Category Archives: Anti-Androgen

Fluridil and Flutamide

To date, I have covered two anti-androgens in detail on this blog: Spironolactone and RU58841. Two other anti-androgens, fluridil and flutamide, are also fairly popular in the hair loss world. Due to their similar names, many people confuse the two, so I am writing one post to cover both products. I also do not want to write too many separate posts on anti-androgens.


Flutamide (brand name Eulexin) is a synthetic anti-androgen that was first approved by the US FDA in 1989 to treat prostate cancer in men. The drug is sold under numerous brand names. According to the wikipedia entry on Flutamide, the drug has now largely been replaced with newer anti-androgens with fewer side effects.

I am not so sure if this is true when it comes to scalp hair regrowth applications since numerous hair loss forum members continue to use flutamide. Moreover, topical application of flutamide via nanoparticles could results in fewer or no side effects.

An interesting study from 2011 where a women with hair loss saw no results when on Spironolactone plus topical Minoxidil, but did see hair regrowth when on Flutamide.

An interesting study comparing Finasteride, Flutamide and Spironolactone for treating hirsutism (all three almost equally effective in reducing body hair modestly).


The chemical name for Fluridil is Topilutamide. Fluridil is currently sold via the brand name Eucapil, a topical product that is manufactured by Czech Republic based company Interpharma that holds patent rights to Fluridil.

Sometimes you can find it for sale on Amazon.

The company claims that Eucapil is not absorbed systematically and it has thus far not resulted in any side effects. Interpharma was founded in 1932, and became a subsidiary of Japan’s Otsuka Pharmaceutical in 2008. Eucapil is only approved for sale in several European countries, but many people around the world seem to be getting their hands on the product easily.

The one and only study on Pubmed regarding Fluridil is from 2002, and suggests a modest benefit (anagen hair quantity increased from 76 percent to 87 percent) for hair loss sufferers with no major side effects. Also see this one other important paper on Fluridil.  Eucapil’s before and after photos of scalp hair when using Fluridil seem decent, but perhaps they are exhibiting a best case scenario.

Fluridil versus Flutamide

Over the years, on all major hair loss forums people have created a number of threads asking whether fluridil or flutamide is better for treating hair loss.

If you do a google search for each product, flutamide has 423,000 results and fluridil has only 15,900 results. Clearly, this is a no contest when it comes to importance (by comparison, Spironolactone has 728,000 results and RU58841 has 78,600 results).

Moreover, if you do a search on Pubmed, flutamide has 3,238 results (although the majority are not related to scalp hair loss issues). Meanwhile, fluridil has only two results (!), with only one of those two being of significance. So based on popularity, it seems like flutamide is the way to go.

It is also likely that because flutamide is so heavily studied, its side effects are unlikely to result in any major surprises. However, based on effectiveness, the superiority of flutamide over fluridil is is not clear when reading hair loss forum testimonials.


There are numerous anti-androgens available in the market today. If I were to take one just for scalp hair loss, I would only use a topical one in order to limit side effects. When it comes to effectiveness on scalp hair, do not expect miracles. While all anti-androgens seem to result in at least modest benefits for scalp hair, regrowing hair on totally bald scalps is not likely.

As far as flutamide versus fluridil, I am not sure which one is more effective, but fluridil seems to be somewhat safer. However, flutamide is by no means dangerous from what I have read on the various hair loss forums and studies.

It is imperative to consult a doctor prior to trying such drugs, as my opinions and conclusions are just based on internet research. I am neither a doctor, nor educated or experienced in any kind of medical field.

Spironolactone for Hair Loss

Spironolactone and Hair Loss
Spironolactone for hair loss.

On this blog, I have often discussed the only two (Finasteride and Minoxidil) FDA approved drugs to treat hair loss. Finasteride is an oral drug that inhibits the enzyme 5α-reductase, which in effect then reduces the harmful-to-hair dihydrotestosterone (DHT). Minoxidil is an antihypertensive medication that also happens to benefit scalp hair when used topically. This post covers a hair growth medication called Spironolactone (brand names Aldactone or Carospir).


When it comes to hair loss medications, one area that I have neglected is anti-androgens such as Spironolactone, which have many favorable reviews. I did discuss RU-58841 in one post at the start of this year, but there are numerous other anti-androgens out there. In general, the potential side effects from anti-androgens are more severe than from Finasteride and Minoxidil. Moreover, scalp hair regrowth is typically more significant with Finasteride and Dutasteride.

Note that while some strict definitions consider Finasteride to also be an anti-androgen due to its inhibition of DHT, I only consider drugs that inhibit the binding of testosterone to androgen receptors as being anti-androgens. Finasteride, while reducing DHT, actually raises testosterone levels by around 10 percent. Also worth noting is that the popular Nizoral shampoo might have some anti-androgenic properties per several recent studies.

In this post I will discuss the most popular “true” anti-androgen in the world: Spironolactone.

Spironolactone for Hair Loss

Spironolactone (generally sold under the brand name Aldactone) is also referred to as “Spiro” and is a synthetic drug available via prescription. It belongs to a class of drugs known as potassium-sparing diuretics, and is used primarily as a diuretic and antihypertensive in the treatment of heart failure and hypertension.

However, secondary anti-androgenic applications have become more prevalent in recent decades. Spironolactone can stop hair loss, reduce body hair (hirsutism), reduce acne, help women with polycystic ovary syndrome (PCOS) and improve seborrheic dermatitis.

In 2020, a study found topical Spironolactone 1% gel and Minoxidil 5% gel to be an effective combination treatment for hair loss. An older study from 1998 concluded that topical Spironolactone inhibits dihydrotestosterone receptors in human sebaceous glands

Spironolactone Side Effects

While this drug may seem like a miracle product that can kill many birds with one stone, potential side effects are significant and plentiful. For men, feminization is a real danger when taking Spironolatone, meaning that you can developed gynecomastia (larger breasts) and see your testicles shrink. Men can also develop premature ejaculation and become infertile (although in most cases it seems like this side effect is not permanent) when taking this drug.

Less traumatic side effects include drowsiness, dry skin, excess urination, headache, nausea and vomiting. Spiro can potentially even lead to death from severe allergic reactions, hyperkalemia, kidney failure and more, although I have not read about this happening to any hair loss forum members. In general, the doses that hair loss patients take tend to be on the lower side.

You can learn a lot more about Spiro and its use to treat hair loss by tracking patients that take this product and post about it in the various online hair loss forums. I have never tried to take Spironolactone since I am very cautious when it comes to taking any kind of drug.

Mechanism of Action

Aldactone (Spironolactone) is a specific pharmacologic antagonist of aldosterone. It primarily acts through competitive binding of receptors at the aldosterone dependent sodium-potassium exchange site. Aldactone causes an increase in sodium and water excretion rates, while potassium is retained. The drug therefore acts as both a diuretic as well as an antihypertensive via this dual mechanism.

Spironolatone for Male-To-Female Transsexuals

I first learnt about Spironolactone when I read testimonials and forum posts from numerous male-to-female (MTF) transsexuals out of my own curiosity many year ago. It seems like estrogen and Spiro are the two main drugs that MTF transsexuals are almost always given.

Moreover, transsexuals often have to take a much higher dosage (100-200 mg per day to start, and considerably higher doses if ineffective) of Spiro compared to men or women who are only tackling balding. It is therefore important for you to visit transsexual/transgender forums on the internet and ask questions if you ever intend to take Spiro.