SARMs Glossary: Hormone, Lab and Anti-Doping Terms

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A

Adverse event

An unwanted effect of a drug or other treatment.

Adverse events range from mild to severe and can be life-threatening. Also called an adverse effect or adverse reaction. source

ALT (alanine transaminase)

A liver enzyme; high blood levels can signal liver injury.

ALT is found mainly in the liver. When liver cells are damaged they release ALT into the blood, sometimes before any symptoms appear. source

Anabolic-androgenic steroid (AAS)

A lab-made steroid derived from testosterone that builds muscle and tissue.

Anabolic steroids are used in medicine to repair tissue and increase appetite and muscle growth. At supraphysiological doses they completely suppress the body's own testosterone and sperm production. source

Androgen receptor

The protein inside cells that binds androgens such as testosterone.

Androgens are hormones that promote male sex characteristics. Their receptors are found in male reproductive tissue and some other tissues. SARMs are designed to act on this receptor. source

Aromatase

The enzyme that converts androgens such as testosterone into estrogens.

Aromatase is encoded by the CYP19A1 gene. Aromatase inhibitors block it and so lower estrogen. source

Aromatase inhibitor (AI)

A drug that blocks aromatase and so lowers estrogen.

Examples are anastrozole, letrozole and exemestane. They are used to treat some breast cancers. WADA bans aromatase inhibitors at all times under S4.1. source

Azoospermia

No sperm in the semen.

It can happen because sperm are not made or because they are blocked. Causes include hormone problems, genetic conditions and surgery. source

B

Bioavailability

How much of a dose reaches the bloodstream, and how fast.

Bioavailability depends partly on the dosage form and how it is made. It is usually assessed from the area under the blood concentration-time curve (AUC). source

Bone mineral density (BMD)

A measure of the mineral content of bone, used to check bone strength.

BMD is used to diagnose osteoporosis and predict fracture risk. In older men, a year of anastrozole lowered spine BMD compared with placebo. source

C

Case report

A detailed report on the diagnosis, treatment and follow-up of one patient.

Case reports also give some background details about the patient, such as age and sex. source

Cholestasis

A condition in which the flow of bile from the liver is blocked.

The blockage can be in the liver or in the bile ducts. Cholestatic liver injury with jaundice was reported in two young men after ligandrol and/or ostarine followed by post-cycle substances. source

Clinical trial

A research study that tests how well a medical approach works in people.

Trials test new ways to screen for, prevent, diagnose or treat a disease. Also called a clinical study. source

Cmax

The highest concentration of a drug in the blood after a dose.

Cmax is read from the blood concentration-time curve after a dose. source

COA (certificate of analysis)

A document listing the tests run on a batch, the limits and the results.

Under FDA's GMP guidance for drug ingredients, a COA names the product and batch, lists each test with its acceptance limits and numerical results, and is dated and signed by the quality unit, with the original manufacturer named. source

Complete response letter (CRL)

An FDA letter saying a drug application will not be approved in its present form.

The letter describes the specific deficiencies. Repros announced one for enclomiphene in December 2015. source

Compounding (503A)

When a licensed pharmacy prepares a medicine for an individual patient.

In the US, FDA sorts nominated bulk substances into categories while it decides which may be used. Enclomiphene citrate sits in Category 1, "under evaluation", as of May 2026. source

CYP2D6

A liver enzyme that breaks down many drugs, including clomiphene.

CYP2D6 is the main enzyme in clomiphene metabolism, and gene differences in it change the breakdown. In people who are poor CYP2D6 metabolizers, enclomiphene exposure (AUC) was about 7 times higher. source

D

Detection window

How long after use a test can still find a drug or its metabolites.

After 30 days of clomiphene 50 mg/day, the zuclomiphene isomer was found in urine for 121 to more than 261 days. source

Dietary supplement

A product taken by mouth that contains a dietary ingredient such as a vitamin, mineral, herb or amino acid.

In the US, the term is defined by the 1994 DSHEA law, and FDA does not approve supplements before they are sold. source

Double-blind

A trial where neither participants nor researchers know who gets which treatment.

Blinding makes the results less likely to be biased. source

DVT (deep vein thrombosis)

A blood clot in a deep vein of the leg or lower pelvis.

Symptoms may include pain, swelling, warmth and redness in the area. source

E

Endogenous / exogenous

Endogenous means made inside the body; exogenous means coming from outside.

Endogenous testosterone is the testosterone the testes make themselves. Exogenous testosterone or steroids come from outside and suppress the body's own production. source

Estradiol (E2)

The main form of estrogen, present in both men and women.

Estrogens matter in men too, for healthy cholesterol and blood sugar levels, bone and muscle strength and brain function. The aromatase enzyme converts androgens such as testosterone into estrogens. source

F

Fasting glucose

Blood sugar measured after not eating or drinking (except water) for at least 8 hours.

It is used to screen for or monitor prediabetes and diabetes and to check for side effects of medicines that affect blood sugar. source

Free testosterone

The share of testosterone in blood that is not bound to proteins.

Free testosterone is more available for the body to use when building bone and muscle. Most testosterone is bound to SHBG or albumin, so total and free levels can move differently. source

FSH (follicle-stimulating hormone)

A pituitary hormone that drives sperm production in men.

In men, FSH acts on the testes to make sperm. It helps control how much sperm the testicles make and how healthy the sperm are. It is usually tested together with LH. source

G

Ghrelin

A hormone involved in appetite that also regulates GH release.

Ghrelin is encoded by the GHRL gene. WADA lists lenomorelin (ghrelin) among growth hormone secretagogues. source

GHRH (growth hormone-releasing hormone)

A hormone that triggers GH release from the pituitary.

GHRH analogs include CJC-1295, sermorelin and tesamorelin. WADA bans GHRH and its analogs under S2.2.4. source

GHRP (growth hormone-releasing peptide)

Short peptides that trigger GH release, such as GHRP-2, GHRP-6 and hexarelin.

WADA lists GHRPs among growth hormone releasing factors banned at all times (S2.2.4). source

GH secretagogue (GHS)

A substance that makes the body release more growth hormone.

Examples on WADA's list include ibutamoren (MK-677), ipamorelin, anamorelin, macimorelin and lenomorelin (ghrelin). All are banned at all times under S2.2.4. source

GnRH (gonadotropin-releasing hormone)

A hormone from the hypothalamus that makes the pituitary release LH and FSH.

GnRH is the first step of the HPTA. In men, the LH and FSH it releases cause the testicles to make testosterone. It is also called LHRH. WADA lists GnRH (gonadorelin) and its agonist analogs among testosterone-stimulating peptides banned in males (S2.2.1). source

Growth hormone (GH)

A pituitary hormone that controls growth and how the body uses glucose and fat.

Also called somatotropin. In adults GH affects bone and muscle health. GH levels change through the day, so a single standard blood test often does not give helpful information. source

Gynecomastia

Growth of breast gland tissue in males.

It can be caused by hormone imbalances, some illnesses or certain drugs. In men on the anti-androgen bicalutamide, tamoxifen cut the risk by about 82% in trials, while anastrozole showed no significant benefit. source

H

Half-life

The time it takes for a drug's level or activity to fall by half.

For drugs cleared at a steady rate, half-life equals 0.693 divided by the elimination rate constant. Half-life helps predict how long a drug stays in the body and how long it takes to reach steady state. source

HbA1c

A blood test showing average blood sugar over the past 2–3 months.

It measures the share of hemoglobin coated with glucose. It may be used to screen for or diagnose type 2 diabetes and prediabetes. source

hCG (human chorionic gonadotropin)

A hormone that WADA classes as a testosterone-stimulating peptide in males.

WADA lists chorionic gonadotrophin (CG) and LH among testosterone-stimulating peptides prohibited in males (S2.2.1). In a 2026 study of men after short steroid use, hCG 1,500 IU three times weekly was combined with clomiphene. source

HDL cholesterol

The "good" cholesterol, which carries cholesterol back to the liver.

HDL helps remove cholesterol from the body. Clomiphene 50 mg/day lowered HDL vs placebo in a 12-week trial in obese men. source

Hematocrit

The share of blood volume made up of red blood cells.

Levels that are too high or too low can signal a blood disorder, dehydration or other conditions. Testosterone is involved in making red blood cells, and EMA listed raised hematocrit as a safety concern for enclomiphene. source

Hepatotoxicity (drug-induced liver injury)

Liver damage caused by a medicine or other substance.

Some medicines are directly toxic to the liver, and large doses of many medicines can damage a normal liver. FDA reports liver injuries needing hospital care in people taking products sold as SARMs. source

HPLC (high-performance liquid chromatography)

A lab method that separates the parts of a sample by pushing it through a column at high pressure.

The high pressure shortens the time compounds stay on the column, giving narrower peaks and better selectivity and sensitivity. source

HPTA (hypothalamic-pituitary-testicular axis)

The hormone chain from the brain to the testes that controls testosterone and sperm production.

The hypothalamus releases GnRH, which makes the pituitary release LH and FSH. In men, these hormones make the testicles produce testosterone, and FSH drives sperm production. Estrogen holds this chain back. SERMs such as enclomiphene block that estrogen brake, so the pituitary releases more LH and FSH. The general name, used for men and women, is the HPG (hypothalamic-pituitary-gonadal) axis. source

Hypogonadism

When the testes or ovaries make little or no sex hormone.

In men the glands are the testes. The cause can be primary, when the testes themselves do not work properly (for example Klinefelter syndrome, infection, radiation or trauma), or secondary, when the problem is in the pituitary or hypothalamus. source

I

IGF-1 (insulin-like growth factor 1)

A growth factor linked to GH activity, often measured as a marker of it.

IGF-1 stimulates the growth of many types of cells and is similar to insulin. It is secreted by the liver and regulated in part by GH, so studies use it as a stand-in marker for GH. source

Insulin resistance

When the body responds less to its own insulin.

It can lead to high insulin levels or high blood sugar. In healthy men, 6 weeks of anastrozole reduced insulin sensitivity in one trial. source

Isomer

One of two or more compounds with the same formula but a different arrangement of atoms.

Isomers can behave differently. Clomiphene is a mix of two isomers: enclomiphene (trans) and zuclomiphene (cis). source

L

LC-MS (liquid chromatography–mass spectrometry)

A method that separates compounds by liquid chromatography and identifies them by mass spectrometry.

Mass spectrometry sorts ions by their mass-to-charge ratio, which helps confirm what a compound is. LC-MS is used for drug screening, including in anti-doping labs. source

LH (luteinizing hormone)

A pituitary hormone that tells the testes to make testosterone.

LH is made in the pituitary gland. In males it acts on the testes to make cells grow and make testosterone. Low testosterone with low or normal LH points to a problem in the brain or pituitary (secondary hypogonadism). source

Limit of detection (LOD)

The smallest amount of a substance a test can reliably detect.

Example: WADA requires labs' initial screen for clomifene to detect 1.0 ng/mL or less in urine. source

Lipid panel (cholesterol test)

A blood test of cholesterol (LDL and HDL) and triglycerides.

Too much LDL ("bad") cholesterol raises the risk of heart disease. The anastrozole label advises considering cholesterol monitoring. source

Liver function tests (LFTs)

A group of blood tests that show how well the liver is working.

They usually include ALT, AST, ALP, GGT, bilirubin and albumin. The tamoxifen label advises periodic liver function tests. source

M

Meta-analysis

A method that combines data from several studies on the same question.

The results of a meta-analysis are usually stronger than those of any single study. source

Metabolite

A substance made when the body breaks down a drug, food or its own tissue.

Some metabolites are active. Tamoxifen's main metabolite, N-desmethyltamoxifen, appears to act like tamoxifen and has a half-life of about 14 days. source

Minimum reporting level (MRL)

A concentration below which an anti-doping lab does not report a finding.

From 2026, WADA set an MRL of 2.0 ng/mL for clomifene in urine, because eating eggs or poultry from treated hens can leave traces. source

N

Negative feedback

The body's brake: high hormone levels tell the brain to send less signal hormone.

Exogenous androgens suppress the body's own testosterone production through negative feedback. SERMs block estrogen's brake on the HPTA, so the pituitary releases more LH and FSH. source

O

Observational study

A study that observes people or measures outcomes without giving a treatment.

Most evidence on post-cycle therapy comes from observational studies. source

Off-label use

Using a prescription drug for a condition it is not approved for.

Clomiphene in men is an example: the US label covers ovulatory dysfunction in women. source

Oligospermia

A lower than normal number of sperm in the semen.

In the enclomiphene Phase 3 trials, a sperm concentration below 10 million/mL was counted as a failure. source

P

PCT (post-cycle therapy)

Drugs taken after a steroid or SARM cycle to speed up hormone recovery.

PCT most often uses SERMs, hCG or aromatase inhibitors. Evidence is limited and mostly observational, and spontaneous recovery occurs in most people within months of stopping. source

Peptide

A molecule made of two or more amino acids joined together.

Peptides with many amino acids are called polypeptides or proteins. Health Canada says injectable peptides such as BPC-157, TB-500, CJC-1295 and ipamorelin are regulated as prescription drugs in Canada. source

Pharmacodynamics (PD)

What a drug does to the body.

Pharmacodynamics covers receptor binding and the effects that follow. For enclomiphene, the rise in LH and testosterone is a pharmacodynamic effect. source

Pharmacokinetics (PK)

What the body does to a drug: absorption, distribution, metabolism and excretion.

Pharmacokinetics determines how fast a drug starts to work, how strong the effect is and how long it lasts. source

Phase 1, 2 and 3 trials

The steps of testing a new treatment in people, from safety to large comparisons.

Phase 1 tests safety, side effects, best dose and timing, often in a small group. Phase 2 tests whether the treatment works. Phase 3 compares it with a standard treatment and may include hundreds of people. source

Placebo

An inactive treatment that looks the same as the real one.

The effects of the active drug are compared with the effects of the placebo. source

Preclinical study (animal, in vitro)

Research in animals or in the lab, done before testing in humans.

In vitro means in the laboratory (outside the body); in vivo means in the body. Sarmguide labels animal and cell evidence as such. source

Prescription-only medicine (Schedule 4)

In Australia, a medicine that can only be supplied with a prescription.

The TGA classes SARMs as Schedule 4 (prescription-only) substances, which cannot be advertised to the public. source

Prolactin

A pituitary hormone; high levels in men can lower sex drive.

Prolactin's main role is milk production. In men, higher-than-normal levels (hyperprolactinemia) can affect how the testicles work and can cause lower sex drive and erectile dysfunction. source

PSA (prostate-specific antigen)

A prostate protein measured in blood.

PSA can rise with prostate cancer, an enlarged prostate, prostate inflammation, urinary infections and some medicines. EMA listed PSA rises as a safety concern for enclomiphene. source

Pulmonary embolism (PE)

A sudden blockage of an artery in the lung, usually by a blood clot.

Most come from a DVT that breaks loose. It can be life-threatening. Medicines that contain hormones are among the listed causes, and the tamoxifen label warns about it. source

Purity

How free a sample is of contaminants or other substances.

Labels are not always accurate: in a 2017 test of 44 products sold online as SARMs, only 52% contained a SARM and only 41% held the labeled amount of active compound. source

R

Randomized controlled trial (RCT)

A trial in which people are assigned to groups by chance.

Using chance makes the groups similar, so the effects of the treatments can be compared more fairly. source

Research chemical ("not for human consumption")

A label sellers put on compounds sold online without approval.

Health Canada says "For Research Use Only – Not for Human Consumption" labeling does not make products legal or exempt from the rules. UK Anti-Doping says sellers use such wording to get around restrictions. source

S

S0 (non-approved substances)

WADA's catch-all ban on drugs with no approval for human therapeutic use.

It covers any pharmacological substance not addressed elsewhere on the List and with no current approval for human therapeutic use, such as drugs in development, discontinued drugs and designer drugs. BPC-157 is named as an example. source

SARM (selective androgen receptor modulator)

A class of experimental drugs designed to have effects similar to testosterone.

Examples include ostarine (enobosarm), ligandrol (LGD-4033), RAD-140, S-23 and YK-11. No SARM has been approved for human use by any medicines regulator. They are prohibited in sport under S1 (anabolic agents). source

Secondary hypogonadism

Low testosterone caused by the hypothalamus or pituitary, with low or normal LH and FSH.

Also called hypogonadotropic hypogonadism. Men have low testosterone with low or inappropriately normal LH and FSH. Enclomiphene was developed for this group. source

Semen analysis (sperm count)

A test of the quantity and quality of semen and sperm.

It checks things like sperm count and how well sperm move. Problems can make it harder to conceive. source

SERM (selective estrogen receptor modulator)

A drug that acts like estrogen in some tissues and blocks it in others.

Tamoxifen, raloxifene, clomiphene and enclomiphene are SERMs. In men, blocking estrogen feedback on the HPTA makes the pituitary release more LH and FSH, which raises testosterone. WADA bans SERMs at all times under S4.2. source

SHBG (sex hormone binding globulin)

A liver protein that binds testosterone and estrogen and controls how much is active.

Sex hormones bound to SHBG cannot work with tissues; free hormones can. Some drugs raise SHBG: tamoxifen 20 mg/day raised it by about 20% in healthy men. source

Specified substance

A banned substance more likely to have been taken for a reason other than performance.

WADA stresses that Specified substances are not less important or less dangerous; the label mainly affects sanctions. S0, S4.1 and S4.2 substances are Specified; S1 and S2 substances are not. source

Spermatogenesis

The process by which the testes make sperm.

It runs in three phases (mitosis, meiosis and spermiogenesis). After steroid use, sperm production took about a year to recover in one prospective study, longer than testosterone. source

Steady state

The point where drug intake and removal balance and blood levels stop rising.

With regular dosing, levels keep rising for about 5 to 6 half-lives before steady state is reached. Drugs with long half-lives take longer. source

Suppression (HPTA suppression)

When outside hormones shut down the body's own testosterone and sperm production.

Supraphysiological androgen doses can fully suppress endogenous testosterone and sperm production. In one prospective study, testosterone recovered within 3 months in most men, but sperm took about a year and 11% still had low testosterone after a year. source

T

Testosterone

The main male sex hormone, made mostly in the testes.

In both sexes testosterone helps control sex drive and muscle and bone growth. In males it is also involved in sperm production and making new red blood cells. Most testosterone in blood is bound to proteins such as SHBG and albumin; a standard test measures total testosterone. source

Tmax (peak time)

The time after a dose when the blood level is highest.

Peak time is the most widely used general index of how fast a drug is absorbed: the slower the absorption, the later the peak. source

TRT (testosterone replacement therapy)

Treatment that supplies testosterone from outside the body.

TRT controls symptoms but often suppresses the HPG axis, which can impair sperm production. Low sperm counts or no sperm can occur 12 to 24 weeks after starting testosterone alone. source

U

Unapproved drug

A drug that a regulator has not reviewed and approved for safety and effectiveness.

FDA says products sold as SARMs are unapproved drugs, not dietary supplements, and are illegally marketed. source

V

VTE (venous thromboembolism)

A blood clot that blocks a vein, including DVT and pulmonary embolism.

EMA cited a risk of venous thromboembolism when it refused a license for enclomiphene (EnCyzix) in 2018. source

W

WADA Prohibited List

The yearly list of substances and methods banned in sport.

WADA updates it every year; the 2026 List took effect on 1 January 2026. Sections S0–S5 and the prohibited methods are banned at all times (in and out of competition); S6–S9 are banned in competition. source

Z

Zuclomiphene

The cis-isomer of clomiphene, which clears slowly and builds up.

The Clomid label says zuclomiphene has a longer half-life than enclomiphene and stayed detectable for over a month after single doses. In men on long-term clomiphene, the median zuclomiphene level was about 20 times the enclomiphene level. source