What is 7-Keto?
7-Keto is also known as 7-keto-DHEA, 7-keto-dehydroepiandrosterone, 7-oxo-dehydroepiandrosterone, or 3-acetyl-7-oxo-dehydroepiandrosterone. It is a compound produced by the metabolism of the steroid prohormone dyhydroepiandrosterone (DHEA). However, unlike DHEA, it is not directly converted into testosterone or oestrogen (Davidson et al, 2000). It is biologically active and has been said that 7-keto can help with weight loss through increasing metabolism.
7-Keto occurs naturally in the human body. It is not found in appreciable amounts in everyday foods, but it is available as a dietary supplement.
7-Keto Benefits for Fat Loss
One of the best known functions of 7-keto is its ability to ramp up thermogenesis and increase metabolism. Unlike caffeine, this is achieved without any central nervous system stimulation (Davidson et al, 2000). It is a relatively well studied compound that has shown promise as a weight loss supplement. In one study, human volunteers receiving 7-keto supplementation in conjunction with diet and exercise were found to have lost almost 3 times more weight compared to those receiving a placebo, diet, and exercise (Zenk et al, 2002). Similar studies found equally positive results, with similar reductions in body weight among those supplemented with 7-keto (Kaiman et al, 2000), as well as reductions in hip circumference (Zenk et al, 2005).
The way 7-Keto works in its ability to increase fat loss, is by increasing the body's resting metabolic rate, possibly by increase thyroid hormone production (Kaiman et al, 2000). This has been repeatedly demonstrated in various studies. One study found that 7-keto was able to increase resting metabolic rate by around 7.2% when combined with diet and exercise, compared to 0.7% from diet and exercise alone (Zenk et al, 2005). In another study involving dieting subjects, it was found that dieting alone caused a decrease in metabolism by 3.9%, whereas supplementation with 7-keto during dieting resulted in an increase of metabolism by 1.4% (Zenk et al, 2007).
7-Keto Negatives & Side Effects
7-Keto has undergone quite a few safety and clinical trials. In a human safety trial, it was found that doses of up to 200 mg 7-keto/day resulted in no adverse effects. It was concluded that 7-keto is safe and well tolerated by healthy individuals (Davidson et al, 2000), and all studies cited above reported no adverse events. Toxicological studies in rats fed a huge single dose (2000 mg/kg) also found no signs of toxicity (Lardy et al, 1999). Likewise, monkey studies also showed no serious health effects when animals were given increasing doses of 7-keto of up to 1000 mg/kg/day. However, it was observed that animals experienced vomiting at higher doses (Henwood et al, 1999).
Because 7-keto is a metabolite of DHEA, which is an androgenic steroid hormone precursor, it is on the List of Prohibited Substances and Methods of the World Anti-Doping Agency. Therefore, the use of 7-keto is not suitable for those competing at high level sports that are under the jurisdiction of the World Anti-Doping Agency.
7-Keto Recommended Doses and Ingredient Timing
7-Keto has been shown to be effective at 200 mg/day (Kaiman et al, 2000 ; Zenk et al, 2002). This is also a dose that has been shown to be safe (Davidson et al, 2000). This dosage can be split up into 100 mg serves, to be taken 30 minutes before exercise or food.
In the United States and certain other countries 7-Keto may be found as a stand-alone supplement and as an ingredient in certain fat loss supplements. To the best of knowlege there is only one 7-Keto product available in Australia, this being "Powerzone Nutrition 7-Keto Formulation" which has been supplied by Powerzone Nutrition Australia since approximately 2007.
7-Keto can be stacked with a variety of other fat loss ingredients such as L-carnitine and inositol. It can also be stacked with stimulant based thermogenics such as caffeine and green tea. However, if you were after a nonstimulant thermogenic, avoid such combinations.
Davidson et al (2000), Safety and pharmacokinetic study with escalating doses of 3-acetyl-7-oxo-dehydroepiandrosterone in healthy male volunteers. Clin Invest Med, 23: 300-310
Henwood et al (1999), An Escalating Dose Oral Gavage Study of 3β-Acetoxyandrost-5-ene-7,17-dione (7-oxo-DHEA-acetate) in Rhesus Monkeys. Biochemical and Biophysical Research Communications, 254: 124-126
Kaiman et al (2000), A randomized, double-blind, placebo-controlled study of 3-acetyl-7-oxo-dehydroepiandrosterone in healthy overweight adults. Current Therapeutic Research, 61: 435-442
Lardy et al (1999), An Acute Oral Gavage Study of 3β-Acetoxyandrost- 5-ene-7,17-dione (7-oxo-DHEA-acetate) in Rats. Biochemical and Biophysical Research Communications, 254: 120-123
Zenk et al (2002), The effect of 7-Keto Naturalean™ on weight loss: A randomized, double-blind, placebo-controlled trial. Current Therapeutic Research, 63: 263-272
Zenk et al (2005), Effect of lean system 7 on metabolic rate and body composition. Nutrition, 21: 179-185
Zenk et al (2007), HUM5007, a novel combination of thermogenic compounds, and 3-acetyl-7-oxo-dehydroepiandrosterone: each increases the resting metabolic rate of overweight adults. The Journal of Nutritional Biochemistry, 18: 629-634