4-Androstene-3,6,17-trione
Encyclopedia
4-Androstene-3,6,17-trione (also marketed as "6-OXO" or 4-etioallocholen-3,6,17-trione) is a drug
or nutritional supplement that may increase the testosterone-estrogen ratio, but has no proven effect on body composition. Its use can be detected in urine.
4-Androstene-3,6,17-trione (4-AT) is a potent irreversible aromatase inhibitor
that inhibits estrogen biosynthesis by permanently binding and inactivating aromatase in adipose and peripheral tissue. Aromatase
is responsible for the conversion of testosterone
to estradiol
. Blocking aromatase causes the body to decrease in levels of estradiol, which then results in increase of LH
and consequently, testosterone
. Since testosterone has myotropic activity and estradiol does not, elevated testosterone levels increase muscle mass. However, there appear to be no human or animal studies testing the hypothesis that 4-AT will produce an anabolic effect.
4-AT is also used by steroid
or prohormone
users to counteract estrogen
level increases caused by aromatization during their steroid cycle. This helps minimize side effects such as gynecomastia
but can lead to acne
. Also, after a steroid cycle, the compound may be used to shorten the recovery from the testicular suppression that can be the result of the use of steroids.
A recent United States
patent
application claims an 88% increase in plasma testosterone levels in men, while decreasing estrogen levels by 11%. The subjects took 300 mg orally twice a day for four weeks without taking any other drugs or supplements.
Baylor University conducted an eight-week study to determine the effects of 300 mg or 600 mg of 6-OXO in resistance-trained males. Compared to baseline, free testosterone increased by 90% for 300 mg group and 84% for 600 mg group, respectively. Also dihydrotestosterone
and the ratio of free testosterone to estradiol
increased significantly. The report concluded that "[t]he results of this study indicate that eight weeks of 6-OXO supplementation had no effect on body composition or clinical safety markers, but incompletely inhibited aromatase activity and significantly increased endogenous DHT levels that were attenuated after a three-week washout period." This study did not utilize a control group and was funded in part by two producers of commercial 4-AT.
In a FDA Warning Letter
dated July 7, 2006, the U.S. Food and Drug Administration (FDA) argues that marketing of 4-AT (aka, 6-OXO) violates the Federal Food, Drug, and Cosmetic Act and as such products containing it are adulterated by legal definition.
On June 18, 2008, Health Canada issued a warning that 4-AT and 6-OXO had a health risk related to blood clotting and recommended all users immediately cease use. However this warning is based on a single domestic adverse reaction case report "in which an individual with no known predisposing medical conditions developed seizures and blood clots in his brain".
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
or nutritional supplement that may increase the testosterone-estrogen ratio, but has no proven effect on body composition. Its use can be detected in urine.
4-Androstene-3,6,17-trione (4-AT) is a potent irreversible aromatase inhibitor
Aromatase inhibitor
Aromatase inhibitors are a class of drugs used in the treatment of breast cancer and ovarian cancer in postmenopausal women. AIs may also be used off-label to treat or prevent gynaecomastia in men....
that inhibits estrogen biosynthesis by permanently binding and inactivating aromatase in adipose and peripheral tissue. Aromatase
Aromatase
Aromatase is an enzyme responsible for a key step in the biosynthesis of estrogens. It is a member of the cytochrome P450 superfamily , which are monooxygenases that catalyze many reactions involved in steroidogenesis. In particular, aromatase is responsible for the aromatization of androgens into...
is responsible for the conversion of testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
to estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
. Blocking aromatase causes the body to decrease in levels of estradiol, which then results in increase of LH
LH
LH, Lh, or lh may stand for:*Laurel and Hardy*Leasehold *Left-handed or left hand*Letterhead, the heading at the top of a sheet of letter paper*lh, a digraph for many languages...
and consequently, testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
. Since testosterone has myotropic activity and estradiol does not, elevated testosterone levels increase muscle mass. However, there appear to be no human or animal studies testing the hypothesis that 4-AT will produce an anabolic effect.
4-AT is also used by steroid
Anabolic steroid
Anabolic steroids, technically known as anabolic-androgen steroids or colloquially simply as "steroids", are drugs that mimic the effects of testosterone and dihydrotestosterone in the body. They increase protein synthesis within cells, which results in the buildup of cellular tissue ,...
or prohormone
Prohormone
A prohormone is a substance that is a precursor to a hormone, usually having minimal hormonal effect by itself. The term has been used in medical science since the middle of the 20th century. The primary function of a prohormone is to enhance the strength of the hormone that already occurs in the...
users to counteract estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
level increases caused by aromatization during their steroid cycle. This helps minimize side effects such as gynecomastia
Gynecomastia
Gynecomastia or Gynaecomastia, , is the abnormal development of large mammary glands in males resulting in breast enlargement. The term comes from the Greek γυνή gyné meaning "woman" and μαστός mastós meaning "breast"...
but can lead to acne
Acne vulgaris
Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...
. Also, after a steroid cycle, the compound may be used to shorten the recovery from the testicular suppression that can be the result of the use of steroids.
A recent United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
application claims an 88% increase in plasma testosterone levels in men, while decreasing estrogen levels by 11%. The subjects took 300 mg orally twice a day for four weeks without taking any other drugs or supplements.
Baylor University conducted an eight-week study to determine the effects of 300 mg or 600 mg of 6-OXO in resistance-trained males. Compared to baseline, free testosterone increased by 90% for 300 mg group and 84% for 600 mg group, respectively. Also dihydrotestosterone
Dihydrotestosterone
Dihydrotestosterone is an androgen or male sex hormone. The enzyme 5α-reductase synthesises DHT in the prostate, testes, hair follicles, and adrenal glands...
and the ratio of free testosterone to estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
increased significantly. The report concluded that "[t]he results of this study indicate that eight weeks of 6-OXO supplementation had no effect on body composition or clinical safety markers, but incompletely inhibited aromatase activity and significantly increased endogenous DHT levels that were attenuated after a three-week washout period." This study did not utilize a control group and was funded in part by two producers of commercial 4-AT.
In a FDA Warning Letter
FDA Warning Letter
The United States Food and Drug Adminstration defines a Warning Letter as "...a correspondence that notifies regulated industry about violations that FDA has documented during its inspections or investigations...
dated July 7, 2006, the U.S. Food and Drug Administration (FDA) argues that marketing of 4-AT (aka, 6-OXO) violates the Federal Food, Drug, and Cosmetic Act and as such products containing it are adulterated by legal definition.
On June 18, 2008, Health Canada issued a warning that 4-AT and 6-OXO had a health risk related to blood clotting and recommended all users immediately cease use. However this warning is based on a single domestic adverse reaction case report "in which an individual with no known predisposing medical conditions developed seizures and blood clots in his brain".