Testosterone isobutyrate

Testosterone isobutyrate, sold under the brand names Agovirin-Depot and Perandren M among others, is an androgen and anabolic steroid medication and a testosterone ester which is used for indications such as low testosterone levels in men and delayed puberty in boys.[1][4] It is available only in the Czech Republic and Slovakia.[1] The medication is administered by injection into muscle once every 1 to 2 weeks in males.[1] Unlike most other testosterone esters, which are provided as oil solutions, testosterone isobutyrate is formulated as a microcrystalline aqueous suspension.[1]

Testosterone isobutyrate
Testosterone isobutyrate.svg
Testosterone isobutyrate molecule ball.png
Clinical data
Trade namesAgovirin-Depot, Perandren M, Testocryst, Virex-Cryst
Routes of
Intramuscular injection
Drug classAndrogen; Anabolic steroid; Androgen ester
ATC code
Pharmacokinetic data
Duration of action~2 weeks[1][2][3]
  • [(8R,9S,10R,13S,14S,17S)-10,13-dimethyl-3-oxo-1,2,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-17-yl] 2-methylpropanoate
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.013.293 Edit this at Wikidata
Chemical and physical data
Molar mass358.522 g·mol−1
3D model (JSmol)
  • CC(C)C(=O)O[C@H]1CC[C@@H]2[C@@]1(CC[C@H]3[C@H]2CCC4=CC(=O)CC[C@]34C)C
  • InChI=1S/C23H34O3/c1-14(2)21(25)26-20-8-7-18-17-6-5-15-13-16(24)9-11-22(15,3)19(17)10-12-23(18,20)4/h13-14,17-20H,5-12H2,1-4H3/t17-,18-,19-,20-,22-,23-/m0/s1

Medical usesEdit

Testosterone isobutyrate is used in the treatment of hypogonadism in men and delayed puberty in adolescent boys.[1] It is also used in the treatment of Klinefelter's syndrome, aplastic anemia, Cushing's syndrome (as an anabolic to preserve lean body mass), postmenopausal osteoporosis in women, advanced breast cancer in women, breast pain in women, and cachexia.[1] Testosterone isobutyrate has been used in masculinizing hormone therapy for transgender men as well.[5][6]

Available formsEdit

Testosterone isobutyrate is provided in the form of a 25 mg/mL microcrystalline aqueous suspension packaged in 2 mL ampoules (5 ampoules per box).[1] This equates to a dose of 50 mg per ampoule.[1] Testosterone isobutyrate (25 mg) is also available in combination with estradiol benzoate (2.5 mg) under the brand name Folivirin (1 mL ampoules).[7][8][9][10][11]

Side effectsEdit

Side effects of testosterone isobutyrate include virilization among others.[1]


Testosterone isobutyrate is a prodrug of testosterone, and hence is an agonist of the androgen receptor, the biological target of endogenous androgens like testosterone and dihydrotestosterone.[1] It produces both androgenic and anabolic effects, as well as weak estrogenic effects due to metabolism of testosterone into estradiol.[1]

In contrast to most other testosterone esters, which are used as amorphous oil solutions, testosterone isobutyrate is provided in the form of a microcrystalline aqueous suspension.[1] It has very low water solubility and forms a long-lasting microcrystalline depot within muscle upon intramuscular injection.[1] This respository slowly dissolves over time.[1] As a result, testosterone isobutyrate has a prolonged duration of action of approximately 2 weeks.[1][2][3] It is administered at intervals of once every 1 to 2 weeks in men.[1] Microcrystalline testosterone isobutyrate in aqueous suspension requires a larger needle (21 gauge) than oil solutions due to the presence of solid crystals in the suspension.[1] It can produce local irritation, pain, and redness upon injection.[1]


Testosterone isobutyrate, or testosterone 17β-(2-methylpropanoate), is a synthetic androstane steroid and a derivative of testosterone.[12][13] It is an androgen ester; specifically, it is the C17β 2-methylpropanoate (isobutyrate) ester of testosterone.[12][13]


Microcrystalline testosterone isobutyrate in aqueous suspension was first described in 1952.[1][14] It was introduced for medical use shortly thereafter.[1] Around the same time, testosterone enanthate in oil solution was introduced for medical use.[1] It became the dominant long-acting injectable form of testosterone, and limited the commercial success of testosterone isobutyrate.[1] The combination of microcrystalline estradiol benzoate and testosterone isobutyrate in aqueous suspension was introduced under the brand name Femandren M by 1953.[15]

Society and cultureEdit

Brand namesEdit

Brand names of testosterone isobutyrate include Agovirin-Depot, Perandren M, Testocryst, and Virex-Cryst.[12][13][16][17] It has also been marketed in combination with estradiol benzoate under the brand names Femandren M and Folivirin.[7][8][9][10][11]


Testosterone isobutyrate is available only in the Czech Republic and Slovakia.[1][16] It was originally manufactured by the pharmaceutical company SPOFA[18] intermittently manufactured by Biotika,[1] and is now manufactured by BB Pharma.[19]

See alsoEdit


  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y William Llewellyn (2011). Anabolics. Molecular Nutrition Llc. pp. 314–322. ISBN 978-0-9828280-1-4.
  2. ^ a b Hans Schuermann; Rudolf Doepfmer (13 March 2013). Fertilitätsstörungen beim Manne. Springer-Verlag. pp. 260–. ISBN 978-3-642-94784-1.
  3. ^ a b Joachim Ufer (1960). Hormontherapie in der Frauenheilkunde: Grundlagen und Praxis. Gruyter. p. 153. ISBN 9783111138770.
  4. ^ http://www.sukl.cz/download/pil/PI15709.pdf
  5. ^ Heresová J, Pobisová Z, Hampl R, Stárka L (December 1986). "Androgen administration to transsexual women. II. Hormonal changes". Exp. Clin. Endocrinol. 88 (2): 219–23. doi:10.1055/s-0029-1210600. PMID 3556412.
  6. ^ Hampl R, Hána V, Heresová J, Brzek A, Marek J, Stárka L (January 1989). "Srovnání vylucování trí v Ceskoslovensku registrovaných androgenů" [Comparison of the excretion of 3 androgens registered in Czechoslovakia]. Sbornik Lekarsky (in Czech). 91 (1): 16–20. ISSN 0036-5327. PMID 2717876.
  7. ^ a b http://www.sukl.cz/download/pil/PI15789.pdf
  8. ^ a b Kubíková, Drahomíra (2014). "Menopauzální symptomy a hormonální substituční terapie" [Menopausal symptoms and hormone replacement therapy]. Praktické Lékárenství (in Czech). 10 (2): 68–73. ISSN 1801-2434.
  9. ^ a b Marek Josef; a kolektiv (14 May 2010). Farmakoterapie vnitřních nemocí: 4., zcela přepracované a doplněné vydání. Grada Publishing a.s. pp. 380–. ISBN 978-80-247-9524-9. In addition, testosterone isobutyrate in FOLIVIRIN, Biotika, an injection containing 25 mg testosterone isobutyrate and 2.5 mg estradiol benzoate is available. It is applied every 4-6 weeks depending on the effect.
  10. ^ a b Georg Arends; Heinrich Zörnig; Hermann Hager; Georg Frerichs, Walther Kern (14 December 2013). Hagers Handbuch der pharmazeutischen Praxis: Für Apotheker, Arzneimittelhersteller, Drogisten, Ärzte u. Medizinalbeamte. Springer-Verlag. pp. 1163–. ISBN 978-3-662-36329-4.
  11. ^ a b Hans Hermann Julius Hager; Walther Kern; Paul Heinz List; Hermann Josef Roth (29 July 2013). Hagers Handbuch der Pharmazeutischen Praxis: Für Apotheker, Arzneimittelhersteller, Ärzte und Medizinalbeamte: Wirkstoffgruppen II Chemikalien und Drogen (A-AL). Springer-Verlag. pp. 109, 141, 178. ISBN 978-3-662-25655-8.
  12. ^ a b c J. Elks (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 641–642. ISBN 978-1-4757-2085-3.
  13. ^ a b c Index Nominum 2000: International Drug Directory. Taylor & Francis. January 2000. ISBN 978-3-88763-075-1.
  14. ^ Drescher H (April 1952). "Unsere Erfahrungen mit einer neuartigen Testosteron-isobutyrat-Kristallsuspension" [Experiences with a New Testosterone Isobutyrate Crystal Suspension]. Dtsch. Med. Wochenschr. (in German). 77 (14): 431–2. doi:10.1055/s-0028-1115985. PMID 12988767.
  15. ^ Ciba Symposium: 1953/57:Index. Ciba. 1953. p. 197. Femandren M. C'est le nom des nouvelles ampoules cristallines destinées au traitement associé œs- trogène-androgène. Elles renferment, sous forme de microcristaux, 2,5 mg de mono- benzoate d'œstradiol et 50 mg d'isobutyra- te de testostérone; elles sont indiquées pour traiter les cas où il convient d'administrer simultanément de l'hormone femelle et de l'hormone mâle et où il importe aussi d'obtenir un effet prolongé, par exemple lors de symptômes d'insuffisance à la ménopause ou après castration. L'effet d'une injection se prolonge pendant 3-6 semaines.
  16. ^ a b "Testosterone".
  17. ^ I.K. Morton; Judith M. Hall (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. ISBN 978-94-011-4439-1.
  18. ^ K. Lissak (6 December 2012). Hormones and Brain Function. Springer Science & Business Media. pp. 145–. ISBN 978-1-4684-2007-4.
  19. ^ "Agovirin Injection - bbpharma.sk".

External linksEdit