There are two drugs on the market approved by the Federal Drug Administration (FDA) for the treatment of hair loss: minoxidil (Rogaine) and finasteride (Propecia).
But that doesn’t mean they are the only drugs prescribed by doctors for patients who suffer from pattern balding. In fact, there are many drugs that are used for off-label purposes, including dutasteride.
In this post, I’ll introduce the drug dutasteride and its most common uses. This will include a brief rundown of how the drug works.
Then, I’ll highlight the research that shows its possible efficacy (and tolerability) in the treatment of hair loss.
And at the end, I’ll offer some advice on how to decide if dutasteride is the right option for you.
Let’s get started!
What Is Dutasteride?
Dutasteride, also known by its brand name of Adovart, is a synthetic 4-azasteroid compound that’s most commonly used to treat enlarged prostates.
An enlarged prostate, also known as Benign Prostastic Hyperplasia (BPH), is a medical condition caused by a buildup of Dihydrotestosterone (DHT) levels (1).
But what is DHT, and where does it come from?
DHT is an androgen hormone that occurs from the interaction between testosterone (the male sexual hormone) and 5-alpha-reductase (5AR) (an enzyme) (2).
This androgen hormone plays a critical role in male sexual development and function.
It makes sense, then, that blocking DHT directly would cause serious issues within the body.
And that’s why some drugs – including dutasteride – inhibit 5AR instead.
There are two isoforms of 5-alpha-reductase – Type I and Type II – and the drug dutasteride is believed to inhibit both. In this way, dutasteride works by reducing DHT levels within the prostate so as to reduce prostate volume and size (3).
How Does It Work to Combat Hair Loss?
To understand how dutasteride works, you first need to understand why hair loss occurs.
There are many types of hair loss, but the most common is Androgenetic Alopecia (AGA) (4). This is a genetic condition in which the individual experiences progressive thinning and pattern balding.
The exact cause of AGA is unknown, but there are a few theories. The most common is that those with AGA have sensitivity to the androgen hormone DHT.
As mentioned above, an increased level of DHT or a sensitivity to this hormone can trigger BPH. But researchers also believe it plays a role in AGA.
For those with AGA, it’s believed that the presence of DHT triggers miniaturization of the hair follicle. If left untreated, this will lead to thinning and eventual baldness.
So, where does dutasteride fit in?
It would make sense that reducing DHT levels at the scalp would stop miniaturization and, therefore, prevent hair loss. One way to do this is by inhibiting the activity of 5-alpha-reductase.
Just like it does at the prostate, dutasteride inhibits the activity of 5-alpha-reductase at the scalp (5).
And with less DHT, there’s less risk of miniaturization and hair fall.
One question still lingers, though, and that’s whether DHT is the only cause of hair loss.
The answer? Well, according to recent research, no.
There’s no doubt that DHT plays a role in the development – and progression – of this hair loss condition. But it’s far from the only contributing factor.
Other factors believed to contribute to AGA include mechanical tension (which triggers androgen receptor sensitivity) and lifestyle choices (6).
Dutasteride: The Scientific Proof
This drug is not currently approved by the FDA for the treatment of hair loss. That doesn’t mean that it’s not prescribed for this purpose, though.
So, is there proof of dutasteride’s positive effects?
Study: Dutasteride improves male pattern hair loss in a randomized study in identical twins (2007)
A twin study, published in 2007, followed seventeen pairs of teens with diagnosed androgenetic alopecia over a one-year period (7).
In this randomized, double-blind, placebo-controlled study, one of the twins from each set was given 0.5mg of Adovart each day for one year. The other twin was given a placebo pill.
Various means were used to track results. These include hair counts, before and after photographs, and patient surveys.
At the end of the one-year study, the results were clear.
Based on analysis of the investigator assessment, the twins who took Adovart saw less hair loss (and even some growth) when compared to their placebo-taking counterpart.
And of the sixteen sets of twins that finished the study, fifteen of them were able to reliably determine which twin was given Adovart and which was given the placebo.
But even more important than efficacy is safety.
How can researchers and doctors be sure that dutasteride is safe to prescribe to patients with hair loss? A 2010 study looked to determine just that (8).
Study: Efficacy, safety, and tolerability of dutasteride 0.5 mg once daily in male patients with male pattern hair loss (2010)
153 men between the ages of 18 and 49 and diagnosed with AGA were recruited for this study. The men were split into two groups: one which took 0.5mg of Adovart daily, and the other which took a placebo.
Throughout the six-month study, researchers utilized changes in hair counts, subject assessment, and before and after images to determine efficacy and tolerability.
As the conclusion of the study succinctly states, “This study clearly showed that 0.5 mg of dutasteride improved hair growth and was relatively well tolerated for the treatment of male pattern hair loss.”
Dutasteride Versus Finasteride
Finasteride is one of two drugs currently approved by the FDA for treatment of AGA. It’s quite similar to dutasteride in its mechanism, though there are some significant differences.
The main similarity between dutasteride and finasteride are that they are 5-alpha-reductase inhibitors.
These drugs work to inhibit the activity of the enzyme, 5-alpha-reductase, so as to lower the DHT levels within the blood serum and at the hair follicles.
Dutasteride and finasteride have a significant difference though, and that’s what types of 5-alpha-reductase they inhibit.
Finasteride works by inhibiting just one type (Type II), while dutasteride works by inhibiting both types (Type I and Type II) (9).
It seems obvious that dutasteride would be more effective at combating hair loss. And while this may be true on the surface, there are some things to keep in mind.
Namely, the risk of side effects.
So, how can you know which of the two drugs is right for you?
Study: Superiority of dutasteride over finasteride in hair regrowth and reversal of miniaturization in men with androgenetic alopecia (2017)
A recent study performed by Indian researchers hoped to answer the question, “is dutasteride more effective than finasteride (11)?”
To answer this question, they recruited ninety men between the ages of 18 and 40 with diagnosed androgenetic alopecia.
The men were then randomly split into groups: the first would take 0.5mg of dutasteride daily, while the second would take 1mg of finasteride daily. This would continue for 24 weeks.
The efficacy variables used by researchers were hair counts in the target area from modified phototrichograms and global photography evaluation by blinded and non-blinded investigators.
The participants were also evaluated on a monthly basis for any sign of side effects.
As one might expect, “dutasteride was shown to be more efficacious than finasteride… .”
But what about an increased risk of side effects?
One might expect that a drug which blocks both types of 5AR as opposed to just one would have greater risks.
According to the aforementioned study, though, “the side-effect profiles were comparable.”
There are some limitations to this study that you should keep in mind, however.
The first major limitation is in its length.
This study which compared the efficacy and tolerability of finasteride versus dutasteride was carried out for a total of 24 weeks. That’s certainly not enough time to see significant results.
Even more, 24 weeks – or about six months – is not enough time to determine long-term side effects of a drug.
The second limitation is in the study’s size.
With just ninety men (and no women), the results cannot be extrapolated to the hair loss community at large.
As such, there is a need for further research on the topic before solid conclusions can be drawn.
Off-Label Drug Use
You may be wondering just how common it is for doctors to prescribe a medication for off-label use.
The process for a drug to become approved by the FDA is long and expensive. This is true even for drugs – like dutasteride – which have been approved for other purposes.
And believe it or not, dutasteride isn’t even the first drug for hair loss that’s been used off-label.
In fact, both drugs currently approved for pattern balding – minoxidil and finasteride – have similarly been prescribed by doctors in the past.
Minoxidil, for example, was initially developed under the brand name Loniten for hypertension (12). An unexpected side effect was hair growth, though, and this resulted in off-label prescriptions of the drug to patients with AGA.
So, is off-label drug use unethical? Unsafe? Reckless?
No, not necessarily.
When speaking with your doctor about using a prescription medication for a condition other than what it was approved for, it’s important that you trust their judgement.
But it’s also important that you understand there are certain risks you’re taking by doing so.
The good news?
If a drug has been approved to treat one condition, then the side effects of this drug have already been cataloged and carefully considered.
As such, your doctor can help you to decide if the risks are worth the benefits.
Side Effects and Complications
The most common side effects associated with 5-alpha-reductase inhibitors, and dutasteride in particular, are sexual in nature (13).
The side effects most commonly experienced in males include loss of libido, erectile dysfunction, and decreased ejaculatory volume (14).
And while 5-alpha-reductase inhibitors are largely prescribed to men, they are becoming increasingly popular in female sufferers of pattern hair loss.
The risks for women, however, can be much more significant.
These risks include defects in male fetuses (if used when pregnant), gastrointestinal discomfort, and changes in menstruation.
This is why 5-alpha-reductase inhibitors are considered a last resort for female hair loss sufferers.
So, how likely are you to suffer from a side effect as a result of taking dutasteride? One study consisting of 712 subjects helps to shed light on the answer to this complicated question (15).
Study: Safety and tolerability of the dual 5-alpha reductase inhibitor dutasteride in the treatment of androgenetic alopecia (2016)
Of the 712 subjects to participate in the study, a total of 110 (15.4%) reported an adverse effect.
Four subjects (0.6%) reported Severe Adverse Events (SAEs), including right radius fracture, follicular tonsillitis, and acute appendicitis.
Sixty-six (9.3%) subjects reported Adverse Drug Reactions (ADRs). The most common included:
- Decreased libido (9 subjects, 1.3%)
- Dyspepsia (8 subjects, 1.1%)
- Impotence (7 subjects, 1.0%)
- Fatigue (5 subjects, 0.7%)
But other ADRs were also reported, and these included sexual function abnormality (4 subjects, 0.6%), gynecomastia (2 subjects, 0.3%), and ejaculation disorder (1 subject, 0.1%).
As you can see, complications are possible. But the risks may be worth it to you, so speak with your doctor before making a final decision.
Is Dutasteride Right for You?
So, who should consider dutasteride as a treatment for AGA?
You may consider dutasteride if other drug options, such as minoxidil and finasteride, proved ineffective.
This drug may also be a good option if your hair loss is aggressive, and you want to take an equally aggressive approach to regrowth.
You should not use dutasteride if you are:
- Pregnant, or planning to become pregnant
- Fertile and not using birth control to prevent pregnancy
- Unable to tolerate other 5-alpha-reductase inhibitors, such as finasteride
- At an increased risk of developing prostate cancer
Also keep in mind that while taking dutasteride and for six months afterwards, you cannot donate blood. This is because the drug may be passed to pregnant women or children via blood transfusion.
While early research on the topic seems to suggest that dutasteride is a more effective hair growth drug than finasteride, there is still room for further research.
This includes a more in-depth look at the risk of side effects, as well as which populations would benefit most from its use.
And remember, there are other options on the market to consider, including minoxidil and finasteride. It’s sometimes best to start there and branch out to experimental treatments only once the conventional ones have been exhausted.
Do you have questions about dutasteride for hair growth and whether it’d be right for you? It’s a good idea to make an appointment with your doctor to talk about the risks and possible benefits.