Testosterone replacement therapy clinics glossary

Short, plain-English definitions of the terms you'll meet when choosing a Testosterone Replacement Therapy provider in Florida.

What is a PSA (prostate-specific antigen) test?: A blood test that measures prostate-specific antigen levels to screen for prostate health changes, commonly ordered before starting and periodically during testosterone replacement therapy.
What is a subcutaneous injection?: A subcutaneous injection deposits medication into the fatty tissue layer directly beneath the skin, rather than into muscle, using a shorter needle inserted at a shallow angle.
What is an aromatase inhibitor?: An aromatase inhibitor is a medication that blocks the enzyme aromatase, preventing the conversion of testosterone to estrogen in the body during testosterone replacement therapy.
What is an intramuscular injection?: An intramuscular injection is a shot that delivers medication directly into muscle tissue, used widely in testosterone replacement therapy to administer testosterone into the body.
What is bioavailable testosterone?: Bioavailable testosterone is the sum of free testosterone and albumin-bound testosterone, representing the portion of testosterone that tissues can actually use.
What is clomiphene (Clomid) for men?: Clomiphene (Clomid) is a selective estrogen receptor modulator prescribed off-label to men to stimulate the pituitary gland and boost natural testosterone production, often used as an alternative or complement to direct testosterone replacement.
What is enclomiphene?: Enclomiphene is the active isomer of clomiphene citrate that blocks estrogen receptors in the pituitary gland, signaling the body to increase testosterone production while maintaining sperm count and testicular function.
What is estradiol (E2) in men?: Estradiol (E2) is the main form of estrogen present in men's bodies, produced when testosterone converts through the enzyme aromatase. During TRT, estradiol levels require monitoring because excess can cause gynecomastia, water retention, and mood changes, while too little may impair bone health and sexual function.
What is free testosterone?: Free testosterone is the small fraction of testosterone circulating unbound in the bloodstream that is available to interact with cell receptors and produce biological effects.
What is FSH (follicle-stimulating hormone)?: FSH is a pituitary hormone that stimulates sperm production in the testes and is measured during hormone panels to assess male reproductive health and fertility.
What is hCG (human chorionic gonadotropin)?: hCG is a peptide hormone that mimics luteinizing hormone (LH) during testosterone replacement therapy to preserve testicular size, sperm production, and fertility.
What is hematocrit?: Hematocrit is a blood test that measures the percentage of red blood cells relative to total blood volume, expressed as a percentage.
What is HPTA restart and post-cycle therapy (PCT)?: Post-cycle therapy (PCT) and HPTA restart refer to medical protocols designed to restore the hypothalamic-pituitary-testicular axis and natural testosterone production after stopping exogenous testosterone administration.
What is hypogonadism?: Hypogonadism is a condition in which the body produces abnormally low levels of testosterone, occurring as either a testicular problem (primary) or a pituitary/hypothalamic problem (secondary).
What is LH (luteinizing hormone)?: Luteinizing hormone (LH) is a pituitary hormone that signals Leydig cells in the testes to produce testosterone and is measured to distinguish primary hypogonadism (testicular failure) from secondary hypogonadism (pituitary or hypothalamic dysfunction).
What is polycythemia?: Polycythemia is an abnormal increase in red blood cell production that can occur as a side effect of testosterone replacement therapy.
What is primary vs secondary hypogonadism?: Primary hypogonadism is low testosterone due to testicular failure, while secondary hypogonadism results from insufficient signaling by the pituitary gland or hypothalamus.
What is SHBG (sex hormone binding globulin)?: SHBG is a protein produced by the liver that binds to testosterone in the blood, making it unavailable for tissue use and affecting how testosterone levels are measured and interpreted.
What is testosterone cypionate?: Testosterone cypionate is a synthetic testosterone ester administered by intramuscular injection, designed to replace or supplement natural testosterone levels in people with deficiency or as part of gender-affirming care.
What is testosterone enanthate?: Testosterone enanthate is a synthetic testosterone compound with an enanthate ester attached, formulated for intramuscular injection in hormone therapy, with a longer half-life than propionate but shorter than undecanoate.
What is testosterone pellet therapy?: Testosterone pellet therapy is a hormone replacement method in which small pellets containing testosterone are surgically implanted under the skin to release the hormone gradually over three to six months.
What is the HPTA (hypothalamic-pituitary-testicular axis)?: The HPTA is the biological feedback system connecting the hypothalamus, pituitary gland, and testes that controls testosterone production and male sexual function in the body.
What is total testosterone?: Total testosterone is the laboratory measurement of testosterone in the bloodstream, including both protein-bound and free hormone forms, used as the primary screening test for testosterone replacement therapy.
What is transdermal gel?: Transdermal gel is a topical testosterone preparation applied to the skin once daily, allowing the hormone to penetrate through the dermis and enter the bloodstream.