Medically reviewed by Mary Lucas, RN
Written by Our Editorial Team
Last updated 1/15/2021
Male pattern baldness is a very common issue. According to study data, one in every six men aged 18 to 29 is affected by moderate to extensive hair loss. By age 40 to 49, upwards of half of all men are affected.
If you’re starting to lose your hair, you’ve likely heard of finasteride. A type of oral medication, it works by blocking the hormones that cause male pattern baldness to develop. Used daily, it can stop your hair loss and even help you to regrow “lost” hair.
The typical dosage of finasteride for hair loss is 1mg per day. However, it’s also possible to take finasteride at a lower dosage while still inhibiting the hormones that cause hair loss.
Below, we’ve explained how finasteride works for hair loss, as well as the most effective dosage for finasteride. We’ve also looked at the data to see how finasteride performs at dosages below 1mg per day as a treatment for male pattern baldness.
Research shows that 1mg per day is generally the most effective finasteride dosage for treating and preventing hair loss. If you’re losing your hair, starting with this dosage is a good way to get the full benefits of finasteride.
Using finasteride at a lower dosage than 1mg per day is okay, although research shows that it may be less effective at treating hair loss.
Although research is limited, using finasteride at a reduced dosage may lower your risk of experiencing some side effects.
The 5mg version of finasteride is designed for treating prostate enlargement and is not recommended for hair loss. Our 1mg vs. 5mg finasteride guide goes into more detail on how this version of finasteride works.
Regardless of the specific dosage you use, results from finasteride aren’t immediate. It takes three to four months for finasteride to produce an improvement in your hair, even with consistent daily use. Make sure to be patient — the results are worth it.
Finasteride is a popular, well-known prescription medication for treating hair loss. It first arrived on the market in the early 1990s as a treatment for benign prostatic hyperplasia. In 1998, it was approved by the FDA as a treatment for male pattern baldness.
Hair loss from male pattern baldness occurs as a result of your genetics and exposure to certain hormones. Chief among these is a hormone called dihydrotestosterone, or DHT.
As we’ve explained in our guide to DHT and hair loss, DHT is a byproduct of testosterone — an important male hormone that your body produces. While it’s essential early in life, as you grow older, DHT can attack your hair follicles, causing them to stop producing new hairs.
Finasteride works by inhibiting an enzyme called 5α-reductase — an enzyme that’s responsible for converting testosterone into DHT. By doing this, finasteride causes DHT levels in your body to decrease, allowing your hair to avoid DHT-related damage.
Research shows that finasteride is highly effective at reducing DHT. For example, when used at a high dosage, finasteride can reduce DHT levels in your body by more than 70 percent.
This reduction in DHT shields your hair from hormonal damage, slowing down or stopping your hair loss if you’re genetically prone to male pattern baldness.
The standard dosage of finasteride for hair loss is 1mg per day. If you buy generic finasteride or the brand Propecia® online or from a drugstore, this is dosage you’ll typically receive.
Used at a 1mg per day dosage, research shows that finasteride is extremely effective at slowing down and stopping hair loss from male pattern baldness.
For example, a large-scale study carried out in Japan looked at the effects of finasteride over 10 years in men with male pattern baldness. More than 530 men used finasteride daily at a typical dosage of 1mg, with their progress recorded via scalp photographs and a questionnaire.
Over the course of 10 years, 99.1 percent of the men that took part in the study experienced a prevention of male pattern baldness progression. Put simply, their hair loss stopped after they started using finasteride, with no worsening over a 10-year period.
91.5 percent of the men in the study experienced a slight, moderate or significant improvement in their hair growth over the course of the 10-year study period.
In other words, despite being genetically prone to male pattern baldness, almost all of the men that took part in the study saw their hair either stop falling out or grow back after they started to use finasteride at a 1mg daily dosage.
Several other studies of finasteride have shown similar results at a dosage of 1mg per day. For example, clinical trials from the late 1990s found that 83 percent of men who used finasteride at a 1mg per day dosage experienced no further hair loss over two years of treatment.
In the same trials, 66 percent of men who used finasteride at 1mg per day saw improvements in hair growth.
In short, the standard 1mg per day dosage of finasteride is highly effective at stopping hair loss from male pattern baldness. If you’re just starting finasteride, taking it at the normal dosage will usually give you good, reliable results.
While 1mg of finasteride per day is a safe and effective dosage for most people, it’s also okay to take finasteride at a lower dosage.
Although they’re uncommon, finasteride can cause side effects. If you experience side effects at a 1mg per day dosage, reducing your dosage of finasteride could make them less noticeable, or even cause them to disappear entirely.
Research shows that finasteride still works relatively well as a male pattern baldness treatment at dosages below the 1mg per day level.
For example, a study published in the Journal of the American Academy of Dermatology looked at the effects of finasteride on DHT at dosages of 0.01, 0.05, 0.2 and 1mg per day over 42 days of treatment.
Although the study didn’t specifically measure hair loss, the researchers found that DHT levels in the skin of the scalp decreased by the following levels:
13 percent with a non-therapeutic placebo
14.9 percent with 0.01mg of finasteride per day
61.6 percent with 0.05mg of finasteride per day
56.6 percent with 0.2mg of finasteride per day
64.1 percent with 1mg of finasteride per day
As you can see, even the relatively low dosages of finasteride (0.05mg per day and 0.2mg per day) caused a noticeable reduction in DHT levels.
Another study, also published in the Journal of the American Academy of Dermatology, looked at the effects of these finasteride dosages on hair loss. The study measured changes in hair loss through clinical photography, hair counting and self-assessment by patients.
The researchers concluded that all dosages of finasteride above 0.2mg per day were effective at treating hair loss. However, they noted that a daily dosage of 1mg was superior to the lower dosage of 0.2mg per day.
In short, finasteride still works as a treatment for male pattern baldness at lower dosages than 1mg per day, although its effects are noticeably weaker.
Used as prescribed, finasteride works well at slowing down, stopping and sometimes reversing hair loss from male pattern baldness. Apply the following tips and techniques to make sure you get the best possible results from finasteride:
Use finasteride and minoxidil together. While finasteride is effective on its own, it’s even more effective when it’s combined with minoxidil, an over-the-counter treatment that stimulates hair growth.
A study published in 2015 compared the effects of finasteride and minoxidil together to each treatment separately. The researchers found that the combination of finasteride and minoxidil outperformed either treatment used on its own.
We’ve talked more about using these medications together in our guide to finasteride and minoxidil.
Use a DHT-blocking shampoo. DHT-blocking shampoos may help to lower the amount of DHT on your scalp, protecting your hair follicles and potentially reducing your hair loss further.
Good DHT-blocking ingredients include saw palmetto (an active ingredient in our Thick Fix Shampoo) and ketoconazole, which may disrupt the DHT pathway in your skin.
Quit smoking. Although research hasn’t linked smoking to male pattern baldness, there is evidence that tobacco smoking can damage the DNA of your hair follicle — a factor that might contribute to certain types of hair loss.
If you smoke, try to kick the habit. Our guide to quitting lists your options for managing nicotine cravings, avoiding smoking triggers and giving up on smoking for good.
Be patient, even if you don’t see results right away. Although finasteride works well as a treatment for male pattern baldness, you usually won’t see any results for three to four months after you start taking it.
This is because it takes time for your hair to respond to the medication. Be patient and keep using finasteride daily, even if its effects aren’t obvious. Over time, you’ll begin to notice an improvement in your hair’s thickness, density and coverage.
Photograph yourself to monitor your progress. Because finasteride works gradually, it’s surprisingly easy to ignore or lose track of the improvements you’ve made since you started treatment.
To track your progress accurately, try photographing your scalp every month. Take your photos in similar lighting conditions so that you can identify areas where hair has grown back, gotten thicker or generally improved in appearance.
Finasteride is typically used to treat hair loss at a dosage of 1mg per day. Research shows that this dosage is effective at slowing down or stopping hair loss. In some cases, it can even cause you to regrow hair in areas of your scalp with significant thinning.
If you’re prone to side effects from finasteride at a 1mg per day dosage, it’s okay to reduce your dosage. Research shows that finasteride dosages as low as 0.2mg per day are still effective at preventing hair loss, although less so than the typical 1mg per day dosage.
To get the best results from finasteride, try combining it with other treatments such as minoxidil and a hair loss prevention shampoo.
Worried about losing your hair? By taking action and responding to hair loss early, you can slow down any further hair loss, retain the hair you already have and even regrow hair in some areas of your scalp with noticeable thinning.
Our guide to male pattern baldness goes into more detail about how and why hair loss happens, the symptoms you might notice if you’re losing your hair, as well as what you can do to treat and reverse hair loss before it becomes a problem.
Insider tips, early access and more.