You can read differing times quoted by different sources but most endocrinologist regard it as being fine as long as it is before 11am.
What is worth keeping in mind is the politics of endocrinology in many countires.
If you live in a country that has a strict interpretation of pathology reference ranges and you know or suspect your levels to be boarderline then you would want a latter test if you hold out hope of being prescribed TRT.
In the UK I have known endocrinologists to refuse to treat young men with 10 nmol/l but be quite happy to treat old men with 9.9nmol/l.
This of course is absurd, but it is not something that you can get an individual endocrinologist to overturn. So an 11am blood test might open up a range of treatment options to you that a 8am test doesn’t. I am sure you will agree this is well worth keeping in mind if you are in one of these countries… 