Spironolactone for Hair Loss: All You Need to Know

Androgenetic alopecia or patterned alopecia is a widespread and frustrating form of hair loss that is usually multifactorial. Apart from genetic factors, hormones play a crucial role. Even though there are FDA-approved options for the treatment of hair loss, they have shown limited success in women. Various side effects further restrict their use.

That’s why off-label treatments like spironolactone have generated dermatologists’ interest as a solution to hair loss woes in women.

What is spironolactone, and how does it work

Spironolactone is an aldosterone receptor antagonist, traditionally used as a ‘diuretic’, which helps to reduce the excess water in the body. It is FDA-approved for the treatment of fluid retention and is also used to treat patients with heart failure and high blood pressure. Apart from this, spironolactone also possesses a significant anti-androgen effect, which is why it is effective in treating hormonal hair loss.

Androgens are the sex hormones that are primarily responsible for making the hair follicles smaller and eventually making them fall out. Spironolactone blocks androgen production, as well as the binding of dihydrotestosterone (DHT) to the androgen receptors in the target tissue (e.g.hair follicle).

This anti-androgen property of spironolactone has also been used in the treatment of hormonal acne and hirsutism.

Spironolactone formulations and effectiveness for hair loss treatment

Spironolactone is one of the most common systemic anti-androgen medications used to treat female pattern hair loss.

It is available in the following formulations:

Oral (tablets)

Spironolactone is not FDA-approved for any type of hair loss but has shown pretty impressive success in pilot studies. Approximately 90% of women using it for over a year reported an arrest in hair loss.

In a study, spironolactone given to 40 women for a duration of one year, showed hair growth in around 44% of the women. The result was comparable to another conventional anti-androgen medication called cyproterone acetate.

Interestingly, even though it is well established that androgens play an essential role in androgenetic hair loss, none of the women in the study showed raised levels of androgens in the blood. However, they still benefited from anti-androgen therapy. That indicates that the results of spironolactone are probably not dependent on any particular parameter in blood.

In another study, 100 women received a combination of minoxidil 0.25 mg and spironolactone 25 mg and were followed prospectively for 12 months. The hair shedding and visual loss of hair on the scalp decreased significantly in the women who continued the therapy for 12 months. Two women discontinued the treatment due to allergic reactions.

A retrospective analysis of 79 women consuming a mean daily dose of spironolactone 100 mg was done recently. It concluded that women with higher severity of androgenetic alopecia responded better, compared to women with milder androgenetic alopecia. The improvement in hair loss was better in those who took spironolactone for 6 months or longer. Treatment was discontinued by 3.8% of women due to adverse effects.

Spironolactone works well when combined with other therapies such as topical minoxidil. A randomized control trial was conducted recently, in which 40 women used a combination of topical minoxidil 5% once daily and 80-100 mg of oral spironolactone for a duration of 24 weeks. The hair density and hair shaft diameter improved significantly. 

It is to be noted that there were two other groups studied – the topical minoxidil monotherapy group, and the topical minoxidil plus scalp microneedling group. Side effects were most common in the group with spironolactone and topical minoxidil, the most common being scalp pruritus (due to topical minoxidil). The topical minoxidil plus scalp microneedling group also had hair follicle diameter improvement, suggesting that it was superior to the other two groups.

Spironolactone is especially suitable for females with two or more conditions due to increased sensitivity to androgens like acne, very oily skin, or increased facial hair. Studies on men using oral spironolactone are limited, due to the sexual side effects and feminization. Topical spironolactone is an emerging treatment option that aims to improve hair density minus the side effects.

Topical (gel and solution)

A study found that 5% spironolactone cream can inhibit the androgen receptors in sebaceous glands and hence can be theoretically used in the treatment of acne. But topical spironolactone was not investigated much in the treatment of androgenetic alopecia, until recently. 

A randomized control trial was done on 60 patients (39 males and 21 females). They were divided into 3 groups to apply a medicated gel on the scalp for 12 months. Group 1 used 1% spironolactone gel, Group 2 used 5% minoxidil gel, and Group 3 used a combination of both gels.

There was clinical improvement in all groups at the end of 12 months. Topical spironolactone and topical minoxidil had comparable results, but the combination group had the best results. Patients using only spironolactone gel had minimal side effects compared to the other two groups.

A study was done on 32 patients, half of them used topical spironolactone, and the other half used topical finasteride for six months. Topical spironolactone was found to be superior to topical finasteride in both male and female groups, increasing hair density.

Topical spironolactone seems to be a promising adjunct to topical minoxidil. It can also be considered alternative therapy for those who do not tolerate the side effects of topical minoxidil or finasteride.

Dosages and duration of therapy

The standard dose of oral spironolactone is 100-200 mg a day, but studies with low doses as little as 25 mg combined with other anti-androgens (like oral minoxidil) have shown positive results. The dose should be raised slowly to control and monitor the side effects. Topical 1% spironolactone has to be applied twice daily.

Initial improvement is seen in about 6-8 months. Most studies have found the best results after using spironolactone for 12 months. The treating physician decides the therapy endpoint, but as long as there are no contraindications like side effects or pregnancy, the therapy must be continued for at least two years.

Combination therapy with low-level laser light, topical minoxidil, and/or iron supplementation augments the results of low-dose spironolactone and reduces the risk of side effects.

Spironolactone vs. finasteride in the treatment of hair loss

There are unfortunately no notable head-to-head studies that compare oral spironolactone to oral finasteride that would let us come up with a reliable conclusion. Topical spironolactone was superior to topical finasteride in one study, but it was done on a limited number of patients.

The choice to start spironolactone or finasteride depends on factors like age, desire to get pregnant soon, and other co-existing health or skin-related concerns.

Spironolactone in male pattern hair loss

Although it is theoretically effective in males, oral spironolactone is seldom used in the treatment of male pattern hair loss. This is due to the chances of feminizing effects like breast enlargement. It can also cause loss of libido and sexual dysfunction in males, even causing a decrease in fertility and sperm count. There are other much more effective and FDA-approved options available like finasteride or dutasteride.

Topical spironolactone appears to be an interesting option as these side effects have not been documented so far. However, more studies on the safety and efficacy in males are required.

Side effects of spironolactone in women

The side effect profile of spironolactone is usually mild, and the drug is well tolerated in the doses usually prescribed for female pattern hair loss. The most common side effects include:

Because of the side effects mentioned above, spironolactone should not be started without consulting a physician. Regular monitoring of electrolytes and blood pressure is recommended, especially in the first few months of treatment.

Conclusion

Current therapy options for female pattern hair loss are limited. Oral finasteride is neither as safe nor as effective in females as in males.

This gap is very elegantly filled by spironolactone as it is an effective and well-tolerated option. It is one of the most prescribed off-label therapies for female pattern hair loss, as a monotherapy or in combination with other therapies.

The only caution that needs to be exercised is that it should be taken only under a physician’s direction and with regular monitoring.

Topical spironolactone can be considered a low-risk adjunctive therapy in both men and women. It can also be considered in those who do not respond well to topical minoxidil.