Spironolactone is an oral medication that is primarily used in medicine to treat heart failure and high blood pressure. While it has not been approved by the U.S. FDA (Food and Drug Administration) to treat acne, doctors sometimes prescribe it for that purpose as well. This is called off-label prescribing, and it is a common practice with many medications.1
The reason that doctors prescribe spironolactone to treat acne is that it is an anti-androgen.1High levels of androgens (male hormones that are present in both males and females) contribute to acne. As a 2014 article in Clinics in Dermatology states, “Androgens play an important role in [skin oil] production and excretion. This subsequently contributes to the formation of acne lesions.”2Because anti-androgens reduce the amount of androgens in the body, they can help clear up acne lesions.
Because spironolactone’s anti-androgen activity can cause undesirable side effects, such as breast enlargement in men, it usually is prescribed only to women when treating acne. The recommended dosage for acne treatment ranges from 25–200mg per day. Once acne is reduced, the recommended maintenance dosage ranges usually from 25–50mg per day. Researchers recommend starting with a low dose and increasing the dose only if necessary to control acne symptoms.3
Spironolactone usually is prescribed with a combined oral contraceptive (COC, more commonly known as the birth control pill), though it can be taken alone.
Doctors also sometimes combine spironolactone with oral antibiotics. This is controversial since antibiotics produce only moderate benefit and come with a plethora of side effects. However, according to a 2012 review in The Journal of Clinical and Aesthetic Dermatology:
“Spironolactone has been used safely and effectively in combination with oral antibiotics including tetracyclines, erythromycin, and amoxicillin.”3
Oral Spironolactone Is Moderately Effective in Treating Acne
Six small studies performed to date indicate that oral spironolactone is at least moderately effective in treating acne.
A 1984 study in the British Journal of Dermatology investigated the efficacy of spironolactone in both men and women with severe acne. Although the researchers examined men, doctors almost always prescribe spironolactone only to women. They randomly assigned 36 participants (17 men and 19 women) to receive one of five treatments.
- 50mg of spironolactone
- 100mg of spironolactone
- 150mg of spironolactone
- 200mg of spironolactone
- A placebo
This was a double-blind study, meaning that neither the participants nor the researchers knew which treatment each person received. Only 26 of the participants completed the three-month study, which found that improvement in acne was related to the dosage of spironolactone: 80% of those taking 150 or 200mg experienced improvement in their acne; 60% of those taking 50 or 100mg experienced improvement, and only 10% of those taking the placebo experienced improvement. More than half of the women (58%) had minor side effects, such as menstrual irregularities, but none of the women stopped the study because of this. None of the men experienced enlarged breasts. Overall, this study found that spironolactone significantly improved acne with only minor side effects.4
Researchers in a 1986 study in the same journal gave 21 women 200mg of spironolactone daily for three months. The researchers randomly assigned the women to a treatment group or to a placebo group. This study found that the group taking spironolactone experienced a 66% improvement in the number of acne lesions after three months. In contrast, the women in the placebo group did not experience improvement in their acne. Seventy-three percent of the women who did not take a COC also experienced menstrual side effects, but all of the women persisted. Two women dropped out of the study because of nausea.5
A 2000 study in the Journal of the American Academy of Dermatology assessed spironolactone’s effectiveness by looking at the medical records of 85 women with acne who had been treated for a maximum of 24 months with spironolactone in dosages ranging from 50–100mg per day, either alone or alongside other acne treatments. This study found that 33% of the women experienced significant improvement in their acne; 27.4% experienced partial improvement, and only 7% experienced no improvement.6
A 2005 study in the Journal of the European Academy of Dermatology and Venereology looked at the effectiveness and side effects of spironolactone in women with acne. Researchers treated 35 women with 100mg of spironolactone per day for 16 days each month, which is an unusual dosing pattern, for three months. This study found that 85.7% of the women experienced clinically significant improvement in their acne. When considering all of the women, the reduction in acne lesions was 79% after three months of treatment. The only side effects that this study mentioned were menstrual irregularities, which half of the women experienced but which resolved within three months.7
A 2006 study in Aesthetic Plastic Surgery investigated the effectiveness and safety of spironolactone in Asians. Researchers gave 139 acne patients (116 women and 23 men) 200mg of spironolactone per day for eight weeks and then reduced the dosage by 50mg for every four weeks. The study lasted for 20 weeks total. Three of the men developed enlarged breasts, so the researchers stopped the treatment in all men. Eighty percent of the women experienced menstrual irregularities, and some dropped out consequently. Only 64 of the women completed the study. Of these, 53% of the women rated their acne improvement as excellent, and 47% rated their improvement as good. Overall, the treatment was less effective in men than in women.8
A 2008 study in the Journal of the American Academy of Dermatology investigated the effectiveness and safety of a combination treatment consisting of spironolactone and a COC in 27 women with severe facial acne. Researchers treated the women with 100mg of spironolactone and the COC for six months. All women tolerated both treatments well, with minimal or no side effects. After six months, 11% of the women were free of acne; 74% experienced significant improvement, and 7.4% experienced some improvement.9
Topical Spironolactone Appears to Also Be Moderately Effective in Treating Acne
Spironolactone it is almost always prescribed for acne in its oral form, but is also available in topical form.
We only have two studies to look at that examine the effectiveness of topical spironolactone for treating acne, but it appears to also be effective.
A 1990 study in the Italian journal, La Clinica Terapeutica, evaluated the effectiveness of a 5% spironolactone preparation for one month in 20 patients (9 females and 11 males). This study found that acne cleared in 30% of the patients and improved in 65%. The participants did not report side effects.10
A 2012 study in the Journal of Dermatological Treatment compared the effectiveness of a 5% spironolactone gel with that of a placebo. The researchers randomly assigned 78 patients with mild to moderate acne to either a treatment group (30 females and 8 males) or a placebo group (34 females and 6 males). Participants applied the medication twice per day for six weeks, leaving the medication on the acne lesions for two to three hours each time before washing it off. After six weeks, the total number of acne lesions in the treatment group decreased by 71%, compared to only 36% in the placebo group.11
What Are the Side Effects of Oral Spironolactone?
As with all medications, spironolactone can cause side effects, particularly at higher doses. Most people tolerate low doses of spironolactone well, even for long periods of time. Side effects that can occur at dosages higher than 100mg per day include:
- Menstrual irregularities, such as increased or decreased menstrual bleeding or breakthrough bleeding, which is bleeding that occurs between periods. Adding a COC to the treatment reduces these side effects.
- Tenderness or enlargement of the breasts, in both males and females. Adding a COC to the treatment can reduce this side effect.
- Orthostatic hypotension, which is a sudden drop in blood pressure when standing up that can result in dizziness or fainting.
- Reduced libido (sex drive).
- Excessively high potassium level in the blood. This is a dangerous side effect that can cause life-threatening heart problems. However, it is not common in healthy young people. Because of this side effect, people with kidney problems should not use spironolactone. In addition, spironolactone cannot be used with certain medications, including diuretics (medications that increase urination and can result in too much potassium in the blood) and ACE inhibitors, which often are used for high blood pressure.3
Side effects that do not seem to be related to dose include:
Spironolactone can also come with these other side effects:
Males should not take spironolactone because it can cause side effects related to its anti-androgen effects. These include impotence, enlarged breasts, and loss of libido.
Women who are pregnant or may become pregnant should not take spironolactone because it can cause birth defects, especially feminization of a male fetus. This is one reason that spironolactone often is prescribed with a COC.3
While the American Academy of Pediatrics classifies spironolactone as “probably compatible” with breastfeeding, women who are breastfeeding should carefully approach the decision to take spironolactone, as studies in rats indicate that it can cause tumors in the fetus.3