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What is Finasteride and Dutasteride?

If you search for, ‘Medication used to treat hair loss’, you will certainly come across finasteride and dutasteride. Both belong to a class of medication called 5-Alpha Reductase Inhibitors (5-ARIs).

Dihydrotestosterone (DHT) is an androgen hormone that is strongly linked to hair loss and research has shown DHT to be responsible for genetic pattern baldness in both males and females.

We all have a balance of testosterone in the body and the enzyme 5-Alpha Reductase converts testosterone to DHT. Since both finasteride and dutasteride are 5-ARIs, they work by preventing your body from converting testosterone into DHT. It’s this reduction of DHT that helps improve hair growth by preventing hair miniaturisation in hair follicles sensitive to DHT. Hair follicle miniaturisation is when the hair follicle constricts, making it harder for hair to grow.

Due to their mechanism of action, both finasteride and dutasteride are commonly known as DHT Blockers.

During childhood and adolescence DHT plays a vital role in development. However, as an adult, DHT is less essential for our everyday health and well-being. For those who are genetically predisposed to hair loss, the DHT can bind to androgen receptors around the hair follicles in the scalp and causes hair miniaturisation that leads to gradual thinning and hair loss. Eventually, this over time leads to complete hair loss in those DHT sensitive areas on the scalp.

Typically, DHT sensitivity hair follicles start to shrink and weaken from the age of 20 onwards. The sooner you begin treatment the better your outcomes for hair growth will become.

Although both finasteride and dutasteride are DHT blockers, they each have differences in their effectiveness, suitability, side effects and general prescribing legalities.

Finasteride is the older drug of the two, currently with a license at a 1mg oral dose to be used for male patterned baldness. Dutasteride was developed later and is only licensed for benign prostatic hyperplasia (prostate enlargement).

Dutasteride has been shown to help treat and prevent hair loss. Since it’s not approved for hair loss it is prescribed to our patients as an off-licence treatment.

Both are effective in reducing DHT production and certainly helps those who have hair loss due to DHT sensitivity.

The 5-Alpha Reductase enzyme exist in two forms, type 1 and type 2. Finasteride is selective and inhibits the form type 2, whereas dutasteride inhibits both forms. Due to this dutasteride seems to have better activity in the reduction of DHT. However, the selection of which one will give you a better result will be down to which form of enzyme converts testosterone to DHT more effectively in your body.

To find out which is more suitable for you, we recommend you have our DNA analysis performed so we can create your personalised hair loss formula that will give you the best hair growth.

Both will adjust testosterone levels and have the potential of sexual side effects, although rare.

Both have a similar side effect profile, as their functionality are almost identical.

Side effects of finasteride commonly seen are:

· Erectile dysfunction

· Decreased semen volume

· Reduced sexual libido

· Testicular discomfort

· Depression

Dutasteride side effects are very similar:

· Erectile dysfunction

· Problems ejaculating

· Decreased sex drive

Many patients find these alarming, but rest assured they are uncommon and only affect a small percentage of patients.

Some uncommon side effects of both finasteride and dutasteride that may be serious are:

· Increased male breast size

· Discomfort or pain of the breasts

· Discharge from nipples

· Rash, itching, hives and swelling of the face and lips

· Breathing difficulty

· Peeling skin

If these do occur, you must take them seriously and contact your GP immediately.

Several studies have shown that these side effects are rare, reversible and in general are not permanent.

Both finasteride and dutasteride have been shown to be well tolerated by patients.

Trying to decide between the two is confusing. This is why we offer a DNA analysis and a remote consultation to determine the safest and most effective choice for you as an individual.


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