Topical vs transdermal: What's the difference?

By Annie Conner, PharmD
Edited by Terri Kroh, PharmD

Did you know the skin has an endocannabinoid system? Preclinical studies have found a potential role for medical marijuana in inflammatory skin diseases and localized pain. For many patients suffering from chronic pain, topical and transdermal formulations of medical marijuana can be a great option for reducing pain while avoiding side effects traditionally associated with inhaling or ingesting THC. Examples include lotions, creams, salves, and balms which are applied externally.

But what is the difference between products labeled “topical” and those labeled “transdermal”?

Topical preparations are formulated to produce a local effect, working at the site of application. So, for example, if you have muscle spasms in your lower back, you apply the topical to your lower back; if you have neuropathy in your feet, you apply the topical to your feet. In general, topical preparations are more beneficial for surface-level pain and inflammation. As topicals cannot pass through all of the skin layers and into the blood circulation, they do not cause the euphoria that vaporized or ingested THC can.

Examples of topical products in the Pennsylvania medical marijuana program include Cresco Remedi Extra Strength Pain Lotion, Ilera’s Breathe, Soothe, and Ease, and Terrapin Resolute Remedies salves.

By definition, transdermal preparations can penetrate through multiple tissue layers and even into bloodstream for delivery to remote parts of the body. However, because of the structure of the THC and CBD molecules, further research is needed to determine the extent to which this occurs, and to go a step further, what, if any, euphoria it can cause. Transdermal may be more beneficial for aches and pains in deeper tissue layers.

Dr. Solomon’s THC-Rich and 1:1 Balanced Lotions are examples of transdermal products.

While there are limited studies published regarding the absorption of cannabis-containing ointments, creams, or lotions through the skin, we do have anecdotal patient experiences reporting positive results. The transdermal applications of MMJ show a lot of promise and perhaps one day will another option to vaporization or ingestion.