Your T levels will be high in 24-48 hours, same for FT.
Then FT–aromatase–>E2 has no time delay at all.
E2 levels will elevate in 2-3 days.
When you take a constant dose of anastrozole, because of half-life, it takes about one week for serum levels of anastrozole to reach steady state levels.
Taking anastrozole at time of first T injection or next day makes a lot of sense.
Contrary to what some guys state here, needing anastrozole is the norm, not the exception.
1/2mg anastrozole per week with 200mg/week testosterone is 1/4th the amount typically needed by normal responders, so you have a dose suited to over-responders. So crashing E2 simply is not a risk. However, having this dose will allow the first on-TRT E2 lab results to be used to calculate a dose correction based on a target E2 level and E2=22pg/ml seems to work very well for almost all guys, however there are a few who are “wired” differently and do not react the same as most.
Allowing E2 to be uncontrolled on 200mg/week T is insane. E2 will oppose the desired effects of T in the brain and liver production of SHBG is expected to increase in response to E2 even as high T levels oppose that. If one has had a hint of gyno in the past there is great risk.