There are really two answers, because this product works on two levels.
Instantly — the beige tint covers your dark circles the moment you apply it. You'll see the difference in the mirror before you leave the house on day one. No waiting.
Around 4 weeks — this is when the treatment side shows up. The REBORNIC calcium rebuilds the thinning skin that makes dark circles visible in the first place, so you'll start noticing your under-eyes look lighter even on days you don't apply it. That's usually when people start asking what you've changed.
By 8 weeks — the structural improvement is real. Firmer, more resilient under-eye skin and visibly reduced pigmentation, meaning there's less to cover than when you started.
The key is using it consistently, morning and night. And you're covered by our 30-day guarantee — if you don't see your dark circles visibly lighten, we'll refund you in full, even if the jar is empty.