On The Shelf
Mickie Cathers
Hair loss (androgenetic alopecia) is a common condition, impacting self-esteem and mental health, and despite ongoing research to find effective treatments, there are only two FDA-approved medications available. Patients affected by hair loss seeking a natural alternative remedy often look to rosemary oil as a promising complementary option.
Background
Androgenetic alopecia is a progressive condition of hair thinning and loss due to circulating androgens, affecting both men and women differently. Men often experience a receding hairline and thinning on the crown, while women typically retain their frontal hairline but see thinning on the crown. Dihydrotestosterone plays a key role in this type of hair loss by binding to androgenic receptors in the scalp, leading to hair follicle miniaturization.
Two FDA-approved treatments for androgenetic alopecia are finasteride and minoxidil. Finasteride is a type II 5-a reductase inhibitor which is effective in managing androgenetic alopecia by inhibiting dihydrotestosterone. While finasteride offers a solution for male-pattern hair loss and select cases of female-pattern hair loss, there are potential adverse effects such as decreased libido and, in rare cases, depression and suicidal ideation.
Minoxidil is a topical medication that promotes hair growth by enhancing blood flow around hair follicles. Despite its efficacy, it does not directly reduce dihydrotestosterone, the main culprit of hair follicle miniaturization. Adverse effects may include scalp irritation and potential lightheadedness due to its vasodilatory effects.
While FDA-approved drugs remain the standard, rosemary oil is a popular herbal supplement for treating androgenetic alopecia.
Is there a benefit?
Rosmarinus officinalis L., better known as rosemary, is an ancient plant belonging to the Lamiaceae family. Rosemary is an evergreen perennial shrub with a rich history across various civilizations. As far back as 3000 B.C., rosemary was used to perfume the deceased in Egypt in preparation for the afterlife and as a component in sun protection creams. Rosemary is recognized in the literature for not just UV protection, but also for its potent anti-inflammatory, antioxidant, antifungal, and anti-androgenic properties. Rosemary oil contains bioactive compounds such as carnosic, ursolic, oleanolic, and micromeric acids that help suppress inflammation. The carnosic acid prevalent in rosemary has been shown in studies to inhibit nitric oxide, a key proinflammatory agent.
Rosemary oil also inhibits nuclear factor kB, platelet aggregation, and free radical generation, highlighting its strong anti-inflammatory and antioxidant capabilities. Multiple studies have also revealed that rosemary oil demonstrates significant anti-androgenic properties.
Rosemary’s anti-inflammatory activity may be beneficial in treating androgenetic alopecia, where the accumulation of immune cells is often present. Research has shown that nearly 50% of biopsy samples from patients with alopecia have perifollicular inflammatory infiltrate, suggesting rosemary’s potential in alleviating symptoms.
A 2015 randomized, single-blind trial published in Skinmed provided evidence that rosemary oil’s efficacy in treating androgenetic alopecia is comparable to 2% minoxidil. In this trial, 100 male patients aged 18 to 49 years with androgenetic alopecia used rosemary oil or minoxidil. Both groups saw significant hair count increases after 6 months. Notably, rosemary oil caused less scalp itching compared with minoxidil. Panahi and colleagues identified 12-methoxycarnosic acid as the primary contributor.
Dosage and availability
Rosemary oil extract is sold in stores and online. The extract should always be mixed with another product such as a carrier oil (e.g., coconut or jojoba oil). For application, five drops of rosemary essential oil are mixed with a teaspoon of oil. Rosemary oil extract may also be added to shampoo, conditioner, hair masks, and styling products.
What to tell your patients
Advise patients to always dilute rosemary oil with a carrier oil or another product before application to avoid possible skin irritation. Caution patients to avoid getting essential oil in their eyes and to rinse their eyes immediately with cold water if contact occurs. The safety of rosemary essential oil during pregnancy or breastfeeding is not well known. ■