TL;DR
Surface PIH fades in 3–6 months; deeper melasma can take 6–12 months; without daily SPF, progress stalls entirely. Consistency beats strength.
- Surface PIH
- 3–6 months
- Deeper melasma
- 6–12 months
- Without SPF
- Progress stalls / reverses
- Judge at
- Week 12 minimum
The direct answer
Time depends on depth. Marks sitting in the top skin layer (most acne PIH) improve in a few months; pigment in the dermal layer (melasma, old sun spots) needs closer to a year.
Expected timeline by concern
| Concern | Typical fade | Key requirement |
|---|---|---|
| Fresh acne PIH | 3–6 months | SPF + azelaic acid |
| Sun spots | 4–8 months | SPF re-apply + vitamin C |
| Melasma | 6–12 months | Tranexamic acid + strict SPF |
| Old, deep marks | 12+ months | Layered actives, patience |
What speeds it up
- Daily SPF 50+ is the non-negotiable accelerator.
- Use one or two actives consistently rather than switching weekly.
- Treat active acne so no new marks replace the fading ones.
FAQ
Why have I seen nothing after 4 weeks?
Pigment turnover is slow; 4 weeks is too early. Most people see meaningful change only around week 8–12 of consistent use.
Does stronger percentage work faster?
Not necessarily. Higher strength often means more irritation, which can create new PIH. Consistent mid-strength use wins.
Can professional treatments help?
Yes — clinics offer peels or lasers, but they still require SPF and home care; done on irritated skin they can temporarily darken marks.