Hydroquinone

What it is

Hydroquinone is a small phenolic molecule (1,4-benzenediol) formulated as a topical cream, gel or emulsion for lightening hyperpigmented skin. In the United States it is sold as a prescription product, usually at 4%, alone or combined with tretinoin and a corticosteroid; TRI-LUMA Cream is the approved fixed combination and contains 40 mg of hydroquinone per gram (4%) with fluocinolone acetonide 0.01% and tretinoin 0.05%. It has been in cosmetic skin-lightening products since the 1950s and in medicinal products since the 1960s, and has been prohibited in cosmetic skin-lightening formulations in the European Union since 2001. Over-the-counter hydroquinone skin-lightening products were removed from the US market by a recent ban.

What the research says

The evidence for hydroquinone is moderate for lightening melasma and weak for everything else. Randomised trials show it lightens melasma, but the trials are small, short and poorly reported, and the Cochrane review of melasma treatments judged the whole literature to be of generally poor quality. Hydroquinone alone is clearly less effective than the triple-combination cream that contains it, and a 2023 meta-analysis found 20% azelaic acid reduced melasma severity scores slightly more than hydroquinone. It inhibits tyrosinase, the enzyme that makes melanin. The characteristic harm is exogenous ochronosis, a blue-black paradoxical darkening reported mainly after long use of concentrations above 4%.

Evidence grade: Limited evidence.

How it works

Drug class: Topical depigmenting agent; tyrosinase inhibitor (melanin synthesis inhibitor)

Hydroquinone blocks tyrosinase, the enzyme melanocytes use to turn tyrosine into melanin, so less pigment is made in the treated patch of skin. It acts on pigment production rather than on inflammation, which is why reviewers argue agents with a second anti-inflammatory action may suit melasma better. Because it works on new melanin rather than pigment already in the skin, visible lightening takes weeks and fades when the drug is stopped. (Source 1)

What it is used for

• In the two pivotal 8-week trials the triple-combination cream cleared melasma in 38% and 13% of subjects versus 15% and 4% for hydroquinone 4% plus tretinoin, so the absolute gain over the dual combination was about 23 and 9 percentage points. The Cochrane review put the triple combination ahead of hydroquinone alone at RR 1.58 (95% CI 1.26 to 1.97). Evidence: established. (Source 2)
• Hydroquinone alone lightens melasma in randomised trials, but it is beaten by the triple-combination cream and by 20% azelaic acid on severity scores, and the Cochrane review called the quality of the melasma literature generally poor. A 2022 investigator-blinded systematic review rated confidence in the effect estimates as ranging from very low to high. Evidence: limited. (Source 3)
• Hydroquinone has long been used for these conditions and a 2024 safety review lists them among its uses, but the approved combination product's own label states that its safety and efficacy in hyperpigmentation other than facial melasma have not been studied, and we found no systematic review quantifying benefit for them. Evidence: limited. (Source 4)
• One small randomised split-face laser trial reported that applying 1% hydroquinone around the treated area significantly reduced post-inflammatory hyperpigmentation (p = 0.02), but this was a secondary observation in a 30-patient trial of laser parameters, not a trial designed to test hydroquinone. Evidence: limited. (Source 4)

Interactions

• Other depigmenting and keratolytic topicals applied to the same skin (tretinoin, corticosteroid, azelaic acid, peels) (clinical trial): Combining hydroquinone with tretinoin and a topical corticosteroid works better than hydroquinone alone but irritates more: erythema and desquamation affected 41% and 38% of subjects in the registration trials. (Source 5)
• Sunlight and ultraviolet or visible light exposure (clinical trial): Hydroquinone's effect depends on photoprotection: the trials provided SPF 30 sunscreen to everyone, and a 2022 systematic review found broad-spectrum sunscreen covering visible as well as ultraviolet light increases how well hydroquinone works. (Source 6)
• Benzoyl peroxide, hydrogen peroxide and other oxidising agents (pharmacokinetic study): We found no interaction study for hydroquinone with supplements, foods or alcohol. The documented interactions are local and physical - what else is put on the same patch of skin, and how much light reaches it - and skin penetration varies about tenfold between formulations, which is the pharmacokinetic variable that matters. (Source 7)

Stopping it

• Melasma usually comes back after hydroquinone is stopped, and the approved combination product is not licensed for maintenance; there is no taper and no withdrawal syndrome described. (Source 8)
• Treatment is meant to be stopped once the pigmentation is controlled rather than continued indefinitely, which is also the main way the ochronosis risk is limited, since that risk rises with courses longer than three months. (Source 9)
• If the paradoxical blue-black darkening of exogenous ochronosis appears, the label's position is that treatment should be discontinued. (Source 10)

What goes wrong

Exogenous ochronosis, a blue-black paradoxical darkening, is reported after hydroquinone use, most often with concentrations above 4% and courses longer than three months. (Source 9)

• Systematic review, Very low certainty.
• Size: 56 articles, 126 patients.
• Who: people using hydroquinone, most often middle-aged women of African descent with Fitzpatrick skin types V-VI.
• How long: median duration of use 5 years.
• Result: Reported most often at concentrations greater than 4% (35.7% of cases); only four cases followed courses of 3 months or shorter. No denominator, so no rate can be calculated.
• Funding: not stated in the abstract.

Based on these findings, we conclude that hydroquinone in concentrations above 4% and in treatment courses longer than 3 months may be associated with new-onset ochronosis.

Ochronosis was reported mainly in patients with darker skin and always as facial blue-black or grey-blue reticulate macules. (Source 9)

• Systematic review, Very low certainty.
• Size: 126 patients in 56 published reports.
• Who: hydroquinone users with ochronosis.
• How long: median 5 years of use.
• Result: Middle-aged women 53.2%, African descent 45.2%, Fitzpatrick skin types V-VI 52.4%.
• Funding: not stated in the abstract.

Ochronosis was most often reported in middle-aged women (53.2%), of African descent (45.2%), Black races (55.5%), and Fitzpatrick skin types V-VI (52.4%).

Local irritation is common with the hydroquinone-containing triple-combination cream: 63% of subjects had at least one treatment-related adverse event in the registration trials. (Source 5)

• Official position, Moderate certainty.
• Size: 161 subjects on the active cream.
• Who: adults with moderate to severe facial melasma.
• How long: 8 weeks.
• Result: 102/161 (63%) had at least one treatment-related adverse event; erythema 66 (41%), desquamation 61 (38%), burning 29 (18%), dryness 23 (14%), pruritus 18 (11%), acne 8 (5%). No placebo arm - the comparators were other active combinations.
• Funding: industry-funded (Galderma trials, reported in the FDA label)

There were 102 (63%) subjects who experienced at least one treatment-related adverse event during these trials.

Skin irritation, itching, burning and stinging were the adverse events most often reported across the melasma trials, and were mild and transient. (Source 11)

• Systematic review, Low certainty.
• Size: 20 studies, 2,125 participants.
• Who: adults with melasma.
• How long: short trials.
• Result: No rates given; described qualitatively as mild and transient.
• Funding: independent (Cochrane review)

The adverse events most commonly reported were mild and transient such as skin irritation, itching, burning, and stinging.

Hydroquinone has been linked to leukoderma-en-confetti and occupational vitiligo as well as ochronosis, and was banned from cosmetic skin lighteners in the European Union in 2001 for these reasons. (Source 12)

• Expert review, not systematic, Very low certainty.
• Size: not applicable - discussion within a meta-analysis.
• Who: users of cosmetic skin-lightening products.
• How long: long-term use.
• Result: No rates reported; this is the review authors' summary of the regulatory history.
• Funding: independent - no financial support received.

Because of side effects such as leukoderma-en-confetti, occupational vitiligo, and exogenous ochronosis, hydroquinone has been prohibited from use in cosmetic skin-lightening formulations in countries of the European Union since 2001

How much hydroquinone gets through the skin varies about tenfold between commercial products and does not track the labelled strength. (Source 7)

• Blood level study, Low certainty.
• Size: 10 former OTC and prescription products in human ex vivo skin, plus suction blister sampling from two products.
• Who: human ex vivo skin in Franz diffusion cells, plus in vivo interstitial fluid sampling.
• How long: 48 hours of permeation.
• Result: Total absorption varied from 27 to 279 mcg/cm2/48 h with no correlation to labelled drug concentration.
• Funding: not stated in the abstract.

Total absorption varied from 27 to 279 μg/cm2/48 h, and neither total absorption nor the rates of absorption were found to correlate with labeled drug concentration.

The hydroquinone-containing combination product's label records exogenous ochronosis as a reason to stop treatment and says it affects mainly Black patients. (Source 10)

• Official position, Certainty not rated.
• Size: not stated.
• Who: users of the triple-combination cream.
• How long: not stated.
• Result: No rate given in the label.
• Funding: not applicable - regulator-approved labelling, effective 10/24/2024.

TRI-LUMA Cream contains hydroquinone, which may produce exogenous ochronosis, a gradual blue-black darkening of the skin, the occurrence of which should prompt discontinuation of therapy.

What the evidence supports

The triple-combination cream containing hydroquinone lightened melasma more often than hydroquinone alone. (Source 3)

• Systematic review, Low certainty.
• Size: 20 studies, 2,125 participants across 23 treatments.
• Who: adults with epidermal, dermal or mixed melasma.
• How long: mostly 8 weeks or less.
• Result: Triple-combination cream versus hydroquinone alone RR 1.58 (95% CI 1.26 to 1.97); versus tretinoin plus hydroquinone RR 2.75 (95% CI 1.59 to 4.74)
• Funding: independent (Cochrane review)

Triple-combination cream was significantly more effective at lightening melasma than hydroquinone alone (RR 1.58, 95% CI 1.26 to 1.97) or when compared to the dual combinations of tretinoin and hydroquinone (RR 2.75, 95% CI 1.59 to 4.74)

In the two registration trials, clearance of melasma with the triple combination was 38% and 13% against 15% and 4% with hydroquinone 4% plus tretinoin in the same vehicle. (Source 2)

• Official position, Moderate certainty.
• Size: 641 subjects randomised across two trials; 85/83 and 76/75 in the two arms quoted.
• Who: adults aged 21 to 75, Fitzpatrick skin types I-IV, moderate to severe facial melasma.
• How long: 8 weeks.
• Result: Trial 1: 32/85 (38%) versus 12/83 (15%), p < 0.001. Trial 2: 10/76 (13%) versus 3/75 (4%), p = 0.045. Success was complete clearing of hyperpigmentation.
• Funding: industry-funded (Galderma registration trials, reported in the FDA label)

TRI-LUMA HQ+RA FA+RA FA+HQ Trial 1 Subjects, n 85 83 85 85 Successes, n 32 12 0 3 Proportion of Successes 38% 15% 0 4%

A 2022 investigator-blinded systematic review concluded hydroquinone is effective at lightening melasma but that confidence in the estimates ranged from very low to high. (Source 6)

• Systematic review, Low certainty.
• Size: 36 studies reporting 47 comparisons.
• Who: people diagnosed with melasma.
• How long: varied; mostly short.
• Result: Pooling was possible for only two of 47 comparisons; GRADE confidence very low to high.
• Funding: not stated in the abstract.

Our findings indicate that TCC and its individual components HQ and tretinoin are effective in lightening melasma

What the evidence does not support

Azelaic acid 20% reduced melasma severity scores slightly more than hydroquinone, so hydroquinone was not the better of the two. (Source 13)

• Meta-analysis, Low certainty.
• Size: 6 randomised trials, 673 patients.
• Who: patients with melasma.
• How long: not stated in the abstract; trials were short.
• Result: Mean change in MASI favoured azelaic acid, MD -1.23 (95% CI -2.05 to -0.40), P = 0.004.
• Funding: independent - the authors declared no financial support was received.

The azelaic acid had a lower mean change in melasma area severity index (MASI) than the hydroquinone group [MD= -1.23, 95% CI (-2.05, -0.40), P=0.004]

On the other melasma outcomes - objective response, degree of pigment reduction and adverse events - azelaic acid and hydroquinone did not differ. (Source 13)

• Meta-analysis, Low certainty.
• Size: 6 randomised trials, 673 patients.
• Who: patients with melasma.
• How long: short-term trials.
• Result: No difference on objective response scale, pigment reduction or adverse events; reduction in pigmentation by one level RR 1.13 (95% CI 0.89 to 1.44), P = 0.32.
• Funding: independent - no financial support received.

No difference was observed regarding the improvement via the objective response scale, the reduction in pigmentation, or the adverse events reported.

The Cochrane reviewers judged the melasma treatment literature, hydroquinone included, to be of generally poor quality with inadequate treatments. (Source 11)

• Systematic review, Low certainty.
• Size: 20 studies, 2,125 participants.
• Who: adults with melasma.
• How long: short studies.
• Result: No pooled estimate; the review reports poor methodology, no standardised outcome assessment and short duration.
• Funding: independent (Cochrane review)

The quality of studies evaluating melasma treatments was generally poor and available treatments inadequate.

Pooled adverse-event rates for hydroquinone versus azelaic acid were imprecise to the point of being uninformative, with confidence intervals spanning several hundredfold. (Source 14)

• Meta-analysis, Very low certainty.
• Size: 6 randomised trials, 673 patients.
• Who: patients with melasma.
• How long: short-term trials.
• Result: Local irritation RR 2.23 (95% CI 0.44 to 11.33), P = 0.33; itching RR 2.73 (95% CI 0.03 to 245.21), P = 0.66; scaling RR 3.32 (95% CI 0.52 to 21.15), P = 0.20.
• Funding: independent - the authors declared no financial support was received.

For local irritation, [RR= 2.23, 95% CI (0.44 to 11.33), P=0.33]; for itching, [RR= 2.73, 95% CI (0.03 to 245.21), P=0.66]; and for scaling, [RR= 3.32, 95% CI (0.52 to 21.15), P=0.20}

The meta-analysis comparing hydroquinone with azelaic acid rests on only six small trials, which its authors say limits how far the result generalises. (Source 15)

• Meta-analysis, Very low certainty.
• Size: 6 randomised trials, 673 patients.
• Who: patients with melasma.
• How long: short-term; no long-term follow-up.
• Result: No effect estimate - this is the authors' own appraisal of their evidence base.
• Funding: independent - all authors declared that no financial support was received from any organization for the submitted work.

This meta-analysis does have some limitations, most notably the very small sample sizes of the included publications (only six), which may restrict the generalizability of our results.

Where the evidence is mixed

Azelaic acid 20% beat 2% hydroquinone but did not beat 4% hydroquinone, which is the strength actually prescribed. (Source 3)

• Systematic review, Low certainty.
• Size: 20 studies, 2,125 participants.
• Who: adults with melasma.
• How long: short-term trials.
• Result: Azelaic acid 20% versus 2% hydroquinone RR 1.25 (95% CI 1.06 to 1.48); versus 4% hydroquinone RR 1.11 (95% CI 0.94 to 1.32)
• Funding: independent (Cochrane review)

Azelaic acid (20%) was significantly more effective than 2% hydroquinone (RR 1.25, 95% CI 1.06 to 1.48) at lightening melasma but not when compared to 4% hydroquinone (RR 1.11, 95% CI 0.94 to 1.32)

In a Cochrane-based review of melasma treatments, the triple-combination cream containing hydroquinone lightened melasma more than hydroquinone alone, so hydroquinone works as part of a combination but was outperformed by it when used on its own. (Source 16)

• Systematic review, Low certainty.
• Size: 20 studies, 2125 participants, 23 different treatments.
• Who: people with melasma.
• How long: short-term studies.
• Result: Triple-combination cream versus hydroquinone alone: relative risk 1.58 (95% CI 1.26-1.97)
• Funding: not stated in the abstract.

Triple-combination cream (hydroquinone, tretinoin, and fluocinolone acetonide) was more effective at lightening melasma than hydroquinone alone (relative risk 1.58, 95% confidence interval 1.26-1.97)

Where the research disagrees

Whether topical hydroquinone poses a cancer risk in humans

• Nordlund and colleagues, JEADV 2006 review, narrative review of safety data: However, despite 40-50 years use of hydroquinone for medical conditions, there has not been a single documented case of either a cutaneous or internal malignancy associated with this drug. (Source 17)
• Albzea and colleagues, Cureus 2023 meta-analysis discussion, discussion within a systematic review and meta-analysis, citing animal and metabolite data: However, recent evidence indicates that additional potential long-term impacts, like carcinogenesis, may also be anticipated ⁴⁷. The majority of carcinogenesis is caused by hydroquinone metabolites that are produced in the liver ⁴⁷. (Source 12)

How much

• Reference intake: There is no reference intake for a topical drug. Dosing is set by the prescriber. The approved combination product's label states as a position (effective 10/24/2024) that a thin film is applied to the affected area once daily, at least 30 minutes before bedtime, and that therapy should be discontinued when control is achieved. (Source 18)
• Upper limit: No upper limit is set for a topical drug. The approved strength is a position of the regulator: cream 0.01%/4%/0.05%, that is 40 mg of hydroquinone per gram, applied once daily for short-term use; the label states it is not indicated for maintenance treatment. (Source 8)
• Studied: The two registration trials gave hydroquinone 4% in the triple-combination cream, or hydroquinone 4% with tretinoin 0.05%, once nightly for 8 weeks, with SPF 30 sunscreen and sun avoidance for everyone. (Source 19)
• Studied: The melasma trials pooled by Cochrane used hydroquinone at 2% and at 4%, compared with 20% azelaic acid and with combination creams. (Source 3)
• Studied: A split-face laser trial applied 1% hydroquinone cream nightly to one periorbital area for one month before and from day 8 to one month after each laser session. (Source 4)

A common belief, and what the research shows

The belief: Hydroquinone is a strong bleach that permanently removes dark patches.

What the research shows: It inhibits new pigment rather than destroying existing pigment, and the pigment usually returns when it is stopped. The approved combination product is explicitly not for maintenance and its own label records that “Melasma usually recurs upon discontinuation of TRI-LUMA Cream.” The review literature is also blunt that treatment is not very good: the Cochrane authors wrote that “The quality of studies evaluating melasma treatments was generally poor and available treatments inadequate.”

Questions and answers

What is it?

Hydroquinone is a topical prescription medicine for lightening dark patches of skin. In the United States the usual strength is 4%, used alone or in the approved fixed combination with tretinoin and the corticosteroid fluocinolone acetonide. It has been in skin-lightening cosmetics since the 1950s and in medicines since the 1960s, and it has been banned from cosmetic skin lighteners in the European Union since 2001. (Source 12)

What does it do in the body?

It blocks tyrosinase, the enzyme melanocytes use to make melanin, so the treated skin produces less new pigment. It does not act on inflammation, and it does not remove pigment that is already there, which is why lightening takes weeks and fades after stopping. (Source 1)

Is it good or bad for you?

It depends on the strength and how long it is used. At 4% for a short course in facial melasma it lightens pigment in randomised trials, though the trials are small and short and the Cochrane reviewers called the literature generally poor. Used for years, and especially above 4%, it is associated with exogenous ochronosis, a blue-black darkening that is the opposite of what people want and is hard to treat. Local irritation is common even in short courses. (Source 9)

How do you get more of it?

It is a prescription topical in the United States; over-the-counter hydroquinone skin-lightening products have been banned there. There is no dietary or behavioural way to get more of it, and nothing in the literature supports increasing exposure. Studies that compared commercial hydroquinone products found how much actually crosses the skin varies about tenfold and does not follow the strength on the label. (Source 4)

If it is harmful, what reduces it?

Stopping the cream is the intervention. The label's position is that ochronosis, the main hydroquinone-specific harm, should prompt stopping treatment. Pigment that was suppressed returns after stopping, so melasma usually recurs. The ochronosis systematic review found no satisfactory treatment for the pigment once it has appeared. (Source 20)

Why might someone be low in it or missing it?

Nobody is naturally short of hydroquinone - it is a medicine, not a nutrient. Reasons someone might not be using it include the US ban on over-the-counter products, the European ban in cosmetics since 2001, intolerance of the irritation, and the label's own limits: it is not for maintenance, has not been studied in Fitzpatrick skin types V and VI, and has not been studied in pregnancy or breastfeeding. (Source 8)

Which whole foods contain it or feed it?

No food is a relevant source of hydroquinone as used here, and no food or supplement interaction has been documented for the topical drug. What the literature does show is that photoprotection changes how well it works: in the trials everyone was given SPF 30 sunscreen and told to avoid sun, and a 2022 review found sunscreen covering visible as well as ultraviolet light improved results. (Source 6)

We searched: Europe PMC for hydroquinone with dietary exposure and food; the retrieved records concerned hydroquinone-containing metabolites in metabolomics studies, not dietary sources relevant to the topical drug. Searched Europe PMC and the Cochrane melasma review for supplement, food and alcohol interactions with topical hydroquinone and found none.

What happens if you do not have it?

Nothing physical. Melasma itself causes no pain or medical complications; it is a cosmetic and psychological problem that can weigh heavily on quality of life. Without treatment the pigmentation persists and recurs, and treatment options other than hydroquinone exist, including the triple-combination cream, tretinoin and azelaic acid. (Source 21)

How can you test for it?

There is no routine clinical blood or urine test for hydroquinone and no test is needed to prescribe it. The response is judged by looking at the skin, using severity scores such as the Melasma Area and Severity Index in trials. Research methods can measure it: an in vitro permeation test on human skin plus suction blister sampling of interstitial fluid was used to compare how much hydroquinone different products deliver, and the in vivo and in vitro results agreed. (Source 7)

References

1. Cureus. Azelaic Acid Versus Hydroquinone for Managing Patients With Melasma: Systematic Review and Meta-Analysis of Randomized Controlled Trials (Discussion: mechanism). 2023. DOI 10.7759/cureus.41796. Read the source
2. DailyMed / Galderma Laboratories, L.P.. TRI-LUMA (fluocinolone acetonide, hydroquinone, and tretinoin) cream, for topical use - FDA prescribing information, label effective 10/24/2024 (14 Clinical Studies, Table 2). 2024. Read the source
3. The Cochrane database of systematic reviews. Interventions for melasma. (Main results). 2010. PMID 20614435, DOI 10.1002/14651858.cd003583.pub2. Read the source
4. Archives of dermatological research. An update on the safety of hydroquinone.. 2024. PMID 38850450, DOI 10.1007/s00403-024-02990-6. Read the source
5. DailyMed / Galderma Laboratories, L.P.. TRI-LUMA (fluocinolone acetonide, hydroquinone, and tretinoin) cream, for topical use - FDA prescribing information, label effective 10/24/2024 (6 Adverse Reactions). 2024. Read the source
6. The British journal of dermatology. Self-applied topical interventions for melasma: a systematic review and meta-analysis of data from randomized, investigator-blinded clinical trials. (Results and Conclusions). 2022. PMID 35290681, DOI 10.1111/bjd.21244. Read the source
7. Skin pharmacology and physiology. Bioavailability of Hydroquinone from Topical Formulations: A Product Comparison Study Using the in vitro Permeation Test.. 2025. PMID 40179833, DOI 10.1159/000545618. Read the source
8. DailyMed / Galderma Laboratories, L.P.. TRI-LUMA (fluocinolone acetonide, hydroquinone, and tretinoin) cream, for topical use - FDA prescribing information, label effective 10/24/2024 (1 Indications and Usage; Limitations of Use). 2024. Read the source
9. International Journal of Dermatology. Exogenous ochronosis associated with hydroquinone: a systematic review. (Abstract, Results and Conclusions). 2022. PMID 34486734, DOI 10.1111/ijd.15878. Read the source
10. DailyMed / Galderma Laboratories, L.P.. TRI-LUMA (fluocinolone acetonide, hydroquinone, and tretinoin) cream, for topical use - FDA prescribing information, label effective 10/24/2024 (5.2 Exogenous Ochronosis). 2024. Read the source
11. The Cochrane database of systematic reviews. Interventions for melasma. (Adverse events and Authors' conclusions). 2010. PMID 20614435, DOI 10.1002/14651858.cd003583.pub2. Read the source
12. Cureus. Azelaic Acid Versus Hydroquinone for Managing Patients With Melasma: Systematic Review and Meta-Analysis of Randomized Controlled Trials (Discussion: hydroquinone history and regulation). 2023. DOI 10.7759/cureus.41796. Read the source
13. Cureus. Azelaic Acid Versus Hydroquinone for Managing Patients With Melasma: Systematic Review and Meta-Analysis of Randomized Controlled Trials (Abstract). 2023. DOI 10.7759/cureus.41796. Read the source
14. Cureus. Azelaic Acid Versus Hydroquinone for Managing Patients With Melasma: Systematic Review and Meta-Analysis of Randomized Controlled Trials (Results: Adverse Events). 2023. DOI 10.7759/cureus.41796. Read the source
15. Cureus. Azelaic Acid Versus Hydroquinone for Managing Patients With Melasma: Systematic Review and Meta-Analysis of Randomized Controlled Trials (Limitations and future research). 2023. DOI 10.7759/cureus.41796. Read the source
16. Journal of the American Academy of Dermatology. Systematic review of randomized controlled trials on interventions for melasma: an abridged Cochrane review.. 2014. PMID 24438951, DOI 10.1016/j.jaad.2013.07.044. Read the source
17. Journal of the European Academy of Dermatology and Venereology : JEADV. The safety of hydroquinone.. 2006. PMID 16898897, DOI 10.1111/j.1468-3083.2006.01670.x. Read the source
18. DailyMed / Galderma Laboratories, L.P.. TRI-LUMA (fluocinolone acetonide, hydroquinone, and tretinoin) cream, for topical use - FDA prescribing information, label effective 10/24/2024 (2 Dosage and Administration). 2024. Read the source
19. DailyMed / Galderma Laboratories, L.P.. TRI-LUMA (fluocinolone acetonide, hydroquinone, and tretinoin) cream, for topical use - FDA prescribing information, label effective 10/24/2024 (14 Clinical Studies). 2024. Read the source
20. International journal of dermatology. Exogenous ochronosis associated with hydroquinone: a systematic review. (Abstract, first part). 2022. PMID 34486734, DOI 10.1111/ijd.15878. Read the source
21. Cureus. Azelaic Acid Versus Hydroquinone for Managing Patients With Melasma: Systematic Review and Meta-Analysis of Randomized Controlled Trials (Introduction). 2023. DOI 10.7759/cureus.41796. Read the source