Topical CBD and PEA products showed no skin irritation or sensitization in healthy adults | Research

The takeaway

Three clinical trials and one in vitro study found that topical CBD and palmitoylethanolamide formulations were non-irritating and non-sensitizing on healthy human skin, with only mild phototoxicity from one hemp seed oil product.

Dermatologists, consumers using topical CBD products, and researchers studying cannabinoid skin applications.

No irritation or sensitization from any CBD/PEA product tested

What the researchers found

Patch testing on healthy participants showed no irritation or sensitization from any CBD or PEA product tested. Mild phototoxicity was observed at 48 hours from one hemp seed oil product compared to negative control. In vitro testing showed cannabinoid products were comparable to historically non-irritating products.

Why it matters

As topical CBD products flood the market, basic safety data on skin tolerability has been surprisingly scarce. These controlled assessments provide foundational evidence that these formulations do not cause adverse skin reactions in healthy people.

The numbers in context

3 clinical trials + 1 in vitro study; products included 2 CBD+PEA formulations, 1 hemp seed oil formulation, and 4 concentrations of CBD alone; no irritation or sensitization; mild phototoxicity in 1 hemp seed oil product at 48 hours

How the study worked

Three evaluator-blinded human clinical trials assessed skin irritation, sensitization, and phototoxicity of CBD, PEA, and hemp seed oil formulations via patch testing on healthy adults. An in vitro study tested ocular toxicity using a hen's egg chorioallantoic membrane model.

What this study cannot tell us

Single manufacturer's products tested. Only healthy, non-diseased skin assessed. Short-term patch testing may miss chronic use effects. Products may not represent the broader unregulated CBD market.

How to read the evidence

Multiple evaluator-blinded clinical trials with standardized patch testing, though single manufacturer and healthy skin only.

When this study was published

Published in 2021.

The bigger picture

While this confirms short-term tolerability on healthy skin, the authors note these results cannot be extrapolated to diseased skin or products from other manufacturers, given the vast heterogeneity in commercial CBD product quality.

Questions still open

How do these products perform on inflamed or damaged skin? Would similar results hold across the wide range of commercial CBD products? What are the long-term safety profiles with repeated daily application?

Common questions

Are topical CBD products safe for skin?

These specific formulations showed no irritation or sensitization on healthy skin. However, results may not apply to products from other manufacturers or to people with skin conditions.

Was there any adverse reaction?

Only mild phototoxicity was observed from a hemp seed oil product at the 48-hour time point. No other adverse reactions were detected across all products tested.

Read the original research

Tolerability profile of topical cannabidiol and palmitoylethanolamide: a compilation of single-centre randomized evaluator-blinded clinical and in vitro studies in normal skin.

Clinical and experimental dermatology, 46(8), 1518-1529

View on PubMed ↗Publisher’s paper ↗

Citation

Maghfour, J; Rietcheck, H; Szeto, M D; Rundle, C W; Sivesind, T E; Dellavalle, R P; Lio, P; Dunnick, C A; Fernandez, J; Yardley, H. (2021). Tolerability profile of topical cannabidiol and palmitoylethanolamide: a compilation of single-centre randomized evaluator-blinded clinical and in vitro studies in normal skin.. Clinical and experimental dermatology, 46(8), 1518-1529. https://doi.org/10.1111/ced.14749