Topical CBD and PEA products showed no skin irritation or sensitization in healthy adults
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.
Quick Facts
What This Study 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.
Key Numbers
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 They Did This
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.
Why This Research 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 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.
What This Study Doesn't 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.
Questions This Raises
- ?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?
Trust & Context
- Key Stat:
- No irritation or sensitization from any CBD/PEA product tested
- Evidence Grade:
- Multiple evaluator-blinded clinical trials with standardized patch testing, though single manufacturer and healthy skin only.
- Study Age:
- Published in 2021.
- Original Title:
- Tolerability profile of topical cannabidiol and palmitoylethanolamide: a compilation of single-centre randomized evaluator-blinded clinical and in vitro studies in normal skin.
- Published In:
- Clinical and experimental dermatology, 46(8), 1518-1529 (2021)
- Authors:
- 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
- Database ID:
- RTHC-03309
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked 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.
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Cite This Study
https://rethinkthc.com/research/RTHC-03309APA
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
MLA
Maghfour, J, et al. "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, 2021. https://doi.org/10.1111/ced.14749
RethinkTHC
RethinkTHC Research Database. "Tolerability profile of topical cannabidiol and palmitoyleth..." RTHC-03309. Retrieved from https://rethinkthc.com/research/maghfour-2021-tolerability-profile-of-topical
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.