Medication

Hydroquinone 4%

The prescription strength of the best-studied pigment cream. It works, but it is used in courses of a few months with breaks in between, because the problems come from long unbroken use rather than from the strength.
Dr. Schwarz, MD · Board-certified dermatologistLast reviewed September 8, 2026
16:9 hero for Hydroquinone 4%. Never cropped: the tone strip and the corner logo depend on the full frame.

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Hydroquinone lightens stubborn pigment better than anything else we can put on skin. My caution is not whether to use it, it is how long. Use it in courses: three to four months on, a couple of months off with something gentler holding the ground. Sunscreen every morning is part of the treatment, not an extra.

— Dr. Schwarz, Board Certified Dermatologist

Key Facts

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Also calledHQ, hydroquinone 4% cream
Drug classTopical tyrosinase inhibitor, a pigment lightener
Applied as4% cream, sometimes a gel or solution, and often as part of a triple combination cream
Typical courseCycled, usually three to four months on and then a break
Time to workFirst change at four to eight weeks, judged at about three months
Prescription onlyYes in the United States since 2020

What It Is

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Hydroquinone lightens patches of skin darker than the skin around them. Dermapedia has a separate page on hydroquinone as an ingredient. This page is the 4% prescription strength, the concentration behind most of the melasma research. Four percent is the usual prescription strength in the United States: more effective than 2%, and more irritating. It often comes as a triple combination cream pairing hydroquinone with a retinoid and a mild steroid. The retinoid speeds turnover and helps the hydroquinone get in; the steroid calms the irritation the other two cause. That steroid is why a triple cream is never open-ended. The law changed in 2020. Until then 2% could be sold over the counter in the United States; federal law removed that route, and the Food and Drug Administration acted against unapproved products still on sale. Everything sold legally here now needs a prescription. The European Union has kept it out of cosmetics for years, and other countries allow it with varying oversight.

How It Works

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Pigment is made inside melanocytes, the pigment cells in the lower part of the outer skin layer. The key enzyme is tyrosinase. Hydroquinone blocks it, so less melanin is made. It also damages the packets pigment is stored in and makes the cell less active.

Nothing removes pigment already in the skin. It has to shed on its own, which is why results follow skin turnover and take weeks.

The effect is suppression, not permanent. Melanocytes make pigment again when the cream stops, and without sun protection the patch returns. That is why sunscreen and a maintenance plan matter as much as the cream.

Courses rather than continuous use come down to exogenous ochronosis, an uncommon but real reaction to long-term hydroquinone in which treated skin turns blue-black, gray or sooty, sometimes with tiny gritty bumps. It has been reported most after years of unbroken use, at high strengths, and in people with deeper skin tones. It is hard to treat and can look worse than the pigment you started with.

The cancer question that keeps regulators cautious comes from animal studies using large oral doses. It has not been shown to cause cancer from use on the skin, though that human evidence is reassuring rather than conclusive.

Here is where Hydroquinone 4% acts in the skin.

About Hydroquinone 4%
Skin basics
SLOWS PIGMENT MAKINGCROSSES EASILY

Pigment is made inside melanocytes, cells spaced along the floor of the top layer of skin. Hydroquinone 4% slows the enzyme they use to make it, so less new pigment reaches the surface while what is already there sheds. The prescription strength of the same drug.

Hydroquinone is small and crosses the barrier readily. At 4% more of it reaches the pigment cells, which is why it works faster and why it is prescription-only.

The outermost layer, and the one every moisturizer is aiming at. It is dead — flattened cells stacked like bricks, with a mix of fats as the glue between them. That glue is what holds water in and keeps irritants out.

The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.

The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.

What It Treats

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Close-up of the lower cheek, nose and mouth of a young person with medium-brown skin, turned three-quarters away from the camera against a pale blue background. Scattered flat dark brown marks are spread across the cheek, with a few small raised spots still active among them.
Post-Inflammatory Hyperpigmentation
Strong evidence
The most powerful topical option for stubborn brown marks, used as a short course of around three months rather than continuously. It blocks the enzyme that makes pigment, so it lightens the mark without touching the cause. Long unsupervised use is what leads to ochronosis, which is why this is prescribed and reviewed rather than bought and forgotten.
Melasma
Melasma
Strong evidence
The most established single prescription cream for melasma, applied thinly at night to the patches only. It is used in courses of about three to four months with breaks in between, not continuously for years — unbroken long-term use at high strength is what causes the blue-black discoloration people have heard about. Expect the first month to look like nothing is happening.
Sun Spots (Solar Lentigines)
Sun Spots (Solar Lentigines)
Moderate evidence
The strongest cream for lightening a sun spot, applied thinly to the spot itself rather than the skin around it. It is used in a defined course of about three to four months with a break afterwards, not indefinitely, and it works best combined with a retinoid. It is slower than a single session of freezing or laser, and it is the option to prefer when treatment risk on deeper skin tones is the concern.
Dark Circles Under the Eyes
Dark Circles Under the Eyes
Moderate evidence
The strongest cream available for the pigmented type, and the one most likely to produce visible lightening in three to four months. It is prescribed in short courses with breaks rather than continuously, because long unbroken use can cause a stubborn blue-gray darkening, particularly on deeper skin tones. It is applied thinly and kept off the lid margin and out of the eye.
Close-up of the cheek, nose and mouth of an adult with light skin, turned three-quarters away from the camera against a pale blue background. The surface of the cheek is uneven, dimpled with shallow depressions and small pits that catch the light. There are no active spots — the change here is in the texture of the skin rather than its color.
Acne Scarring
Moderate evidence
Aimed at the flat dark marks sitting alongside the scarring, not at the scar itself. Clearing the pigment first makes it much easier to see how much true texture is there, which is why it usually comes before any texture treatment. It is used in courses rather than indefinitely.

Not the Best For

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Deep or gray-blue pigment
Doesn't work
Pigment sitting in the lower layer of the skin, and gray-blue discoloration, respond poorly. The cream works in the upper layer and does not reach that depth.
Under-eye circles that are not pigment
Doesn't work
It only lightens pigment. Darkness caused by thin skin, shadow from the eye socket or visible blood vessels underneath will not change.

Forms

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4% cream:

Triple combination cream:

Compounded formulations:

Unregulated lightening creams:

Strengths

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Strength matters, but course length matters more. Four percent for three months is a different thing from two percent for three years.

WeakestStrongest
2%4%Above 4%
The lower prescription strength
2%
What used to be sold over the counter in the United States. Gentler, and often enough for marks left by acne.
The usual prescription strength
4%
The subject of this page, and the strength behind most melasma evidence. More effective than 2% and more irritating.
Compounded only
Above 4%
Mixed to order for specific cases. Stronger, harsher, and where ochronosis has most often been reported. Not a strength to go looking for.

Basics

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When to Apply
At night, on clean dry skin, a thin layer on the dark patches only, not the whole face. Sunscreen every morning is part of the treatment; a tinted mineral sunscreen also covers visible light, which matters in melasma.
How to Start
Every other night for the first week or two, then nightly if tolerated. Treat three to four months, break two to three months, and hold the result with something gentler such as azelaic acid, a retinoid, niacinamide or tranexamic acid, before another course if needed.
If It Irritates
Mild redness, stinging and dryness early on are common. Buffer with moisturizer underneath, or drop to every third night. Stop and ask if you get a spreading itchy rash, which can be an allergy, or if the area becomes inflamed, since inflammation darkens skin prone to pigment.
If It’s Not Working
Three months of steady use with daily sunscreen is a fair test. A stronger cream is not the answer. Check the sunscreen, then ask about tranexamic acid tablets or procedures. Melasma driven by heat, hormones and light often needs more than a cream.

Sample Routine

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Here is where Hydroquinone 4% sits in a day, and what goes around it. Pick what you are treating and what your skin is like, and the rest of the routine changes to suit.

What to Expect

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First few minutes | Applying it
A thin layer on the dark patches only, at night. Mild stinging is common at first.
Weeks 1 to 2 | Adjusting
Mild redness, stinging and dryness. No lightening yet.
Weeks 4 to 8 | Working
The patches lighten, usually unevenly and at the edges first. Brown marks from spots or injury clear fastest.
Weeks 12 to 16 | Judge it here
The fair point to assess a course, and your sunscreen habit as much as the cream. Melasma lightens, but it returns without sun protection.
After the course | Holding
Two to three months off with a gentler agent holding the result, then decide about another course.

What to Avoid

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  • Continuous use with no break The most important rule here. Long unbroken courses are the pattern behind exogenous ochronosis.
  • Skipping sunscreen Ultraviolet and visible light drive the pigment the cream suppresses, so skipping it cancels most of the treatment.
  • Spreading it across the whole face It lightens normal skin too, leaving a pale halo around the treated patch.
  • Imported or unlabeled lightening creams Undeclared strengths, undeclared potent steroids and sometimes mercury have all been found in these.
  • Benzoyl peroxide in the same layer It oxidizes hydroquinone and turns the cream, sometimes the skin, a temporary brown. Separate them by time of day.
  • A cream that has turned brown in the tube Hydroquinone oxidizes in air and light. A discolored cream has degraded, so replace it.
  • Picking, waxing and scrubbing Any inflammation in skin prone to pigment leaves a new mark.

Monitoring

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No blood tests. Monitoring here means looking at the skin.

The check that matters comes at three to four months, at the end of a course: has the pigment lightened, and is there any new discoloration.

The thing being watched for is exogenous ochronosis, a blue-black, gray or sooty darkening in the treated area, sometimes with tiny gritty bumps. It is uncommon, reported most often after long unbroken use, at higher strengths, and in deeper skin tones. Any darkening during treatment should be shown to a doctor, not treated with more cream.

With a triple combination cream, the steroid is the other reason for an end date. Steroids thin facial skin over time and can leave redness and small visible blood vessels.

If You Stop

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There is no rebound and no taper. The course simply ends. Pigment returns gradually if nothing takes over, because hydroquinone suppresses pigment production rather than removing the cells that make it. How fast depends on sun exposure and the cause. Marks left by acne often stay faded; melasma usually comes back. Most people do better on a plan than on a stop: a course of hydroquinone, then months of a gentler agent such as azelaic acid, a retinoid, niacinamide, cysteamine or tranexamic acid, with daily sunscreen throughout.

Cost

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Generic 4% hydroquinone cream is usually inexpensive. Triple combination creams cost more, and compounded formulas are the most expensive and are rarely covered, since compounded products usually sit outside insurance formularies. Because pigment treatment is often classed as cosmetic, coverage is inconsistent even for the plain cream and varies a lot between plans. The cost is ongoing rather than one-off. Daily sunscreen and the gentler cream used between courses are part of the plan.

Ask Your Doctor

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If you are pregnant or breastfeeding
Hydroquinone is generally paused, and melasma that starts in pregnancy often settles afterward. Ask the doctor managing your pregnancy before starting or continuing.
If you notice new blue-black darkening
New gray or sooty darkening counts too. Stop and be seen. That is exogenous ochronosis, and continuing makes it worse.
If you have used it for over six months
Continuous use beyond about six months needs a review. Ask for a plan with breaks rather than another repeat prescription.
If you still use a combination cream
Using one past the time you were told matters, because the steroid in it thins facial skin.
If you use a cream bought abroad or online
Bring the packaging. Undeclared steroids and mercury have both been found in these, and stopping a hidden steroid suddenly can cause a flare.
If the patch has not lightened
After three months of steady use with daily sunscreen, a stronger cream is not the next step.
If pigment returned after a peel or laser
That history changes whether those are sensible alongside the cream.

How It Compares

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Five azelaic acid tubes and bottles on white, most marked 10 percent, from Peach Slices, Paula's Choice, Facetheory, The Ordinary and NaturiumLabeled cutaway diagram of a single skin pore, headed Azelaic Acid. The epidermis is a brick-textured band across the top and the dermis is pink below it, with a yellow oil gland at the base of the pore and a small cluster of bacteria inside it. Three callout lines point in: decreases dead cells in pore and kills bacteria are drawn in dark navy as main effects, and decreases inflammation is drawn in gray as a lesser one.
Azelaic acid
Worse
Good evidence in melasma and in marks left by acne, and available over the counter at lower strengths. Slower and milder, but it can be used continuously, which is its real advantage over hydroquinone.
Retinoids such as tretinoin
Different job
Solid evidence, working partly by speeding up turnover. Slow on their own and more irritating, so they are usually the partner rather than the replacement.
Cysteamine cream
Different job
A growing body of trial evidence in melasma, and positioned as a long-term option because it is not associated with ochronosis. It smells strongly, which is the usual reason people stop.
Five serums lined up on white, labeled tranexamic acid or niacinamide with TXA, including SkinCeuticals Discoloration Defense16:9 hero for Tranexamic Acid. Never cropped: the tone strip and the corner logo depend on the full frame.
Tranexamic acid
Different job
The oral form has reasonable evidence in melasma and is used where creams stall, but it needs a doctor because of clotting risk. The topical versions are gentler and less convincing.
Six niacinamide products on white, including The Ordinary 10% + Zinc 1%, Paula's Choice Booster and EltaMD UV ClearLabeled cutaway diagram of a single skin pore, headed Niacinamide. The epidermis is a brick-textured band across the top and the dermis is pink below it, with a yellow oil gland at the base of the pore and a small cluster of bacteria inside it. Two callout lines point in: decreases inflammation is drawn in dark navy as the main effect, and decreases oil production is drawn in gray as a lesser one. Nothing points at the dead cells blocking the pore.
Niacinamide, kojic acid and vitamin C
Different job
Arbutin too. Milder options with weaker individual evidence. Their real place is maintenance between hydroquinone courses rather than doing the main work.
Chemical peels and lasers
Different job
They can reach pigment a cream cannot, and they can also cause pigment. The risk of darkening afterwards is higher on deeper skin tones, so they are used carefully and usually alongside a cream rather than instead of one.
Hydroquinone's case
Different job
It remains the most effective single cream for melasma, and the trade-off is that it is the one that cannot be used indefinitely.

Myths

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  • "It bleaches the skin." It slows pigment production where you apply it. It does not remove skin, and the lightening is not permanent.
  • "It is banned because it causes cancer." The concern comes from animal studies using large oral doses, not from use on the skin. The 2020 United States change was about over-the-counter sales; the European restriction is a cosmetics rule.
  • "Stronger is better." Above 4% irritation rises faster than benefit, and that is the range where ochronosis has most often been reported.
  • "If I use it forever, the melasma will stay away." Continuous use is what causes trouble. Courses with breaks plus daily sun protection is how it is used.
  • "Natural lightening creams are safer." Some imported products sold as natural have been found to contain undeclared hydroquinone, potent steroids or mercury. Unlabeled is not gentle.
  • "It works on every dark spot equally." It works best on flat brown patches in the upper layers. Deeper pigment responds poorly, and anything raised or changing is different.

Questions Patients Ask

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How is this different from over-the-counter hydroquinone?

There is no over-the-counter version in the United States any more. Until 2020, 2% could be sold without one. Four percent is the usual prescription strength, and Dermapedia covers hydroquinone as an ingredient separately.

How long can I use it for?

Courses of three to four months, with a break of two to three months between. Continuous use over years causes the problems, more than the strength.

What is exogenous ochronosis?

A blue-black, gray or sooty darkening of the treated skin, sometimes with tiny gritty bumps, from long-term use. Uncommon, hard to treat, and reported most after long unbroken courses at higher strengths. It is why courses have end dates.

Will the pigment come back if I stop?

Melasma usually does, because hydroquinone suppresses pigment production rather than removing the cells that make it. Marks left by acne often stay faded. Sun protection and a gentler maintenance cream hold the result.

Do I really need sunscreen every day?

Yes. Ultraviolet and visible light drive the pigment the cream is suppressing. Tinted mineral sunscreen also blocks some visible light, which matters in melasma.

Is it safe on deeper skin tones?

It is used on all skin tones, and much of the melasma evidence comes from people with deeper skin tones. Two cautions: ochronosis is reported more often in deeper skin tones, and irritation can leave a new dark mark. Short courses and a doctor watching the skin handle that.

References

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