Why Hair Gets Thinner with Time
Hair often thins as we age. It can be emotionally distressing for many women and, unfortunately, society is less forgiving of a woman with thinning hair than of her male counterparts. (Case in point: my brother’s hairline started receding during his twenties, and he maintains a crew cut to draw attention away from any baldness.)
What is Androgenetic alopecia?
In most cases, female pattern hair loss is caused by androgenetic alopecia, (not to be conflated with the autoimmune condition known as alopecia areata). For women, the hairline doesn’t typically recede; rather, “androgenetic alopecia begins with gradual thinning at the part line. Gradual thinning is followed by increasing diffuse hair loss radiating from the top of the head” (Harvard Health Publishing, 2020).
Androgenetic alopecia, or AGA, is often caused by a cocktail of genetics, the scalp’s microbiome, and circulating androgens. If hair loss is sudden rather than gradual, try a hormonal evaluation to test for excess androgens or thyroid deficiency. Age-related hair loss is not only a matter of literal loss; even the hair shaft’s diameter can decrease. Furthermore, as we age, the amount of time between hair shedding and regrowth can increase.
The Loss of Hair Density
Loss of hair density can be managed, but be wary of products that claim to thicken hair. Currently, minoxidil is the only FDA-approved topical solution for slowing down female AGA. However, its mechanism of action is unclear (Tamashunas and Bergfeld, 2021).
Is Rosemary Oil the Solution to Loss of Hair Density?
In the past, I have used over-the-counter minoxidil. I personally found that it made my scalp dry, irritated, and slightly smelly (these are known side effects). My hairdresser suggested I try rosemary oil on my color-treated hair.
A Google Scholar search revealed that topical rosemary oil may be as effective as minoxidil in treating AGA, but with less itchiness than the latter. Although more clinical trials are needed to confirm rosemary oil’s efficacy, the evidence looks promising. Rosemary oil has localized hyperemic effects (meaning it increases blood flow to the hair follicles) (Panahi et. al. 2015). Per Murata et. al., it may also prevent the binding of dihydrotestosterone, or DHT, to androgen receptors (even though DHT is a derivative of testosterone, it’s produced in both testes and ovaries).
Rosmarinic acid – a phytochemical with anti-oxidative properties has been found to inhibit enzyme called Caspase-1, more abundant in scalps with AGA (Jeong et. al. 2011). And that delicious woody scent that characterizes rosemary? That’s due to pinene, a type of molecular compound known as a terpene; terpenes may have other health benefits, including antiviral potential (Cox-Georgian et. al, 2019).
Again, more research is needed to determine rosemary oil’s efficacy. Three weeks ago, I started applying rosemary oil before washing my hair (which is every other day). It’s too soon to tell, but already I feel my ponytail slightly plumping up, minus the dry, funky-smelling scalp. So if you, like me, are experiencing thinning hair, give rosemary oil a go!
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-Written by Laura Miller