Does Finasteride Work?

Finasteride treats male-pattern hair loss by lowering levels of a hormone called DHT (dihydrotestosterone) in the scalp.

DHT is the main hormone responsible for hair thinning in men.

Over time, DHT causes hair follicles to shrink (miniaturise). As follicles get smaller, the hairs they produce become thinner, shorter, and weaker, until they eventually stop growing altogether.

Finasteride works by blocking an enzyme called 5-alpha reductase, which converts testosterone into DHT. By reducing scalp DHT levels (by about 60-70%), finasteride helps:

• Slow down or stop further hair loss
• Protect existing hair follicles from shrinking further
• Allow weakened follicles to recover, so they can grow thicker hair again

Finasteride does not create new hair follicles, but it can revive miniaturised follicles that are still alive.

This is why it works best in areas that are thinning, rather than areas that are completely bald.

Finasteride is one of the most well-studied and evidence-based medical treatments for male-pattern hair loss (androgenetic alopecia). It works by lowering levels of DHT, the hormone that causes hair follicles to shrink over time.

Clinical research shows it can significantly slow hair loss and, in many men, regrow some hair compared with placebo (a look-alike tablet with no active medicine).

Here’s what the science says in real-world terms:

Real increases in hair count

In large clinical trials where one group took finasteride 1mg daily and another took a placebo:

• Men on finasteride grew noticeably more hairs in a defined thinning scalp area
• On average, they gained:
  • +107 hairs after 1 year
  • +138 hairs after 2 years
• Over longer follow-up, the difference increased to +277 hairs after 5 years compared with placebo
• Men taking placebo continued to lose hair over time

What this means for patients:

Finasteride doesn’t just slow hair loss, it can lead to measurable regrowth in thinning areas.

More hair and visible improvement

When researchers analysed results from multiple trials involving nearly 4,000 men, they found:

• Finasteride was significantly more effective than placebo at improving scalp hair in both the short and long term
• On average, treated men had around a 24% higher hair count than those who took the placebo, with longer treatment
• Independent photo assessments showed:
  • 48% of men had visible regrowth after 12 months
  • 66% after 2 years
  • 48% still showed increased hair after 5 years

What this means for patients:

Around 50-65% of men will see some degree of visible regrowth with long-term use.

Helps follicles stay in growth phase

Research shows finasteride:

• Increases the number of hairs in the growth phase (anagen) compared with placebo
• Reduces the number of follicles entering the shedding phase (telogen)
• Helps miniaturised follicles recover and produce thicker hairs over time

What this means for patients:

Finasteride does not just add new hairs, it helps existing hairs stay thicker and grow for longer.

Improvements can continue with longer use

Long-term studies show that benefits build up over time:

• Hair count and hair weight (a measure linked to thickness and density) continue to improve beyond the first year
• In studies lasting 3–5 years:
  • 65–86% of men had no further hair loss while taking finasteride
  • After nearly 4 years, men on finasteride had over 20% more hair than placebo
  • After 5 years, only 35% of finasteride users had lost further hair (vs 100% on placebo)

What this means for patients:

The longer you stay on finasteride, the better the long-term protection and thickness gains tend to be.

Before starting finasteride, it’s important to understand a few key points to help you get the best results and stay safe while using the treatment.

Start early for best results

Finasteride works by protecting the hair you already have. The earlier you begin treatment, the more hair you’re likely to preserve.

Consistency is important

Taking finasteride every day is crucial. Stopping or skipping doses can reduce its effectiveness.

Results take time

Visible improvements usually appear after 3–6 months, with the best results often seen after a year or more.

Further reading: Finasteride results

Side effects are possible

Some men may notice changes in libido, mood, or sexual function. These are uncommon and often temporary but speak with a pharmacist or doctor if you’re concerned.

Further reading: Finasteride side effects

It doesn’t create new hair follicles

Finasteride helps maintain and thicken existing hairs, but it won’t grow completely new follicles.

Regular check-ins

Discuss your progress and any concerns with your clinician to make sure finasteride is right for you.

Yes, finasteride works for most men with male pattern baldness.

• It slows or stops hair loss in most men:
  Around 65-85% if men had no further hair loss while taking finasteride over 5 years
• It regrows hair in many men:
  Around 50-65% of men saw some hair regrowth or thickening after 1-2 years
• It works best on the crown and mid-scalp
• Hairline and temples respond less predictably
• It takes time:
  • 3-6 months → hair loss slows
  • 6-12 months → early regrowth
  • 12-24 months → best visible results
• You must keep taking it:
  Any hair regrown or maintained is usually lost again within 3-12 months if you stop
• Works best if started early:
  Men with early thinning see better results than those with large bald patches
• Side effects are uncommon:
  • 3.8% of men reported sexual side effects
  • vs 2.1% on placebo in clinical trials
  • Most were mild and reversible after stopping