My own data contradict that graph and are more in line with other studies, and in particular work by Nieschlag finding a half-life for propionate of about 19 hours. Importantly, my measurements suggest there is a rapid rise to peak serum testosterone in the first few hours after an injection, which is followed by a steady decline to the next day's pre-injection trough.

This means injections before bed are probably far from ideal. Closest to natural men might be to inject around 3-5 am and then sleep a few more hours. The rise is testosterone is more rapid than what's seen naturally, but as far as I can tell it's not much of a problem. Personally I just inject first thing upon waking.

For me straight propionate creates swings in serum testosterone of 50% or more about the mean. Natural men experience variations of more like 20-25%. I damp down the variations in propionate by mixing it with a longer ester—enanthate, though cypionate would be fine too.