When searching the internet for the benefits of CBD and hair care or preventing hair loss, it is overwhelming to see hundreds of articles claiming cannabidiol to be the next “miracle cure” for baldness and glossy hair only ever seen in shampoo ads. Most of these blog articles fall back on non-specific facts like “CBD oil is high in vitamins and omega oils”, and that it can “work by helping your body get to the ideal conditions necessary for maximum hair growth” by reducing inflammation, reducing stress and increasing blood circulation.
The question naturally arises: are these claims really true?
In fact, to date very little research has investigated CBD’s effects on hair growth. In 2019, however, a team of researchers from Hungary did examine the potential for cannabidiol in treatments to stop unwanted or excessive hair growth. Their experiments – which we summarize in this article – revealed a very interesting and complex dose-dependent relationship between CBD and hair growth.
Researchers were initially interested in exploring the underlying chemical changes in the body that cause both hair loss and excessive hair growth, resulting from conditions such as alopecia, hirsutism, and telogen effluvium (temporary scalp hair loss).
The body’s hair follicles are the center of the action, where a cyclical change occurs. Under normal conditions, there are three phases in the hair growth cycle; anagen, the active phase of hair growth; catagen, a short temporary phase when hair growth ends and the hair follicle shrinks; and lastly telogen, the resting phase of the hair growth cycle that typically lasts three months, and is usually followed by shedding of the hair shaft.
The processes that control these changes are complex and scientists still not fully understand them, but suspect the role of the neuroendocrine system: the brain’s system to control the release of hormones that regulate all the key aspects of the living body; for example, reproduction, metabolism, eating and drinking, energy production and blood pressure.
Previous experiments have shown that some endocannabinoids play a role in the switching-off and death of hair follicles, but not all of these chemicals seem to trigger the same action and must have different effects on the hair follicle’s control mechanisms. An international research team was therefore keen to explore things further, by looking at whether CBD, a phytocannabinoid, might also have an effect on hair growth/loss.
We already know that cannabidiol has some effect on the pilosebaceous unit, a tiny sensory organ in which the hair follicle sits, and which controls sweat and sebum (oil) production by the sebaceous gland. It also controls the pili muscle to make the hair stand on end and stores new cells for growth. CBD acts to reduce sebum production and has an anti-inflammatory effect on the sebaceous gland, as well as inducing premature ending of the hair growth phase.
Watch this 1:20 minute video segment on the hair growth cycle
Scientists carried out tests in the laboratory using cultured hair and scalp cells. After examining the effects of adding increasing concentrations of CBD, researchers noted that the effects had a “dose-response” relationship. At higher concentrations, CBD caused a decrease in hair shaft growth and started the hair follicles to produce substances that turned the hair follicle into a dormant state or began the process of killing the follicle’s cells.
Further experiments showed that CBD acts by rapidly decreasing the cells of the outer root sheath (ORS) of the hair follicle, made up of cells called keratinocytes, which seem to have a role in promoting epithelial (skin) cells to grow during healing of wounds, etc. This action was not direct, but by a complex process mediated by the release of calcium in the ORS. The researchers discovered that cannabidiol activates the “catagen phase”, halting hair growth. Following further research, this finding may lead to the use of CBD to control unwanted hair growth.
Interestingly, however, at low concentrations, CBD has little effect on the hair cycle or ORS cells but still has an anti-inflammatory effect, by reducing the release of pro-inflammatory cytokines. This may mean that in future, low dosages of CBD could form part of therapies for inflammatory hair loss disorders also (usually caused by high levels of cytokines).
It is important to emphasize that laboratory findings do not necessarily translate into “real world evidence“, and the biological effects of applying cannabidiol as oil or cream, for example, has not been carried out and its effects measured – despite the claims of some CBD product manufacturers.
Szabó IL, Lisztes E, Béke G, Tóth KF, Paus R, Oláh A, Bíró T. The Phytocannabinoid (-)-Cannabidiol Operates as a Complex, Differential Modulator of Human Hair Growth: Anti-Inflammatory Submicromolar versus Hair Growth Inhibitory Micromolar Effects. J Invest Dermatol. 2020 Feb;140(2):484-488.e5. doi: 10.1016/j.jid.2019.07.690. Epub 2019 Jul 29. PMID: 31369737.