Cannabis Topicals: A Comprehensive Guide
Discover the benefits and uses of cannabis topicals, and how they can be an effective part of your wellness routine.
How Do Cannabis Topicals Work?
Cannabis topicals are creams, lotions, balms, salves, oils, and patches that carry THC, CBD, or both. You apply them to skin. The cannabinoids bind CB1 and CB2 receptors found in skin cells and in tissue under the skin. Most products act at the site of use. A small share of the drug enters the bloodstream. That is why a topical rub does not produce the head high that inhaled or eaten THC produces.
What Is in a Topical
A topical has three parts.
- Cannabinoids. THC, CBD, CBG, CBN, or a mix. Labels list total milligrams per container, often 50 mg to 1000 mg.
- Carrier. Coconut oil, shea butter, beeswax, jojoba oil, or a water-based cream. The carrier holds the cannabinoids and spreads them on skin.
- Additives. Menthol, camphor, arnica, lidocaine, or terpenes. These create a cooling or warming feel. They add no cannabinoids.
The Skin Barrier
Skin blocks most chemicals. The outer layer, the stratum corneum, is 10 to 20 micrometers thick. It holds dead cells packed in lipids. THC and CBD are fat-soluble, so they cross lipid layers. THC has a molecular weight of 314.5 g/mol. CBD is the same. Both pass the barrier at a low rate on their own.
Formulators add permeation enhancers to raise the rate. Common ones are ethanol, propylene glycol, terpenes, and DMSO. Wrapping the site with a bandage, a step called occlusion, also raises absorption.
Topical vs. Transdermal
The two words describe two goals.
- Topical: the drug stays in skin and in tissue under it. The effect is local. Blood levels stay low.
- Transdermal: the drug crosses skin and enters blood vessels. The effect is body-wide. Patches use this route.
Transdermal patches carry more drug into the blood than lotions and balms.
The Endocannabinoid System in Skin
Skin cells make their own cannabinoids, anandamide and 2-AG. Keratinocytes, sebocytes, hair follicle cells, fibroblasts, and sensory nerve endings carry CB1 and CB2 receptors. THC binds both receptors. CBD binds CB2 with weak affinity and slows the enzyme FAAH, which breaks down anandamide. CBD also acts on TRPV1, a receptor tied to heat and pain signals.
What the Evidence Shows
Human trial data is thin. Most work comes from animal models and small case series.
- A 2016 study in the European Journal of Pain applied a CBD gel to rat skin. Joint swelling and pain markers dropped in an arthritis model.
- A 2021 case series reported less pain and itch in people with epidermolysis bullosa who used topical CBD.
- The FDA has approved no cannabis topical. Epidiolex, an oral CBD solution for seizures, is the only CBD drug with FDA approval.
Onset and Duration
Topical effects start in 15 to 45 minutes. They last about 2 to 4 hours. Study protocols often use 3 to 4 applications per day. Onset depends on the carrier, the dose, the skin site, and the use of occlusion.
Drug Tests and Legal Status
Urine tests can show THC after topical use. This is rare with lotions and balms. The risk is higher with transdermal patches and with heavy, wrapped applications.
Hemp-derived CBD with 0.3% THC or less is legal under US federal law. THC topicals are legal in states with medical or adult-use programs. Buyers must be 21 or older in adult-use states. Check state rules before you buy.
Label Checks
- Milligrams per container and milligrams per dose are two numbers. Labels often list only the container total.
- THC content above 0.3% makes a product a regulated cannabis item, not a hemp item.
- Third-party lab results should list cannabinoid content and test for pesticides, heavy metals, and mold.