Why Heat (Not Just Sun) Triggers Melasma

By Michael C. · Written and reviewed by Michael C.

Melasma · Published 2026-07-24 · 10 min read · 1912 words · Updated 2026-09-08

Melasma is driven by UV, visible light and heat together, which is why sunscreen alone often isn't enough to control it.

Key takeaways

• Heat and visible light, not only UV rays, are established triggers for melasma flares.
• Tinted mineral sunscreens with iron oxide protect against visible light in a way plain sunscreens don't.
• Hormonal shifts from pregnancy or contraceptives are major underlying drivers of melasma.
• Melasma is managed long-term rather than permanently cured, requiring ongoing sun, heat and pigment control.

Source: SkinLabs Editorial Team ()

Cover image: Nate Johnston — credit