Propecia is a hair loss drug that a lot of men find effective. It’s estimated that around 80-90% of men who use Propecia see some benefit. The majority of men find it prevents further hair loss, but some men who use it also see some regrowth of hair. Propecia is a prescription-only drug, but you can get it online from pharmacy sites that offer a doctor consultation service.

So how long does it take to work? 

Not that long. Generally, it only takes about 3 to 6 months for the full effects of Propecia to become apparent.

On this page, we’ll take a look at available information on the efficacy rates of Propecia at different stages of treatment.

0-3 months

The effects of Propecia do take a little time to develop. It’s not overly likely you’ll notice any significant improvement or difference in hair in, for instance, the first 2 weeks of Propecia treatment.

To help ensure that the treatment is effective, you should continue taking it every day once you have started according to your prescriber’s instructions. If you experience any side effects or notice anything unusual when taking the medicine, talk to your GP.

3-6 months

The summary of product characteristics (SPC) explains that some of the men who took Propecia during clinical trials began to notice improvements as early as 3 months into treatment. 

One study undertaken at the All India Institute of Medical Sciences reported that, at the three month stage, there was no significant statistical difference in ‘appearance of hair’, ‘hair growth’ and ‘bald areas’ between patients taking finasteride and placebo. However, it did note significant improvements in the finasteride group as the study continued (at the 6 month, 9 month and 12 month stages of treatment).

The patient information leaflet advises that it may take up to 6 months for the full effect of Propecia to develop.

So, although improvements to hair counts have been noted in some patients at the 3 month stage, this does not mean that every man will notice them at this point. It can take longer for the medication to have an effect for some people. 

2 years

The summary of product characteristics notes that in clinical trials, increase in hair count peaked in the treatment group at 2 years. On average, an increase of 88 hairs from the baseline, in the standard 5.1 cm2 area, was recorded at the two year point. 

A phase III study looking into the impact of finasteride on androgenetic alopecia recorded a net improvement of 16 percent at two years.

5 years  

The clinical trials found that 48 percent of the participants treated with Propecia were rated as improved in a standardised photographic assessment after five years. On top of this number, a further 42 percent of participants were rated as unchanged. (So in total, 90 percent of men using Propecia after 5 years noted either no further loss or some hair regrowth when compared with baseline.)

After five years of treatment, the average increase in hair count came to 38 hairs per 5.1 cm2 area. This means that even though the peak was reached after two years, a significant improvement was still seen at the five year point. 

Only 25 percent of participants treated with the placebo were classed as improved or unchanged at the five year point.

After stopping taking Propecia

Propecia didn’t become available until the early 2000s, and is a relatively new drug; so how long the treatment continues to be effective for after five years is a subject which needs further study. 

Some men may eventually find that the drug becomes less effective and stop taking it, whereas others may continue taking it beyond five years and still find it effective.

In any case, Propecia is only capable of working for as long as it is taken. The patient information leaflet advises that hair gained while on treatment will likely be lost within 9 months to 12 months of stopping Propecia. 

If you are experiencing hair loss and you would like to know more about whether Propecia might work for you, you can find more information here.

Page last reviewed:  22/01/2020