7-Oxo-Dehydroepiandrosterone, abbreviated as 7-oxo-DHEA, is a natural substance produced in the adrenal glands, gonads and brain. 7-Oxo-DHEA is a metabolite of the steroid hormone DHEA (see DHEA). DHEA and its metabolite dehydroepiandrosterone-3-sulfate, or DHEAS, are the major secretory steroidal products of the adrenal glands and the most abundant steroids in human blood. DHEA has been found to promote leanness in some obese animals, and, in mostly animal studies, has been found to decrease serum cholesterol, to decrease blood glucose in diabetic mice, to enhance immune function, to possess anticancer activity and to improve memory in old mice. DHEA is believed by some to have great importance in human physiology. However, to date, its exact role in human physiology remains unknown. 7-Oxo-DHEA has been studied to better understand, among other things, the biological role of DHEA. A major biochemical difference between 7-oxo-DHEA and DHEA is that DHEA is metabolized to the sex hormones (androgens and estrogens) while 7-oxo-DHEA does not appear to be metabolized to these hormones.
7-Oxo-DHEA is being studied for its possible cognition-enhancing and thermogenic activities. Steroids that are made in the brain are referred to as neurosteroids; steroids that may have thermogenic activity are referred to as ergosteroids. 7-Oxo-DHEA is also known as 3beta-hydroxyandrost-5-ene-7,17-dione,delta5-androstene-3beta-ol-7,17-dione and 7-keto-DHEA. The structural formula is:
7-Oxo-DHEA is marketed as a nutritional supplement. The form of 7-oxo-DHEA most commonly marketed is the 3-acetyl ester of 7-oxo-DHEA, also known as 3-acetyl-7-oxo-DHEA.
Actions & Pharmacology
Supplemental 7-oxo-DHEA has putative cognition-enhancing, thermogenic and immunomodulatory activities.
Mechanism of Action
7-Oxo-DHEA was found to reverse scopolamine-induced cholinergic dysfunction in mice. It is speculated that 7-oxo-DHEA's effect on memory is via allosteric inhibition of the GABAA receptor. In fact, studies have shown that DHEAS is a potent allosteric inhibitor of the GABAA receptor. DHEAS has been found to rapidly reduce GABAA-gated chloride and voltage-gated calcium currents, thereby increasing the general excitability of the hippocampus.
DHEA has been found to promote leanness in genetically obese and normal experimental animals without altering food intake. The amount of DHEA necessary to elicit this response is much larger than is required to obtain responses to hormones, and it was thought that this effect was probably mediated by a metabolite of DHEA. The DHEA metabolite 7-oxo-DHEA was found to be much more effective than DHEA at promoting leanness in experimental animals. 7-Oxo-DHEA appears to promote leanness via a thermogenic effect. 7-Oxo-DHEA has been demonstrated to enhance the activities in rats of the two thermogenic enzymes, liver mitochondrial sn-glycerol 3-phosphate dehydrogenase and cytosolic malic enzyme. It is thought that the induction of these enzymes may account for the thermogenic effect of 7-oxo-DHEA in animal models. 7-Keto-DHEA was shown to be significantly more potent than DHEA per se in the induction of these thermogenic enzymes.
7-Oxo-DHEA has been reported to augment interleukin 2 (IL-2) production by human lymphocytes in vitro. The mechanism of this effect is unknown.
There is little on the pharmacokinetics of 7-oxo-DHEA in humans. Preliminary studies indicate that it is absorbed following ingestion. However, the efficiency of its absorption, as well as its distribution, metabolism and excretion, needs to be elucidated. 7-Oxo-DHEA is not converted to DHEA, nor does it appear to be converted to the sex hormones testosterone and estrogens; DHEA, on the other hand, is.
Indications & Usage
Claims for 7-oxo-DHEA include metabolic enhancements that help promote weight loss and increase lean body mass, favorable effects on immunity, improved memory and various anti-aging effects. These claims are largely extravagant extrapolations from animal and in vitro studies and from very preliminary human studies. Some claim that 7-oxo-DHEA is superior to DHEA itself because 7-oxo-DHEA appears not to be converted to sex hormones (see DHEA).
7-Oxo-DHEA is available in the dietary supplement marketplace. It is marketed as the 3-acetyl ester of 7-oxo-DHEA. Typical dosage is 25 milligrams per day. Doses higher than those stated on the label should be avoided.
LiteratureBobyleva V, Bellei M, Kneer N, et al. The effects of the ergosteroid 7-oxo-dehydroepiandrosterone on mitochondrial membrane potential: possible relationship to thermogenesis. Arch Biochem Biophys. 1997;341:122-128.Hampl R, Hill M, Bí7lek R, et al. Relationship of dehydroepiandrosterone and its 7-hydroxylated metabolites to thyroid parameters and sex hormone-binding globulin (SHBG) in healthy subjects. Clin Chem Lab Med. 2003;41(8):1081-1086.Hampl R, Lapcí7k O, Hill M, et al. 7-Hydroxydehydroepiandrosterone—a natural antiglucocorticoid and a candidate for steroid replacement therapy? Physiol Res. 2000;49 Suppl 1:S107-112.Ihler G, Chami-Stemmann H. 7-oxo-DHEA and Raynaud's phenomenon. Med Hypotheses. 2003;60(3):391-397.Lardy H, Partridge B, Kneer N, et al. Ergosteroids: induction of thermogenic enzymes in liver of rats treated with steroids derived from dehydroepiandrosterone. Proc Natl Acad Sci USA. 1995;92:6617-6619.Rose KA, Stapleton G, Dott K, et al. Cyp7b, a novel brain cytochrome P450, catalyzes the synthesis of neurosteroids 7alpha-hydroxy dehydroepiandrosterone and 7alpha-hydroxypregnenolone. Proc Natl Acad Sci USA. 1997;94:4925-4930.Shi J, Schulze S, Lardy HA. The effect of 7-oxo-DHEA acetate on memory in young and old C57BL/6 mice. Steroids. 2000;65:124-129.Zenk JL, Frestedt JL, Kuskowski MA. HUM5007, a novel combination of thermogenic compounds, and 3-acetyl-7-oxo-dehydroepiandrosterone: each increases the resting metabolic rate of overweight adults. J Nutr Biochem. 2007;18(9):629-634.
Research & Summary
In a recent animal study, 7-oxo-DHEA was tested for its possible ability to reverse chemically induced memory abolition in young mice and for its effects on memory in old mice. Significant positive effects were reported in both test groups, compared with controls. A single dose of 7-oxo-DHEA reportedly completely reversed scopolamine-induced memory impairment in the young mice. And, in the old mice, single doses resulted in significant memory retention, as measured by water maze training, through a four-week test period. Memory retention was not improved in controls or in those animals given DHEA itself.
Several experimental studies have suggested that 7-oxo-DHEA might enhance thermogenesis. Some researchers have concluded that it is a more effective inducer of thermogenic enzymes than its parent steroid, DHEA. In large doses, DHEA has been shown to induce weight loss in genetically obese and in some normal animals without affecting food intake, but similar effects in humans have not been reliably confirmed. Similarly, there is little evidence that 7-oxo-DHEA significantly decreases weight or increases lean muscle mass in humans.
There are some data indicating that 7-oxo-DHEA might favorably impact some immune activities, such as stimulation of interleukin-2 and increased production of CD-4 and CD-8 cells in vitro.
7-Oxo-DHEA is contraindicated in those hypersensitive to any component of a 7-oxo-DHEA-containing product.
7-Oxo-DHEA supplementation should be avoided by pregnant women and nursing mothers.
Those who wish to try 7-oxo-DHEA for any health reason should first discuss its use with his or her physician.
7-Oxo-DHEA may have an effect on platelet membrane fluidity. Therefore, those taking the anticoagulant warfarin (Coumadin) should exercise caution in the use of 7-oxo-DHEA.
Vivid dreams have been reported in some taking 7-oxo-DHEA. Vivid dreams occur during REM (rapid eye movement) sleep, seem very real and are easier to remember.