Here’s the most asked question when it comes to transdermals: Are you going to feel high after trying out a topical? You’ll likely feel something, from pain relief to relaxation, but you aren’t going to get the same head effect that smoking or edibles will produce.
Some of that has to do with the delivery system from the skin into the bloodstream, which is inefficient if the goal is to get as high as possible. And some of it has to do with product strength, as most of these aren’t especially strong (though there are some exceptions) and it would require a ton of lotion or salve to infuse your blood with enough THC to feel high.
Still, your skin can and does act as a transmission system. In very basic scientific terms, it’s a porous boundary that will (over time) allow substances to reach the circulatory system through the veins and arteries that travel under the skin. You can work to make that boundary more porous by doing things like taking a hot bath or a steamy shower before using massage oil, salves or lotions, which will open your pores wider for better absorption. You should also be mindful of where on your body you’re applying the products; especially “venous” (vein-carrying) areas like your wrists, the tops of your feet, behind your knees or the crook of your elbow are good places to dab topical gel or to place a transdermal patch for maximum effectiveness.
Cannabis lotions, creams and salves work nicely on concentrated areas of sore muscles or joint pain, including arthritis or an occasional knot in your back. The antioxidant properties in cannabis can provide relief from skin irritation, also.