anti estrogen pills

Reading time 5 min 27 sec

Describing the strengths of various steroids is a favorite topic for fans of “chemical” bodybuilding. However, any coin has and another side. Probably all of you have heard about such an unpleasant side effect that occurs when using steroids like aromatization. What is it? Speaking in scientific language, aromatization is any process that converts a substance with androgenic activity into a substance with estrogenic activity. However, we will try to review and discuss this definition in ordinary language.

As you know, the majority of anabolic steroids are derived from the male sex hormone testosterone. So all of them have some androgenic activity. And aromatization converts them into various derivatives of the female sex hormone, which accordingly has estrogenic activity. Therefore, in the male body happens an excess of female hormones, which leads to various side effects.

For example, one of the most common effects of aromatization is gynecomastia – the development of fatty deposits under the skin around the nipples (female type breast). It’s quite easy to remove them surgically, however, such a procedure is not pleasant at all. Also, an excessive concentration of estrogen leads to such undesirable results as the accumulation of water and fat in the body, which is a real catastrophe for bodybuilders.

And here comes the logical question – what to do? How to prevent aromatization? There is only one solution – to use antiestrogen.

A bit of biochemistry

Let’s have a look at the antiestrogens mechanism of action in the body. Most steroids aromatize as follows: a steroid molecule, while in the blood in a free state, interacts with a molecule of a special enzyme – aromatase, which turns a steroid into estrogen (the reverse process is impossible). Then the estrogen molecule connects with the estrogen receptor that causes a certain effect. What this effect will depend on the location of the estrogen receptor is located, with which our estrogen molecule was connected.

For example, receptors in breast tissues will cause gynecomastia. And receptors in other parts of the body can lead to even less pleasant consequences. Two methods can avoid these side effects:

  1. to prevent the steroid from connection with aromatase;
  2. to prevent the already formed estrogen molecule from connecting with the estrogen receptor.

Drugs using the first method, we will call further anti-aromatase drugs, and drugs using the second – estrogen antagonists.


Anti-aromatase drugs act as follows. The molecule of such drugs, when it comes to the blood, connects with aromatase in the same method as a steroid would, but does not turn into estrogen. Therefore, aromatase becomes “busy” and the steroid molecule cannot anymore connect with it. Such types of medicine are:


Used in medicine for treating male sexual disorders, Proviron is a rare case of an anabolic steroid with anti-aromatase activity. When enters the body, it cooperates not only with aromatase but also with androgen receptors. Also, Proviron has one very interesting property: it makes muscles to look “harder”, i.e. increases venous, relief.

Why this is happening no one knows. Regarding this, there are only hypotheses that, most likely happen a decrease in the number of estrogen receptors. The dosage of Proviron should be selected individually, depending on the dose of other steroids. Usually, 25 mg of Proviron per day is enough to avoid aromatization of testosterone at a dose of 250 mg weekly. The regular “working” Proviron dosage is considered 25 – 50 mg daily. As a rule, Proviron is taken from 2 to 4 weeks.


Cytadren (aminoglutethimide) is a synthetic anti-aromatase drug. Usually, bodybuilders are interested in Cytadren first of all not as a “fighter” with estrogen, but as a powerful and almost the only drug that can suppress the production of cortisol (a hormone that inhibits protein synthesis). The daily dose of Cytadren should not exceed 250 mg per day. This amount of Cytadren is enough to prevent 750 mg of testosterone aromatization per week.

However, even such a dose can cause such side effects as lethargy or depression if there is a genetic predisposition. In the case, when you use Cytadren as a cortisol suppressant, its dosage can be significantly higher (up to 1 gram per day), and side effects are much stronger. The half-life of the drug is 6 – 8 hours, so its daily dose should be spitted throughout the day. The duration of the Cytadren cycle should not exceed 4 – 6 weeks.


This is one of the most powerful synthetic anti-aromatase drugs. 1 mg of Arimidex per day is as effective as 250 mg of Cytadren per day! The half-life of Arimidex is about 60 hours, so taking it daily is not necessary. However, due to the high price, it is not widely used.

Estrogen antagonists

Estrogen antagonists, when it comes to the system, do not prevent aromatization as such. However, the molecules of estrogen antagonists occupy estrogen receptors without activating them and do not let the usual estrogen connect with the receptor and activate it. Such drugs are:


Nolvadex is the brand name for tamoxifen citrate. In medicine, Nolvadex is used for the treatment of breast cancer in women. This substance acts as estrogen in some tissues and as an estrogen antagonist in others. When Nolvadex is used with steroids during the cycle it contributes muscles to look harder and more relief. Athletes who used Nolvadex during steroid cycles noted that it slightly reduces results. This is most probably because of Nolvadex, acting as an antiestrogen in the liver, reducing the production of insulin-like growth factor (IGF-1). Steroid guru Daniel Duchaine expressed a different point of view: “Testosterone is not an anabolic by itself, but only at a high level of estrogen, only this allows him to fully manifest its properties. The anabolic activity of many steroids decreases with the parallel use of Nolvadex”. However, athletes who use “heavy steroids” like Anapolon or Sustanon on the cycle or like high dosages of AAS have nothing to fear.

But for users who do not want to risk their health and prefer mild low-androgenic steroids (Winstrol, Primobolan), better to think if taking Nolvadex makes sense. The average “working” dosage is approximately 10 – 30 mg per day. Tablets are taken once or twice a day with a meal.


The active substance of this medicine is clomiphene citrate. In medicine, clomiphene is used to stimulate ovulation in women. The clomiphene molecule is very similar to the tamoxifen molecule, and therefore these two drugs have very similar properties, blocking estrogen molecules. And this even though clomiphene itself is a synthetic estrogen! Need to be considered that Clomid is less effective as an antiestrogen than tamoxifen.

However, Clomid has one very useful property that Nolvadex does not: Clomid can restore spermatogenesis and testosterone production in the body, affecting directly on the arch of the hypothalamus-pituitary – testes. This feature makes Clomid the most suitable for use at the end of the steroid cycle. Medical studies showed that the long use of Clomid in high dosage (100 mg per day) by men did not cause any side effects. Usually taking Clomid at the dosage of 25 mg daily is enough to avoid side effects of Nandrolone at the dosage of 400 mg per week. The drug is taken once or twice daily after meals.

We reviewed two groups of drugs that will help you to avoid a major part of the side effects associated with aromatization. However, there is also a third category of antiestrogens – “self-destructive inhibitors.” These drugs destroy the aromatase molecule and self-destructing in this process as well. However, drugs of this group are not currently available on the market at all. There is a drug Lentaron, but it is still in the beta version.


We want to warn you: the dosages of antiestrogens should be approached very carefully, as well as the dosages of any other drugs.

Remember that a certain amount of estrogen is required for the body to function properly. And a complete blockage of estrogen can lead to unpleasant side effects such as decreased libido, depression, and no mood. So, try to keep the balance in everything.