How many sessions of the melasma skin booster do I need to see results on melasma?

I'm hesitant because there are many posts saying that using a melasma skin booster just once doesn't show much change.
I've heard that pigmentation issues like melasma take longer to show results, so I'm wondering how many sessions of the melasma skin booster I need to feel the effects.
I've heard that you usually need at least three sessions to see a difference in skin texture or tone, so I'd like to know if the same applies to melasma.
I know that melasma skin boosters have a cumulative effect and that I need to use them consistently, but the cost is a burden, so I can't easily make a decision.
For those of you who have been consistently receiving melasma skin boosters, please share which session it took to notice changes.