For dark spots! The story of "hydroquinone"

There are approximately 20 types of "quasi-drugs" approved by the Ministry of Health, Labour and Welfare as containing "active whitening ingredients ( ※ )."

 

Representative examples include vitamin C derivatives, tranexamic acid, placenta extract, arbutin, and kojic acid.

 

In fact, hydroquinone is not included in these "quasi-drugs." It is only approved as a "cosmetic ingredient," but it is an ingredient with stronger whitening effects ( * ) than the quasi-drugs listed above .

① I usually write my blog on my days off while checking papers. (Tokaido Shinkansen)

 

Hydroquinone has long been used overseas as a treatment for dark spots, and has been extremely popular among beauty enthusiasts since then.

 

It was approved as a "cosmetic ingredient" in Japan in 2002. It's only been around 20 years.

 

For this reason, information about the properties of hydroquinone and how to use it properly is not widely known. So, I would like to take this opportunity to tell you all about it!

 

 

1. First of all, you should be careful with hydroquinone because it can cause photosensitivity . Therefore, you should only apply it at night .

 

If you apply it in the morning and then go out for leisure activities, your skin will become red and inflamed. It may even worsen melasma, so be careful.

 

 

2. Next is concentration.

 

As mentioned above, hydroquinone is not approved as a "medicine" or "quasi-drug." It is only permitted to be used in cosmetics at a concentration of 4% or less .

 

Although it is a "cosmetic ingredient," many of the "cosmetics containing 4% hydroquinone" are only sold at clinics. Products sold in general cosmetic stores have a concentration of only 1 to 2% .

 

This is because there are risks associated with high concentrations of hydroquinone. There have been many reports of high-concentration hydroquinone causing skin whitening ( vitiligo, which does not return to normal ) and pigmentation ( tissue browning ) . Although it is possible to obtain 10% hydroquinone through personal imports, I do not recommend it.

 

 

②I can concentrate on studying while traveling by train. (Kintetsu Limited Express)

3. And then there's irritant dermatitis.

 

Hydroquinone is a substance that is prone to causing immediate irritation (primary irritation) even with just one application.

 

therefore,

 

( 1 ) Apply it only to the targeted spots. Unlike lotions and sunscreens, do not apply it all over your face .

 

( 2 ) Do not use it on multiple blemishes at once. Instead, gradually increase the area you apply it to, observing the results as you go .

 

Even if you experience irritation with continued use, in most cases the reaction subsides within about two weeks. However, there are rare cases where irritation occurs after using the product for more than a month (chronic irritation). In this case, please consult with a dermatologist about discontinuing use.

 

In fact, many dermatologists had been self-preparing hydroquinone topical preparations in-house and using them for private medical treatment even before the Ministry of Health, Labor and Welfare approved it 20 years ago. However, in most cases, they mixed in steroid ointments to prevent primary irritation (this was also the case at the university hospital where I worked when I was young).

 

However, thanks to recent development efforts by manufacturers, 4% cosmetics that do not contain steroids have become available on the market. I also recommend such products to my patients at my clinic.

 

 

4. Finally, there is the issue of oxidation.

 

Hydroquinone is a very delicate ingredient (poor stability) and easily oxidizes . Not only does it turn yellow, but it also deteriorates and becomes ineffective, causing irritant dermatitis!

 

This is true even for today's best products, so try to use the entire product within three to six months after opening.

 

 

These are the four points about hydroquinone that we would like you to know in particular. If you keep these points in mind, it is a very effective ingredient, so be sure to use it correctly under the guidance of a dermatologist!

③This may give the impression that I am rushing to complete my work while traveling due to a deadline, but studying while traveling long distances on trains and buses is a habit I have had since I was a child. (Kintetsu Limited Express)

(Note ※ )

The word "whitening" is a term that the government has stipulated as acceptable for use in the ingredient labeling of "quasi-drugs," so we have used it in this blog.

Aoharu Evangelist Eriko Koyanagi