SkincarePigmentation GuideAug 2026

Melasma: Why It Happens and What the Evidence Says Actually Fades It

Search for melasma and you mostly get products named after the condition. This page is the other thing: what is going on in the skin, what the controlled trials actually measured, where the evidence disagrees with itself, and why the patches come back. No product is being sold here.

49% vs 18%

mMASI drop at 3 months, oral tranexamic acid vs placebo

15%

Extra MASI improvement when sunscreen also blocked visible light

27.2%

Relapse rate among responders after oral tranexamic acid

What Melasma Is

Melasma is described in the literature as an acquired, symmetrical disorder of pigmentation. Merging brown to grey patches settle on the face, usually across both cheeks, the forehead, the upper lip or the jawline, and they mirror each other side to side. That symmetry is the giveaway, and it is what separates melasma from a single sun spot or a mark left behind by a healed pimple.

The single most useful thing to understand is that it is chronic. The Cochrane review that assessed treatments for it opened by stating that available treatments for melasma are unsatisfactory, and closed by describing the trial quality as generally poor and the available treatments as inadequate (Rajaratnam et al., Cochrane Database Syst Rev 2010, PMID 20614435). That review is now dated, and better trials have run since, but nothing published after it has overturned the shape of the problem. Melasma is managed. It is not cured by a tube of anything.

It is also not trivial to the person who has it. A systematic review of 14 studies covering 1,398 melasma patients using the Melasma Quality of Life scale found a consistent negative effect on emotional wellbeing and social life, with patients most bothered by the appearance of the condition. The same review found the link between severity scores and quality of life scores was mixed, with 5 studies reporting a statistically significant correlation and 7 reporting none (Zhu et al., PLoS One 2022, PMID 35085327). Small patches can bother someone a great deal. That is a documented pattern, not a failure of perspective.

Why It Happens

For a long time melasma was described as simply overactive melanocytes making too much pigment in the top layer of skin. A 2025 review in the International Journal of Dermatology sets out a wider picture drawn from the current literature: changes in the epidermis, alterations to the basement membrane that separates epidermis from dermis, and several dermal findings including solar elastosis, mast cell activity, vascular changes and senescent fibroblasts, with visible light and hormonal fluctuation acting on top of all of it (Ali and Al Niaimi, Int J Dermatol 2025, PMID 40022484).

That matters for expectations. If part of the driver sits below the pigment layer, in the vessels and the supporting tissue, then a cream that shuts down pigment production is treating one part of a multi-part problem. It explains why melasma responds and then rebounds, and why the deeper and mixed types respond less well than surface pigment does.

The exposures most consistently linked to it

Sunlight, including the visible part of the spectrum that standard broad-spectrum sunscreen does not stop.
Hormonal change. In 400 pregnant women examined in Tehran, 15.8 percent had melasma, 95 percent confidence interval 12.3 to 19.4, and 11.3 percent of the melasma cases in that study said theirs appeared after starting an oral contraceptive.
Family history. In that same Tehran group, 54.7 percent of melasma cases had a positive family history.
Skin phototype. That study found a statistically significant relationship between melasma and three things: ethnicity, phototype and grade of parity.
Heat and inflammation are widely discussed as aggravators, and are handled in the pathogenesis literature through vascular and mast cell involvement rather than as a settled independent trigger.

Two cautions on those numbers. They come from a cross-sectional study carried out by clinical examination and questionnaire on 400 pregnant women at the Shahed University hospitals in Tehran, Iran (Moin et al., Int J Dermatol 2006, PMID 16533230), so they describe that group, not women in general and not women in Vietnam. And the same study found no significant relationship between melasma and use of sunscreens, trimester of pregnancy, thyroid or liver history, or eye and hair colour, which is worth knowing because the liver theory circulates widely. The sunscreen result needs care rather than removal. All 400 women were examined and questioned at one point in time, so melasma status and reported sunscreen use were captured together. That cannot separate sunscreen which failed to prevent the patches from sunscreen taken up because of them, and it is not a test of whether photoprotection helps once melasma is being treated.

The Light Problem, Including the Light Sunscreen Misses

Every serious melasma protocol in the literature is built on photoprotection, and there is a specific reason melasma keeps moving despite daily sunscreen. Visible light, the part of sunlight you can see, induces pigmentation in darker skin. A review of tinted sunscreens in the Journal of the American Academy of Dermatology explains the mechanical catch plainly: for a sunscreen to block visible light it has to be visible on the skin. Zinc oxide and titanium dioxide are milled down to nanoparticles precisely so they stop looking chalky, and at that particle size they do not protect against visible light. Tinted products get that protection back by using iron oxides and pigmentary titanium dioxide, which is why they come in shades (Lyons et al., J Am Acad Dermatol 2021, PMID 32335182).

That is not just mechanism. A double-blind randomised trial in San Luis Potosi, Mexico put 68 melasma patients on 4 percent hydroquinone and then randomised the sunscreen: one arm got a sunscreen with iron oxide as a visible-light absorbing pigment, the other got a conventional broad-spectrum UV-only sunscreen, both at SPF 50 or above. Sixty-one finished. At 8 weeks the visible-light arm showed 15 percent greater improvement in MASI, 28 percent greater on colorimetry, and 4 percent greater on histological melanin than the UV-only arm (Castanedo-Cazares et al., Photodermatol Photoimmunol Photomed 2014, PMID 24313385). The 68 and the 61 are both arms combined, not the tinted arm.

A later systematic review of investigator-blinded trials of self-applied topicals reached the same direction, concluding that sunscreen covering both the ultraviolet and visible spectra increases treatment efficacy compared with UV-only protection (Pennitz et al., Br J Dermatol 2022, PMID 35290681). Note what that says. Tinted sunscreen made the hydroquinone work better. It was not tested as a treatment on its own.

Worth naming: a survey subanalysis of 3,000 respondents found that the share who systematically use several sun protection measures together, meaning sunscreen plus shade plus a hat plus clothing plus avoiding midday sun, was 22 percent in China, 13 percent in Indonesia and 3 percent in Japan (Goh et al., Photodermatol Photoimmunol Photomed 2024, PMID 38059515). Those are the three countries surveyed. Vietnam was represented on the paper by a dermatologist from Hanoi Medical University and the National Hospital of Dermatology and Venereology, on the expert panel, not in the survey data. There is no Vietnamese figure in that paper and this page will not invent one.

What Is Actually Inside a Melasma Cream

Products marketed for melasma are mostly built from a short list of ingredients that interfere with pigment production. Here is what the controlled evidence says about each one, and where it stops.

Agent	What the trials found	Evidence weight
Triple combination cream	Hydroquinone 4% with tretinoin 0.05% and fluocinolone acetonide 0.01%. Beat hydroquinone alone, risk ratio 1.58, 95% CI 1.26 to 1.97, in the Cochrane review.	Strongest
Hydroquinone 4%	The comparator almost every newer agent is measured against, and the most studied single topical. Prescription-strength in the countries that regulate it.	Strongest
Cysteamine 5%	Beat placebo on MASI, standardised mean difference -0.84, 95% CI -1.19 to -0.49. No significant difference against hydroquinone 4%, SMD 0.16, 95% CI -0.22 to 0.53.	Moderate, 7 trials
Thiamidol 0.2%	mMASI fell 43% versus 33% for hydroquinone 4% over 90 days, with no statistically significant difference between the two groups.	Single 50-woman trial
Topical vitamin C	Significant lightening on objective pigmentation measures, from a review of 7 publications totalling 139 volunteers. Long-term use may be needed.	Thin, small studies
Tretinoin alone	Reduced severity on objective measures in both placebo-controlled studies Cochrane assessed, though participants themselves rated it significantly improved in one and not the other.	Moderate
Azelaic acid 20%	Beat hydroquinone 2%, risk ratio 1.25, 95% CI 1.06 to 1.48, but did not beat hydroquinone 4%, risk ratio 1.11, 95% CI 0.94 to 1.32.	Covered separately

Sources for that table, in order: Rajaratnam et al., Cochrane Database Syst Rev 2010, PMID 20614435 for the triple combination, tretinoin and azelaic acid rows; McKesey et al., Am J Clin Dermatol 2020, PMID 31802394 for the standing of hydroquinone across 113 studies and 6,897 participants; Mawu and Christopher, Arch Dermatol Res 2024, PMID 39673630 for cysteamine; Lima et al., J Eur Acad Dermatol Venereol 2021, PMID 33988887 for thiamidol; Correia and Magina, J Cosmet Dermatol 2023, PMID 37128827 for vitamin C. Azelaic acid has its own page here, the azelaic acid guide, and this page deliberately leaves the detail there.

Two readings of that table are wrong and both are common. The first is that a newer agent matching hydroquinone means it is better. Cysteamine matching hydroquinone 4 percent is a tie, not a win, and in the same meta-analysis the rate of erythema, irritation, burning, itching and dryness was higher with cysteamine than with placebo, and similar between cysteamine and hydroquinone. The second is that a small trial and a large one carry the same weight. The thiamidol result comes from 50 women in Brazil, mean age 43, 86 percent phototypes III to IV, over 90 days, and both arms in that trial were also given a tinted SPF 60 sunscreen. Adverse effects in the thiamidol arm were described as mild, but allergic contact dermatitis was documented in two participants, reported as 8 percent of that arm.

The triple combination result is also worth reading in full. In a multicentre randomised trial in East and Southeast Asian patients with moderate to severe facial melasma, 64.2 percent of the triple combination group, 77 of 120, reached a global severity score of none or mild at week 8, against 39.4 percent, 48 of 122, on hydroquinone 4 percent. Related adverse events were far more frequent on the triple combination, 63 of 129 at 48.8 percent against 18 of 131 at 13.7 percent, although most were mild and none was severe (Chan et al., Br J Dermatol 2008, PMID 18616780). The better result came with more irritation. Both halves are the finding.

Approved, Or Just Listed

A regulatory point that changes how you read a product page. Appearing in a national drug database is a listing. It is not an approval, and the two are recorded in different fields.

Querying the openFDA National Drug Code directory, filtering the active_ingredients.name field for hydroquinone and restricting to finished products, returns 21 listed products in the United States as of the data refresh dated 4 August 2026. Reading the marketing_category field on each: 1 carries the category NDA, 19 carry the category unapproved drug other, and 1 is unapproved homeopathic. Twenty of the twenty-one are typed as human prescription drugs.

The single NDA entry

Tri-Luma cream, Galderma, application number NDA021112, a topical human prescription drug containing hydroquinone 40 mg per gram, fluocinolone acetonide 0.1 mg per gram and tretinoin 0.5 mg per gram. That is the triple combination formula the trials above tested, expressed as 4 percent, 0.01 percent and 0.05 percent. Its listed marketing start date is 18 January 2002.

So the everyday hydroquinone 4 percent creams in that same directory, including branded prescription skincare lines, sit under unapproved drug other. That is a US regulatory record and it describes the US market. Vietnam has its own registration system under the Drug Administration of Vietnam, and a product legally sold in one country tells you nothing about its status in another. The transferable lesson is narrower and more useful: if a seller says a product is approved, the honest question is approved by which authority, under which number, and in which country.

Oral Tranexamic Acid, The Most Interesting Recent Result

Tranexamic acid is an old clotting medicine that turned out to reduce melasma pigment. It is one of several newer directions in this field, alongside cysteamine and thiamidol, and it is the one where the route of administration changes the answer most sharply.

In a randomised, placebo-controlled, double-blind trial, 44 patients with moderate to severe melasma took 250 mg of tranexamic acid or placebo twice daily for 3 months alongside sunscreen, then continued sunscreen alone for a further 3 months. Thirty-nine completed. At 3 months, modified MASI scores had fallen 49 percent in the tranexamic acid group against 18 percent in the control group. Patients with severe melasma improved more than those with moderate melasma. No serious adverse events occurred in either group. The trial was run at a single centre and enrolled predominantly Hispanic women (Del Rosario et al., J Am Acad Dermatol 2018, PMID 28987494).

A meta-analysis of 24 randomised trials found that adding tranexamic acid to routine treatment improved MASI scores over routine treatment alone at 4, 8, 12 and 16 weeks. However, the authors state that the superiority of tranexamic acid was not detected when the topical or intradermal route was used (Feng et al., J Clin Pharm Ther 2021, PMID 33959984). That distinction gets flattened constantly in marketing copy. A tranexamic acid serum is not the thing that produced the oral trial result.

The largest safety picture comes from a retrospective review of 561 melasma patients given oral tranexamic acid at a tertiary dermatological centre in Singapore between January 2010 and June 2014, 91.4 percent of them women, median treatment duration 4 months. Improvement was recorded in 503 patients at 89.7 percent, 56 at 10.0 percent had no improvement, and 2 at 0.4 percent worsened. Adverse events occurred in 40 patients at 7.1 percent. Most were transient, but one patient developed a deep vein thrombosis that required prompt discontinuation, and she was later diagnosed with familial protein S deficiency. The authors conclude that careful screening for personal and familial risk factors for thromboembolism should be done before starting it (Lee et al., J Am Acad Dermatol 2016, PMID 27206758).

Read that carefully. The figures above are what the trials administered, described for understanding, not a plan for anyone. Tranexamic acid is a prescription medicine with clotting-related contraindications, and the single serious event in the largest series was in a patient with an inherited clotting disorder she did not know she had. Whether it is appropriate, and what screening comes first, is a conversation with a doctor or a pharmacist, not something to work out from a page.

Peels, Lasers and Devices, Where the Evidence Argues With Itself

This is the part of melasma care where two respectable sources reach opposite conclusions, and pretending otherwise would be dishonest.

The evidence-based review says topicals win

Reviewing 113 studies with 6,897 participants, the authors conclude that hydroquinone monotherapy and triple combination cream are the most effective and best studied treatments, whereas chemical peels and laser and light-based therapies are equal or inferior to topicals, but offer a higher risk of adverse effects (McKesey et al., Am J Clin Dermatol 2020, PMID 31802394).

The network meta-analysis ranks lasers first

Pooling 59 randomised trials across 14 therapies, this analysis ranked Q-switched Nd:YAG 1064 nm first for efficacy against placebo, followed by intense pulsed light and ablative fractional laser, with triple combination cream fourth and hydroquinone alone thirteenth of fourteen (Liu et al., Front Med 2021, PMID 34660626, registration CRD42021239203).

Both are peer reviewed. They differ in method: the network meta-analysis builds indirect comparisons between trials that never tested each other directly, using MASI as the common yardstick, while the evidence-based review appraises the trials individually and weighs their quality and duration. Neither is fraudulent and neither settles it. The network analysis does report one thing on combinations: among the 31 studies it counted, 87 percent, 27 of 31, showed combination therapy outperforming single therapy (Liu et al., Front Med 2021, PMID 34660626). That comes from Liu alone. The abstract of the evidence-based review makes no combination versus single comparison, and the full text is behind a subscription with no open access record, so this page will not claim what the rest of it does or does not contain. What its published conclusion does say is that hydroquinone on its own sits on the same footing as the triple combination.

On side effects, the network analysis reported rates for the therapies with more than 80 participants, ranging from 10.1 percent with tretinoin and 17.6 percent with oral tranexamic acid up to 38.0 percent with peeling and 52.3 percent with microneedling. Those are reported side effect rates. They are not discontinuation rates, and they should not be read as the share of people who had to stop. Melasma is also a condition where an aggressive procedure can leave post-inflammatory hyperpigmentation that looks worse than the original patch, which is the specific reason device treatment for melasma belongs with a clinician who treats a lot of it.

Why It Comes Back

The recurrence data is the most useful thing on this page, because it reframes what success even means.

In the placebo-controlled tranexamic acid trial, the treatment group was 49 percent down on modified MASI at 3 months while taking it. Three months after stopping, still using sunscreen, that group sat 26 percent below its own baseline, against 19 percent in the placebo arm. Most of the gap between the two arms had closed. In the Singapore series, of the 503 patients who improved, the relapse rate was 27.2 percent, and responders generally showed their response within 2 months of starting. That same series found patients without a family history of melasma responded better than those with one, 90.6 percent against 60.0 percent, p equals 0.01.

None of that means treatment is pointless. It means melasma behaves like a condition that is controlled while something is being done and drifts back when it is not, which is a completely different mental model from treating an infection. The part that carries over between courses is photoprotection, and it is the piece with a randomised trial showing it improves the result of the cream sitting on top of it.

Creams Bought Off a Shelf

Skin lightening products sold outside a pharmacy channel have a documented contamination problem in some markets, and a documented absence of one in others. Both results deserve stating, because the scare version of this story and the dismissive version are each half right.

Malaysia, 2017: 20 facial skin lightening creams bought from cosmetic stalls, beauty shops, pharmacies and street vendors, analysed by cold vapour atomic absorption spectrometry. Mercury ranged from not detected to 1.13 mg/kg. Every sample was below the US FDA permitted trace level of under 1 ppm except one, from the third price band, manufactured in China. Price band showed no significant association with mercury content, p equals 0.12, and the calculated non-carcinogenic risk from daily use over an assumed 30 years came out below the threshold of concern.
Pakistan, 2025: 12 whitening products from a local market in Faisalabad, analysed by ICP-OES. Mercury ran from 1.12 to 67.41 mg/kg, and concentrations of the metals tested exceeded World Health Organization permissible limits.

Sources: Ho et al., Regul Toxicol Pharmacol 2017, PMID 28554823, and Ahmad et al., Environ Monit Assess 2025, PMID 39930105. Each is a small survey of one local market. Twenty samples in one country and twelve in another cannot be stretched into a statement about global whitening products, and neither study tested anything bought in Vietnam. What they establish jointly is that contamination is a market-level and product-level question, not a category-level one, and that price is not a reliable signal in either direction.

The other risk in this category is the one the ingredient itself carries. A systematic review pooled 126 published cases of hydroquinone-associated exogenous ochronosis from 56 articles: a blue-black or grey-blue discolouration in a reticulate, lace-like pattern on the face, confirmed on biopsy by characteristic banana-shaped fibres in the papillary dermis. Median duration of hydroquinone use before onset was 5 years. Four of the 126 cases were reported after courses of 3 months or shorter and eight after a year or less. It was most frequently reported at concentrations above 4 percent, at 35.7 percent of cases, and where concentration was unknown, at 32.5 percent, and most reported patients were of African descent with Fitzpatrick skin types V to VI (Ishack and Lipner, Int J Dermatol 2022, PMID 34486734). Because this is a pooled review of case reports, it can describe who was reported and after how long, but it cannot give an incidence rate. The practical read is that unsupervised, open-ended, high-strength use is the pattern that shows up, which is exactly what an unlabelled cream bought off a market stall invites.

Where Peptides Do and Do Not Fit

Honest answer first: peptides are not a melasma treatment. Nothing in the trial evidence above involves them. The network meta-analysis names all 14 therapies it ranked and no peptide is among them, and the Cochrane review reports its interventions as bleaching agents, combination creams and a short list of less conventional lighteners, again with no peptide. If a product is sold to you as a peptide solution for melasma, that claim is not resting on any of the evidence reviewed here.

Where the interest is legitimate is adjacent. Copper peptides such as GHK-Cu are studied for skin repair and barrier support, and melasma care frequently involves irritating agents. Recall that in the Asian triple combination trial, related adverse events hit 48.8 percent of the triple combination arm, and in the thiamidol trial two participants developed allergic contact dermatitis. Whether barrier tolerance decides who finishes a course is a reasonable question, not something the sources here measured: in the thiamidol trial the one participant who did not complete it was in the hydroquinone arm, and the authors record that as unrelated to adverse effects (Lima et al., J Eur Acad Dermatol Venereol 2021, PMID 33988887). Tolerating a treatment is in any case a different claim from fading pigment, and the two should not be blurred into one.

For what the copper peptide evidence does and does not cover, including the difference between the topical and other formats, the topical GHK-Cu page sets out the boundaries.

The Short Version

Melasma is a chronic, symmetrical facial pigment condition involving the epidermis, the basement membrane and the dermis, not just surface pigment.
Photoprotection is the foundation, and visible light matters. A sunscreen has to be visible on the skin to block it, which is why tinted formulas exist.
Triple combination cream and hydroquinone are the best studied topicals, and the triple combination produced both better results and more irritation than hydroquinone alone.
Oral tranexamic acid produced a 49 percent versus 18 percent mMASI drop against placebo in a small trial, but the same benefit was not detected for the topical or intradermal route.
A drug appearing in a national database is a listing. In the US directory, 19 of 21 finished hydroquinone products are recorded as unapproved drug other and one carries an NDA.
It comes back. Relapse among responders was 27.2 percent in the largest series, which makes melasma a managed condition rather than a cured one.
None of this is a plan for a specific person. Melasma has a proper diagnosis, prescription options and a real risk of making it worse, so it belongs with a dermatologist.

Frequently Asked Questions

What causes melasma?+

It is a combination, not one trigger. A 2025 review in the International Journal of Dermatology describes melasma as involving overactive pigment cells in the epidermis, a damaged basement membrane between the epidermis and dermis, and changes deeper in the skin including solar elastosis, mast cell activity, new blood vessels and senescent fibroblasts (Ali and Al Niaimi, Int J Dermatol 2025, PMID 40022484). Sunlight and hormonal change are the two exposures most consistently tied to it. In 400 pregnant women examined in Tehran, 15.8 percent had melasma, and 54.7 percent of those cases had a family history of it (Moin et al., Int J Dermatol 2006, PMID 16533230).

What does the evidence say is the most effective melasma cream?+

Two large appraisals point to the same place. A Cochrane review of 20 randomised trials covering 2,125 participants found triple combination cream, which pairs hydroquinone with tretinoin and a corticosteroid, lightened melasma more than hydroquinone alone, with a risk ratio of 1.58, 95 percent confidence interval 1.26 to 1.97. That review states that statistical pooling of its data was not possible because each study used a different set of interventions, so the risk ratio comes from the trials making that one comparison and not from all 2,125 participants (Rajaratnam et al., Cochrane Database Syst Rev 2010, PMID 20614435). An evidence-based review of 113 studies and 6,897 participants reached the same conclusion, that triple combination cream and hydroquinone alone are the most effective and best studied topicals (McKesey et al., Am J Clin Dermatol 2020, PMID 31802394). Triple combination cream is a prescription medicine in the countries that license it, so whether it is appropriate for a given person is a doctor decision.

Is hydroquinone safe to use long term?+

The main documented long-term concern is exogenous ochronosis, a blue-black or grey-blue reticulate discolouration that is harder to treat than the melasma was. A systematic review pooled 126 reported cases from 56 articles. Median duration of use before onset was 5 years, with 4 cases reported at courses of 3 months or shorter and 8 cases at a year or less, and it was most often reported at concentrations above 4 percent (Ishack and Lipner, Int J Dermatol 2022, PMID 34486734). That is a review of published case reports, so it describes who gets reported, not how often it happens. Duration and strength are the two variables it flags, which is why hydroquinone is normally supervised rather than open-ended.

Does oral tranexamic acid work for melasma?+

In the strongest single trial, 44 patients with moderate to severe melasma were randomised to 250 mg of tranexamic acid or placebo twice daily for 3 months alongside sunscreen. At 3 months the tranexamic acid group had a 49 percent reduction in modified MASI score against 18 percent in the control group. The participants were predominantly Hispanic women at one US centre (Del Rosario et al., J Am Acad Dermatol 2018, PMID 28987494). A meta-analysis of 24 trials found tranexamic acid added to routine treatment beat routine treatment alone at 4, 8, 12 and 16 weeks, however that superiority was not detected when the topical or intradermal route was used instead of oral (Feng et al., J Clin Pharm Ther 2021, PMID 33959984). Tranexamic acid is a prescription medicine with clotting-related contraindications, and the largest safety series concluded that personal and family thromboembolism risk should be screened before it is started.

Why does melasma come back after it clears?+

Because the treatments fade the pigment without switching off what drives it. In a retrospective review of 561 melasma patients treated with oral tranexamic acid at a tertiary centre in Singapore, 89.7 percent improved, but among those who improved the relapse rate was 27.2 percent (Lee et al., J Am Acad Dermatol 2016, PMID 27206758). In the placebo-controlled trial above, the tranexamic acid group was 49 percent down at 3 months on treatment and 26 percent down at 6 months, three months after treatment stopped. Sun and hormonal exposure continue after the cream is finished, which is why photoprotection is the part of melasma care that never ends.

Do skin whitening creams sold at market stalls contain mercury?+

It depends entirely on the market, and the published testing does not agree. Twenty facial skin lightening creams bought in Malaysia from stalls, beauty shops, pharmacies and street vendors were tested by cold vapour atomic absorption spectrometry. Mercury ranged from not detected to 1.13 mg/kg, and every sample sat below the US FDA trace level of under 1 ppm except one from the third price band, which was manufactured in China (Ho et al., Regul Toxicol Pharmacol 2017, PMID 28554823). Twelve whitening products from a local market in Faisalabad, Pakistan, tested by ICP-OES, showed mercury from 1.12 to 67.41 mg/kg and exceeded World Health Organization permissible limits (Ahmad et al., Environ Monit Assess 2025, PMID 39930105). Both are small local surveys, neither covers Vietnam, and neither result can be transferred to a shelf in another country.

References

McKesey J, Tovar-Garza A, Pandya AG. Melasma treatment: an evidence-based review. Am J Clin Dermatol. 2020;21(2):173-225. 113 studies, 6,897 participants. PMID 31802394
Rajaratnam R, Halpern J, Salim A, Emmett C. Interventions for melasma. Cochrane Database Syst Rev. 2010;(7):CD003583. 20 studies, 2,125 participants, 23 treatments. PMID 20614435
Chan R, Park KC, Lee MH, et al. A randomized controlled trial of the efficacy and safety of a fixed triple combination (fluocinolone acetonide 0.01%, hydroquinone 4%, tretinoin 0.05%) compared with hydroquinone 4% cream in Asian patients with moderate to severe melasma. Br J Dermatol. 2008;159(3):697-703. PMID 18616780
Del Rosario E, Florez-Pollack S, Zapata L Jr, et al. Randomized, placebo-controlled, double-blind study of oral tranexamic acid in the treatment of moderate-to-severe melasma. J Am Acad Dermatol. 2018;78(2):363-369. PMID 28987494
Lee HC, Thng TG, Goh CL. Oral tranexamic acid (TA) in the treatment of melasma: A retrospective analysis. J Am Acad Dermatol. 2016;75(2):385-392. 561 patients, Singapore. PMID 27206758
Feng X, Su H, Xie J. Efficacy and safety of tranexamic acid in the treatment of adult melasma: An updated meta-analysis of randomized controlled trials. J Clin Pharm Ther. 2021;46(5):1263-1273. PMID 33959984
Castanedo-Cazares JP, Hernandez-Blanco D, Carlos-Ortega B, et al. Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial. Photodermatol Photoimmunol Photomed. 2014;30(1):35-42. PMID 24313385
Pennitz A, Kinberger M, Avila Valle G, et al. Self-applied topical interventions for melasma: a systematic review and meta-analysis of data from randomized, investigator-blinded clinical trials. Br J Dermatol. 2022;187(3):309-317. PMID 35290681
Lyons AB, Trullas C, Kohli I, Hamzavi IH, Lim HW. Photoprotection beyond ultraviolet radiation: a review of tinted sunscreens. J Am Acad Dermatol. 2021;84(5):1393-1397. PMID 32335182
Liu Y, Wu S, Wu H, et al. Comparison of the efficacy of melasma treatments: a network meta-analysis of randomized controlled trials. Front Med. 2021;8:713554. 59 trials, 14 therapies. PMID 34660626
Mawu FO, Christopher PM. Efficacy and safety of cysteamine 5% cream for the management of melasma: a systematic review and meta-analysis of randomized controlled trials. Arch Dermatol Res. 2024;317(1):117. PMID 39673630
Lima PB, Dias JAF, Cassiano DP, et al. Efficacy and safety of topical isobutylamido thiazolyl resorcinol (Thiamidol) vs. 4% hydroquinone cream for facial melasma: an evaluator-blinded, randomized controlled trial. J Eur Acad Dermatol Venereol. 2021;35(9):1881-1887. PMID 33988887
Correia G, Magina S. Efficacy of topical vitamin C in melasma and photoaging: a systematic review. J Cosmet Dermatol. 2023;22(7):1938-1945. PMID 37128827
Ali L, Al Niaimi F. Pathogenesis of melasma explained. Int J Dermatol. 2025;64(7):1201-1212. PMID 40022484
Ishack S, Lipner SR. Exogenous ochronosis associated with hydroquinone: a systematic review. Int J Dermatol. 2022;61(6):675-684. 56 articles, 126 patients. PMID 34486734
Moin A, Jabery Z, Fallah N. Prevalence and awareness of melasma during pregnancy. Int J Dermatol. 2006;45(3):285-288. 400 pregnant women, Tehran, Iran. PMID 16533230
Zhu Y, Zeng X, Ying J, et al. Evaluating the quality of life among melasma patients using the MELASQoL scale: A systematic review and meta-analysis. PLoS One. 2022;17(1):e0262833. PMID 35085327
Goh CL, Kang HY, Morita A, et al. Awareness of sun exposure risks and photoprotection for preventing pigmentary disorders in Asian populations: Survey results from three Asian countries and expert panel recommendations. Photodermatol Photoimmunol Photomed. 2024;40(1):e12932. Survey covered China, Indonesia and Japan. PMID 38059515
Ho YB, Abdullah NH, Hamsan H, Tan ESS. Mercury contamination in facial skin lightening creams and its health risks to user. Regul Toxicol Pharmacol. 2017;88:72-76. 20 samples, Malaysia. PMID 28554823
Ahmad MN, Ashraf UE, Anjum MN, et al. Identification and quantification of selected heavy metals by ICP-OES in skin whitening creams marketed in Pakistan. Environ Monit Assess. 2025;197(3):263. 12 products, Faisalabad. PMID 39930105
US Food and Drug Administration, openFDA National Drug Code directory. Products queried on the active_ingredients.name field for hydroquinone, restricted to finished products, with the marketing_category and application_number fields read per product. Data refresh dated 4 August 2026. open.fda.gov

Note on sourcing: every figure on this page is tied to one of the records above and was read from the abstract or the database field named, not from a secondary summary. Where a result applies to a specific country, clinic or population, that restriction is stated in the same sentence as the number. Where a source qualified its own finding, the qualification is carried with it. No prevalence figure for melasma in Vietnam is quoted here because none was found in the sources searched.