What is the official recommendation for the length of time Cosmelan 1 should be left on skin type II?

There are so many different options for skin lightening. I would start with a shorter interval and increase if necessary. After treatment, I would recommend Melarase AM and Melarase PM with Melapads to maintain results. Best, Dr. KaramanoukianLos Angeles

Cosmelan is an effective depigmenting procedure that should only be applied by a professional. You should believe what your trusted provider says. The amount of time it should be left on the skin will be specific to your skin. There are general recommendations but the professional taking care of your skin is who you should trust. Do not apply this yourself. 

In our office we have patients keep the Part 1 on for 8 hours. You can call Mesoesthetic directly and ask them but seeing as you should be getting this only from a physician - why not just ask your prescribing doctor?  "This answer has been solicited without seeing this patient and cannot be held as true medical advice, but only opinion. Seek in-person treatment with a trained medical professional for appropriate care."