Rub It In: The Surprising Science Behind Cannabis Topicals for Pain Relief

A science-based guide to understanding cannabis balms, creams, and gels

Cannabis topicals are everywhere these days—from high-end wellness boutiques to corner dispensaries. But amid the marketing buzz about "miracle" pain creams and anti-inflammatory balms, what does the science actually tell us? As healthcare professionals and informed consumers, it's crucial to separate evidence from enthusiasm when considering these products.

The Science of Skin: Why Cannabis Topicals Make Sense

Before diving into what works (and what doesn't), let's understand why applying cannabinoids to your skin isn't as strange as it might seem. Your skin isn't just a barrier—it's an active organ with its own endocannabinoid system, complete with CB1 and CB2 receptors, plus TRPV1 channels that respond to cannabinoids.

Think of it this way: when you apply a cannabis topical, you're essentially speaking the skin's own chemical language. The cannabinoids interact with local receptors to potentially reduce inflammation and modulate pain signals without significant amounts entering your bloodstream.

What the Evidence Actually Shows

Let's be clear upfront: the research on cannabis topicals is "promising but preliminary." We're not talking about hundreds of large-scale studies here. Instead, we have a handful of well-designed trials that suggest real benefits for specific conditions.

The Winners: Where Topicals Show Promise

Arthritis in Small Joints

Some of the most promising early clinical data comes from a small crossover trial of 18 patients with thumb arthritis. Using a CBD cream (6.2 mg/mL) twice daily for two weeks, participants experienced significant pain reduction and improved function, with zero adverse events (Heineman et al., 2022).

Psoriasis

A recent study of 51 patients found that 2.5% CBD ointment reduced psoriasis severity by 33%, compared to just 10% with the vehicle alone. Some patients (12%) experienced mild local irritation, but overall tolerance was good (Puaratanaarunkon et al., 2022).

Peripheral Neuropathy

The evidence here is mixed. One case series using 1:1 THC/CBD ointments found that 45% of chemotherapy patients achieved meaningful pain relief (D'Andre et al., 2021). However, a follow-up controlled trial using CBD-only cream showed no difference from placebo (D'Andre et al., 2024).

The Reality Check

These studies share common limitations:

• Small sample sizes (18-52 participants)

• Short treatment periods (2-12 weeks)

• Limited head-to-head comparisons between formulations

Translation? We're seeing signals of benefit, but we're not yet at the level of evidence that would support blanket recommendations.

How Fast Do They Work?

Unlike edibles that can take hours to kick in, or inhaled cannabis that works within minutes, topicals occupy a middle ground. Most users report feeling effects within 20-60 minutes, with peak relief around 2-3 hours. The effects typically last 4-8 hours, depending on the formulation.

Here's what's happening under the hood: the cannabinoids slowly penetrate through your skin's outer layers, accumulating in local tissues. A study of transdermal patches found that even high doses (100 mg CBD + 100 mg THC) resulted in blood levels below 1 ng/mL, far below what would cause intoxication (Van Breemen et al., 2023).

The CBD vs. CBD+THC Debate

One of the most common questions: Should you choose a CBD-only product or one that includes THC?

The penetration factor

In vitro studies show that adding THC to CBD can double the amount of CBD that penetrates the skin. THC's more lipophilic (fat-loving) nature may help pull CBD through the skin barrier more effectively (Jaipakdee et al., 2024).

The clinical reality

We don't have head-to-head trials comparing CBD-only to CBD+THC topicals, and case series using both report similar success rates. However, more studies are needed to determine if the observed increase in skin penetration leads to better pain relief in humans.

The practical consideration

Even with THC-containing topicals, blood levels remain extremely low (under 1 ng/mL), and no studies report intoxication or cognitive effects. However, topical absorption may vary based on formulation, skin condition, and location. Therefore, workplace drug testing is a legitimate concern, especially since a 2022 analysis found 64% of "CBD-only" products contained measurable THC (Johnson et al., 2022).

Practical Tips for Healthcare Professionals

1. Set Realistic Expectations

Topicals work best for localized, superficial pain. Don't expect them to help with deep spinal pain or systemic conditions.

2. Choose the Right Vehicle

• Thick ointments for overnight use on hands and feet

• Quick-absorbing gels for daytime joint flares

• Avoid alcohol-based products on broken or eczematous skin

3. Dose Appropriately

Start with a pea-sized amount (approximately 5 mg CBD) over a 5×5 cm area. If needed, patients can reapply after 45-60 minutes.

4. Monitor Response

Track pain scores over 2-4 weeks. A reduction of ≥1 point on a visual analog scale indicates a meaningful benefit.

5. Watch for Skin Reactions

While generally well-tolerated, up to 12% of patients may experience local irritation.

Guidance for Consumers

Check the Certificate of Analysis (CoA)

Any reputable product should come with third-party testing showing exactly what's in it—and what isn't. This is especially important given the prevalence of mislabeled products.

Start Low and Go Slow

Apply a small amount first. If you don't feel effects within an hour, add another layer rather than slathering on large amounts initially.

Consider Your Situation

• If you're subject to drug testing, stick to broad-spectrum or isolate products with verified 0% THC

• If you have sensitive skin, patch test first

• If you're on multiple medications, topicals have minimal drug interactions, but discuss with your healthcare provider

The Bottom Line

Cannabis topicals represent a low-risk option for managing localized pain and inflammation. The evidence, while limited, suggests real benefits for conditions like arthritis, psoriasis, and possibly neuropathic pain. They offer advantages over systemic cannabis use—no intoxication, minimal drug interactions, and targeted relief.

However, they're not miracle cures. Success depends on:

• Choosing quality products with verified content

• Setting realistic expectations

• Using them as part of a comprehensive treatment approach

• Monitoring response over several weeks

As research continues, we'll likely see more refined recommendations about optimal formulations and specific indications. For now, topicals remain an intriguing option in the expanding toolkit of cannabis-based therapeutics—one that deserves consideration but also careful evaluation.

References

D'Andre, S., et al. (2021). Topical cannabinoids for treating chemotherapy-induced neuropathy: A case series. Integrative Cancer Therapies, 20, 1–8. https://doi.org/10.1177/15347354211061739

D'Andre, S., et al. (2024). Topical cannabidiol for established chemotherapy-induced neuropathy: Pilot randomized placebo-controlled trial. Cannabis and Cannabinoid Research, 9(6), e1556–e1564. https://doi.org/10.1089/can.2023.0253

Heineman, J. T., et al. (2022). A randomized controlled trial of topical cannabidiol for the treatment of thumb basal joint arthritis. Journal of Hand Surgery American, 47(7), 611–620. https://doi.org/10.1016/j.jhsa.2022.03.002

Jaipakdee, N., et al. (2024). Skin deposition and permeation kinetics of cannabidiol and Δ9-tetrahydrocannabinol from cannabis extract gels. Journal of Drug Delivery Science and Technology, 101, 106160. https://doi.org/10.1016/j.jddst.2024.106160

Johnson, E., et al. (2022). CBD product contamination: Quantitative analysis of Δ9-THC in retail products. Drug and Alcohol Dependence, 237, 109522. https://doi.org/10.1016/j.drugalcdep.2022.109522

Puaratanaarunkon, T., et al. (2022). Topical cannabidiol-based treatment for psoriasis: A dual-centre randomized placebo-controlled study. Journal of the European Academy of Dermatology and Venereology, 36(9), e718–e720. https://doi.org/10.1111/jdv.18215

Van Breemen, R., et al. (2023). Examining the systemic bioavailability of cannabidiol and tetrahydrocannabinol from a novel transdermal delivery system in healthy adults. Advances in Therapy, 40, 1234–1246. https://doi.org/10.1007/s12325-022-02345-5