If CBD sounds like the answer to your skin woes, it’s helpful to take a step back and look at the bigger picture. “What we don’t have in CBD is a lot of research. [CBD has] been illegal federally for so long, and it’s been difficult to do research on something that’s previously been considered on par with cocaine or heroin,” says Dellavalle. That’s starting to change, though. The 2018 Farm Bill removed hemp from the definition of marijuana, which meant that CBD products were no longer considered like marijuana. This has paved the way for researchers to conduct more studies on CBD, and for product manufacturers to create and sell CBD products legally, though per the Food and Drug Administration (FDA), it is still illegal to market CBD as a supplement.
First, let’s talk about what CBD is. Cannabidiol (CBD) is an active ingredient in the cannabis plant, according to Harvard Health Publishing. CBD can be derived from either medical marijuana or hemp. Although marijuana contains CBD, CBD doesn’t have psychoactive effects. (THC, tetrahydrocannabinol, is the chemical that causes the high.) All that said, CBD won’t lead to any mind-altering effects.
Indeed, Mona Gohara, MD, a dermatologist in Hamden, Connecticut, and associate clinical professor of dermatology at Yale University in New Haven, Connecticut, prefers to use CBD “in inflammatory skin conditions as they’re fizzling out.” She adds, “I recommend generally using a medication to put out the fire and then using CBD to clean up the carnage.”
In short, you may see less redness overall, and in skin diseases, including eczema and psoriasis, it may also be effective in tamping down itch, possibly because CBD creams may help reduce dryness, per a review published in July 2017 in the Journal of the American Academy of Dermatology. (Dr. Dellavalle was a coauthor of that report.) Keep in mind, though, that the review included only three studies: two in humans but with small sample sizes and one in mice, which doesn’t necessarily translate to human health. Therefore, more studies on the potential benefits of CBD for reducing skin redness are needed.
Unknowns About CBD Dosage
In general, manufacturers add CBD to their products to give them a boost. “CBD is a very cost-effective way to enhance products,” says Austin Katz, cofounder of Sheabrand in Brooklyn, New York. CBD is in a range of products — those that claim to treat acne, dry skin, and eczema — because of its versatility. “I think we’re living in an era where people want to feel empowered to address their needs on their own,” he says.
There are hundreds of other chemicals in the cannabis plant, and researchers don’t know what combinations are best. For instance, terpenes, the essential oils in plants (including cannabis), may exert synergistic benefits, suggests the Clinical Therapeutics study. “So much research needs to be done. We’ll be sorting this out for the next 25 years,” says Dellavalle. On the horizon with more research from universities and companies, says Jackin, may be more targeted and efficacious therapies for conditions like eczema and acne.
For many skin diseases, dermatologists often prescribe topical steroid creams, which act as anti-inflammatory medicines. “These are very safe for most people, and they’re effective, but some people don’t want to use steroids in any way. CBD could be a nonsteroidal therapy to fill that gap,” says Dellavalle. Side effects of topical steroids include thinning of the skin if overused or used long term, but you can help avoid these risks when using them correctly, notes the National Eczema Association. Working with your dermatologist to ensure that you have the right medication at the right dosage can help with this.
A review published in June 2018 in the Dermatology Online Journal, which Dellavalle coauthored, pointed out that while CBD may “have shown some initial promise as therapy for a variety of skin diseases,” there is a need for large, high-quality, randomized, controlled trials, a sentiment echoed in an article published in December 2020 in Cannabis and Cannabinoid Research. Another paper, published in the May-June 2019 issue of Clinics in Dermatology, urges people and their doctors to approach these products with the same caution. Finally, though topical CBD tends to be well tolerated and may have a role in addressing various skin issues (including acne, dryness, and irritation), there’s still ongoing research on the safety of CBD treatment, notes an article published in 2020 in Clinical, Cosmetic, and Investigational Dermatology.
Finally, one of the newest uses for CBD skin care is in sunscreen. Dellavalle notes that it does make sense to add CBD to sunscreen, as its anti-inflammatory properties may help reduce the effects of a sunburn, such as redness. Of course, the idea is to apply sunscreen correctly (following guidelines from the American Academy of Dermatology), but in real life, many people miss areas, and applying a CBD-infused SPF may supply more general absorption and temper the reaction of sunburned spots, he says.
Furthermore, to assess the potentiating and synergistic effect against MRSA, growth curve and time kill assay results showed the combined activity of CBD and BAC reduced bacterial viability by 6-log10 cfu/mL as compared to CBD or BAC alone. Interestingly, CBD was able to potentiate the effects of BAC against MRSA (S. aureus USA300) and other Gram-positive bacteria. The spectrum of use of CBD and BAC on growth of Gram-negative bacteria, including Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella pneumoniae, and Escherichia coli, was also measured. The results obtained from the combined effect of CBD and BAC against these Gram-negative bacteria concluded that the combined activity of CBD and BAC was considered ineffective against Gram-negative bacteria. Due to potent antibacterial properties against Gram-positive bacteria, cannabinoids can be used as an effective helper compound when combined with known antimicrobial actives to fight antibiotic resistant Gram-positive bacteria which cause skin disorders and other infections. 134
The human hair follicle is an immune-privileged miniaturized organ consisting of epithelial and mesenchymal tissue. As part of the pilosebaceous complex, the hair follicle is extensively regulated, the extent of which is still not completely understood. Human scalp hair growth is a complex and dynamic process including a period of keratinocyte proliferation and hair fiber growth (anagen), followed by a stage of apoptotic follicle regression (catagen) and a semi-quiescent stage (telogen). 105 Hair growth abnormalities include lack of hair growth (alopecia), and excessive hair growth (hirsutism and hypertrichosis). Given the success of topically applied compounds to treat hair loss 106 coupled with the detection of major cannabinoid compounds in hair fibers, including CBD, following cannabis consumption 107 and topical application of hemp oil 108 further understanding of how cannabinoid compounds can potentially benefit hair-related issues is needed. 109–111
An orally administered synthetic antagonist of CB1 promoted hair growth stimulation in obese mice but had no effect when applied topically. Whether oral administration of the CB1 antagonist specifically targeted CB1 to induce hair growth was not discussed by Srivastava et al. 113 Bodo et al identified the expression of TRPV1 in human hair follicles and outer root sheath keratinocytes. 114 Activation of TRPV1 in follicle organ cultures leads to inhibition of cell proliferation, while inducing apoptosis and catagen entry. Hair growth activators, HGF, IGF1, and SCF, were also suppressed with TRPV1 stimulation. TRPV3 and TRPV4 were also detected in human hair follicles and outer root sheath keratinocytes, and receptor activation, though not exclusively by cannabinoids, resulted in suppression of hair follicle elongation. 115 , 116 A metabolite of the endocannabinoid anandamide, bimatoprost, is recognized as a topical prostamide treatment for eyebrow hypotrichosis. 117 Khidhir et al also showed human scalp hair follicles possess select prostamide receptors within the dermal papilla. Working with human scalp, organ-cultured hair follicles, bimatoprost treatment resulted in follicle growth and it stimulated hair regrowth when applied to mouse skin. 118 A limited clinical study showed bimatoprost application also accelerated hair regrowth in alopecia areata patients to a greater extent than a topical steroid treatment. 119 Szabo et al in a pilot study using ex vivo human hair follicles and primary outer root sheath keratinocytes found systemic-like application of CBD had dose-dependent opposing effects on hair growth dynamics. 116 At the 0.1 µM and 1.0 µM doses, the hair shafts grew similar to controls, while at the 10 µM dose, growth was significantly suppressed and follicle catagen was induced. As CBD dosage increased, keratinocyte proliferation decreased. The researchers proposed that CBD concentration may lead to differential receptor activation, with low doses favorably affecting hair growth pathways and higher doses activating suppression targets such as TRPV4.
Modulation of the ECS by endocannabinoids and phytocannabinoids in presynaptic neurons in the central and peripheral nervous systems.
The ECS is an evolutionarily conserved network of molecular signaling that plays a role in bodily homeostasis. 1–3 The ECS is made up of multiple components: (a) signaling molecules called endocannabinoids, (b) specific receptors, and (c) enzymes that synthesize and breakdown endocannabinoids and transporters of endocannabinoids. The most well-researched functions of the ECS are related to modulation of the central nervous system (CNS) and immune function in the body. Recent research has indicated the critical role of the ECS in maintaining skin homeostasis and barrier function, and its dysregulation has been implicated in various skin disorders like atopic dermatitis, itch, acne, hair growth/loss, and hyper/hypopigmentation. 4–7
Chemical Structures of 9 endocannabinoids found in human skin.
Schematic representation of the key components of the ECS in different cellular compartments of the skin.
Modulation of Hair Growth
The significance of the ECS in maintaining skin homeostasis and the resulting dermatological conditions from its imbalance has garnered scientific attention. Despite promising research on the topical therapeutic potential targeting the ECS, much remains unknown on the complexity of interactions of cannabinoids with other systems of the human body. A good example of this is the unintended interaction of BIA 10–2474 (a FAAH inhibitor intended for treating pain and anxiety) with the lipid network in human cortical neurons resulting in metabolic dysregulation of the nervous system. 141 , 142 Though the outcomes of this study are stemming from oral treatment at higher doses, it does have sound advice to treat any topical application of cannabinoids with due diligence. While many topical CBD products appear to be relatively well tolerated, topical safety studies are underway, and the evidence is still emerging.
Wound healing is an intricate process which includes three overlapping phases – inflammation, proliferation, and maturation/tissue remodeling. 87–89 It is plausible that the complex process of wound healing is influenced by ECS signaling, as it modulates epidermal proliferation and differentiation, fibroblast functions, and cutaneous inflammation. CB1 and CB2 receptor involvement during the wound healing process in various immune and fibroblast cells are based on murine models. 90–92 In these models, various cannabinoid analogs have generated a wound healing response possibly associated with activation of CB1 and/or CB2 receptors, upregulation of anti-inflammatory factors, indirect activation of TRPV1 and epidermal growth factor receptors, and inhibition of the FAAH enzyme. 91 , 93 , 94 The evidence of the clinical application of PCBs, especially CBD, for wound healing is scarce. A single study reported three patients suffering from Epidermolysis bullosa (a rare skin disorder characterized by pain and blistering) had faster wound healing, less blistering and amelioration of pain with self-reported topical use of cannabidiol. 95 , 96