Generally speaking, topicals have far fewer cannabinoids in them than what you smoke, vape or eat, but even if they didn’t, you wouldn’t feel high with this application method.
Cannabis-infused lotions, salves, oils, sprays, and other transdermal methods of relief work by binding to a network of receptors called CB2. These CB2 receptors are found throughout the body and are activated either by the body’s naturally-occurring endocannabinoids or by cannabis compounds known as “phytocannabinoids” (e.g., THC, CBD).
Even if a topical contains active THC, it still won’t induce the “high” you’d get from smoking or ingesting cannabis. Cannabinoids penetrate to the system of CB2 receptors. Transdermal patches, however, could have psychoactive effects with a high enough THC content.
Because topicals are usually unable to get users high, it would stand to reason that it’s not possible to fail a drug test as a result of their use. In principle, this is true; but there is not a lot of research on this topic yet and there are some caveats.
One caveat is THC transdermal patches. These work similarly to a nicotine patch, providing patients with a strong dose of the active ingredient that is absorbed into the bloodstream through the skin. As such, the use of THC-rich cannabis patches is likely to result in a failed drug test.
We advise erring on the side of caution. If it is necessary for you to pass a drug test, allow 30 for THC to leave your system entirely.