Dear East Coast Muscle,
'GHB' will help your overall results in 'ketosis'. However, please, never mix 'GHB' with Humilin or any other insulin. Why, you ask? Because it can be deadly!!! The only way I can tell you to use insulin/GHB is by this method:
Sun-> shots of insulin to lower blood sugar and get into ketosis in 8-12 hours. STAY AWAKE FOR AT LEAST 2hours after LAST insulin shot.
DO NOT TAKE GHB that day because insulin can kick in at night and you would need to be self conscious enough to eat carbs if you are in need of carbs.
Now, on Mon you can start your 'GHB' in order to goto sleep better. Please do me a favor and do not abuse 'GHB' for a personal high. I have seen so many bodybuilder fall because they have used 'GHB' as a tool to get "HIGH". Remember, bodybuilding is all about reaching your goals with hard work and intensity, and doing 'GHB' for a personal high will HINDER your RESULTS because you can (AND WILL IF YOU ABUSE IT) become addicted to it.
To answer you question, 'GHB' when used w/ insulin, will not keep you out of ketosis. It will not throw you out of Ketosis either (from personal experience).