This article will describe these differences and explain the reasons behind them.
You will also learn about spironolactone’s mechanism of action and side effects. Finally, we will cover how long the results take and what is the best way to use this treatment today.
What is Spironolactone?
Spironolactone is a medication that has been used for almost 60 years (1), It is available in countless brands, but the most widely known commercial name is Aldactone. It is sold in almost all countries around the world.
It is classed as an aldosterone antagonist (2). Aldosterone is a steroid hormone secreted by the adrenal glands.
Over time, doctors have come to prescribe spironolactone for various conditions. You can find it in tablets of various strengths from 25 to 100mg,
How Does It Work?
Spironolactone has various effects on the human body. Its two main effects are antihypertensive and antiandrogen.
Some people secrete excessive amounts of aldosterone. One common side effect of this is increased blood pressure.
By blocking aldosterone, spironolactone can lower blood pressure. It can also work for hypertensive patients with normal levels of aldosterone. Spironolactone also has diuretic effects, increasing the expulsion of fluids from the body.
The drug also has antiandrogenic properties. In other words, it inhibits the activity of the male hormones (androgens). It does this by blocking the Androgen Receptors (AR).
This is the receptor on the cells where the male hormones like testosterone and dihydrotestosterone (DHT) bind (3). By blocking this receptor, spironolactone prevents these hormones from exerting their normal function.
For this reason, spironolactone can be an effective treatment for women with problems arising from excessive androgen activity.
What Conditions Can It Treat?
Officially, the drug is sold as an aldosterone antagonist. Here are its FDA-approved indications:
- edema (fluid buildup)
- heart failure
Due to its anti-androgenic properties, doctors prescribe spironolactone to women off-label for various conditions:
- Excessive hair growth (hirsutism). It is a common symptom in women who suffer from Polycystic Ovarian Syndrome (PCOS). This condition is caused by an excess amount of androgens in the body (4)
- Acne. Another condition related to excessive androgen activity. Long and short-term use of spironolactone is possible (5).
- Female pattern hair loss (FPHL), which we will now discuss.
Spironolactone & Female Pattern Hair Loss
Understanding Female Pattern Hair Loss
Pattern hair loss affects well over half of women at some point in their life. Unlike men, women never go completely bald (6). The psychological effects, however, can be equally devastating.
In women with FPHL, the hair thins uniformly. The first sign of this is a wider part. This becomes more apparent with time, eventually forming the so-called “Christmas tree” pattern. You can see this in the illustration below.
Unlike male baldness which has the same cause for all men, FPHL seems to be made up of various groups. In other words, though we group all women with pattern hair loss under FPHL, the underlying causes will often be different.
Some cases of FPHL are linked to excess androgens, others to hypothyroidism and the rest to various (unknown) causes.
When Will Spironolactone Work?
Since spironolactone is an antiandrogen, it will only be effective for women whose hair loss is due to androgen excess.
For example, a 2015 study looked at women with FPHL treated with oral spironolactone at a clinic setting (7). Some of the women provided their own assessment of the drug’s efficacy. For others, the researchers assessed the results through patient records. Here were the combined results:
- 8%: worse thinning
- 38%: no change
- 32%: mild improvement
- 22%: increased thickness
In other words, 54% of women showed some improvement. The rest saw no change or worsened.
In Combination With Minoxidil
Combining spironolactone with other treatments can increase its effectiveness.
A very interesting study was performed on a 53-year-old woman with female-pattern baldness (8).
The woman initially received a 200 mg oral dose of spironolactone daily. She had visible hair regrowth at the 12-month mark. This eventually plateaued by the 24-month mark.
At this point in the study, the treating doctor prescribed a twice-daily dose of minoxidil 5% solution. The woman’s hair growth then resumed.
(See how 5% performed against 10% minoxidil here.)
Case studies like this suggest that combination treatment with minoxidil can give superior regrowth (we will discuss this more below). In the words of the study’s authors:
…supplementation with spironolactone is effective in preventing further hair loss and promoting hair growth. And, while the results plateaued after two years of use, the combination of spironolactone and minoxidil had further positive results.
Spironolactone For Male Baldness?
Men lose their hair very differently from women. Unlike women, they never go completely bald. Their baldness also progresses along with a distinctive pattern.
The first signs of hair loss are at the temples. This is followed by the mid-frontal hairline and then the crown of the head. Eventually, the baldness in the frontal area and crown fuse, making the entire top of the head bald.
You can see this natural progression of male pattern baldness in the figure below.
Male Baldness & DHT
Unlike women, all cases of male pattern baldness share the same underlying cause and mechanism of action.
The culprit is the male hormone DHT. DHT binds to the ARs on the hair follicles, initiating a process called miniaturization.
With every new hair cycle, the hair follicles literally shrink in size. The cycle itself is also altered: normally, each follicle grows a hair for 2-5 years before entering a rest phase that lasts around 3 months.
In miniaturized follicles, these times are reversed. The follicles most of their time in the resting phase, and hardly any in the active growth phase.
The hair shaft does not even get a chance to protrude past the scalp before the follicle re-enters the resting phase.
Scientists don’t understand the exact mechanism through which DHT leads to hair loss. What is certain is that inhibiting this hormone’s actions with medication is an effective treatment for baldness (9).
Over 80% of men who use DHT-blockers like finasteride or dutasteride will stop losing further hair. Around two-thirds will also see some regrowth, though this is typically mild.
Topical Spironolactone for AGA
We saw that DHT links to the ARs on the hair follicles, initiating the miniaturization process. A good question is since spironolactone blocks the AR receptor, why don’t doctors prescribe it for male hair loss?
Why Can’t Men Take Oral Spironolactone?
The answer is that the AR is also where the other androgens – including testosterone – exert their action. Blocking the AR in otherwise healthy men can have very unpleasant effects.
Around 10% of men who take low-dose spironolactone (25mg daily) for treating their heart failure develop gynecomastia or breast tenderness (10,11). Other side effects include impotence and reduced libido.
At higher doses, spironolactone is prescribed to biological men who want to transition into transgender women (12).
Clearly, prescribing such medication to otherwise healthy men with hair loss is out of the question.
An alternative for men with hair loss is topical spironolactone. Topical application means that the drug will block the AR only in the scalp and hair follicles.
Since the ARs in the rest of the body remain unaffected, there is no risk of gynecomastia, feminization, or any other unpleasant systemic side effects.
A recent study looked at the effect of adding spironolactone to minoxidil treatment for men with AGA (13). It also looked at how well spironolactone works on its own, compared to minoxidil.
The researchers split participants with male and female pattern baldness into three groups:
- topical minoxidil gel 5% only
- topical spironolactone gel 1% only
- combination treatment, minoxidil + spironolactone gel
There were 39 men and 21 women in the study. In all groups, the patients applied the gel twice daily.
After 12 months, here were the results:
- minoxidil only: 90% of patients in group 1 had some improvement
- spironolactone only: 80% of patients improved
- combination treatment: 100% of patients improved
Subjects with at least some regrowth were classed as improved. To further assess the improvement, the researchers broke down these improved patients into groups of poor, fair, good, excellent, and complete improvement.
Subjects in the combination treatment group were more likely to have excellent results (40%) compared to either of the other two groups (20-25%).
Across all groups, patients with moderate alopecia tended to respond better. A major limitation of this study is that it did not report the results separately for men and women.
None of the male patients reported gynecomastia, loss of libido, incompetence, or any other systemic side effects. The side effects of topical spironolactone were localized at the scalp. We will discuss these now.
Side Effects of Spironolactone
Because the routes of spironolactone administration are very different for men and women, so are the side effects. Let’s look at these in turn.
Oral Spironolactone (Women)
Women who take spironolactone for their hair loss should look out for the following side effects (14):
- facial hair
Women who respond to therapy can also expect to see a temporary phase of increased hair shedding 3-6 weeks after the start of treatment. This is very similar to minoxidil shedding and is temporary in nature. After a few weeks, the shedding will go away on its own.
Topical Spironolactone (Men)
The topical version of spironolactone produces completely different side effects than the oral one. The most common are (15):
- contact dermatitis
We saw that men who take topical spironolactone do not develop the systemic side effects of the oral version. They can, however, expect the temporary hair shedding a few weeks into treatment, just like women.
How to Obtain Topical Spironolactone
Topical spironolactone is not widely available in the United States or most countries around the world.
You will require a doctor’s prescription to start treatment. A compounding pharmacy will then be able to prepare the topical for you.
Applying Spironolactone to the Scalp
If you are applying topical spironolactone to your scalp you will be doing so under a doctor’s supervision. The doctor will advise you how often to apply it and how much to use.
Most likely, the application will be done twice daily. If you combine it with minoxidil through a compounding pharmacy, you will be applying both medications from the same bottle.
Limit application to the problem areas – there is no need to apply it to the non-balding scalp.
Application is simple: begin with a pea-sized amount of spironolactone on your fingertips. Rub your fingertips together, and then massage the cream into your scalp in a gentle, circular motion. Rub it in until the gel or cream is fully absorbed.
How Much Does it Cost?
Having been on the market for several decades, spironolactone is now a very affordable medication.
If you are a woman, you can expect to pay under $20 a month for your pills. Your insurance will usually cover spironolactone.
The cost for the topical will be slightly higher. Prices will vary depending on the location and the rates of the compounding pharmacy.
How Long Until I See Results?
Regardless if you take the oral or topical form, you will need at least 3 months to see the first results.
After 6 months, you will have a good idea of how well you are responding to treatment. Together with your doctor, you can then decide if spironolactone is an appropriate long-term treatment for your hair loss.
Though the FDA has not approved spironolactone against female pattern hair loss, this has not stopped doctors from prescribing it off-label to millions of women worldwide.
For many women, it will be a relatively safe, effective, and affordable solution. Women can also combine it with topical minoxidil (which the FDA has approved) to get even better results.
The hormonal effects of spironolactone prohibit its systemic use for men with hair loss. Instead, men can apply it topically. While limited, the available research suggests that spironolactone is a useful treatment for male hair loss, especially as part of a combined treatment regiment (hair loss stack).
Adding spironolactone to a minoxidil preparation will be an appealing option for many men with hair loss who want to: a) max out their topical’s strength while b) avoiding systemic treatments.
The topical version is also relatively safe with only mild topical side effects.
Regardless if you use spironolactone topically or systemically, always bear in mind that it is a very powerful medication. Make no changes to your treatment unless you discuss them with your doctors first.