Solar Flare, semi permanent hair dye orange - 118 ml - Lunar Tides

Q: will it transfer if I get sweaty?

No it does not transfer. My husband works in a kitchen and he gets quite sweaty but no the color has never dropped or transferred when freshly dyed or after a few washes. Even when wet it’ll barely wash out

Q: Does it work on dark brown hair

No. I had hoped it would myself but it didn't do anything it seems to my light brown hair.

Q: How long does it stay in?

There are multiple factors that come into play when it comes to longevity. Such as condition of hair, types of shampoo used in hair as well as frequency of shampoo use, temperature of water used to wash hair, etc. But so far mine has been in my hair for almost two months now without fading.