Behind the ingredient: hydroquinone

Kick dark spots to the curb with this powerhouse ingredient.

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Curology Team
May 17, 2021 · 3 min read

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We’re here to share what we know — but don’t take it as medical advice. Talk to your medical provider if you have questions.

Though very common, hyperpigmentation can be tough. Maybe your time in the sun left you speckled like a banana, or maybe you’re experiencing a change in hormones. Whatever the reason, we feel you. There are lots of treatment options out there, ranging from simple daily sunscreen use to in-office laser treatments — but today’s spotlight is on one special, topical ingredient: hydroquinone.

At Curology, we value transparency — so before we dive into the nitty-gritty, we’d like to address the context of hydroquinone. The controversy around this ingredient stems from the historical trend of skin-lightening or bleaching, which was driven by racist beauty ideals prizing light skin. Its misuse as a skin lightener or “bleach” stems from unjust, biased beauty ideals, which have historically been portrayed by the media.¹ Generally, dermatologists and medical experts agree that using hydroquinone to lighten overall skin tone is misuse, and they do not advise using it in this way.

All said, please know that hydroquinone is generally safe to use and is one of the most effective ingredients for treating hyperpigmentation, as long as it’s being used responsibly and as directed.

So, how does hydroquinone work?

Hydroquinone works for hyperpigmentation by acting as a tyrosinase inhibitor. I know that’s a mouthful — let us explain!

First, here are some important terms:

  • Melanin: Melanin is the natural pigment in our skin.

  • Melanocytes: Melanocytes are the cells in our skin that produce melanin.

  • Tyrosinase: Tyrosinase is a protein that’s needed to make melanin from melanocytes.

This basically means that hydroquinone stops your skin from making new pigment by blocking the melanocytes from making more melanin.²

How should hydroquinone be used?

Hydroquinone is a topical medication that is used to lighten hyperpigmented areas (like those pesky sunspots). It’s available with a prescription from your medical provider. A thin layer should be applied to dark spots and patches with the fingertips. Some dermatologists suggest using a Q-tip if there are only a few dark spots.

Another important tip: hydroquinone should only be used consistently for a few months followed by a break period of another few months.³ If you’re using a prescription-strength hydroquinone product, your medical provider will provide the specific “on-time” and “off-time.”

And don’t forget about sun protection! Dark spots can actually get worse from sun exposure, so it’s important to be consistent with sunscreen while using hydroquinone (and treating dark spots in general).

What are the possible side effects of hydroquinone?

Most people respond well to hydroquinone, so the best thing you can do for your skin is to follow your healthcare professional’s instructions — just keep an eye out for any irritation, itching, rashes, or allergic reactions.⁴

Ochronosis, another possible (but rare!) side effect, is a gradual blue/black or gray/blue darkening of the skin that is rarely seen after prolonged use of hydroquinone, especially at high concentrations.⁵ It’s also important to note that there are other potential unwanted effects besides these (learn more about them here).

When used responsibly, hydroquinone is one of the most effective ingredients when treating hyperpigmentation. There’s so much to learn, and we hope this blog was a useful resource for you!

• • •

  1. Elisabeth Darj, et al. The fairer the better?. Use of potentially toxic skin bleaching products. African Health Sciences. 2015;15(4):1074–1080. doi:10.4314/ahs.v15i4.4

  2. Vanessa Ngan. Hydroquinone. DermNet NZ. (2005, n.d.)

  3. Chelsea Schwartz, et al. Hydroquinone. StatPearls [Internet]. (2020, Jan.)

  4. Vanessa Ngan. Hydroquinone. DermNet NZ. (Ibid.)

  5. Chelsea Schwartz, et al. Hydroquinone. StatPearls [Internet]. (Ibid.)

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