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the principal male sex hormone (androgen) that is produced by Leydig's cells of the testes in response to luteinizing hormone secreted by the pituitary gland. It is also produced by the adrenal cortex in both males and females. Its chief function is to stimulate the development of the male reproductive organs, including the prostate, and the secondary sex characters, such as the beard. It encourages growth of bone and muscle, and helps maintain muscle strength.

Testosterone is obtained for therapeutic purposes by extraction from animal testes or by synthesis from cholesterol in a laboratory. It is used to treat male hypogonadism and delayed male puberty as well as to relieve symptoms in some forms of metastatic breast cancer in females, and is used as the base for various esters (e.g., cypionate, enanthate, propionate). Women normally secrete a certain amount of male hormones; however, if the hormone balance is disturbed and there is overproduction of male hormones in a woman, masculinization may develop.


Axiron, Androderm, AndroGel, Andropatch, Fortesta, Striant, Testim, Testogel, Testopel Pellets, Testos

testosterone cypionate


testosterone enanthate

Delatestryl, PMS-Testosterone Enthanate

Pharmacologic class: Hormone

Therapeutic class: Androgenic and anabolic steroid, antineoplastic

Controlled substance schedule III

Pregnancy risk category X

FDA Box Warning

Virilization has occurred in children secondarily exposed to testosterone gel.

Children should avoid contact with unwashed or unclothed application sites in men using testosterone gel.

Health care providers should advise patients to strictly adhere to recommended instructions for use.


Responsible for normal growth and development of male sex organs and maintenance and maturation of secondary sex characteristics. Also decreases estrogen activity, which aids treatment of some breast cancers.



Buccal system: 30 mg

Gel: 1% (25 mg, 50 mg), 1.62% (metered-dose pump delivers 20.25 mg/actuation), 2% (10 mg/one metered-dose pump actuation)

Injection (aqueous suspension): 100 mg/ml

Pellets (subcutaneous implant): 75 mg

Solution (topical): 30 mg/metered-dose pump actuation

Transdermal system: 2 mg/day, 4 mg/day

testosterone cypionate

Injection: 100 mg/ml, 200 mg/ml

testosterone enanthate

Injection (in oil): 200 mg/ml

Indications and dosages

Male hypogonadism

Adult males: 10 to 25 mg (testosterone) I.M. two to three times weekly or 50 to 400 mg (enanthate) I.M. q 2 to 4 weeks for 3 to 4 years. Or 150 to 450 mg (pellet) implanted subcutaneously q 3 to 6 months. Or, 4 mg (transdermal system) daily, adjusted to 2 mg or 6 mg based on serum testosterone level. Or, 60 mg (one 30-mg actuation of Axiron topical solution applied to each axilla) daily at same time each morning, adjusted to 30 mg (one pump actuation) or increased from 60 to 90 mg (three pump actuations) or from 90 to 120 mg (four pump actuations) based on serum testosterone concentration from single blood draw 2 to 8 hours after applying solution and at least 14 days after starting treatment or following dosage adjustment. Or, 40 mg (four actuations of Fortesta topical gel) applied to clean, intact skin of thighs once daily in morning, adjusted to 10 mg (one pump actuation) or up to 70 mg (seven pump actuations) based on total serum testosterone level 2 hours after applying gel at approximately 14 days after starting treatment or following dosage adjustment. Or, 50 mg testosterone gel (AndroGel 1%) daily applied topically, adjusted up to 75 mg daily within 14 days, with subsequent dosages up to 100 mg daily. Or, 30 mg (buccal system) to gum region b.i.d. Or, 50 to 400 mg I.M. (cypionate) q 2 to 4 weeks.

Delayed puberty

Adult males: 50 to 200 mg I.M. (enanthate only) q 2 to 4 weeks for limited duration (4 to 6 months); or 150 to 450 mg subcutaneously (pellets) q 3 to 6 months

Inoperable breast cancer in women 1 to 5 years after menopause

Adults: 200 to 400 mg I.M. (enanthate) q 2 to 4 weeks


• Hypersensitivity to drug, its components, or tartrazine

• Males with breast cancer or suspected prostate cancer

• Females (buccal or transdermal systems or gel)

• Pregnancy or breastfeeding


Use cautiously in:

• diabetes mellitus; edema associated with serious cardiac, hepatic, or renal disease; sleep apnea; hypercalcemia

• children younger than age 18 (safety and efficacy not established).


• Evaluate elderly patients and patients at increased risk for prostate cancer for presence of prostate cancer before starting testosterone replacement therapy.

• Inspect aqueous solution for injection. If crystals are visible, warm bottle and shake contents to dissolve crystals.

• Rotate I.M. injection sites within upper outer quadrant of gluteus maximus. Inject deeply into muscle.

• Apply gel once daily to clean, dry, intact skin on shoulder, upper arm, or abdomen.

• Place buccal system just above incisor tooth. Have patient hold it in place for 30 seconds to ensure adhesion. Rotate to other side of mouth with each application.

Adverse reactions

CNS: headache, depression, emotional lability, nervousness, anxiety, asthenia, memory loss, dizziness, vertigo, cerebrovascular accident

CV: edema, peripheral edema, deepvein phlebitis, heart failure

GI: bleeding

GU: hematuria, urinary tract infection, impaired urination, scrotal cellulitis, benign prostatic hyperplasia, scrotal papilloma (with transdermal use), prostatitis, libido changes, breast pain or tenderness, gynecomastia, virilization in females, excessive hormonal effects in males

Hematologic: polycythemia, leukopenia, suppressed clotting factors

Hepatic: hepatic adenoma (with long-term enanthate use)

Metabolic: hyperphosphatemia, hypernatremia, hypercalcemia, hypoglycemia, hyperkalemia

Musculoskeletal: myalgia

Respiratory: sleep apnea

Skin: acne; rash, itching, burning, discomfort, irritation, burn-like blister, erythema (with transdermal use); pain, local edema, and induration at injection site (with I.M. or subcutaneous use)

Other: accidental injury, flulike symptoms, hypersensitivity reaction


Drug-drug. Corticosteroids: increased risk of edema

Hepatotoxic drugs: increased risk of hepatotoxicity

Insulin, oral hypoglycemics: decreased blood glucose level

Oral anticoagulants: increased anticoagulant effect

Oxyphenbutazone: increased oxyphenbutazone blood level

Propranolol: increased propranolol clearance

Drug-diagnostic tests. Bilirubin, liver function tests: abnormal results

Calcium, cholesterol, hematocrit, hemoglobin, phosphate, prostate-specific antigen (with topical use), sodium: increased levels

Clotting factors, creatine excretion, glucose, serum creatinine, thyroxine, thyroxine-binding globulin: decreased levels

Urine creatine and creatinine: decreased excretion

Urine 17-ketosteroids: increased excretion

Drug-herbs. Chaparral, comfrey, germander, jin bu huan, kava, pennyroyal: increased risk of hepatotoxicity

Patient monitoring

• Monitor electrolyte levels, liver function tests, blood and urine calcium levels, lipid panels, CBC with white cell differential, and semen studies.

• Assess diabetic patient carefully for hypoglycemia.

• Closely monitor neurologic status. Stay alert for sleep apnea.

• Assess for early signs of excessive hormonal effects in females (virilization). If these occur, drug withdrawal may be indicated.

Patient teaching

Instruct patient to immediately report signs and symptoms of liver problems, including nausea, vomiting, yellowing of skin or eyes, and ankle swelling.

• Teach prepubertal male about signs and symptoms of excessive hormonal effects, such as acne, priapism, increased body and facial hair, and penile enlargement.

• Teach postpubertal male about signs and symptoms of excessive adverse hormonal effects, such as erectile dysfunction, gynecomastia, epididymitis, testicular atrophy, and infertility.

Tell female patient to immediately report signs of masculinization, such as excessive body or facial hair, deepening of voice, clitoral enlargement, and menstrual irregularities.

• Advise female of childbearing age to use barrier contraceptives. Caution her not to breastfeed.

• Tell patient which transdermal patches can be applied to scrotum. Instruct him to apply patch daily to clean, dry skin after removing protective liner to expose drug-containing film. To prevent irritation, instruct him to apply each patch to a different site, waiting at least 1 week before reusing same site.

• Advise patient to apply topical gel once daily to clean, dry skin on shoulder, upper arm, or abdomen. Tell him that after opening packet, he should squeeze entire contents into palm and apply immediately. Instruct him to wait until gel dries before getting dressed.

• Teach patient to place buccal system in comfortable position just above incisor tooth and hold it in place for about 30 seconds to ensure adhesion. Tell him to use opposite side of mouth with each application. Caution him not to dislodge buccal system, especially when eating, drinking, brushing teeth, or using mouthwash. If system doesn't properly adhere or falls out during 12hour dosing interval, tell him to discard it and apply new system. If it falls out within 4 hours of next dose, tell him to apply new system and keep it in place until next regularly scheduled dose.

• Instruct patient to apply topical solution to clean, dry, intact skin of axilla area only and to allow application site to dry completely before dressing. Advise patient to wash axilla with soap and water to remove any testosterone residue if direct skin-to-skin contact with another person is anticipated.

• Tell patient drug shouldn't be used to enhance athletic performance or physique.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.


The most potent naturally occurring androgen, formed in greatest quantities by the interstitial cells of the testes, and possibly secreted also in small amounts by the ovary and adrenal cortex; may be produced in nonglandular tissues from precursors such as androstenedione; used in the treatment of hypogonadism, cryptorchism, certain carcinomas, and menorrhagia. Various preparations are used therapeutically.


/tes·tos·te·rone/ (tes-tos´tĕ-rōn″) the principal androgenic hormone, produced by the interstitial (Leydig) cells of the testes in response to stimulation by the luteinizing hormone of the anterior pituitary gland; it is thought to be responsible for regulation of gonadotropic secretion, spermatogenesis, and wolffian duct differentiation. It is also responsible for other male characteristics after its conversion to dihydrotestosterone. In addition, testosterone possesses protein anabolic properties. It is used as replacement therapy for androgen deficiency in males, in the treatment of delayed male puberty or hypogonadism, and in the palliation of certain breast cancers in females; used as the base or various esters (e.g., cypionate, enanthate, propionate).


1. A steroid hormone, C19H28O2, produced primarily in the testes and responsible for the development and maintenance of male secondary sex characteristics. Testosterone synthesized from plant sources, often in the form of an ester, is used in the medical treatment of testosterone deficiency.
2. Any of several synthetic compounds that mimic the physiologic activity of testosterone, used as drugs in the medical treatment of testosterone deficiency and as doping agents by athletes.


a naturally occurring androgenic hormone.
indications It is prescribed for androgen deficiency, for female breast cancer, and for stimulation of growth, weight gain, and red blood cell production.
contraindications Cancer of the male breast or prostate, liver disease, pregnancy or suspected pregnancy, or known hypersensitivity to this drug prohibits its use.
adverse effects Among the more serious adverse effects are hepatic dysfunction, fluid retention, masculinization, acne, and erythrocythemia.


 Endocrinology The principal and most potent of the C-19 androgenic steroids, produced from its precursor hormone, progesterone, by the Leydig cells of testis, and, in far lesser amounts, in the ovary and adrenal cortex, and drives the development and maintenance of ♂ sex characteristics Activity Nitrogen retention, buildup of protein, induction and maintenance of 2º ♂ characteristics–eg, facial hair; testosterone secretion is in turn regulated by LH, which is produced by the anterior pituitary Indications Treatment of sexual dysfunction, weight loss, depression Ref range ♂–total, 300–1000 ng/dL; free, 5.1–41.0 ng/dL; ♀–total, 20-90 ng/dL; free, 0.1–2.3 ng/dL ↑ in ♂ sexual precocity, hyperplasia of adrenal cortex, adrenogenital syndrome, polycystic ovary syndrome ↓ in Alcoholism, anterior pituitary gland hypofunction, estrogen therapy, Klinefelter syndrome–aka 1º hypogonadism, testicular hypoactivity. See Sublingual testosterone. Cf Progesterone.


The most potent naturally occurring androgen, formed in greatest quantities by the interstitial cells of the testes and possibly secreted also by the ovary and adrenal cortex of the suprarenal gland; used in the treatment of hypogonadism, cryptorchism, certain carcinomas, and menorrhagia.
Compare: bioregulator


The principal male sex hormone (androgen) produced in the INTERSTITIAL cells of the TESTIS and, to a lesser extent in the OVARY. Testosterone is ANABOLIC and stimulates bone and muscle growth and the growth of the sexual characteristics. It is also used as a drug to treat delayed puberty or some cases of infertility or to help to treat breast cancer in post-menopausal women. It may be given by mouth, depot injection or skin patch. The drug is on the WHO official list. Brand names are Andropatch, Restandol, Sustanon, Testogel and Virormone.


a steroid ANDROGEN produced by the LEYDIG CELLS between the SEMINIFEROUS TUBULES of the TESTIS. It causes the development and maintenance of accessory sex organs, the genitalia and the SECONDARY SEXUAL CHARACTERS.


Male hormone produced by the testes and (in small amounts) in the ovaries. Testosterone is responsible for some masculine secondary sex characteristics such as growth of body hair and deepening voice.

anabolic steroids

usually refers to a group of synthetic drugs based on the male sex hormone testosterone secreted by the testes, and having similar anabolic and other androgenic actions to this and other androgens from the adrenal cortex in both sexes. These drugs are misused in sports, especially where enhanced power and strength are beneficial such as weight lifting and cycling. Used in conjunction with a training programme, they lead to an increase in muscle size and power. They may also lessen fatigue and improve tissue repair. Use in children can lead to premature fusion of the epiphyses, stunting skeletal growth. Side effects are common and potentially serious. They include psychological changes (notably aggression), liver damage, cardiovascular (raised blood pressure) and endocrine effects (masculinization in females, testicular atrophy and reduced sperm count in males.) See also adrenal glands, hormones; Table 1.
Table 1: Hormones
Site of productionName of hormoneMain targetsInvolved in regulating:Secretion controlled by:
HypothalamusReleasing and inhibiting hormonesAnterior pituitary (via local blood vessels)Secretion of anterior pituitary hormonesOther brain regions; feedback re regulated hormones and their actions
Neurohormones released from posterior pituitary:
OxytocinUterus, breastsLabour and lactationAfferent information from target organs
Antidiuretic hormone (ADH, vasopressin)KidneysWater loss: ECF volume and osmolalityHypothalamic osmoreceptors
Anterior pituitary(Human) growth hormone (H)GHMost cellsGrowth and metabolismHypothalamic releasing and inhibiting hormones via local blood vessels
ProlactinBreastsMilk production
Trophic hormones:
Thyroid-stimulating (TSH)Thyroid glandThyroid secretions
GonadotrophinsOvary or testisGerm cell maturation and hormone secretions
Adrenocorticotrophic (ACTH)Adrenal cortexCortisol secretion
Pineal bodyMelatoninWidespread, including brain, thymus, etc.
  • Sleep/wake cycle
  • Antioxidant
  • Immune system
Hypothalamus; varying light input from retina
  • Thyroxine
  • Triiodothyronine
  • Calcitonin
  • Most cells
  • Bone, kidneys, gut
  • Cellular oxidative metabolism
  • Decreases ECF [Ca2+]
  • TSH from anterior pituitary. Negative feedback from blood hormone concentration
  • ECF [Ca2+]
ParathyroidsParathormoneBone, kidneys, gut
  • Calcium and phosphorus absorption, secretion and turnover in bone.
  • Increases ECF [Ca2+]
ECF [Ca2+]
Adrenal: Cortex
  • Cortisol
  • Aldosterone
  • Androgens
  • Most cells
  • Kidneys
  • Gonads & other tissues
  • Metabolism
  • Response to stress
  • Na and K balance
  • Sex characteristics and reproductive function
  • ACTH from anterior pituitary
  • ECF [Na+] [K+]
  • Renin-angiotensin
  • ACTH
  • Adrenaline
  • Noradrenaline
Heart, smooth muscle, glandsCardiovascular and metabolic adjustments to activity and stressSympathetic nervous system
Atrial wallAtrial natriuretic hormoneKidneysBlood volume; increases sodium (therefore also water) loss in urineStretch of atrial wall by venous pressure
Gonads: TestisAndrogens (mainly testosterone)Genitalia and other tissuesReproductive function and sex characteristicsAnterior pituitary gonadotrophins
  • Oestrogens
  • Progesterone
Uterus, breasts and other tissuesMenstrual cycle, pregnancy, lactation
  • Insulin, glucagon
  • Somatostatin
  • Most cells
  • Other secretory cells in the pancreas
Blood levels, storage and cellular uptake of nutrients, notably glucose, but also proteins and fatsBlood levels of nutrients; autonomic nervous system; other gastrointesinal hormones
Alimentary tract
StomachGastrinGastric acid-secreting cellsGastrointestinal functions: motility, digestive juices and other secretionsLocal chemical and mechanical factors in the alimentary tract
Small intestine
  • Secretin
  • Cholecystokinin- pancreozymin (CCK-PZ)
  • Somatostatin, motilin
  • Other peptide hormones including vasoactive intestinal peptide (VIP)
  • Widespread on
  • GI tract
Several GI functions including bile flow, pancreatic enzyme and exocrine secretionsIngestion of food, distension of GI tract


the male gonad, the site of spermatogenesis, whence sperm are discharged via the vas deferens into the urethra at ejaculation. This and also testicular endocrine function (secretion of testosterone and related hormones) are under the control of gonadotrophic hormones from the anterior pituitary, and in turn of the hypothalamus.


male hormone (released primarily from interstitial cells of testes), but also from adrenal cortex and ovaries, in much smaller amounts


Most potent naturally occurring androgen, formed in greatest quantities by interstitial cells of testes; used to treat some carcinomas, and other conditions.


the most important male sex hormone (androgen) produced by the Leydig cells of the testes in response to luteinizing hormone (LH) secreted by the pituitary. Its chief function is to stimulate the development of the male reproductive organs and the secondary sex characters, such as the crest. It is necessary for the appearance of normal male sexual behavior. It encourages growth of bone and muscle, and helps maintain muscle strength. It is occasionally secreted in large amounts also by granulosa-theca cell tumors of the ovary, especially in mares.

testosterone cyclopentylpropionate, testosterone cypionate, testosterone propionate
esters with a long period of activity.
testosterone-responsive dermatosis
a bilaterally symmetrical alopecia, primarily affecting the flanks, ventral abdomen and caudomedial aspect of the thighs of male dogs. The cause is believed to be hypotestosteronism.
References in periodicals archive ?
The favorable findings in this trial likely would have been even better if the researchers had made a concerted effort to individualize treatment and target optimal ranges of total testosterone (Life Extension[R] suggests 700 to 900 ng/dL) and free testosterone (Life Extension[R] suggests 20 to 25 pg/mL) as well as balance estradiol levels within a range of 20 to 30 pg/mL following testosterone restoration in these aging men.
There is no question that in men with symptoms of testosterone deficiency, testosterone replacement therapy produces substantial benefits.
The mean Serum Triglyceride in the Low Serum Testosterone group (157 +/- 58.
Serum Non-HDL Cholesterol (Non-HDL CHO) and Serum Testosterone
For the primary outcome of mean lumbar spine trabecular volumetric bone mineral density, testosterone treatment was associated with a mean increase of 7.
Researchers also noted that the magnitude of the increase in spine trabecular bone mineral density from baseline was significantly associated with changes in total testosterone and estradiol.
Any decrease in testosterone level brings a decrease in manhood, an unbearable thought for some men.
The Real Significance of the Reference Limits and Interval for Testosterone
The Endocrine Society's recommendation for targeted screening states that for men with chronic diseases (eg, diabetes mellitus, end-stage renal disease, and chronic obstructive lung disease), measurement of testosterone may be indicated by symptoms such as sexual dysfunction, unexplained weight loss, weakness, or mobility limitation.
Measuring total serum testosterone should be the initial test for suspected testosterone deficiency.
However, in some cases, doctors prescribe testosterone to even those men who are experiencing a natural decline of the hormone with age - referred to as "low T.
html) Live Science , a 2013 study found that almost 25 percent of men receiving prescription testosterone were not measured for the levels of the hormone in their systems before the treatment started.