ATD (androstatrienedione)

ATD (androstatrienedione, chemical name: 1,4,6-Androstatriene-3,17-dione) is a potent aromatase inhibitor, popular as part of supplemental stacks, which include testosterone boosters. As an aromatase inhibitor, it will help keep estrogen in check by preventing testosterone from aromatizing into estrogen. Currently, it is not listed as a controlled substance in the USA, but there are rumors it's on the chopping block due to new anti-prohormone regulations. In the past 5 years, numerous raids on ATD suppliers by government agents have occurred, which signaled that many were selling poor quality, fake or mislabeled ATD. After all, what's the point of selling ATD when you can sell Aromasin, which is cheaper to make.


Fig 1. ATD Chemical Structure

Table of Contents

Suicidal Aromatase Inhibitors (AIs)

Suicide aromatase inhibitors, such as ATD or aromasin, will permanently bind to the aromatase enzyme, this prevents estrogen rebound after you discontinue the AI. Other aromatase inhibitors, such as letrozole and arimidex do not have this ability, so there is a chance of estrogen levels rising after use is discontinued.

How it works

ATD inhibits estrogen biosynthesis by binding and inactivating the aromatase enzyme. Also, it naturally increases testosterone levels by lowering its conversion to estrogen. Higher testosterone levels typically mean increased strength, muscle, and a decrease in body fat.


Bodybuilders and athletes will use ATD on cycle to help permanently disable the aromatase enzyme. This should prevent estrogen related side effects such as gynecomastia (bitch tits), excessive water retention, high blood pressure, and insomnia.

Another benefit of ATD is that it has 90% androgenic activity in muscle tissue with only 10% androgenic activity in the hypothalamus. Therefore, you should theoretically hold more muscle when using it. In addition, ATD blocks the negative androgen feed back loop, which will decrease estrogen production while increasing testosterone production.


On a steroid cycle, shutdown occurs when the pituitary glands go dormant, and no longer produce LH (luteinizing hormone). It is LH that stimulates the testes (leydig cells) to produce testosterone. When an athlete is using anabolic-androgenic steroids (AAS) with ATD, it will reduce 'shutdown' and help disable the estrogen enzyme, so very little estrogen rebound will occur.

There is a split in the bodybuilding community as to whether ATD should be used for PCT, or not. Some will not recommend ATD to be used during post cycle therapy (PCT) because of the possibility of interfering with natural testosterone and the HPTA. However, some feel as though it aids in recovery by boosting testosterone and decreasing estrogen after cycle. Both uses are possible, but the quality of ATD on the market remains unknown. Therefore, be warned when considering using ATD, especially from non-approved suppliers.

Side Effects

Studies have shown that ATD may inhibit libido and sexual potency, which may be related to its effects at lowering estrogen. There is also a chance of dry joints any time ATD (an aromatase inhibitor) is used, so it's important not to abuse this compound.

False Drug Test Results

ATD converts to 1,4,6-testosterone, which could cause false readings for higher testosterone levels. Another issue is that its metabolites are similar to that of Equipoise (Boldenone), and this can lead to false positive drug tests. In fact, due to the poor quality of the underground ATD supply, much of it has been tainted with illegal substances. These will cause positive drug tests.


Dosages will range from 25-100mg per day with a 4-8 week duration. Those that choose to run ATD during post cycle therapy should use it as a kickstart. If used as a stand alone, it is important to keep an eye on blood work levels. You never want estrogen levels to drop too low.


ATD is a powerful suicide aromatase inhibitor that is temporarily legal over the counter. It can be used on cycle, stand alone, or during post cycle therapy. It works like aromasin to permanently disable the estrogen enzyme and prevent rebound after cycle. However, the quality of ATD remains a big question mark in the industry. After multiple government raids on ATD suppliers, I wouldn't suggest trusting anyone out there selling the supplement version of it.



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