Testosterone isobutyrate, sold under the brand names Agovirin-Depot and Perandren M among others, is an

androgen An androgen (from Greek ''andr-'', the stem of the word meaning ) is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes ...

and

anabolic steroid Anabolic steroids, also known as anabolic-androgenic steroids (AAS), are a class of drugs that are structurally related to testosterone, the main male sex hormone, and produce effects by binding to the androgen receptor (AR). Anabolism, Anaboli ...

medication and a

testosterone ester This is a list of androgen esters, including esters (as well as ethers) of natural androgens like testosterone and dihydrotestosterone (DHT) and synthetic anabolic–androgenic steroids (AAS) like nandrolone (19-nortestosterone). Esters ...

which is used for indications such as low testosterone levels in men and

delayed puberty Delayed puberty is when a person lacks or has incomplete development of specific sexual characteristics past the usual age of onset of puberty. The person may have no physical or hormone, hormonal signs that puberty has begun. In the United States ...

in boys. It is available only in the

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

and

Slovakia Slovakia, officially the Slovak Republic, is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the west, and the Czech Republic to the northwest. Slovakia's m ...

. The medication is administered by injection into muscle once every 1 to 2 weeks in males. Unlike most other testosterone esters, which are provided as

oil solution An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturat ...

s, testosterone isobutyrate is formulated as a

microcrystalline A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination. There is little agreement on the range of crystal sizes that should be regarded as microcrystalline, but ...

aqueous suspension.

Medical uses

Testosterone isobutyrate is used in the treatment of

hypogonadism Hypogonadism means diminished functional activity of the human gonad, gonads—the testicles or the ovary, ovaries—that may result in diminished biosynthesis, production of sex hormones. Low androgen (e.g., testosterone) levels are referred t ...

in men and

in adolescent boys. It is also used in the treatment of

Klinefelter's syndrome Klinefelter syndrome (KS), also known as 47,XXY, is a chromosome anomaly where a male has an extra X chromosome. These complications commonly include infertility and small, poorly functioning testicles (if present). These symptoms are often not ...

aplastic anemia Aplastic anemia (AA) is a severe hematologic condition in which the body fails to make blood cells in sufficient numbers. Normally, blood cells are produced in the bone marrow by stem cells that reside there, but patients with aplastic anemia ...

Cushing's syndrome Cushing's syndrome is a collection of signs and symptoms due to prolonged exposure to glucocorticoids such as cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, ...

(as an

anabolic Anabolism () is the set of metabolic pathways that construct macromolecules like DNA or RNA from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catab ...

to preserve

lean body mass Lean body mass (LBM), sometimes conflated with , is a component of body composition. Fat-free mass (FFM) is calculated by subtracting body fat weight from total body weight: total body weight is lean plus fat. In equations: :LBM = BW ...

), postmenopausal osteoporosis in women,

advanced breast cancer Metastatic breast cancer, also referred to as metastases, advanced breast cancer, secondary tumors, secondaries or stage IV breast cancer, is a stage of breast cancer where the breast cancer cells have spread to distant sites beyond the axillary l ...

in women, breast pain in women, and

cachexia Cachexia () is a syndrome that happens when people have certain illnesses, causing muscle loss that cannot be fully reversed with improved nutrition. It is most common in diseases like cancer, Heart failure, congestive heart failure, chronic o ...

. Testosterone isobutyrate has been used in

masculinizing hormone therapy Masculinizing hormone therapy, also known as transmasculine hormone therapy, is a form of hormone therapy and gender affirming therapy which is used to change the secondary sexual characteristics of transgender people from what is typically perce ...

for

transgender men A trans man or transgender man is a man who was assigned female at birth. Trans men have a male gender identity, and many trans men undergo medical and social transition to alter their appearance in a way that aligns with their gender identi ...

as well.

Available forms

Testosterone isobutyrate is provided in the form of a 25 mg/mL

aqueous suspension packaged in 2 mL

ampoule An ampoule (also ampul and ampule) is a small sealed vial which is used to contain and preserve a sample, usually a solid or liquid. Ampoules are usually made of glass. Modern ampoules are most commonly used to contain pharmaceuticals and chem ...

s (5 ampoules per box). This equates to a dose of 50 mg per ampoule. Testosterone isobutyrate (25 mg) is also available in combination with

estradiol benzoate Estradiol benzoate (EB), sold under the brand name Progynon-B among others, is an estrogen medication which is used in hormone therapy for menopausal symptoms and low estrogen levels in women, in hormone therapy for transgender women, and in the ...

(2.5 mg) under the brand name Folivirin (1 mL ampoules).

Side effects

Side effect In medicine, a side effect is an effect of the use of a medicinal drug or other treatment, usually adverse but sometimes beneficial, that is unintended. Herbal and traditional medicines also have side effects. A drug or procedure usually use ...

s of testosterone isobutyrate include

virilization Virilization or masculinization is the biological development of adult male characteristics in young males or females. Most of the changes of virilization are produced by androgens. Virilization is a medical term commonly used in three medical a ...

among others.

Pharmacology

Testosterone isobutyrate is a

prodrug A prodrug is a pharmacologically inactive medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be ...

testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...

, and hence is an

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

of the

androgen receptor The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone, in th ...

, the

biological target A biological target is anything within a living organism to which some other entity (like an endogenous ligand or a drug) is directed and/or binds, resulting in a change in its behavior or function. Examples of common classes of biological targets ...

endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...

s like

and

dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone primarily involved in the growth and repair of the prostate and the penis, as well as the production o ...

. It produces both

ic and

effects, as well as weak

estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...

ic effects due to

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

of testosterone into

estradiol Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles. Estradiol is responsible ...

. In contrast to most other testosterone esters, which are used as

amorphous In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid) is a solid that lacks the long-range order that is a characteristic of a crystal. The terms "glass" and "glassy solid" are sometimes used synonymousl ...

s, testosterone isobutyrate is provided in the form of a

aqueous suspension. It has very low water solubility and forms a long-lasting microcrystalline

depot Depot may refer to: Places * Depot, Poland, a village * Depot Glacier (disambiguation) * Depot Island (disambiguation) * Depot Nunatak * Depot Peak Brands and enterprises * Maxwell Street Depot, a restaurant in Chicago, United States * Of ...

within

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

upon

intramuscular injection Intramuscular injection, often abbreviated IM, is the medical injection, injection of a substance into a muscle. In medicine, it is one of several methods for parenteral, parenteral administration of medications. Intramuscular injection may be ...

. This repository slowly dissolves over time. As a result, testosterone isobutyrate has a prolonged

duration of action Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms (fo ...

of approximately 2 weeks. It is administered at intervals of once every 1 to 2 weeks in men. 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. It can produce local

irritation Irritation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant. Irritants are typically thought of as chemical age ...

pain Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...

, and redness upon injection.

Chemistry

Testosterone isobutyrate, or testosterone 17β-(2-methylpropanoate), is a

synthetic Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...

androstane Androstane is a C19 steroidal hydrocarbon with a gonane core. Androstane can exist as either of two isomers, known as 5α-androstane and 5β-androstane. File:androstane.png, 5α-Androstane File:androstane 5beta.png, 5β-Androstane Pharmacolog ...

steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...

and a

derivative In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...

. It is an

androgen ester An androgen or anabolic steroid ester is an ester of an androgen/anabolic steroid (AAS) such as the natural testosterone or dihydrotestosterone (DHT) or the synthetic nandrolone (19-nortestosterone). Esterification renders AAS into metabolism-res ...

; specifically, it is the C17β

2-methylpropanoate Isobutyric acid, also known as 2-methylpropanoic acid or isobutanoic acid, is a carboxylic acid with structural formula ( CH3)2CH COOH. It is an isomer of butyric acid. It is classified as a short-chain fatty acid. Deprotonation or esterificatio ...

(isobutyrate)

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

of testosterone.

History

Microcrystalline testosterone isobutyrate in aqueous suspension was first described in 1952. It was introduced for medical use shortly thereafter. Around the same time,

testosterone enanthate Testosterone enanthate is used in the treatment of low testosterone levels in men. It is also used in hormone therapy for women and transgender men. It is given by injection into muscle or subcutaneously usually once every one to four weeks. ...

was introduced for medical use. It became the dominant long-acting injectable form of testosterone, and limited the commercial success of testosterone isobutyrate. The combination of microcrystalline

and testosterone isobutyrate in aqueous suspension was introduced under the brand name Femandren M by 1953.

Society and culture

Brand names

Brand names of testosterone isobutyrate include Agovirin-Depot, Perandren M, Testocryst, and Virex-Cryst. It has also been marketed in combination with

under the brand names Femandren M and Folivirin.

Availability

Testosterone isobutyrate is available only in the

and

. It was originally manufactured by the

pharmaceutical company The pharmaceutical industry is a Medicine, medical industry that discovers, develops, produces, and markets pharmaceutical goods such as medications and medical devices. Medications are then administered to (or Self-medicate, self-administered b ...

SPOFA intermittently manufactured by Biotika, and is now manufactured by BB Pharma.

References

External links

Agovirin Depot (testosterone isobutyrate) - William Llewellyn's Anabolic.org
{{Estrogen receptor modulators Anabolic–androgenic steroids Androstanes Isobutyrate esters Cyclic ketones Testosterone esters