About Zagallo

Zagallo is a new AGA remedy next to Propecia

Its hair growth effect is 1.6 times than that of Propecia! Zagallo (dutasteride) prescription

GlaxoSmithKline (GSK) new AGA treatment
Zagallo 0.5mg 30 tablets 10,000 yen
Ministry of Health, Labor and Welfare approved drug / drug price standard not listed package insert *only availabe in Japanese

There are no medical examination fees, consultation fees, or prescription fees, so there is no charge other than medicine. (Health insurance card is not required) Since it is an in-hospital prescription, the prescription will be completed in about 10 minutes from the visit. Zagallo is an adult male-only drug and cannot be taken by women or minors. If you have any medicines you are taking, please write down the name of the medicine or bring the medicine with you. Click here for Zagallo ‘s generic dutasteride capsule 0.5mg ZA “Towa” and “Mylan”.

Zagallo 0.5mg 30 tablets

Zagallo (Dutasteride) is the second new AGA treatment after Propecia

Zagallo is a hair growth drug developed by GlaxoSmithKline Co., Ltd. (GSK) in the UK as a treatment for AGA “male pattern baldness”. Zagallo is the second AGA treatment after Propecia (finasteride).
AGA is a condition in which the hair on the forehead and the crown of the head, which is common in adult men, is thinned. Dutasteride, a component of Zagallo, was approved by the Ministry of Health, Labor and Welfare in 2009 as a treatment for benign prostatic hyperplasia, and is used in Japan under the drug name Avolve, but was newly approved as an AGA treatment in September 2015. Came down. In other words, Zagallo and Avolve have different names, but the ingredients are the same dutasteride. Dutasteride has been used in Japan for more than 7 years since 2009 as a treatment for benign prostatic hyperplasia, and Zagallo, the same ingredient, is not a completely new drug, so it can be said to be highly safe.

Actions and effects of Zagallo (dutasteride), differences from Propecia

Like Propecia, it suppresses the action of 5α-reductase, which is involved in the production of DHT, which causes AGA, but Propecia suppresses only type II of 5α-reductase, whereas Zagallo suppresses it. Since it can suppress both type I and type II of 5α-reductase, it can be expected to have a better hair growth effect than Propecia. In clinical trials, Zagallo 0.5 mg has been reported to have about 1.6 times the hair growth effect of Propecia 1 mg.

The mechanism of action of Zagallo and its effect on the hair cycle

You can feel the effect in 3 months at the earliest, usually about 6 months from the start of taking. If you feel that the effect of Propecia (Finasteride) is not good, try Zagallo. It may be a good choice for those who are new to AGA treatment.

Features of Zagallo (Summary)

It suppresses both type I and type II of 5α-reductase, which increases DHT, the causative agent of thinning hair. (Propecia suppresses only type II) As a result, a hair growth effect about 1.6 times that of Propecia can be expected.

Hair growth effect of Zagallo (Dutasteride)

Diagram of hair growth effect of Zagallo

*Change in hair count from baseline at 24 weeks (clinical results)
Compared to Propecia (finasteride) 1 mg, Zagallo 0.5 mg has about 1.6 times more hair.

* Number of non-vellus hairs with a diameter of 30 μm or more within a 2.54 cm circle on the crown
(the figure is taken from the GSK site) Hair growth effect of Zagallo (dutasteride), comparison with finasteride Hair growth effect of
Zagallo (dutasteride)

Hair thickness at 24 weeks * Change from baseline (clinical results)

Compared to Propecia (Finasteride) 1 mg, Zagallo 0.5 mg has significantly increased hair thickness. * Total thickness of non-vellus hair with a diameter of 30 μm or more within a circle with a diameter of 2.54 cm on the crown
(the figure is taken from the GSK site) Figure of Zagallo hair growth effect

Example photo of Zagallo (Dutasteride)

Photos B to C are 24 weeks (half a year) after switching from finasteride to Zagallo, but there is a big change in the hair growth effect.
Reference: International Journal of Dermatology 2014,53,1351-1357

Side effects of Zagallo (dutasteride)

The main side effects are decreased libido (2%), erectile dysfunction (5%), erectile dysfunction (1%), etc., and less than 1% have depressed mood, gynecomastia, breast discomfort, etc. Rare cases include dysgeusia, testicular pain, and liver dysfunction. The side effects are similar to those of Propecia, but the frequency of occurrence seems to be slightly higher. If you have symptoms of erectile dysfunction, stopping Zagallo usually improves it. It has a good hair growth effect, so if you don’t want to stop Zagallo, you should try an ED treatment. Our hospital has more than 16 years of treatment experience for ED treatments, so please feel free to contact us.

Prescribing genuine medicine in the box unopened

Please be careful about unapproved domestically unapproved imported medicines in bottles and sheets without Japanese names at bargain clinics. Even if unapproved drugs in Japan have serious side effects, the drug side effect relief system is not applied. We prescribe Zagallo in an unopened box from a domestic manufacturer. The drug sheet in the box is a genuine domestic product with Japanese description.

Precautions when taking Zagallo

This medicine is for men and cannot be taken by women. It is safe for men over the age of 20 and should not be taken by minors. Do not break the capsule. Absorption of Zagallo powder into the body of pregnant women can affect the foetation. You need to continue taking it for 6 months to feel the effect, but if you do not feel the effect after that, stop taking it.


It is marketed by GlaxoSmithKline as a treatment for benign prostatic hyperplasia with the same ingredient (0.5 mg), but the additives are slightly different compared to Zagallo. Due to the different indications in the package insert, caution should be exercised in hospitals and clinics that prescribe Avolve, which is cheaper than Zagallo, as a treatment for androgenetic alopecia in men. If serious side effects occur due to drugs with different indications, the drug side effect relief system may not be available.

Be careful if you have liver dysfunction

Zagallo is metabolized in the liver and has a long half-life of 3 to 5 weeks. It has not been verified for administration to people with hepatic dysfunction, so it cannot be taken by people with severe hepatic dysfunction. PSA (Prostate Specific Antigen) levels are halved while taking. It affects the PSA level of the blood marker for prostate cancer, and the value is halved, so please be careful if you have a PSA test. The effect will disappear after 6 months or more after discontinuing Zagallo. Blood donation is prohibited for those who are taking this medicine. The Japanese Red Cross Society’s Blood Division requires that those taking Zagallo donate blood after a 6-month washout period. (It takes a long time to completely remove from the blood, so it is longer than one month of Propecia)


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