Testosterone replacement therapy glossary

Short, plain-English definitions of the terms you'll meet when choosing a testosterone replacement therapy provider in Florida.

What are bioidentical hormones?: Bioidentical hormones are pharmaceutical compounds with the exact molecular structure of hormones naturally produced by the body, such as testosterone, estrogen, and progesterone.
What is a compounding pharmacy?: A compounding pharmacy is a licensed facility that mixes, prepares, and dispenses customized medications to individual patient specifications, including hormone formulations not available commercially.
What is a subcutaneous injection?: A subcutaneous injection deposits medication into the fatty tissue layer just below the skin, using a shorter needle than intramuscular injections.
What is an intramuscular injection?: An intramuscular injection is a method of administering testosterone directly into muscle tissue using a needle, allowing the hormone to be absorbed into the bloodstream over time.
What is anastrozole?: Anastrozole is an aromatase inhibitor medication that blocks the enzyme responsible for converting testosterone to estrogen, commonly prescribed during TRT to manage estrogen levels.
What is andropause?: Andropause is the gradual decline in testosterone levels that occurs in some men as they age, often accompanied by symptoms like low energy, mood changes, and reduced sexual function.
What is bioavailable testosterone?: Bioavailable testosterone is the portion of total testosterone that is not bound to sex hormone-binding globulin (SHBG) and is therefore available for tissue uptake, comprising free testosterone plus albumin-bound testosterone.
What is clomiphene (Clomid) for men?: Clomiphene (Clomid) is a selective estrogen receptor modulator prescribed off-label to men to stimulate endogenous testosterone production while preserving sperm production, offering an alternative to exogenous testosterone replacement therapy.
What is estradiol (E2) in men?: Estradiol (E2) is the main estrogen hormone in men, produced when testosterone converts via the aromatase enzyme, and is monitored during TRT to prevent gynecomastia and other complications.
What is follicle stimulating hormone (FSH)?: Follicle stimulating hormone (FSH) is a pituitary gland hormone that directly regulates spermatogenesis and testicular function in men. It is measured alongside LH and testosterone in baseline and monitoring hormone panels for TRT candidates.
What is free testosterone?: Free testosterone is the small fraction of testosterone circulating unbound in the blood that is available to bind to receptors and produce biological effects, as opposed to testosterone bound to carrier proteins.
What is hematocrit?: Hematocrit is a blood test that measures the percentage of red blood cells in your total blood volume, expressed as a percentage.
What is hormone pellet insertion?: Hormone pellet insertion is a minor in-office procedure in which compounded testosterone pellets are surgically implanted under the skin to deliver steady hormone replacement therapy, typically lasting three to six months.
What is human chorionic gonadotropin (hCG)?: Human chorionic gonadotropin (hCG) is a hormone that mimics luteinizing hormone (LH) and is prescribed during testosterone replacement therapy to maintain testicular size, sperm production, and natural hormone production.
What is hypogonadism?: Hypogonadism is a medical condition in which the body produces insufficient testosterone, classified as either primary (testicular failure) or secondary (hypothalamic or pituitary dysfunction).
What is luteinizing hormone (LH)?: Luteinizing hormone (LH) is a pituitary gland hormone that signals the testes to produce testosterone; abnormal LH levels help clinicians differentiate primary hypogonadism (testicular failure) from secondary hypogonadism (pituitary or hypothalamic dysfunction).
What is prostate specific antigen (PSA)?: Prostate specific antigen (PSA) is a protein produced by the prostate gland that is measured through blood tests to monitor prostate health, particularly before and during testosterone replacement therapy.
What is sex hormone binding globulin (SHBG)?: SHBG is a carrier protein that binds testosterone and other sex hormones in the bloodstream, reducing the amount of free (active) hormone available to body tissues.
What is testosterone cypionate?: Testosterone cypionate is a synthetic testosterone ester dissolved in oil and injected intramuscularly, releasing slowly over 7-14 days and forming the backbone of most US testosterone replacement therapy.
What is testosterone enanthate?: Testosterone enanthate is a long-chain esterified form of testosterone that is injected intramuscularly and absorbed slowly over approximately one week, making it a standard choice for testosterone replacement therapy.
What is testosterone gel/topical?: Testosterone gel is a topical formulation applied to the skin that delivers testosterone through transdermal absorption to raise hormone levels in people with low testosterone.
What is testosterone undecanoate?: Testosterone undecanoate is a long-acting esterified form of testosterone that requires injection only every 10 to 14 weeks, or can be taken orally, making it useful for patients seeking less frequent dosing intervals in testosterone replacement therapy.
What is the difference between primary and secondary hypogonadism?: Primary hypogonadism occurs when the testes fail to produce adequate testosterone despite normal pituitary signaling, while secondary hypogonadism results from insufficient hormone signals from the pituitary or hypothalamus.
What is total testosterone?: Total testosterone is a blood serum measurement that combines both protein-bound and free testosterone to assess overall testosterone levels in the body.