Why Melasma Comes Back: Sunlight, Visible Light, Hormones, and Maintenance

Melasma comes back because it's a chronic condition with several drivers, and clearing a patch doesn't remove any of them. Ultraviolet light, visible light, hormones, and your own biology all play a part.

Daily broad-spectrum protection plus a maintenance plan from a dermatologist is a realistic goal. A one-time cure is not.

Why melasma keeps coming back

A 2022 review on melasma and photoprotection reports that melasma can last 10 to 20 years. Lightening a patch doesn't touch what caused it.

A 2025 international consensus of 38 dermatologists from 11 countries called broad-spectrum photoprotection essential and described melasma as a condition for long-term management with a dermatologist. Broad-spectrum means protection against both ultraviolet A (UVA) and ultraviolet B (UVB).

That framing matters more than any single product. If you treat melasma as a problem you solve once, it will keep surprising you.

How much do ultraviolet and visible light matter?

More than most people think, and visible light is the part that gets missed.

Sunlight includes UVB, UVA, and visible light, the part you can see. One estimate cited in the 2022 review attributes reactive oxygen species generation to UVB at 4%, UVA at 46%, and visible light at about 50%. Those percentages do not measure each wavelength's share of melasma. Most sunscreens were built around the first two.

That's the gap tinted sunscreens can help fill. The review reports that tinted sunscreen formulations containing iron oxides can attenuate up to 85% of light from 415 to 465 nanometers, in the blue-violet range.

A 2014 trial put that to the test. Sixty-eight people were randomized and 61 completed eight weeks under intense sun. Both groups used sun protection factor (SPF) 50 or higher and 4% hydroquinone. One group's sunscreen also contained iron oxide for visible-light coverage, and that group improved 15% more on melasma scores. The published abstract didn't report a significance test for that gap, and it didn't state how much sunscreen people used or who funded the work. Those numbers show what iron oxide added on top of hydroquinone, not what sunscreen does by itself.

A 2015 study was published as a short research letter with no readable abstract, so I'm relying on the 2022 review's summary of it. As summarized there, 40 patients over six months got either a tinted iron-oxide sunscreen or a non-tinted one with identical UV filters, and melasma worsened more in the non-tinted group. One author was affiliated with Bioderma.

The hormone piece

A significant one. The 2022 review reports that melasma affected up to half of pregnant women in one Mexican population. It also cites research finding that each extra 10 hours a week working outdoors during pregnancy raised the odds of developing melasma by about 27%.

Those findings connect pregnancy and light exposure to onset. They don't show either factor acting alone.

A 12-month Moroccan trial gave SPF 50+ sunscreen to 200 pregnant Moroccan participants. Among the 185 who completed it, 2.7% developed new melasma, compared with 53% in the investigators' earlier work. One caveat on that comparison: it was against a historical group, not a control group running at the same time. Three review authors received consultancy fees from ISDIN and two were ISDIN employees.

Talk to a clinician about estrogen-containing birth control or hormone therapy. And the Illuminate Rx carton says not to use the product while pregnant or breastfeeding.

Screens get blamed a lot

Screen light gets blamed a lot, and the evidence is weak.

The 2025 global consensus puts blue light from a screen at 100 to 1,000 times weaker than sunlight, and cites a study where eight hours a day of it for a week didn't make melasma any worse. The consensus summary doesn't say how many people were in that study, or what the comparison group received. So it's a signal, not an answer.

Disclosure on that paper: The publication lists Beiersdorf grant 001/2025. Beiersdorf provided editorial help and reported no role in the design, data, or decision to submit, and several authors reported company fees.

What a maintenance plan looks like

• Wear a tinted broad-spectrum sunscreen that contains iron oxides for visible-light coverage.
• Use enough, and reapply. For regular outdoor exposure, the global consensus advises about a quarter teaspoon for the whole face and reapplication at least twice a day.
• Add physical protection. A hat, shade, and less direct outdoor light when you can manage it.
• Keep your topicals clinician-guided. Prescription choices and maintenance schedules should come from a dermatologist who has looked at your skin.
• Follow the package directions on anything cosmetic. Illuminate Rx calls for broad-spectrum SPF 30 or higher during the day. My search found no PubMed-indexed paper or ClinicalTrials.gov record through August 16, 2026 that names or tests Illuminate Rx, so there's no product-specific timeline for me to promise you.

Next step

Read the linked research and review the how to use page. An article or a photo can't confirm melasma. See a board-certified dermatologist for diagnosis questions, and have any new, changing, bleeding, or painful spot examined in person.