GP Bolasterone


Manufacturer: Geneza Pharmaceuticals
Substance: DiMethylTestosterone
Package: 20 tablets (50 mg/tab)
Common Name(s): Bolasterone, Myagen, Calusterone



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GP Bolasterone is the trade name for the synthetic steroid released by Geneza Pharmaceuticals. GP Bolasterone is intended for oral administration and is produced as 50 mg tablet. Each tablet of GP Bolasterone contains 50 mg of DiMethylTestosterone hormone, and is commercialized in high grade multi-layered sachets, specially designed to protect the contents from temperature changes or damages during shipment. Each sachet contains 20 tablets.

Bolasterone (aka Myagen) is structurally related to Methyltestosterone. Bolasterone is simply DiMethyltestosterone (7a,17a-Dimethyltestosterone) but with an additional methyl group (hence “dimethyl”) at the C7 position. The first methyl group (at the 17th position) allows the steroid to pass through the liver and remain active in the blood. The Second methyl group (at the 7th position) prevents it from binding freely to Sex Hormone Binding Globulin (SHBG), thereby allowing much of it to remain unbound and in an active state, and therefore greatly increasing its potency.

Bolasterone is a fairly potent anabolic steroid, measured in human subjects to have approximately twice the anabolic effect of methandrostenolone. Despite being a derivative of testosterone, bolasterone is considerably more anabolic than it is androgenic in nature. GP Bolasterone is mainly prescribed for the treatment of advanced breast cancer in women, but was also investigated for use on lean tissue sparing activity.

GP Bolasterone is very popular oral steroid being used by bodybuilders in Europe. Bolasterone had functions similar to GP Methan 10, but it has long since been discontinued. Several years ago Bolasterone became the first big name counterfeit steroid to be internationally marked. Belonging to a group of steroids titled the DDR compounds, inferring they came from East Germany, this steroid was billed as the best drug ever made. It became very popular partially because several respected steroid experts were in on the production of it, and gave it rave reviews in their publications.


Bodybuilders and athletes would often use GP Bolasterone in bulking cycle, where adding extra weight wasn’t a concern. Bolasterone is a very estrogenic steroid by nature, and one can expect to see all of the common estrogen related side effects, especially in higher doses. Estrogen related side effects include increased water and fat retention and gyno. To combat this side effects, athletes often prefer to run some sort of anti estrogen compound such as GP Anastrozole or GP Exemestane during cycle. GP Bolasterone can also produce androgen related side effects as well such as oily skin, acne, and increased body and facial hair. In women, androgen can cause masculizing side effects such as deepening of the voice, the growth facial hair, and clitoral enlargement.

GP Bolasterone is a C17aa compound, which means that it can be toxic to liver if taken in doses too large or for periods too long. Because of this, users are urged to try to keep cycles under 8 weeks and to run some sort of liver protection product such as LIV 52. Like all anabolic steroids, GP Bolasterone will shut down the body’s natural Testosterone production, making a post cycle therapy protocol necessary after the drug’s use has been discontinued. Users often choose to run compounds such as GP Clomiphene and HCG (Human Chorionic Gonadotropin) to get the body to start producing testosterone naturally again.


Clinical studies have demonstrated that significant nitrogen retention and weight gain can be induced with a daily dosage of 1-2 mg dayly, while using GP Bolasterone. In the case of bodybuilders and athletes looking for performance enhancement purposes, users often choose run a dosage of 2-5 mg daily for a period of 6-8 weeks. This level is sufficient for strong increases in muscle size and strength, although such gains will likely be accompanied by significant water retention due to estrogen.

GP Bolasterone is generally not recommended for women due to its very strong nature and tendacy to produce virilizing side effects.

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