Hydroquinone is one of the most widely discussed ingredients for dark patches. DermNet reports about 50 years of topical use, and it remains part of many dermatologists’ approach to melasma.
It is also surrounded by mixed messages. Some people see it as essential, others as dangerous. The sources tell a more measured story: hydroquinone can be effective when used under supervision, and it has real risks when used at high strength, for long periods or from unregulated products.
In the US, the UK and many other countries, hydroquinone is a prescription medicine. If you are interested in it, talk to a dermatologist.
How hydroquinone works
Melanin is made with the help of an enzyme called tyrosinase. DermNet explains that hydroquinone reversibly blocks tyrosinase and selectively damages melanocytes and melanosomes, the cells and structures that make and carry pigment.
Two practical points follow from this:
- Hydroquinone reduces the production of new melanin. It does not remove pigment that is already deep in the skin.
- It works on epidermal (surface) pigmentation rather than dermal (deeper) pigmentation, according to DermNet.
This is one reason results vary. DermNet notes that melasma sitting mainly in the deeper layer usually responds poorly to treatment.
What it is used for
DermNet lists common uses as:
- Melasma
- Post-inflammatory hyperpigmentation
- Freckles
- Lentigines, including sun spots
The AAD describes hydroquinone as a common melasma treatment that helps even out skin tone.
Combination creams
Hydroquinone is often combined with other ingredients. DermNet notes that it is paired with a topical retinoid to increase effect, and with a low-potency steroid to reduce irritation.
DermNet’s melasma page describes the most successful topical regimen as a triple combination of hydroquinone, tretinoin and a moderate-potency topical steroid. It reports that this clears or improves 60 to 80% of cases. BAD also describes combination creams of this type and stresses that they should only be used when prescribed.
How it is regulated
United States
The legal position in the US changed in 2020. According to an FDA drug safety communication, the CARES Act finalized the status of over-the-counter (OTC) skin lightening products, and OTC products containing hydroquinone became unapproved, misbranded drugs. Manufacturers were required to remove unapproved products from the market from September 23, 2020.
In April 2022, the FDA issued warning letters to 12 companies still selling these products. The agency advises consumers not to use OTC skin lightening products that contain hydroquinone.
The FDA page describes a single approved hydroquinone drug: a prescription product for short-term treatment of dark spots linked to moderate to severe facial melasma, to be used under a licensed health care professional’s supervision. The AAD likewise notes that hydroquinone is no longer sold over the counter in the US.
Other countries
DermNet notes that in New Zealand and many other countries hydroquinone is available only on prescription, and it may need to be prepared by a compounding pharmacist. It also points to safety concerns raised in Europe, Japan and the US. In the UK, BAD states that hydroquinone can only be prescribed by doctors.
Rules differ between countries, so DermNet advises checking with your national medicines regulator.
How it is typically used
DermNet outlines a common approach under medical guidance. The table below summarizes it. Your prescriber’s instructions take priority over any general schedule.
| Step | What DermNet describes |
|---|---|
| Strength | Creams or lotions at 1 to 5% |
| Patch test | Try on a 1 cm area first |
| Starting | A thin film once daily, increasing to twice daily if no irritation after a week |
| Where | Only on the darker areas, avoiding eyes and mouth |
| Intensive phase | Twice daily for about 3 months |
| Maintenance | Twice weekly after that |
| No benefit | Stop if no improvement after 3 months |
Other practical points from DermNet:
- Avoid using it with other topical products, especially benzoyl peroxide.
- Wait about 10 minutes before applying sunscreen or makeup.
- Stop if there is marked redness, scaling, itching or weeping.
BAD advises that hydroquinone should only be used for a few weeks at a time to prevent over-lightening. The exact duration is something your dermatologist will set.
Side effects
Irritation and allergy
DermNet notes that irritant contact dermatitis is likely at strengths above 4%. A short break or a topical steroid usually settles it. Some formulations contain metabisulfite, which can cause allergic reactions.
Darkening and ochronosis
Paradoxically, hydroquinone can sometimes darken skin. BAD notes it may occasionally cause the skin to become darker.
The best-known serious effect is exogenous ochronosis, a blue-black or gray-blue discoloration. A 2022 systematic review in the International Journal of Dermatology analyzed 56 published case reports covering 126 patients. It found:
- Most cases involved concentrations above 4%, or unknown concentrations.
- The median duration of use was 5 years. Few cases involved courses of 3 months or less.
- Cases were most often reported in middle-aged women and in people with darker skin (Fitzpatrick types V to VI).
- Patches typically appeared as lace-like blue-black or gray-blue spots on the face.
The authors concluded that strengths above 4% and courses longer than 3 months may be associated with new ochronosis. The FDA notes that ochronosis may be permanent. It has also received reports of skin rashes and facial swelling linked to OTC lightening products.
Cancer concerns
DermNet explains that high-dose oral hydroquinone caused cancer in rats. It reports no human cancer cases after about 50 years of topical use.
Pregnancy and breastfeeding
DermNet states that safety in pregnancy and breastfeeding has not been established. BAD advises avoiding hydroquinone and retinoid creams during pregnancy. Melasma that appears in pregnancy may fade a few months after delivery, according to BAD.
Sun protection still matters
Hydroquinone does not replace sun protection. BAD notes that protecting the skin from the sun helps treatments work better, and DermNet describes lifelong sun protection as part of melasma care. The AAD suggests applying melasma medication first, then sunscreen, then any camouflage makeup.
Questions to ask your dermatologist
- Is my pigmentation likely to respond, given its depth?
- What strength and schedule do you recommend, and for how long?
- Should it be combined with a retinoid or steroid?
- What signs mean I should stop and contact you?
- What is the plan for maintenance once the intensive phase ends?
Sources
- Hydroquinone DermNet
- FDA works to protect consumers from potentially harmful OTC skin lightening products U.S. Food and Drug Administration
- Exogenous ochronosis associated with hydroquinone: a systematic review International Journal of Dermatology (via Europe PMC)
- Melasma: Diagnosis and treatment American Academy of Dermatology
- Melasma (facial pigmentation) DermNet
- Melasma patient information leaflet (June 2024) British Association of Dermatologists
This article is general information, not medical advice. It does not replace an examination, and treatment for pigmentation should be planned with a dermatologist or another qualified clinician who has seen your skin.
