How Long Before Finasteride Starts Working?

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Medically reviewed by Ho Anh, MD Written by Our Editorial Team Last updated 9/18/2017

Finasteride, which blocks the conversion of testosterone to DHT, is one of the most popular hair loss drugs on the market. It’s also one of the most effective, with a proven record of helping men maintain their hair and even grow back some of the hair they’ve previously lost.

Like most medicines, it takes time to see results from finasteride. Depending on the severity of your hair loss, it might take several months before you notice any improvement in the thickness of your hair.

Finasteride Starts Blocking DHT Immediately

As a drug, finasteride actually begins working immediately, meaning it will have an effect on your body as soon as you metabolize the first pill.

This means that you will have lower DHT levels as soon as the first dose of finasteride gets into your system. On average, finasteride reduces the amount of DHT in your body by approximately 70%, which is enough to stop male pattern hair loss in its tracks.

Even though finasteride has a short half-life, it accumulates in your system. This means that a daily dose (usually 1mg, although it can vary) is enough to keep DHT production low, meaning it’s constantly working to protect your hair.

It Takes Three to Four Months to See Results

Assuming you follow the instructions and take finasteride every day, you’ll generally start to see results by month three or four. However, it usually takes six to nine months to see the full effects of finasteride, since hair follicles require plenty of time to produce new hairs.

It’s important to remember that finasteride doesn’t always cause you to regrow hairs that you’ve previously lost. Most people who take finasteride do so to stop further hair loss, rather than as a way to regrow hair.

This means that you might not notice any improvement in your hair from finasteride, even though it’s constantly working by preventing any extra hair from falling out.

It’s also important to remember that your hair will still fall out as part of its natural growth cycle (in order to be replaced by newer hairs), meaning you’ll still notice some stray hairs inside the shower, on your comb or in your hands even after you start using finasteride.

It Takes About One Year to See "Final" Results

Most of the time, you’ll see the "final" results from finasteride after about a year of using the drug on a daily basis. If you forget to take the pill some days or skip weeks or months of treatment, it can prevent finasteride from working as effectively as it normally would.

The key thing to keep in mind is that you shouldn’t stop taking finasteride just because it doesn’t produce any visible improvement in your hairline or hair thickness. If you stop taking finasteride, your DHT levels will go back to their natural amount and you could start to lose hair again.

When used properly, finasteride is highly effective at preventing hair loss. Just remember to stay patient while it takes effect since your hair follicles need several months to move into the growth phase and start producing new hair.

If you'd like to learn more about finasteride — and its potential side effects — check out our blog: Fact or Fiction: Diving Into the Side Effects of Finasteride

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.