Central to protection, sensation and regulation is the topic of skin. Skin wrinkles. Skin gets blemishes. Skin burns. Skin protects. Skin is the largest organ in our body (the integumentary system), protects us from the elements and microbes and allows for sensory input. Skin protects us but how do we protect our skin?
What is skin?
“Skin” is comprised of several tissues and structures, The outermost layer of skin is our waterproof barrier, the epidermis, which is 4-5 layers of epithelial cells and 90% of these cells are keratinocytes. These rapidly dividing cells provide our first-line defense to the outer world, with a lifespan that can be ended by sun exposure and skin diseases. Keratinocytes signal to other skin cells including melanocytes (providing pigment); fibroblasts, (wound healing), immune cells, hair follicles and nerve cells! So, you can see on the surface (pun intended) how important skin is.
The next layer, the ‘stratum basale’ generates new cells for the epidermis. This is where nerves and melanocytes reside. Beneath this is the dermis, where the immune system, nerves, blood and lymph vessels, sebaceous gland (releasing fat-rich protective barrier) and connective tissue hold it all together. Underneath this layer is the hypodermis, or subcutaneous fat that insulates and protects us.
Cannabidiol is a nonintoxicating cannabinoid, found in cannabis species, and has been studied for its effects on skin. CBD does not convert to THC in the body, and applied topically is not significantly measured in blood (meaning it does not have systemic effects). One reason for this is that it loves fat and so will mostly get sequestered in the subcutaneous fat layer.
One potential benefit of trying CBD topically is in regulating the production of sebum. This effect may therefore help with acne along with addressing hormonal causes. There is also inflammation associated with acne, and CBD is known to have anti-inflammatory and anti-oxidant potential. This can come in to play with aging of skin and also damage from the sun. Topically, CBD may also help to stop itch associated with eczema or minor skin irritations.
Pre-clinical studies show promise
Going deeper, CBD has been shown in pre-clinical studies to help protect keratinocytes, and to reduce their proliferation. This could be useful in the diagnoses of psoriasis or in older people with the development of keratoses, both of which are an over-proliferation of this cell type or plugs of keratin that cause bumps known as “chicken skin”.
There is not strong evidence that CBD is effective for pain when applied topically, but it may help to soothe minor aches and pains. There is also some investigation into cannabinoids and the potential benefit for skin cancers, but as yet no evidence, particularly as the dose for this effect is likely much higher than what is typically available in topical products.
So, using CBD topically is considered to be safe, with no systemic effects. There is really no proof yet from controlled clinical trials to support these potential benefits, so any use would be your own personal experiment!
Michelle Sexton, ND
Dr. Sexton is an Assistant Adjunct Professor for the University of California, San Diego Department of Anesthesia.
Dr. Sexton’s NIH-funded pre and post-doctoral research was on the topic of cannabinoids and their roles in neuro-inflammation and neuro-degeneration. She is a member of the International Cannabinoid Research Society, the International Association of Cannabinoid Medicine and the Society of Cannabis Clinicians. She maintains a medical practice in San Diego, CA and she sees patients for integrative neurology, chronic inflammation, chronic pain, autoimmune diseases and cancer support.