The main concern with hydroquinone is unmonitored overuse. Overuse (high concentrations for prolonged periods of time) can lead to a rare condition called ochronosis.
Hydroquinone (HQ) is the one of the most well-known topical skin lightening ingredients for treating multiple forms of hyperpigmentation, including hyperpigmentation related to melasma, sunspots, and dark spots from inflammation (inflammation can be caused by acne, trauma, contact dermatitis, and eczema for example).
Hydroquinone works by inhibiting an enzyme called tyrosinase, which is responsible for creating the pigment melanin; less enzyme activity means less melanin (the pigment in our skin). Although proven effective with proper use, and widely used by dermatologists with close monitoring, it is has become controversial on the internet.
The myth that it will “bleach” skin. HQ is not a “bleach” but a tyrosinase inhibitor, which means it reduces the enzyme responsible for producing excess pigment, known as melanin. The effect is not permanent. Some also worry that it will unevenly lighten skin beyond the hyperpigmented areas; this is possible, especially in those with darker skin tones. This is the so-called “halo” effect. So as not to produce unwanted lightening, Docent dermatologists typically prescribe HQ as a spot treatment to be applied only to affected areas, even using a Q-tip for more precision. (For lighter skin tones, as there is less concern for uneven fading.)
The myth that HQ is carcinogenic. This falsehood arises from a single study conducted on rats that involved an impractically high dose and isn’t relevant to humans. Moreover, subsequent human studies have found HQ to be safe, with appropriate monitoring by a dermatologist.
The myth that HQ is banned in the U.S. and Europe. In the Unites States, as of September 2020, it is only available with a prescription. The same status has always been the case in Europe. Why? Unmonitored use can lead to side effects, which we discuss below.
The main concern with hydroquinone is unmonitored overuse. Overuse (high concentrations for prolonged periods of time) can lead to a rare condition called ochronosis. The is another form of skin darkening that can be difficult to treat once it occurs. Therefore, it is important to give your full medication history to your dermatologist and to follow your dermatologist’s instructions to stop when it is time. It should also not be used when pregnant, trying to conceive, or while breastfeeding.
Like many topical prescription medications, hydroquinone can also cause irritation. The is particularity the case when combined with tretinoin, with which hydroquinone is frequently paired to increase impact.
Finally, hydroquinone can lead to increased sun sensitivity (as can retinoids, such as tretinoin). However, one should always use sunscreen anyway, especially when you’re trying to address hyperpigmentation. We recommend SPF 30+ at a minimum, reapplying every two hours when you’re outside, and even wearing when inside. Wide-brimmed hats and finding shade while outside are also recommended!
Depending on the dosage and patient, many dermatologists will typically stop the hydroquinone after three months to give the skin a “break” from the ingredient. To not interrupt the results, we then lock in the results with other prescription compounds such as azelaic acid, kojic acid, tranexamic acid, niacinamide and tretinoin. Your dermatologist will help develop a plan specifically tailored for you and your skin’s needs.