it's use according to recent research.

The way in which a medicine is introduced into the body is referred to as the “route of administration” and differs according to the medicine's purpose, each route has individual effects, onsets and duration of effects, varying rates of absorption [9], and health risks or benefits in regards to safety as well as ethical and moral circumstances, varying according to each person's specific health and wellness needs [1,8]. The topical route is the application of medicine to the uppermost layer of skin and mucous membranes, and is an often confusing, undervalued and underused way to medicate with cannabis which has successfully treated pain and inflammation, a variety of skin diseases, specifically painful and difficult to heal wounds, and rare skin disorders. It provides moisture, nourishes and protects the skin [10]. An advantage of the topical route over other routes is that the skin itself covers the entire body, providing a large surface area with the potential to interact with the topical cannabis. Topicals, the common term used for topical cannabis within cannabis culture, are easy to apply to the body and to adjust the dose. Conveniently an assortment of cannabis-infused products have developed ranging from creams, lotions, ointments, balms, gels, bath bombs to salves [12]. Some of these such as bath bombs, give the ability to treat most of the skin with a single application, while others are limited to the location where the product has been applied.

It is a wonder why people don't take advantage of this form of medicating more often, and why science hasn't been able to keep up with the availability of products on the market. In recent years in Canada the non-legal markets, and more recently, but to a much less extent the legal market, have been flooded with topical cannabis products despite the fact that very limited research has been carried out upon it. As of December 2019 topical cannabis has been legal within Canada, however, very few products have made it to the shelves likely due to regulations from Health Canada and a lack of quantitative research completed on human subjects [27]. Currently as with most research completed thus far on the health benefits of cannabis, very few studies have advanced to the point of testing on humans and have been conducted on lab animals and in test tubes only. Testing trials take a significant amount of money, and several years to collect and process data before it advances to later stages when they begin testing on humans. The information elucidated in the process gives us clues as to how a substance could behave within the complex environment of the human body, however until we reach the point of human testing we can only rely on the general direction in which this robust data points us towards. Unfortunately due to the significant time and resources that rigorous scientific research costs, it can result in a lag between product availability and scientific data testing the efficacy of such products. When there is a lack of scientific proof, patients are left to their own devices and often turn to the internet for answers. Many forums and websites exist which delve into patient's experiences and while there is value in documenting this information as much can be learned, this can however lead to unsafe and harmful medicating practices because the information in such environments is not based on scientific fact and should not be considered medical advice or recommendation [26]. Despite the risks, those suffering from chronic and debilitating illnesses are driven by a lack of effective treatment and poor quality of life to search for alternatives to the typical Western Medical treatment prevalent in North America. Topical application of cannabis is a potent and multipurpose alternative that is impossible to overdose on, causes few negative side effects and little chance of toxicity [12]. The clues collected from early testing thus far suggest that topical application of cannabis acts on the local skin and tissues, does not uptake into the bloodstream and therefore does not produce psychoactive effects, or the “high” that other routes provide [11]. For those of us looking to get lit as a tit, topical cannabis use isn't going help, but it does have a complex and important role in maintaining the skin's function, and when out of balance disorders and diseases of the skin manifest [13].

So, how does topical cannabis effect and become absorbed into the skin you ask? The entire skin system, including the cutaneous and mucous membranes, structures such as sweat and sebaceous glands, hair follicles and nails [11] is brimful with Endocannabinoid receptors, functioning to maintain balance, as well as to form and regenerate the skin barrier [13]. Such receptors include CB1 and CB2, as well as receptors which act upon the cell surface and nucleus namely 5-HT, TRPV,GPR and PPARγ, PPARα, PPARδ, and NF‐κB [14]. Each type of ECS receptor is found in different amounts throughout the structures of the skin and varies in it's ability to bind with the different types of cannabinoids, terpenes and flavonoids; the medicinally active chemicals contained within cannabis [11]. When the skin's ECS is out of balance, diseases of the skin including acne, scleroderma, abnormal hair growth, dermatitis, pigmentation disorders, itch, skin cancers, keratin diseases, psoriasis [13] and conditions favourable for wound formation occur [12]. Early trials with topical cannabis suggest it's efficacy in pain treatment, promoting wound closure [14], in the treatment of rare diseases of the skin such as epidermolysis bullosa, pyoderma gangrenosum, calciphylaxis (difficult to heal and painful wounds), as well as chronic leg wounds in those with Sickle Cell Disease [12]. Such rare diseases have ineffective treatment and has significant impact on quality of life of diagnosed individuals, and although topical cannabis development is in its infantile stages, it is proving to be a promising emerging treatment for an otherwise largely mysterious group of diseases effecting the skin [12].

Significant relief from wound-related pain was observed due to the effects of topical cannabis in studies from 2017 and 2018 involving small samples of patients with pyoderma gangrenosum and cancerous wounds [15, 16]. Findings showed a rapid rate of pain relief was reached due to the interaction between topically absorbed cannabinoids and ECS receptors located within peripheral pain receptors and immune cells of the skin [15]. Interestingly, a study from 2003 supported the idea that the ECS is able to treat and prevent pain at multiple different levels by mechanisms acting locally within the skin, as well as within the spine and central nervous system. When cannabinoids were administered into the spine through the intrathecal route, it reduced pain in a synergistic manner with the locally administered topical form of cannabis [21]. Another study showed therapeutic value of topical cannabis containing the cannabinoids CBG and CBGV in the treatment of skin disorders that involve inflammation and dryness [24]. In the case of acne, topical cannabis has a multifaceted method of attack which includes neutralizing pro-acne molecules, providing anti-inflammatory effects, and via the suppression of keratinocyte development [19,20] and potent antibacterial effects that CBD provides [18]. Topically applied CBD provided a significant decrease in the intense and sharp pain, cold and itchy sensations associated with peripheral neuropathy often experienced by diabetics in a study from 2020 [23].

A study conducted on mice in 2019 suggested that the terpene beta-caryophyllene was responsible for enhancing wound healing through multiple mechanisms. One such mechanism via the cannabinoid delta-9 THCA interacting with the receptor PPARy, was found to be a key part of the processes involved in the healing of skin wounds [17, 12]. In 2020, an observational study was conducted on patients diagnosed with calciphylaxis, a skin disorder presenting as chronic, painful, and difficult to heal wounds with a high susceptibility to infection and necrosis or tissue death. This condition is often associated with a high level of death (up to 80% within the first year of diagnosis), co-morbidity, and a poor quality of life. When topical cannabis was applied to the wound and surrounding tissues the patients experienced an accelerated rate of healing to the point that they were able to reach a state of wound closure, which was often not possible previously. The patients also experienced a clinical and statistically significant reduction in pain caused by the wound and used less pain medication. Despite the limitations of the study, as it was open label and a very small sample size of patients, it is remarkable that these patients were able to heal to the point of wound closure with the help of topical cannabis [12].

The use of cannabis in topical form has existed since ancient times dating back to 2700BC [27], and science has only begun to recognize it for it's vast potential [11]. In comparison to other treatments, topical cannabis is safe to use, non-toxic, non-invasive, and has no risk of over-dose, over-use, nor addiction as it is unable to effect beyond the local tissues it is applied to [8]. It is easy to apply and to adjust the dosage, and interacts with the skin through multiple medical compounds of the cannabis plant. Since the skin is highly populated with a variety of ECS receptors, pain receptors, and immune cells, topical cannabis has untapped potential for treating illnesses associated with imbalances of the ECS [13]. Of note, another route of administration mimics the effects of topical in the case of cannabis, as it remains locally absorbed and acts upon the immediate surrounding tissues and glands. The rectal or vaginal route of administration via suppository is often overlooked as treatment option until late disease stages. Few studies have breached this route, however it has shown promise in treating gynecological pain, for nausea/vomiting in cancer patients who have ineffective control by other means, chronic lower back and extremity pain, as well as in treatment for certain cancers [28]. With applications in antibiotics, anti-inflammatory, treatment of rare and mostly untreatable diseases, exceptional wound healing, analgesia, and dermatology as well as the cosmetic industry, topical cannabis is a potent and valuable method of cannabis consumption. As testing advances to human subjects, topical cannabis is exciting and carries vast potential for a plethora different illnesses effecting many.