Male Pattern Baldness or androgenetic alopecia is the most common cause of hair loss in men. It affects roughly 80% of Caucasian males. Male pattern baldness is characterized by hair follicles that gradually shrink in size, which causes baldness over time. Androgenetic alopecia is often a result of genetic predisposition; however, further studies also show that it may be partly due to androgen. Dihydrotestosterone (DHT), the primary androgen causing androgenetic alopecia in men affected by this type of hair loss have increased serum concentrations of DHT.
Pharmacologic therapy aims to stimulate hair follicles and decrease DHT levels through topical minoxidil or 5AR inhibitors. These 5AR inhibitors commonly known as Finasteride (Propecia®, Proscar®) and Dutasteride (Avodart®) are traditionally known treatments for benign prostatic hyperplasia (BPH). Both of these require medical prescription. However, only finasteride gained FDA approval to treat hair loss, while dutasteride does not. Minoxidil can stimulate hair growth effectively as well. Topical minoxidil (Rogaine®) like Finasteride is FDA-approved for hair loss treatment and is available for over-the-counter purchase.
Although dutasteride has a similar mechanism of action to finasteride, it may cause confusion as to why dutasteride is still not FDA-approved for treatment of hair loss in the USA. Interestingly, dutasteride is approved for hair loss treatment in South Korea and Japan, but not yet in the United States and Europe. Nonetheless, it is still widely used and often prescribed off-label by physicians if deemed appropriate for their patients.
In a 2014 study conducted over 29 weeks among 917 men with male pattern baldness, oral dutasteride appeared to be more effective than finasteride in treating hair loss. The men were randomized to receive dutasteride 0.02, 0.1, or 0.5 mg/day, finasteride 1 mg/day, or placebo. The results showed that Dutasteride 0.5 mg was superior to Finasteride 1 mg at weeks 12 and 24 in terms of increasing hair count. Dutasteride had appeared to offer improved results compared with finasteride in the short-term. However, long-term data is still needed to validate and support these results.
Dutasteride have very common side effects, these include:
The inability to achieve or keep an erection (erectile dysfunction or impotence in men)
Decreased sex drive / low libido
Even though sex-related side effects to the medication as mentioned may sound serious and alarming, but they remain to be rare and affect only a small percentage of men using finasteride and dutasteride. A lot of these side effects also became less common during long-term treatment.
In rare cases, 5-alpha reductase inhibitors dutasteride and finasteride may also cause more serious side effects such as:
Appearance of lumps, painful sensations, and discomfort of the breasts
Swelling of the breasts and nipples or increased breast size in men
Rash, hives, itching and swelling of the lips and the face
Some discharge coming from the nipples
Difficulty swallowing and/or breathing
The above reactions / side effects are quite rare, but could be serious when they manifest. Make sure to inform your healthcare provider immediately in case you experience any of these side effects right after taking either dutasteride or finasteride
While finasteride can help reduce overall prostate cancer risk for men, some studies show that it could be associated with an increased risk of high-grade prostate cancer in older men.
But analysis further points out that this could be linked to some detection bias and confounding factors and not simply on finasteride itself. Either way, this research is based solely on the effects of finasteride at a much higher dosage (5mg) than the regular dosage given for treating men’s hair loss.
Overall, studies demonstrated that for the majority of men in general, finasteride is a safe and effective hair loss medication. Side effects tend to be rare, and if they appear are often reversible and not permanent.
Likewise, data from other studies also show that dutasteride is well tolerated and generally safe, even at higher dosage when used for treating BPH. Side effects also tend to be rare, and if they appear are still reversible and generally not permanent.