Acne Dark Spots: Why Sunscreen Is the Most Proven Way to Stop PIH
If you're chasing serums to fade acne marks, you're skipping the single highest-evidence step — daily SPF is what stops post-inflammatory hyperpigmentation from getting worse.
A systematic review of post-inflammatory hyperpigmentation prevention in skin of color found that sunscreen — alone or combined with other ingredients — was the most consistently successful preventative measure, because UV exposure drives further darkening of post-acne marks.
Dermatologists treating skin of color emphasize that controlling UV exposure is foundational for hyperpigmentation, since even small amounts of sun can deepen and prolong post-acne marks regardless of which fading actives a person layers on top.
Questions we get a lot
Does sunscreen actually fade acne dark spots?
Sunscreen's biggest role is preventing the marks from getting darker. A systematic review in skin of color found sunscreen, alone or with other ingredients, was the most consistently successful measure for preventing post-inflammatory hyperpigmentation. UV exposure darkens existing marks, so daily SPF protects the fading progress that actives and time provide.
Do I need sunscreen if my acne marks are indoors most of the day?
Yes. UV and visible light reach skin through windows and during short outdoor trips, and that exposure can deepen post-acne marks. Because sunscreen was the most consistently effective preventative measure in the review, daily use is recommended even if you spend most of your day inside.
r/SkincareAddiction: 'My acne is gone but the brown spots won't fade — am I wasting money on serums if I'm not wearing sunscreen?'