Dutasteride vs Finasteride for Hair Loss
Hair loss is a common part of the aging process, especially for men, but it can begin in just about any decade of life. If you’re noticing thinning hair or bald spots, you’re not alone — and if you’re considering hair loss treatments, you may have come across the medications finasteride and dutasteride.
Is one better than the other? Or should you be using finasteride and dutasteride at the same time? While these hair loss medications work the same way to promote hair regrowth, there are some medical and legal differences.
Keep reading to learn the key differences of dutasteride vs finasteride for hair loss so you can figure out which makes the most sense for your needs.
Dutasteride vs Finasteride: How They Work
Before we get into the differences between finasteride and dutasteride, let’s cover some of the basics about these medications — namely, how they slow down male pattern baldness (male androgenetic alopecia).
Finasteride and dutasteride belong to a class of medications called 5-alpha reductase inhibitors, or 5-ARIs.
They prevent the conversion of testosterone into a different type of androgen hormone called dihydrotestosterone, or DHT — a process driven by an enzyme called 5-alpha reductase.
DHT is strongly linked to hair loss, with research showing that it’s the primary hormone responsible for androgenetic alopecia.
It can bind to androgen receptors in your scalp and gradually cause hair follicles to stop producing new hairs. Over time, this can result in a receding hairline, thinning of your hair around the crown (the area at the top of your head), and near-total hair loss.
So, by blocking the effects of the enzyme that converts testosterone into DHT and reducing DHT levels throughout your body, 5-alpha reductase inhibitors can slow down, stop, or even reverse the negative effects that DHT can have on your hair growth cycle.
Just remember that while these medications are effective treatments for hair loss, they’re usually not a cure for baldness.
Comparing Finasteride vs Dutasteride
Although finasteride and dutasteride work similarly, they differ in effectiveness, adverse effects, and legal availability.
We’ve detailed these below, along with more information on how each medication works and what you can expect from each hair loss treatment.
Finasteride Was Developed First
The Food and Drug Administration (FDA) initially approved finasteride to treat benign prostatic hyperplasia (BPH), an enlarged prostate gland. By lowering DHT levels, finasteride helps reduce prostate enlargement.
The oral tablet version of finasteride was developed in the 1970s, patented in the 1980s, and FDA-approved in 1992 for BPH under the brand name Proscar®. The drug was approved for male pattern hair loss under the brand name Propecia® in 1997.
When used for hair loss, finasteride is prescribed at a lower daily dosage (1mg per day) than the stronger 5mg version used to treat BPH.
“Oral finasteride is one of only two FDA-approved medications for hair loss — the other being topical minoxidil — and there is a lot of independent data showing its effectiveness,” says Dr. Knox Beasley, MD.
On the other hand, dutasteride, which comes in 0.5mg tablets, received its FDA approval as a treatment for BPH in 2001 under the brand name Avodart®.
Only Finasteride is FDA-Approved to Treat Hair Loss
Although research shows that dutasteride is effective at treating hair loss, the FDA has yet to approve it as a hair loss treatment.
Dutasteride is approved by the FDA, but only for the treatment of benign prostatic hyperplasia. This means that it’s gone through the FDA’s rigorous testing and research process but solely as a drug marketed for prostate volume reduction.
But if only finasteride is approved to treat hair loss, why are we even talking about dutasteride for hair loss?
Although the FDA may not have approved dutasteride for this use, it’s still effective at preventing male pattern baldness. Since the FDA has yet to approve it for this specific purpose, it can only be prescribed as an “off-label” treatment for hair loss in the United States.
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Finasteride and Dutasteride Are Both Proven to Treat Hair Loss
While the FDA has only approved finasteride as a treatment for hair loss, studies have largely shown that both finasteride and dutasteride are effective at cutting DHT production and treating male pattern hair loss.
One 2006 study compared the effects of finasteride and dutasteride on 416 men between 21 and 45 years old who received either dutasteride, finasteride, or a placebo treatment.
They noted that both finasteride and dutasteride successfully increased scalp hair growth over 24 weeks and that both groups had similar side effects.
It’s worth noting that although finasteride and dutasteride were both effective at treating hair loss and promoting hair growth, the researchers found that the men who took dutasteride had thicker hair — and a higher average hair count — after 24 weeks than the men who used finasteride.
It's also important to note that the finasteride dosage used in the study was five times the FDA-approved amount for hair loss.
A 2019 review, which featured data from three studies comparing dutasteride and finasteride as treatments for male pattern baldness, came to a similar conclusion.
The researchers found that although both medications are effective at treating hair loss in men, dutasteride “seems to provide a better efficacy compared with finasteride,” with a broadly similar rate of potential side effects.
In short, while both medications work to treat hair loss, some evidence suggests that the efficacy of dutasteride for hair loss may be higher than that of finasteride.
Of course, this doesn’t mean finasteride isn’t effective at stopping hair loss in men.
“While I counsel my patients that the main goal is to prevent further hair loss, I’ve had a number of patients see significant regrowth while taking oral finasteride,” notes Dr. Beasley.
This reflects the findings of several studies, which have all observed that finasteride reduces hair loss and, for many men, leads to real improvements in hair growth.
A 2003 review of studies on men with mild to moderate hair loss who used finasteride found that many saw hair regrowth and experienced no adverse effects from the medication.
Another study in Japan looked at the effects of finasteride over ten years and found that it was effective at treating male pattern baldness.
In this study, 99.1 percent of balding men who used finasteride over ten years reported that their hair loss stopped during treatment, while 91.5 percent experienced improved hair growth.
In general, most men with hair loss who use finasteride report that their hair loss either slows down, stops, or reverses with long-term treatment.
Dutasteride Blocks More DHT Than Finasteride
One reason that dutasteride may be a slightly more effective treatment than finasteride is that it appears to prevent more testosterone from being converted into DHT.
A 2004 review comparing dutasteride and finasteride found that while finasteride was more selective in the types of 5-alpha reductase enzymes it blocked, dutasteride reduced DHT significantly more.
Why does dutasteride seemingly have more of an effect on DHT than finasteride? One theory is that dutasteride has a longer half-life, meaning it stays in the body longer than finasteride after it’s taken.
Dutasteride’s half-life is approximately five weeks, so one dose can remain in the body for over a month.
Finasteride, on the other hand, has a half-life of approximately five to six hours. This means that each dose of finasteride lasts for a significantly shorter period of time in your body than a typical dose of dutasteride.
While data suggests that dutasteride may increase hair growth in men more than finasteride, this doesn’t mean that off-label dutasteride is necessarily a better hair loss treatment option. It depends on your situation.
Both Take Time to Work
How long does it take to see results from dutasteride or finasteride? Well, it takes time to grow new hairs from a root to a place where you can see visible length.
With consistent use, you can generally expect dutasteride and finasteride to show some results after several months. However, it can take a year or more to see the full effects of hair loss medications, including hair regrowth.
Two studies found that 0.5mg dutasteride and 1mg finasteride, taken for at least five years by men with androgenetic alopecia, both demonstrated long-term clinical effectiveness and safety.
Dutasteride vs Finasteride Side Effects
Finasteride and dutasteride both work by inhibiting the 5-alpha reductase enzyme and reducing the amount of DHT in your body. Does this mean they have similar side effects? Let’s take a look.
The most common side effects of finasteride are:
Inability to get or maintain an erection (erectile dysfunction, or ED)
Gynecomastia (male breast tissue growth)
Decreased ejaculation volume
Sexual side effects, like reduced sexual desire
Testicular pain or discomfort
Finasteride may also cause or contribute to psychological effects, including an increased risk of depression.
The most common side effects of dutasteride are very similar:
Erectile dysfunction
Decrease in sex drive
Problems ejaculating
Gynecomastia
Still, Dr. Beasley says, “I always discuss the potential side effects of finasteride [with patients]. However, the risk of sexual side effects is very low.”
In clinical trials of Avodart, a version of dutasteride used to treat BPH, a slightly higher percentage of men reported sexual side effects, such as erectile dysfunction, during the first six months of treatment vs. those using the placebo.
Although uncommon, 5-alpha reductase inhibitors such as finasteride and dutasteride may also cause more serious side effects. These include:
Swelling of the breasts and nipples
Lumps, pain, and discomfort in the breasts
Discharge from the nipples
Difficulty breathing and/or swallowing
Rash, itching, hives, and swelling of the face and lips
Peeling skin
These reactions are rare but may be signs of a severe problem. If you experience any of these side effects after taking finasteride or dutasteride, it's important to contact your healthcare provider as soon as possible for medical advice.
Although finasteride may lower overall prostate cancer risk for men, some research suggests that it may be associated with an increased risk of high-grade prostate cancer in older men.
Finally, there’s some research suggesting that both finasteride and dutasteride may have adverse effects on fertility in some men, leading to a significant decline in sperm count — though most participants experienced a reversal once they stopped the medication. This is a particularly important side effect for men to be aware of if they’re trying to expand their family.
Overall, studies show that finasteride is a safe medication for most men. Side effects are rare and usually reversible.
Likewise, research suggests that dutasteride has good long-term efficacy and safety, even at the higher doses used for prostate gland volume reduction in men with BPH.
Side effects and adverse events from dutasteride are generally rare, often transient, and usually go away after you stop treatment.
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Dutasteride vs. Finasteride for Hair Loss: Which is Right for You?
The wide world of hair loss treatments can be overwhelming. If you’re weighing the pros and cons of finasteride or dutasteride, here are the key takeaways:
They work similarly. Both are 5-alpha reductase inhibitor medications that stop your body from converting testosterone into DHT, a hormone that causes male pattern hair loss.
Only finasteride is FDA-approved for hair loss. Dutasteride is effective for treating hair loss but is only FDA-approved for benign prostatic hyperplasia. Healthcare providers may prescribe dutasteride off-label for hair loss.
Dutasteride may have a slight edge. Both effectively reduce hair loss, although some studies suggest dutasteride is better at blocking DHT and encouraging thicker hair growth.
They both come with side effects. Like all medications, side effects are possible with either finasteride or dutasteride. Both can pose the risk of erectile dysfunction and decreased sex drive.
We offer finasteride online, along with other hair loss treatments, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate for your needs.
We also offer minoxidil, which is FDA-approved for hair loss. This topical solution — applied to the scalp as either a minoxidil foam or a liquid minoxidil solution — is thought to stimulate hair growth.
Ready to take the next step in finding the right hair loss treatment for you? Start by taking our free online hair loss assessment.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment or medication.