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Ok so I'm writing this thread due to seeing a ton of people lately running Aromasin EOD. We need to think of half lives of AI's just like we think about the half lives of esters of gear. Some of this is copy and paste info as I'm too lazy to write everything out in my own words, and some of this is in my own words. So here we go....
First let's define what an AI is and what they're used for.
AI is short for Aromatase Inhibitor. Aromatase Inhibitors prevent the conversion of androgens into estrogen in fat, muscle, breast, and brain. Aromatase inhibitors work by inhibiting the action of the enzyme aromatase, which converts androgens into estrogens by a process called aromatization. As breast tissue is stimulated by estrogens, decreasing their production is a way of suppressing recurrence of the breast tumor tissue. Estrogen is produced and acts locally in these tissues, but any circulating estrogen, which exerts systemic estrogenic effects in men and women, is the result of estrogen escaping local metabolism and spreading to the circulatory system.
What are the different types of AI's?
There are many different AI's out there. The most common used in the BB world are exemestane (Aromasin or "stane"), anastrozole (arimidex or "adex"), Letrozole (femera or "letro") Some people might argue that tamoxifine, or nolvadex, can be used as an AI. Nolva is NOT an AI. Nolva is a SERM. It has been used in plenty of studies and was the go to drug for years for gyno help in the BB world. It still is used by BB for reducing gyno but has actually been shown in recent studies to not affect steroid induced gyno as well as it has in gyno caused by puberty in males. Which brings me to another point, taking Nolva will not prevent high e. SERMs DO NOT lower estrogen. SERMs block estro from attaching to the breast tissue. They sit in the estrogen receptor and there is no room for the estrogen to attach to the receptor making it impossible for the cells to recieve estrogens signals to grow and multiply. After all, were not just trying to prevent gyno, were trying to control our estrogen levels which we do by taking AI's.
Breakdown of types of AI's
Aromasin- Exemestane is an irreversible, steroidal aromatase inactivator, structurally related to the natural substrate androstenedione. It acts as a false substrate for the aromatase enzyme, and is processed to an intermediate that binds irreversibly to the active site of the enzyme causing its inactivation, an effect also known as "suicide inhibition." In other words, Exemestane, by being structurally similar to the target of the enzymes, permanently binds to those enzymes, thereby preventing them from ever completing their task of converting androgens into estrogens. No need to taper dosage on stane as there is no risk of estro rebound. In laymans terms it kills estrogen.
Arimidex- Anastrozole binds reversibly to the aromatase enzyme through competitive inhibition, inhibits the conversion of androgens to estrogens in peripheral tissues (outside the CNS), and a few CNS sites in various regions within the brain. Adex needs to be tapered down as it can cause an estro rebound as it doesn't kill estro, it attaches itself to it.
Letrozole- Letro, just like arimidex, reversably binds to the aromatase enzyme. It also needs to be tapered. Letro is probably the most toxic and harshest of the 3. Be careful with letro as it will put you on your ass.
What are the half lives of these AI's and how often should you take them?
Here's where we get to the point of all this jiber jabber I have posted.
Letrozole -Letro's half life is about 2 days. It reaches steady blood plasma levels in 2-6 weeks (study showed this at a daily dose of 2.5mg although I couldn't imagine taking this stuff at 2.5mg ed for 6 weeks) So basically you can dose letro eod although when I read the word "about" 2 days, personally I'd dose everyday. Like I said above, letro is no joke. If using for an AI, start at a VERY VERY low dose like .25 mg ed. This stuff will crash your E and have your joints feeling like they're made of concrete. It's also been shown to increase the risk of osteoperosis and has been shown to weaken bone structure. Also don't forget to taper letro so you don't get an estro rebound!!
Arimidex - Adex's half life is shown to be 48.6 hours which means it is ok to dose adex EOD (every other day). A usual starting dose is .25-.5 mg EOD. Just like letro, taper down once coming off so you don't rebound.
Aromasin - Stane's half life is 27 hours which means to achieve stable blood plasma levels, it needs to be dosed ED (everyday) A usual starting dose is 12.5mg ed. If I run it all the way through cycle instead of just starting when signs of high e are noticed, I start at 6.25mg ED. You do not need to taper with aromasin as like was shown above, it's a suicidal inhibitor and you won't get any estro rebound. Aromasin is the AI of choice for me for this reason.
I hope this info clarifys things for people. Like I said in the beginning, think of AI's, SERMs, hell even peptides and SARMs, the same way you think regarding esters in different compounds of gear. The goal is to achieve stable blood plasma levels. We do this by recognizing the half lives of these chemicals. The more stable our blood plasma levels, the greater the effect of whatever chemical we're using has AND the less chance we have for side effects from that chemical.
-Colt
First let's define what an AI is and what they're used for.
AI is short for Aromatase Inhibitor. Aromatase Inhibitors prevent the conversion of androgens into estrogen in fat, muscle, breast, and brain. Aromatase inhibitors work by inhibiting the action of the enzyme aromatase, which converts androgens into estrogens by a process called aromatization. As breast tissue is stimulated by estrogens, decreasing their production is a way of suppressing recurrence of the breast tumor tissue. Estrogen is produced and acts locally in these tissues, but any circulating estrogen, which exerts systemic estrogenic effects in men and women, is the result of estrogen escaping local metabolism and spreading to the circulatory system.
What are the different types of AI's?
There are many different AI's out there. The most common used in the BB world are exemestane (Aromasin or "stane"), anastrozole (arimidex or "adex"), Letrozole (femera or "letro") Some people might argue that tamoxifine, or nolvadex, can be used as an AI. Nolva is NOT an AI. Nolva is a SERM. It has been used in plenty of studies and was the go to drug for years for gyno help in the BB world. It still is used by BB for reducing gyno but has actually been shown in recent studies to not affect steroid induced gyno as well as it has in gyno caused by puberty in males. Which brings me to another point, taking Nolva will not prevent high e. SERMs DO NOT lower estrogen. SERMs block estro from attaching to the breast tissue. They sit in the estrogen receptor and there is no room for the estrogen to attach to the receptor making it impossible for the cells to recieve estrogens signals to grow and multiply. After all, were not just trying to prevent gyno, were trying to control our estrogen levels which we do by taking AI's.
Breakdown of types of AI's
Aromasin- Exemestane is an irreversible, steroidal aromatase inactivator, structurally related to the natural substrate androstenedione. It acts as a false substrate for the aromatase enzyme, and is processed to an intermediate that binds irreversibly to the active site of the enzyme causing its inactivation, an effect also known as "suicide inhibition." In other words, Exemestane, by being structurally similar to the target of the enzymes, permanently binds to those enzymes, thereby preventing them from ever completing their task of converting androgens into estrogens. No need to taper dosage on stane as there is no risk of estro rebound. In laymans terms it kills estrogen.
Arimidex- Anastrozole binds reversibly to the aromatase enzyme through competitive inhibition, inhibits the conversion of androgens to estrogens in peripheral tissues (outside the CNS), and a few CNS sites in various regions within the brain. Adex needs to be tapered down as it can cause an estro rebound as it doesn't kill estro, it attaches itself to it.
Letrozole- Letro, just like arimidex, reversably binds to the aromatase enzyme. It also needs to be tapered. Letro is probably the most toxic and harshest of the 3. Be careful with letro as it will put you on your ass.
What are the half lives of these AI's and how often should you take them?
Here's where we get to the point of all this jiber jabber I have posted.
Letrozole -Letro's half life is about 2 days. It reaches steady blood plasma levels in 2-6 weeks (study showed this at a daily dose of 2.5mg although I couldn't imagine taking this stuff at 2.5mg ed for 6 weeks) So basically you can dose letro eod although when I read the word "about" 2 days, personally I'd dose everyday. Like I said above, letro is no joke. If using for an AI, start at a VERY VERY low dose like .25 mg ed. This stuff will crash your E and have your joints feeling like they're made of concrete. It's also been shown to increase the risk of osteoperosis and has been shown to weaken bone structure. Also don't forget to taper letro so you don't get an estro rebound!!
Arimidex - Adex's half life is shown to be 48.6 hours which means it is ok to dose adex EOD (every other day). A usual starting dose is .25-.5 mg EOD. Just like letro, taper down once coming off so you don't rebound.
Aromasin - Stane's half life is 27 hours which means to achieve stable blood plasma levels, it needs to be dosed ED (everyday) A usual starting dose is 12.5mg ed. If I run it all the way through cycle instead of just starting when signs of high e are noticed, I start at 6.25mg ED. You do not need to taper with aromasin as like was shown above, it's a suicidal inhibitor and you won't get any estro rebound. Aromasin is the AI of choice for me for this reason.
I hope this info clarifys things for people. Like I said in the beginning, think of AI's, SERMs, hell even peptides and SARMs, the same way you think regarding esters in different compounds of gear. The goal is to achieve stable blood plasma levels. We do this by recognizing the half lives of these chemicals. The more stable our blood plasma levels, the greater the effect of whatever chemical we're using has AND the less chance we have for side effects from that chemical.
-Colt