There have been quite a few discussions on forskolin and increasing melanocytes on this and other forums but I must say I'm getting results:
I used the formula Orazio used in 2009 on mice: mixed 80 grams of coleus forskohlii 20 % with 60 ml propyglene glycol and 140 ethanol. I've been doing this for 2-3 weeks on a spot near my wrist and the color difference is very obvious especially when I'm outside. People ask me if I have a big birthmark over there. I'm a type 1 and haven't been in the sun.
The solution though is pretty dirty, would be very dirty if you apply it this way all over your body but it's definetely not a stain, I've been using all sorts of pads and lotions to remove sunless tanners and it doesn't remove anything.
Of course we have to look into another way for penetration or putting it into a lotion but it works for melanocytes increase.
I used melanotan before and it also darkened my hair. I shaved the hair on my wrist and so far the new growth is still ginger yellowish. If it also increases melanocytes, there must be a way to reach hair follicles too, maybe something needs to be added to have an impact on the melanocytes of hair.