Androstenediol refers to two steroid isomers that are marketed as dietary supplements and mainly used by body builders. The two androstenediol isomers are delta4-androstenediol and delta5-androstenediol. The difference between the two isomers is in the position of the double bond in the cyclopentanoperhydrophenanthrene ring structure. Delta4-androstenediol has a double bond between carbons 4 and 5; delta5-androstenediol has a double bond between carbons 5 and 6.
Delta4-androstenediol is also known as 4-androstene-3beta, 17beta-diol and (3beta, 17beta)-androst-4-ene-3, 17-diol. Delta5-androstenediol is also known as 5-androstene-3beta, 17beta-diol, androst-5-ene-3beta, 17beta-diol, (3beta, 17beta)-androst-5-ene-3, 17-diol and Adiol. The molecular formula of both delta4-androstenediol and delta5-androstenediol is C19H30O2, and the molecular weight of these substances is 290.45 daltons.
Delta4-androstenediol and delta5-androstenediol are synthesized in the adrenal gland and gonads from dehydroepiandrosterone (DHEA) via the enzyme 17beta-hydroxysteroid dehydrogenase. They are metabolized to testosterone via the enzyme 3beta-hydroxysteroid dehydrogenase. Delta5-androstenediol is similar in structure to methandriol.
4-androstenediol (4-AD) is an effective prohormone to testosterone. Naturally found in several tissues of the body, 4-AD is converted to testosterone via the enzyme 3beta-HSD. 4-AD converts to testosterone at a significantly higher rate than other commercially available prohormones (such as androstenedione), and also does not have the weakness of conversion to estrogen and/or DHT prior to conversion to testosterone. This makes 4-AD the best testosterone prohormone on the market.
Since testosterone is the target hormone, the effects of 4-AD supplementation will be consistent with an increase in testosterone levels. Since testosterone converts to both estrogen and DHT, both androgenic and estrogenic side effects can be expected. Although not commonly used as a standalone because of these side effects, 4-AD is used in most prohormone stacks. Since exogenous steroids shut down natural production of testosterone via negative feedback, 4-AD can help reduce the side effects of low testosterone and low estrogen experienced with many substances (such as loss of libido) while also providing additional anabolic benefit. 19-nordiol and 4-AD and 1-AD or 1-test and 4-AD are both common stacks. 4-AD is also recommended to counteract some of the side effects of methyl-1-test.
4-AD is best used as a transdermal, as it has low oral bioavailability. 300-600 mg is the commonly used transdermal dosage when stacking, while higher doses (700-1000 mg) are used as a standalone. Oral 4-AD doses, even when stacking, may go up to as much as 1.5 g daily, although most use 600-900 mg. This is generally spread out over 3-4 doses. Sublingual 4-AD can also be used as a preworkout stimulant.
Supplemental delta4- and delta5-androstenediol may be metabolized to testosterone in both men and women. Whether increases in testosterone levels that may be produced by taking oral delta4- or delta5-androstenediol would be sustained long enough to show increases in nitrogen retention and muscle strength and mass is unknown. Delta5-androstenediol is similar in structure to methandriol, a one-time popular injectable anabolic steroid. Delta5-androstenediol has been demonstrated to enhance the immune response against infection in mice. It is thought that this is due, in part, to delta5-androstenediol's possible role in counter-regulating the immunosuppressive effects of glucocorticoids. That is, delta5-androstenediol may have antiglucocorticoid activity.