Thread: What AI is right for you? Anastrozole, Exemestane or Letrozole

This is a question thats been asked over and over, but hopefully after reading this you will have a much better understanding of what will best suit your needs. Exemestane and its uses. Half life : 27 hours
Exemestane (Aromasin) is a Type 1 inhibitor and so therefore is a steroidal inhibitor or suicidal aromatase inhibitor. It’s called this because it lowers estrogen production in the body by attaching to the aromatase enzyme, and permanently deactivating it, and being a steroidal type 1 inhibitor it has androgenic effects. It is especially good as a test boosting AI as it prevents SHBG releasing more free test and as it averages an 85% rate of estrogen suppression which translates to an overall reduction in estradiol levels of about 50%, as well as raising testosterone to a significant degree it makes it quite exciting. Because its a type 1 inhibitor it offers other promising aspects, once it deactivates the aromatase enzyme those particular enzymes will no longer function, even if your body produces more aromatize, it cant do anything because it cant bind. In this case, the advantage of using a suicidal aromatize inhibitor is that it really won’t cause much, if any, noticeable “rebound” in estrogen when you cease using it, so no rebound gyno which is quite possible with Anastrozole and letrozole. Also as well as reducing water retention, having no negative impact on good cholesterol, no chance of rebound gyno, its androgenic effects make it great to use in pct, as say pre workout boost, 25mg taken and hour or so before training always does its job for me, and helps keep strength up during PCT with is mild androgenic effect. Talking of PCT it is also the only AI that should be used with Nolva, it doesnt interfere with the actions of nolvadex, nolva will reduce about 60 percent of the effect of both letro and arimadex.. so it seems pointless, thought they are great on cycle for reducing estrogen, once into PCT its a different story and Aromasin is king. Remember we said above it permanently deactivates the aromatize enzyme.. well it means it doesnt need to be taken everyday.. and it will still increase IGF levels substantially, which normally plummet in pct, and still prevent any estrogen and water retention…. this permanent effect on the Aromatize enzyme maybe the reason why nolva doesn’t interfere with it. So in summary it has the potential to increase testosterone by upwards of 40 percent, increase Insulin like growth factor im muscle, stimulate androgen receptors, lower estrogen, increase free test, has numerous uses, doesnt impair bone mineral content or have any adverse effect on your lipids… Aromasin is quite simply the King of AI’s during PCT. I used Nolva as an example here as 25 mgs is as effective in studies as 150mg of clomid.
Anastrozole and its uses. Half life : 46.8 hours. Arimidex is a type-II aromatize inhibitor. In the case of Arimidex, or any Type-I inhibitor, it works by binding to the substrate the aromatize enzyme thus rendering it inactive and therefore unable to convert test into estrogen.. At a dose of around both 0.5mg and 1mg estrogen was decreased by around 50% in studies, while increasing testosterone, lh and fsh. During a cycle and obviously not during pct for the reasons mentioned above, it can prevent fat gain, and the watery appearance caused by aromatising compounds as they will be unable to convert to estrogen at anything like the normal rate. Blood plasma concentrations become stable by 7 consecutive 1mg daily doses, although maximal estrogen inhibition is reached by day 4, on cycle as it s milder than letrozole, bone mineral content and cholesterol isn’t to adversely affected its affect on estradiol was maintained for up to 6 days after cessation of daily dosing with 1 mg anastrozole, and it doesn’t seem to slow the function of the thyroid either. In blocking estrogen conversion it is quite effective but no where near as effective as letro wich we will now look at.
Letrozole and its uses. Half life: 40 hours Again letro is a type 2 inhibitor, which means that it competitively binds to the aromatize enzyme and inhibits the enzyme’s ability to metabolize testosterone into estrogen. In an extract from a study, Letrozole actually reduced estrogen in one test subject to undetectable levels , In another clinical study, intravenous administration of Letrozole (2.5mcg for 28 days), Letrozole lowered Estrogen by 46% in the young men tested, and 62% in the elderly subjects. In addition, Letrozole also significantly increased LH levels to a remarkable 339 and 323% in the young and the elderly, respectively and Testosterone by 146 and 99%, respectively. Letrozole was also able to produce a peak LH response to GRH equal to a 152 and 52% increase from baseline in either young or older men, respectively. So you may think, wow that could be used in pct, Yes it could, but it is so effective at reducing estrogen, that joints, and bones suffer, and you can expect your cholesterol lipid profile to plumet accordingly.. On cycle if using heavy aromatising compounds Letro in small doses IS very effective 0.5mg ive seen used WITH GREAT RESULTS over and over, but another reason why its not good in pct, is the negative impact on libido, as estrogen is needed for healthy sexual function, wich wont be a problem on cycle if your using steroids like test prop. Now to the final area in wich letro is untouchable..Letrozole is the only pharmacological treatment for gyno that to have ever worked in bodybuilders. In a study conducted on rodents, Letrozole was able to effectively destroy breast tissue tumors, and it’s also been effective on many bodybuilders who have used it to eliminate an existing case of gynocomastia. 2.5mcgs seems to be a very useful dose in this regard, remember though with letro tapering off is vital otherwise rebound estrogen spikes will occur.. so slowly tapering the dose down is best… Summary. For Post cycle therapy Aromasin is remarkable in its overall function both on increasing test, and lowering estrogen, and it doesn’t interfere with FSH and nolvadex. On mild cycles Arimadex (Anastozole) is probably your best choice, it lowers estrogen, keeps you drier, doesn’t impact to much on cholesterol… but if used in PCT must be tapered off to avoid rebound Gyno. Talking of Gyno, Letrozole is the beast, it is just about the only thing you can take that will reduce pre existing Gyno, and it is exceptional if your using a number of wet compounds on cycle, again if running it during pct with clomid.. not nolva it should be reduced, and tapered off to avoid rebound gyno.

Nice info

Adex on cycle...aromasin for pct...never used letro.

Good read

Thanks for taking the time to put this together. Very helpful

That aromasin half life is in women, men is less than 9' but great info and I appreciate the read

Great info never read enough on AIs. Thanks for the post

Dex or letro on cycle. dex 0.25mg- 0.5mg eod , letro 0.25-0.6mg eod-e3d.

Nice