Testosterone isobutyrate

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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]
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.013.293 Edit this at Wikidata
Chemical and physical data
Molar mass358.514 g/mol g·mol−1
3D model (JSmol)

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]

Medical uses[edit]

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]

Medications and dosages used in masculinizing hormone therapy for transgender men

Medication Brand names Type Route Dosage
Testosterone undecanoate Andriol, Jatenzo Androgen Oral 40–80 mg/2–3x day (with meals)
Testosterone Striant Androgen Buccal 30 mg 2x/day
Natesto Nasal spray 11 mg 3x/day
AndroGel, others Transdermal gel 25–100 mg/day
Androderm, others Transdermal patch 2.5–10 mg/day
Axiron Axillary solution 30–120 mg/day
Testopel Subcutaneous implant 150–600 mg/3–6 months
Testosterone enanthate Delatestryl, others Androgen Injection (IM or SC) 50–100 mg/week or 100–250 mg/2–4 weeks
Testosterone cypionate Depo-Testosterone, others Androgen Injection (IM or SC) 50–100 mg/week or 100–250 mg/2–4 weeks
Testosterone isobutyrate Agovirin Depot Androgen Injection (IM or SC) 50–100 mg/week
Mixed testosterone estersa Sustanon 250, others Androgen Injection (IM or SC) 250 mg/2–3 weeks or 500 mg/3–6 weeks
Testosterone undecanoate Aveed, Nebido, others Androgen Injection (IM or SC) 750–1,000 mg/10–14 weeks
GnRH analogue Various GnRH modulator Parenteral (various) Variable
Elagolix Orilissa GnRH antagonist Oral 150 mg/day or 200 mg/twice a day
Medroxyprogesterone acetateb Provera, others Progestin Oral 5–10 mg/day
Depo-Provera, others Injection (IM) 150 mg/3 months
Depo-SubQ Provera 104 Injection (SC) 104 mg/3 months
Lynestrenolb Orgametril, others Progestin Oral 5–10 mg/day
Finasteridec Propecia, Proscar 5α-Reductase inhibitor Oral 1 mg/day
Dutasteridec Avodart 5α-Reductase inhibitor Oral 0.5 mg/day
Footnotes: a = Specifically 12% testosterone propionate, 24% testosterone phenylpropionate, 24% testosterone isocaproate, and 40% testosterone decanoate. b = For suppression of menses only. c = For prevention/treatment of scalp hair loss only. Sources: See template.

Androgen replacement therapy formulations and dosages used in women

Route Medication Form(s) Major brand name(s) Dosage
Oral Testosterone undecanoatea Capsule Andriol, Jatenzo 40–80 mg 1x/1–2 days
Methyltestosteroneb Tablet Metandren; Estratest 0.5–10 mg/day
Normethandronea,b Tablet Ginecoside 5 mg/day
Tibolonea Tablet Livial 1.25–2.5 mg/day
Prasterone (DHEA)c Tablet N/A 25–100 mg/day
Sublingual Testosteroned Tablet N/A 0.25–0.5 mg/day
Methyltestosterone Tablet Metandren 0.25 mg/day
Transdermal Testosteronea Patch Intrinsa 150–300 μg/day
Testosterone Cream; Gel AndroGel 5–10 mg/day
Vaginal Testosteroned Cream; Gel N/A ? mg 1x/1–3 days
Testosteroned Suppository N/A 1 mg 1x/2 days
Prasterone (DHEA) Insert Intrarosa 6.5 mg/day
Intramuscular Testosterone enanthateb Oil Delatestryl; Primodian Depot 25–100 mg 1x/4–6 weeks
Testosterone cypionateb Oil Depo-Testost.; Depo-Testadiol 25–100 mg 1x/4–6 weeks
Testosterone isobutyratea,b Water Femandren M, Folivirin 25–50 mg 1x/4–6 weeks
Testosterone EBHb,e Oil Climacteron 150 mg 1x/4–8 weeks
Nandrolone decanoate Oil Deca-Durabolin 25–50 mg 1x/6–12 weeks
Prasterone enanthatea,b Oil Gynodian Depot 200 mg 1x/4–6 weeks
Subcutaneous Testosterone Implant Testopel 50–100 mg 1x/3–6 months
Footnotes: a = Not available or no longer available in the United States. b = Alone and/or in combination with an estrogen. c = Over-the-counter. d = Compounded only. e = Discontinued. Sources: See template.

Available forms[edit]

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 effects[edit]

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]

Parenteral durations of androgens/anabolic steroids

Compound Brand name(s) Type Duration
Testosterone (aq. susp.) Andronaq, Sterotate, Virosterone Androgen 2–3 days
Testosterone propionate Androteston, Perandren, Testoviron Androgen 3–4 days
Testosterone phenylpropionate Testolent Androgen 8 days
Testosterone isobutyrate (aq. susp.) Agovirin Depot, Perandren M Androgen 14 days
Mixed testosterone estersa Triolandren Androgen 10–20 days
Mixed testosterone estersb Testosid Depot Androgen 14–20 days
Testosterone enanthate Delatestryl Androgen 14–20 days
Testosterone cypionate Depovirin Androgen 14–20 days
Mixed testosterone estersc Sustanon 250 Androgen 28 days
Testosterone undecanoate Aveed, Nebido Androgen 100 days
Testosterone buciclate (aq. susp.)d 20 Aet-1, CDB-1781e Androgen 90–120 days
Nandrolone phenylpropionate Durabolin Anabolic 10 days
Nandrolone decanoate Deca Durabolin Anabolic 21 days
Methandriol (aq. susp.) Notandron, Protandren Androgen 8 days
Methandriol bisenanthoyl acetate Notandron Depot Androgen 16 days
Metenolone acetate Primobolan Anabolic 3 days
Metenolone enanthate Primobolan Depot Anabolic 14 days
Note: All are via i.m. injection of oil solution unless noted otherwise. Footnotes: a = TP, TV, and TUe. b = TP and TKL. c = TP, TPP, TiCa, and TD. d = Studied, but never marketed. e = Developmental code names. Sources: See template.


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]

Structural properties of major testosterone esters

Androgen Structure Ester Relative
mol. weight
T contentb
Position Moiety Type Lengtha Rank Group
1.00 1.00 11 Short
Testosterone propionate
Testosterone propionate.svg
C17β Propanoic acid Straight-chain fatty acid 3 1.19 0.84 10 Short
Testosterone isobutyrate
Testosterone isobutyrate.svg
C17β Isobutyric acid Aromatic fatty acid – (~3) 1.24 0.80 9 Moderate
Testosterone cypionate
Testosterone cypionate.svg
C17β Cyclopentylpropanoic acid Aromatic fatty acid – (~6) 1.43 0.70 8 Moderate
Testosterone phenylpropionate
Testosterone phenpropionate.svg
C17β Phenylpropanoic acid Aromatic fatty acid – (~6) 1.46 0.69 7 Moderate
Testosterone isocaproate
Testosterone isocaproate.svg
C17β Isohexanoic acid Branched-chain fatty acid – (~5) 1.34 0.75 6 Moderate
Testosterone caproate
Testosterone caproate.svg
C17β Hexanoic acid Straight-chain fatty acid 6 1.35 0.75 5 Moderate
Testosterone enanthate
Testosterone enanthate.svg
C17β Heptanoic acid Straight-chain fatty acid 7 1.39 0.72 4 Moderate
Testosterone decanoate
Testosterone decanoate.svg
C17β Decanoic acid Straight-chain fatty acid 10 1.53 0.65 3 Long
Testosterone undecanoate
Testosterone undecanoate.svg
C17β Undecanoic acid Straight-chain fatty acid 11 1.58 0.63 2 Long
Testosterone buciclated
Testosteronebuciclate structure.png
C17β Bucyclic acide Aromatic carboxylic acid – (~9) 1.58 0.63 1 Long
Footnotes: a = Length of ester in carbon atoms for straight-chain fatty acids or approximate length of ester in carbon atoms for aromatic fatty acids. b = Relative testosterone content by weight (i.e., relative androgenic/anabolic potency). c = Duration by intramuscular or subcutaneous injection in oil solution (except TiB and TB, which are in aqueous suspension). d = Never marketed. e = Bucyclic acid = trans-4-Butylcyclohexane-1-carboxylic acid. Sources: See individual articles.


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 culture[edit]

Brand names[edit]

Brand names of testosterone isobutyrate include Agovirin-Depot, Perandren M, Testocryst, and Virex-Cryst.[12][13][16][17][16] 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][17] It was originally manufactured by the pharmaceutical company SPOFA[18] intermittently manufactured by Biotika,[1] and is now manufactured by BB Pharma.[19]

See also[edit]


  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.
  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 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.
  17. ^ a b "Testosterone".
  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 links[edit]