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 laboratory-synthesized hormones with a molecular structure identical to those the human body produces naturally, typically used in hormone replacement therapy.
What is 503A vs 503B compounding pharmacy?: 503A and 503B are two FDA regulatory categories for compounding pharmacies: 503A handles patient-specific preparations, while 503B operates as licensed outsourcing facilities that can distribute compounded drugs to other pharmacies and providers.
What is a PSA (prostate-specific antigen) test?: A PSA test is a blood test that measures levels of prostate-specific antigen to screen for prostate health conditions and is often required before starting or continuing testosterone replacement therapy.
What is an aromatase inhibitor (AI)?: An aromatase inhibitor is a medication that blocks the enzyme aromatase, which converts testosterone to estrogen, used during testosterone replacement therapy to manage estrogen-related side effects.
What is anastrozole?: Anastrozole is an aromatase inhibitor medication that blocks the enzyme responsible for converting testosterone into estrogen, commonly prescribed alongside TRT to prevent unwanted side effects from elevated estrogen levels.
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 increase natural testosterone production while preserving fertility.
What is compounded testosterone?: Compounded testosterone is a custom-prepared hormone medication made by a licensed pharmacist in a compounding pharmacy, rather than a mass-manufactured FDA-approved product.
What is enclomiphene?: Enclomiphene is the potent isomer of clomiphene citrate that directly stimulates the pituitary gland to increase natural testosterone production, used as an oral alternative to injectable testosterone therapy.
What is estradiol (E2) in men?: Estradiol (E2) is the main form of estrogen present in male bodies, derived from testosterone conversion, and a key marker tracked during testosterone replacement therapy to prevent complications from hormonal imbalance.
What is free testosterone?: Free testosterone is the portion of testosterone circulating in the bloodstream unbound to proteins, directly available for cellular action. Clinics measure it to assess the hormonally active fraction independent of total testosterone levels.
What is hCG therapy in testosterone replacement?: hCG (human chorionic gonadotropin) is a hormone used alongside testosterone replacement therapy to preserve natural testicular function and fertility by stimulating the testes to continue producing testosterone.
What is hematocrit?: Hematocrit is the percentage of red blood cells in your total blood volume, measured as part of routine blood work to check oxygen-carrying capacity.
What is Low T (hypogonadism)?: Hypogonadism, or Low T, is a medical condition in which the testes produce abnormally low levels of testosterone, typically diagnosed when serum testosterone falls below 300 ng/dL.
What is post-cycle therapy (PCT)?: Post-cycle therapy (PCT) is a medically supervised protocol designed to help the body restart its natural production of testosterone and other hormones after a person stops taking testosterone replacement therapy or performance-enhancing drugs.
What is primary hypogonadism?: Primary hypogonadism is low testosterone resulting from the testes' inability to produce adequate testosterone, despite normal or elevated hormonal signaling from the pituitary gland.
What is secondary hypogonadism?: Secondary hypogonadism is low testosterone resulting from insufficient signaling by the hypothalamus or pituitary gland, rather than from testicular disease.
What is SHBG (sex hormone-binding globulin)?: SHBG is a protein produced by the liver that binds to testosterone and other sex hormones in the bloodstream, reducing the amount of free (active) testosterone available to the body's tissues.
What is subcutaneous vs intramuscular injection?: Subcutaneous and intramuscular injections are two distinct routes for administering testosterone that differ in injection depth, needle gauge, and tissue absorption rates.
What is testosterone cypionate?: Testosterone cypionate is a synthetic testosterone ester with a long half-life, typically injected intramuscularly every 7-10 days as part of testosterone replacement therapy.
What is testosterone enanthate?: Testosterone enanthate is a synthetic testosterone ester with a 7-10 day half-life, administered as an injectable used in testosterone replacement therapy typically on a weekly schedule.
What is testosterone gel or cream (topical testosterone)?: Testosterone gel or cream is a topical formulation of testosterone applied directly to the skin for absorption into the bloodstream, used in testosterone replacement therapy.
What is testosterone pellet therapy?: Testosterone pellet therapy is a form of hormone replacement in which small cylinders containing testosterone are surgically inserted under the skin to release the hormone gradually over several months.
What is the HPTA (hypothalamic-pituitary-testicular axis)?: The HPTA is the feedback system linking the hypothalamus, pituitary gland, and testes that regulates testosterone and sperm production through gonadotropin release and negative feedback inhibition.
What is total testosterone?: Total testosterone is a blood serum measurement of all testosterone present in the bloodstream, including both the hormone bound to carrier proteins and the unbound portion available to cells.