Ingredient Spotlight: Hydroquinone

Have you noticed dark, uneven patches on your face or body? Skin discoloration is often the result of excess melanin production – the pigment that gives skin it’s color. Many factors like UV exposure, pollution, hormones and acne can induce hyperpigmentation that becomes hard to remove once it surfaces. If you have already done your research, you might’ve noticed there’s a lot of contradictory information out there. Especially when it comes to hydroquinone, an ingredient that’s been used for over 50 years. As one of the most effective skin bleaching agents on the market, I find it interesting it also happens to be one of the most controversial skincare products. But is it really as scary as we’ve been told? The truth comes down to this: when hydroquinone is formulated properly and used by the consumer correctly, it’s not a harmful ingredient at all. I’ll explain.

What is Hydroquinone


Hydroquinone (HQ) can be synthetically made or naturally found in wheat, berries, coffee and tea. It acts as a pigment-producing inhibitor and antioxidant in the skin. It works amazingly well at brightening and lightening stubborn skin disorders like melasma, hypermentation and dark spots. 

How it works

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HQ works by halting the production of melanin within skin cells by inhibiting the activity of tyrosinase, an enzyme needed to make melanin. Slowly melanocytes (cells) stop producing pigment and the skin begins to lighten. As long as lightening agents are applied, you’ll continue inhibiting tyrosinase and hence, reduce uneven pigmentation. When you discontinue using hydroquinone, the skin’s natural supply of tyrosinase will begin producing melanin again. 

The History – Why is it controversial?

Hydroquinone products were first banned in South Africa when concentrations of 20% and higher were being used everyday to lighten the skin. This began causing a disorder called Exogenous Ochronosis, which causes the skin to scar and turn a shade of blue. High amounts of mercury iodine and other illegal contaminants were found in those products, likely to be the main cause of the side effects seen. Once researchers discovered this information, the ban was lifted. While some parts of Europe, such as France, still follow suit with the ban, other countries like Spain allow over-the-counter and prescription products to be sold at a standard 2% or 4%. 

The Claims vs. Facts

1. Claim: Hydroquinone causes too many negative side effects

Fact: Ochronosis is a very rare side effect that has only been seen in individuals with darker skin tones (Fitzpatrick 4+), who are using high concentrations for years at a time. Most cases reported were also found to be from products sold at illegal markets, containing mercury and glucocorticoids. There’s been very few reported cases of hydroquinone causing this when purchased from a regulated market.

My advice: Always choose 100% quality formulated skincare if you choose to use hydroquinone. Do not order products from Amazon, Craigslist, E-Bay etc. The product could be tampered with and it’s not worth taking the chance of using something potentially dangerous.

Hydroquinone should be used in segments to avoid rebound pigmentation. I instruct my clients to use HQ consistently for 4-5 month cycles, and then alternate with natural brighteners like kojic acid, azelic acid, licorice root, vitamin C. Doing this greatly lowers the chance of possible side effects! Check with an esthetician or dermatologist before you buy medicated products. Everyone’s skin is different and some cannot tolerate HQ.

2. Claim: HQ causes skin sensitivity such as redness and increased risk of sun damage

Fact: Yes, HQ can be harsh on the skin, especially when used in prescription concentrations of 4%, 6%, 8% and 10%. The trick to avoiding topical irritation is to introduce it slowly and remember that less is more.

My advice: Start out with an over-the-counter strength of 2%. I have seen incredible results with low percentages used correctly over time! Begin by using it just a few days per week, applying a pea-size amount with a light, thin coat all over. Avoid the eye, nose and mouth corners. Never spot-treat with HQ – the best results come from lightening evenly. As your skin adjusts to the product, slowly increase it’s usage until you’re using it every night. And of course, sunscreen is a must every morning!

3. Claim: HQ causes cancer in rodents.

Fact: When you read past the headline, you’ll find the rodents were given heavy doses of hydroquinone daily and they developed cancer. In a 2006 review in the Journal of the American Academy of Dermatology, Dr. Jacob Levitt, M.D. reports that topical applications of hydroquinone in standard product concentrations are not carcinogenic to humans. According to Dr. Levitt, use of hydroquinone in mouse studies led to an actual decrease in cancerous liver tumors, suggesting protective effects of hydroquinone. According to Dr. David J. Goldberg, a clinical professor of dermatology at the Mount Sinai School of Medicine reports, “Over 100 scientific articles confirm it is a safe topical for humans; no independent studies prove the opposite.”

My advice: HQ is not intended to be a forever product, nor is it intended to be used in high doses daily. It’s temporary use is to get your skin to where you want it, and then switch to natural, plant-derived brighteners for long-term skin health.

4. Claim: HQ is cytotoxic

Fact: When HQ slowly reacts with oxygen, it forms chemicals like hydroxybenzoquinone which can kill melanocytes, the cells responsible for producing melanin. This can make the skin appear discolored or stained. You can avoid this by keeping your HQ products refrigerated for the best preservation. If you notice the product turning a yellow color, throw it out. Do not use HQ with other oxygen-containing ingredients such as benzoyl peroxide.

Bottom line: Use what you feel most comfortable with and know that there are many options when it comes to treating discoloration!



Paula’s Choice
Future Derm
Skin whitening with HQ
Hydroquinone Ban in EU
CIR Safety
HQ complications and controversies
What’s wrong with hydroquinone?


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