Genabol — norbolethone

Norbolethone is an orally active derivative of nandrolone. Structurally, this steroid differs from normethandrolone (Orgasteron) only by the substitution of the 13-methyl group with an ethyl. As is common for a member of the nandrolone family, norbolethone is more anabolic than androgenic in nature. Early animal studies place the anabolic index of this agent at 20 as compared to oral methyltestosterone (the standard of comparison for oral anabolic/androgenic steroids), meaning that it has 20 times higher anabolic than androgenic activity. Although this figure may not translate perfectly to real-world human use, we can still expect a favorable balance of anabolic to androgenic effect. Comparisons to other commercially available agents would probably place norbolethone in a, similar category to norethandrolone, both being effective anabolic derivatives of nandrolone, but with some additional estrogenic and progestational activity that makes them somewhat dissimilar to more purely anabolic agents such as Winstrol, Primobolan, and Anavar. Norbolethone is most appropriately considered a bodybuilding drug, and is less ideally suited for the needs of competitive athletes.

Brand name Genabol, Norbolethone
Androgenic 17
Anabolic 350
Standard Testosterone propionate
Chemical Names 13-ethyl-17-hydroxy-18,19-dinor-17a-pregn-4-en-3-one
Estrogenic Activity moderate
Progestational Activity moderate

Genabol History

Norbolethone was first described in 1963. The drug was developed by Wyeth (Genabol, 2.5 mg), and put into human clinical trials between 1964 and 1972. It was investigated as a potential medicine to treat low body weight and children with short stature. Effective doses used in the studies were as low as 1.25 mg per day in children, but generally included a common adult dose of 2.5 mg to 10 mg per day. A detailed series of investigations into the metabolic effects of norbolethone (using 2.5 mg to 10 mg per day for up to 6 weeks) in adult and elderly men and women recovering from surgery or illness in 1968 determined that optimal protein retention was achieved at 7.5 mg per day (10 mg per day was shown to offer no advantage in this study). Although the drug was deemed highly anabolic with minimal androgenic properties, and effective doses had been determined, norbolethone was ultimately never released as a commercial prescription agent. As such, after the clinical trials were published, little mention was made of this drug for approximately thirty years.

Norbolethone was thrown into headlines in mid-2002, when it was announced that Dr. Don Catlin of the UCLA Analytical Laboratories had discovered that athletes were using this drug to beat the drug screens being conducted at his facility. Because norbolethone was never sold as a commercial steroid, the athletic bodies were not looking for it during earlier tests. A private chemist (later identified as Patrick Arnold) realized this, and manufactured it for the specific purpose of beating the drug screen. Catlin was clued into its use after identifying several "negative" samples that had signs of endogenous steroid suppression (potentially indicating steroid use). The norbolethone doping scandal that resulted was the first modern appearance of the "designer steroid" phenomenon. These are non-commercial steroids that do not show up on a drug screen by virtue of their anonymity. For as long as they are not known to drug-testing facilities, they will not be detected. Drugs like norbolethone are highly valued commodities among competitive athletes.

Once Catlin identified norbolethone, he promptly devised and released a method for the detection of its metabolites in the urine. Several world-class athletes were ultimately suspended for using this drug during competition, including U.S. Olympic cyclist Tammy Thomas. With this press release, norbolethone immediately lost any value it formerly had as an undetectable designer steroid. It has been "discovered," so to speak, and is now actively screened for during any serious steroid urinalysis test. There is little doubt that most of the athletes that were using this compound have long since abandoned it and moved on to better things. Charlie Francis, the man who coached Ben Johnson when he tested positive for steroids at the 1988 Summer Games, would later comment that norbolethone was being widely used at the 2000 Sydney Games, two years before the IOC caught wind of its existence.

How is Genabol Supplied

Norbolethone is not available as a prescription drug product. When produced as an experimental drug by Wyeth it was found in the form of a 2.5 mg tablet.

Structural Characteristics of Genabol

Norbolethone is a modified form of nandrolone. It differs by 1) the addition of an ethyl group at carbon 17-alpha to protect the hormone during oral administration and 2) the introduction of an ethyl group at carbon 13-alpha, which seems to intensify steroid anabolic activity.

Genabol Side Effects (Estrogenic)

Norbolethone has not been extensively studied in humans. Based on its structure, it is expected that norbolethone is aromatized. It should convert to a synthetic estrogen with a high level of biological activity (13,17alpha-diethyl-estradiol). This should be a moderately estrogenic steroid. Gynecomastia may be a concern during treatment, particularly with higher doses. At the same time water retention can become a problem, causing a notable loss of muscle definition as both subcutaneous water retention and fat levels build. Sensitive individuals may want to keep the estrogen under control with the addition of an anti-estrogen such as Nolvadex®. One may alternately use an aromatase inhibitor like Arimidex® (anastrozole), which is a more effective remedy for estrogen control. Aromatase inhibitors, however, can be quite expensive in comparison to standard estrogen maintenance therapies, and may also have negative effects on blood lipids.

Based on its structure, it is expected that norbolethone has some activity as a progestin in the body. The side effects associated with progesterone are similar to those of estrogen, including negative feedback inhibition of testosterone production and enhanced rate of fat storage. Progestins also augment the stimulatory effect of estrogens on mammary tissue growth. There appears to be a strong synergy between these two hormones here, such that gynecomastia might even occur with the help of progestins without excessive estrogen levels being present. The use of an anti-estrogen, which inhibits the estrogenic component of this disorder, is often sufficient to mitigate gynecomastia caused by progestational anabolic steroids.

Genabol Side Effects (Androgenic)

Although classified as an anabolic steroid, androgenic side effects are still possible with this substance. This may include bouts of oily skin, acne, and body/facial hair growth. Anabolic/androgenic steroids may also aggravate male pattern hair loss. Women are additionally warned of the potential virilizing effects of anabolic/androgenic steroids. These may include a deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement. Note that in androgen-responsive target tissues such as the skin, scalp, and prostate, structure suggests that the relative androgenicity of norbolethone is reduced by its reduction to dihydo-norbolethone. The concurrent use of a 5-alpha reductase inhibitor such as finasteride or dutasteride may interfere with site-specific reduction of norbolethone action, increasing the tendency of the drug to produce androgenic side effects. Reductase inhibitors should be avoided with this steroid if maintaining low relative androgenicity is desired.

Genabol Side Effects (Hepatotoxicity)

Norbolethone is a cl 7-alpha alkylated compound. This alteration protects the drug from deactivation by the liver, allowing a very high percentage of the drug entry into the bloodstream following oral administration. Cl 7-alpha alkylated anabolic/androgenic steroids can be hepatotoxic. Prolonged or high exposure may result in liver "damage. In rare instances life-threatening dysfunction may develop. It ‘is advisable to visit a physidan periodically during each cycle to monitor liver function and overall health. Intake of cl 7-alpha alkylated steroids is commonly limited to 6-8 weeks, in an effort to avoid escalating liver strain. Severe liver complications are rare given the periodic nature in which most people use oral anabolic/androgenic steroids, although cannot be excluded with this steroid, especially with high doses and/or prolonged administration periods. Studies examining the sulfobromophthalein (BSP) retention effects of norbolethone and sixteen other anabolic/androgenic steroids in animals determined the drug to be among the most active. Increased BSP retention is a common marker of hepatic stress. Later studies in humans determined that the drug was well tolerated in doses of 10 mg per day or less for up to 6 weeks of continuous use.

The use of a liver detoxification supplement such as Liver Stabil, Liv-52, or Essentiale Forte is advised while taking any hepatotoxic anabolic/androgenic steroids.

Genabol Side Effects (Cardiovascular)

Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis. The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. Norbolethone has a strong effect on the hepatic management of cholesterol due to its structural resistance to liver breakdown and route of administration. Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction.

To help reduce cardiovascular strain it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active AAS administration. Supplementing with fish oils (4 grams per day) and a natural cholesterol/antioxidant formula such as Lipid Stabil or a product with comparable ingredients is also recommended.

Genabol Side Effects (Testosterone Suppression)

All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are expected to suppress endogenous testosterone production. Without the intervention of testosterone-stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.

Genabol Administration (General)

Prescribing guidelines generally advise that oral steroids can be taken with or without meals. The difference in bioavailability is generally not regarded as substantial. However, a 2016 study on newborn infants did find the absorption of oxandrolone to be significantly improved when dissolved directly in fat (MCT oil). If the diet includes considerable fat content, taking this oral steroid with meals might be more advantageous.

Genabol Administration (Men)

Norbolethone was never approved for use in humans.

Prescribing guidelines are unavailable. Human studies determined an optimal clinical dose to be 7.5 mg per day. When used for physique- or performance-enhancing purposes, a dosage of 10-15 mg per day would be applied, taken for 6-8 weeks. The results at these doses should be measurable improvements in strength and muscle size, which may be accompanied by increased water retention, fat gain, and a loss of definition.

Genabol Administration (Women)

Norbolethone was never approved for use in humans. Prescribing guidelines are unavailable. Human studies determined an optimal clinical dose to be 7.5 mg per day. When used for physique- or performance-enhancing purposes, a dosage of 5 mg per day would likely be applied, taken for 4-6 weeks. Although primarily anabolic in nature, women are still warned of the potential for virilizing activities, especially with higher doses.

Genabol Availability

Norbolethone is unavailable as a prescription drug product.


Wlliam Llewellyn (2017) - Anabolics

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