T Nation

High E2 and Anastrozole

Hi, I’ve been on TRT for a few weeks now (100mg per week split into 2); however, lately I’ve had a few symptoms consistent with high E2 such as hot flashes, lethargy, weak erections, no morning wood, bit of anxiety etc. I didn’t think I needed anastrozole being on a low dose but I got some anyway. So I took 0.25mg today and in a matter of hours most of my symptoms disappeared. So my question is, is this normal, can E2 be lowered this quickly or is this maybe a placebo effect?

I think I might carry on doing anastrozole until my blood tests in three weeks at 0.25mg every 3 days. Will this be enough? Ideally I want to be close to a good balance when I go for the blood test so it won’t take much to dial it in.


Anastrazole has a 50 hour half life so it does work fairly quickly, however not within a few hours to notice a difference. Starting an AI without bloodwork is a decision I understand if you are feeling the effects of what you believe is an increase in E2 levels. Dialing in can only be done with blood work, through the rule of thumb is 1mg per week (in divided doses) per 100mg of testosterone per week. Are you also taking HCG? If so at what dose and frequency?

It was about six hours I noticed it. My girlfriend was very happy as my libido was sky high and wood was strong - I feel it just can’t be a placebo effect if I’m having such pronounced physical benefits. I’m getting a complete blood work up in a few weeks and I have asked my doc for a full copy of my results. I think I’ll keep it to 0.25mg E3D and wait for my test.

Oh yeah, if I’m taking 100mg split into 2 doses a week plus AI E3D, when would be the best time to take the blood test?

I’m not currently on HCG but it will be added early next year.


Your levels are still in flux, it take 4-6 weeks for everything to stabilize and a few months to feel if it made a difference. You’re way too early in treatment to realized the full benefits of TRT.

It wasnt placebo. Absorption of anastrozole is rapid and maximum plasma concentrations typically occur within 2 hours of dosing under fasted conditions, longer if taken with food. You really should get a blood work snap shot of your e2 levels before introducing a new variable, but I’m sure you’re anxious for relief. Because of anastrazoles half life, I prefer every other day, smaller doses. As others mentioned, complete stabilization takes weeks since estrogen blood serum levels in men are the result of aromatization versus clearance rates barring exogenic sources and that pendulum takes time to settle.

If you start to feel like you’re peeing a lot, sleepy all the time, have chronic head aches in your forehead behind your eyes, less vascularity, low level depression, unusual cold in extremities, your e2 may have been driven too low.

Get follow up blood work in a month to see where your e2 is. Low e2 is less pleasant than high. Something to consider in our often “more is better” mindset, ie be careful with anastrozole.

Hostile I don’t want to get into an argument over this, but my understanding is that adex doesn’t lower E2, it competes with T to bind to the aromatase enzyme thus reducing the rate of T->E2. The liver actually clears the E2. So you make less E2 when on adex but it doesn’t have any effect on your current level. This is why you want to match adex with your T injection. That’s my understanding anyway. Which means this was a placebo effect.

I agree with the mechanism of reduction you stated. That being said, I also can feel it at the two hour mark every Time I dose. Blood serum levels peak at two hours, so I believe there’s other factors at work that may not be understood in alleviation of certain symptoms.

Okay, got it. I know when my E2 creeps up and I increase my adex dose, I can feel the effects of lower E2 pretty quickly. Like the next morning.

Thanks for all your input guys, much appreciated. It looks like my new protocol of 100mg test per week and 0.5mg of anastrazole shouldn’t cause problems, but I’ll look out for the signs of low E2 as you mention Hostile and if they appear, I’ll either stop or cut back the dosage of the AI.

Blood tests are due in three weeks so it won’t be long until I can get a clearer picture. When would be the best day to get my bloods done if I’m taking 50mg of test on Tuesday morning, 50mg on Friday evening and the AI on Wednesday and Saturday?


I’d probably shoot for a snapshot of your blood work on Thursday. You may want to start with .25mg anastrozole twice per week instead of 0.5mg twice per week. If you’ve never experienced low estrogen consider yourself lucky. You can always increase your AI dose. Once your estrogen is driven low, it takes 1-2 weeks for it to rise and feel relief. It’s really unpleasant

Why do you take the adex on different days than the T. Adex is a competitive drug so you want to match T with adex. I think most guys take them together.

I’ve done both and take my ai on off injection days too. Ksman has said that this way last be slightly more effective but typically suggests most do both on the same day for efficiency sake. The idea behind taking the AI dose the following day is after T injections, it takes time for T to increase and then subsequently again for T to aromatize to E. That delay may be better met with slightly delayed ai dosing.

Okay, but I think we may be guilding the lily. If we are injecting T twice weekly, the peaks and troughs are not huge. I know I’d forget once in awhile if I did it your way. To each his own, my uneducated guess is the difference in the protocols would result in such small differences as to be essentially moot. Again just my 2 cents. Carry on…

Yeah, I’d tend to agree with you. After a lot of trial and error, that style is what I’ve fallen into and what I’ve found has me feeling the best.

Can’t argue with results