How Much Arimidex or Letrozole Is Needed on a Testosterone Cycle?

Initial values to try, I figure a base of 0.36 mg/day for letrozole where no testosterone is being taken but there is a need to reduce high or moderately high estradiol OR 0.36 mg for each 200 or 250 mg/week of testosterone that is being taken, but not more than 1.0 mg/day as the initial value and typically not as an adjusted value either.

The numbers don’t need to be that precise. The 0.36 value results simply from 2.5 mg/week being divided into 7 parts.

Dosing also can be every other day instead of daily, provided the total weekly dosage is the same.

With Arimidex I never developed an adjusted-for-testosterone-amount method, but have recommended 0.5 mg every other day and adjusting from there. This also works.

For your proposed cycle, it would be the 1.0 mg letrozole per day figure, as 700 mg/week is about 3 times the 200-250 mg/week figure, and multiplying 0.36 mg by three gets us up to the 1.0 mg/day suggested initial-dose ceiling — but there should be a follow-up test of estradiol levels. Or if not doing that — the test isn’t expensive though and results are back quickly — then at least being ready to reduce if there are symptoms suggesting low estradiol: joint problems, depression, or low libido.

But it is better to get the actual test because the absence of those symptoms doesn’t prove that estradiol hasn’t been driven too low. There could still be a problem.

And likewise, having one or more of those symptoms doesn’t prove estradiol has been driven too low, either. It is only suggestive. But if one finds from experience that changing aromatase inhibitor amount clearly matches up with change in the symptoms, then that is a good basis for adjustment. Still (repeating myself) better to get the test.