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Why Primobolan is Primo

This blog post contains citations referenced in my video, which you can watch here.

A. A review of the literature failed to discover any androgen receptor binding studies for methenolone. How websites report an androgenic to anabolic ratio is unclear.

B. Human liver function:

a. It was originally thought that methenolone enanthate and acetate (and nandrolone phenoproprionate) would not produce liver stress, in contrast to 17-alkylated steroids[1].

b. Methenolone enanthate appears to have improved albumin turnover in cirrhotic patients[2].

C. Human female breast cancers:

a. Methenolone enanthate was (ineffectively) used to treat females with breast cancers. It was shown to produce virilization and not to convert to estrogen[3].

b. In a group of 28 cancerous women given methenolone enanthate, 12 developed dyslipidemia that regressed upon discontinuation[4].

D. Human anemia:

a. The acetate version has been used to treat female anemics at 20 mg[5].

b. It produced cholestatic jaundice in some anemics at 1-2 mg/kg[6].

E. Human metabolism:

a. In men, a single dose of methenolone acetate produced methenolone in urine for up to 90 hours after administration, totaling to 1.6% of the oral dose.

b. Several other metabolites were found, consequent to oxidation of the 17-hydroxyl group and a reduction of the A-rings[7].

c. The major metabolite is 3alpha-hydroxy-1-methylen-5alpha-androstan-17-one, which can be detected in urine up to 5 days after a single ingestion of the drug[8].

d. Methenolone sulfate and other sulfated metabolites form a core component of the metabolism of methenolone in man[9].

F. Vision:

a. There is a US patent on the use of methenolone or nandrolone to treat dry eyes[10].

G. Erythropoiesis:

a. Methenolone acetate was shown to increase erythropoietic activity of bone marrow cells, either by increasing the sensitivity of erythropoietic cells or their numbers[11].

b. When compared to testosterone, oxymetholone, and metholone, methenolone produced a more erythropoietic effect than testosterone (though metholone produced the most)[12]. This indicates that the virilization and erythropoietic effects work through different mechanisms.

c. A study found that halotestin (fluoxymesterone) and methenolone similarly increased hematopoiesis in rodents, as well as iron uptake into blood[13].

H. Bone development:

a. Like other AAS, methenolone enanthate was shown to increase bone development in growing female rodents and decrease it in male rodents[14].

b. It halts the growth of young rodents[15].

c. In rodents, methenolone produced a favorable healing profile for fractured bones despite its less androgenic nature. Early calcium callus concentrations were raised less than with testosterone, but later repair was comparable[16].

d. Via agonism of the androgen receptor, DHT, fluoxymesterone (halotestin), and methenolone are mitogenic on in vitro bone cells, meaning they cause bone cell division and proliferation[17].

I. Renal function:

a. Even without improving muscular development, methenolone enanthate was shown to increase kidney weights in growing male rodents[18].

J. Cardiac function:

a. It was shown to produce left ventricular hypertrophy in pubertal rodents, with more pronounced effects occurring among the female rodents[19].

[1] MARQUARDT, G. H., LOGAN, C. E., TOMHAVE, W. G., & DOWBEN, R. M. (1964). Failure of non-17-alkylated anabolic steroids to produce abnormal liver function tests. The Journal of Clinical Endocrinology & Metabolism, 24(12), 1334-1336. [2] Knöbel, H., & Becker, K. (1975). Effect of an anabolic steroid (methenolone enanthate) on the intra-and extravasal albumin pool in liver cirrhosis. Zeitschrift fur Gastroenterologie, 13(6), 583-587. [3] Notter, G. (1975). Treatment of disseminated carcinoma of the breast by metenolone enanthate. Acta Radiologica: Therapy, Physics, Biology, 14(6), 545-551. [4] Garbrecht, M., Lehmann, U., O'Brien, S., Stolzenbach, G., & Müllerleile, U. (1981). Hyperlipoproteinaemia during additional methenolone administration in the treatment of metastasizing carcinoma of the breast. Deutsche Medizinische Wochenschrift (1946), 106(13), 400-403. [5] Hamamoto, K., Ohno, T., & Ogawa, H. (1996). Myelodysplastic syndrome with CREST syndrome successfully treated with metenolone--A case report. [Rinsho ketsueki] The Japanese journal of clinical hematology, 37(4), 362-365. [6] Palva, I. P., & Wasastjerna, C. (1972). Treatment of aplastic anaemia with methenolone. Acta haematologica, 47(1), 13-20. [7] Goudreault, D., & Massé, R. (1990). Studies on anabolic steroids—4. Identification of new urinary metabolites of methenolone acetate (primobolan®) in human by gas chromatography/mass spectrometry. The Journal of steroid biochemistry and molecular biology, 37(1), 137-154. [8] Björkhem, I., & Ek, H. (1983). Detection and quantitation of 3α-hydroxy-1-methylen-5α-androstan-17-one, the major urinary metabolite of methenolone acetate (Primobolan®) by isotope dilution—Mass spectrometry. Journal of steroid biochemistry, 18(4), 481-487. [9] Fragkaki, A. G., Angelis, Y. S., Kiousi, P., Georgakopoulos, C. G., & Lyris, E. (2015). Comparison of sulfo‐conjugated and gluco‐conjugated urinary metabolites for detection of methenolone misuse in doping control by LC‐HRMS, GC‐MS and GC‐HRMS. Journal of Mass Spectrometry, 50(5), 740-748. [10] Endo, K., Fujii, S., & Oki, K. (2018). U.S. Patent Application No. 15/563,108. [11] Mori, M., Chiba, S., Suzuki, S., Kosaka, K., Miura, Y., & Takaku, F. (1974). Effect of methenolone acetate on erythropoietin responsive cells in rat bone marrow. Biochemical and Biophysical Research Communications, 60(1), 281-287. [12] Duarte, L., Sánchez Medal, L., Labardini, J., & Arriaga, L. (1967). The erythropoietic effects of anabolic steroids. Proceedings of the Society for Experimental Biology and Medicine, 125(4), 1030-1032. [13] Hotta, T., Hirabayashi, N., Utsumi, M., & Yamada, H. (1978). Basic study on hematopoiesis-activating function of androgen. Effects of fluoxymesterone and methenolone in vivo. [14] Bozkurt, I., Pepe, K., Ozdemir, M., Ozdemir, O., & Coskun, A. (2011). Morphometric evaluation of the effect of methenolone enanthate on femoral development in adolescent rats. Scientific Research and Essays, 6(7), 1634-1638. [15] ÖZDEMİR, M., & Sefa, L. Ö. K. (2019). The Effects of Methenolone Enanthate Supplement with Exercise on Rats’ Bones. Turkish Journal of Sport and Exercise, 21(2), 276-280. [16] Frankle, M., & Borrelli, J. (1990). The effects of testosterone propionate and methenolone enanthate on the healing of humeral osteotomies in the Wistar rat. Journal of Investigative Surgery, 3(2), 93-113. [17] Kasperk, C. H., Wergedal, J. E., Farley, J. R., Linkhart, T. A., & Turner, R. T. (1989). Androgens directly stimulate proliferation of bone cells in vitro. Endocrinology, 124(3), 1576-1578. [18] Holt, T. L., Ward, L. C., Thomas, B. J., Davey, J. F., & Shepherd, R. W. (1990). The effect of an anabolic steroid, methenolone enanthate, on growth, body composition and skeletal muscle protein synthesis in the growing rat. Nutrition Research, 10(5), 535-545. [19] Ozdemir, O., Bozkurt, I., Ozdemir, M., & Yavuz, O. (2013). Side effect of metenolone enanthate on rats heart in puberty: Morphometrical study. Experimental and Toxicologic Pathology, 65(6), 745-750.


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