Hair loss in your twenties and thirties: finasteride or dutasteride?

Hair loss in your twenties and thirties — what is the difference between finasteride and dutasteride?

Hello. This is Dr. Lee Yumin, medical director of MeSOnBom Clinic in Hongdae.

Seeing patients recently, I feel that interest in hair care is greater than ever, among both men and women.

In particular, far more younger patients now come to be prescribed hair loss medication pre-emptively, from their twenties.

The release of various domestic generics of the original drugs has lowered the cost, which appears to be a significant factor in the growing number of people taking them.

Today I have gathered the questions asked most often by those starting medication or considering a change, and set out the answers on medical grounds.

This is one of the most common questions.

To answer it, let us look at a paper published in March 2022 in JAMA Dermatology.

The study compared the efficacy of the main drugs used for male pattern hair loss.

The ranking was as follows.

1st: dutasteride 0.5mg

2nd: finasteride 5mg

3rd: oral minoxidil 5mg

4th: finasteride 1mg

5th: topical minoxidil 5%

6th: topical minoxidil 2%

7th: oral minoxidil 0.25mg

The commonly prescribed dutasteride product is 0.5mg, and the finasteride product is 1mg.

So on single-drug efficacy alone, the dutasteride class can be considered more effective than the finasteride class.

Specialist hair loss clinics often prescribe dutasteride together with a quarter tablet of oral minoxidil to maximise the effect.

If taking two oral medications feels like too much, combining dutasteride (or a generic) with topical minoxidil 5% alone can still give a much better result.

The main reason many men hesitate over medication is concern about sexual function.

To answer directly: there is no conclusive evidence that dutasteride causes worse sexual side effects than finasteride.

A meta-analysis published by Korean researchers in 2019 found that both drugs increased the risk of sexual side effects — erectile dysfunction, reduced libido, ejaculatory disorder — by an average of around 1.57 times.

Broken down by drug, finasteride 1mg showed an increase of 1.66 times and dutasteride 0.5mg 1.37 times.

Numerically the risk with dutasteride was lower, but the paper notes this was not a statistically significant difference and requires further research.

In other words, there is no need to avoid a more effective treatment out of a vague fear that the stronger drug must bring far worse side effects.

Unlike men, women cannot take finasteride or dutasteride, so the choices are very limited.

Female hair loss causes enormous stress too.

For women we usually recommend combined management along these lines.

Oral minoxidil (a quarter tablet)

Topical minoxidil 2% (we recommend the foam form, which is easier to use than the liquid)

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Minoxidil can bring side effects such as swelling in some people, and the topical form causes scalp inflammation in others.

So rather than a prescription of six months or more from the outset, I recommend starting with three months.

Once you have checked what suits you, it is wiser to be re-prescribed without any ingredient that caused problems.

(Prescription medicines cannot legally be resold and cannot be refunded.)

The most unfortunate cases in hair loss treatment are those who say they took it for a month, saw no effect and stopped.

The cycle of hair shedding and regrowing takes at least several months.

So whatever the drug, you need to take it consistently for at least a year to judge the effect accurately.

Conversely, if there is no change at all after a year or more, I advise stopping.

Also, stopping medication returns the hair to its previous state — the progression of hair loss — within a year.

It is sobering, but you have to approach it with a long view: that you will be taking this for decades.

Even the wealthiest people in the world have not escaped hair loss.

It takes real, sustained effort to maintain.

I hope today's summary offers a clear answer to those troubled by hair loss, and I wish everyone reading success in it. Thank you.