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Male hormone glossary

Improve your understanding of technical terms around male hormones.

There are many technical words and abbreviations when it comes to male hormones. We break them down in a way that’s easy to understand.  

This glossary will help you distinguish DHT from DHEA, and free testosterone from total testosterone. 

Adrenal glands 

The adrenal glands are two glands that sit on top of the kidneys and produce several hormones including aldosterone, cortisol, and DHEA. These hormones help to regulate blood pressure, salt levels, metabolism, the stress response, and sexual development, among others.  


Albumin is a protein made by the liver that carries testosterone and other substances around the body.  

Anabolic steroids 

Anabolic steroids refer to a synthetic compound that resembles testosterone and promotes muscle growth. Anabolic steroids can be prescribed by a healthcare professional, or they may be used illegally by some athletes and sports players (illegally) to enhance performance.  

In the UK anabolic steroids are Class C drugs, meaning it’s not an offence to possess them, but manufacturing, supplying, or exporting them without a licence is illegal.  


Androstenedione is a hormone that is usually converted into testosterone and oestrogen. 

Cardiovascular risk 

Cardiovascular risk is the risk of developing any disease that affects the heart or blood vessels. These include conditions like heart attacks, strokes, peripheral arterial disease, and venous blood clots (deep vein thromboses or pulmonary emboli).  


Cortisol is a steroid hormone produced by the adrenal glands that plays a key role in the body’s natural stress response.  

Dehydroepiandrosterone (DHEA) 

DHEA is a hormone primarily produced by the adrenal glands. The body uses DHEA to make other male hormones and oestrogens. Levels peak in the 20s and steadily decline with age.  

Dihydrotestosterone (DHT) 

DHT is a hormone made from testosterone in the prostate, testes, and other tissues. It is needed to develop and maintain male sex characteristics. DHT is linked to hair loss and high amounts may increase the growth of prostate cancer.   

Erectile dysfunction 

Erectile dysfunction is the inability to get and keep an erection firm enough for sexual intercourse.  


Erythropoiesis is the process of producing red blood cells.  

Free testosterone 

Free testosterone is testosterone that is not bound to proteins in the blood allowing it to act on tissues. Free testosterone is more active than bound testosterone.  

Follicle-stimulating hormone (FSH) 

FSH is a hormone produced in the pituitary gland. In females, it acts on the ovaries to make the follicles and eggs grow. In males, it acts on the testes to help make sperm.  


Gynaecomastia is the enlargement of men’s breast tissue, sometimes referred to as ‘man boobs’, usually due to a hormone imbalance.  


Haematocrit is the ratio of red blood cells to the total volume of blood. A high haematocrit can make the blood thicker and increase the risk of blood clots. This sometimes occurs as a side effect of testosterone replacement therapy (TRT).  


Hypogonadism refers to the reduced function of the gonads (testes or ovaries). In males, this equates to a reduction in testosterone production. Hypogonadism can be primary, secondary, or mixed, depending on the source of the problem.  

Intramuscular injection 

An intramuscular injection is an injection directly into the muscle, usually into the deltoid (shoulder muscle) or buttock.  


Libido is another term for sexual desire.  

Luteinising hormone (LH) 

LH is a hormone made in the pituitary gland. In females, it acts on the ovaries to make follicles release eggs and to make hormones that get the uterus ready for implantation. In males, it acts on the testes to cause cells to grow and make testosterone.  


Metabolism refers to the chemical reactions that occur in the body’s cells, providing energy and keeping cells alive.  


Oestrogen is a type of hormone made by the body that helps develop and maintain female sex characteristics. Oestrogen is also important in men for modulating libido, erectile function, and sperm production.  


Polycythaemia is a condition with abnormally high concentrations of red blood cells in the blood. Thicker blood and sluggish blood flow mean it can increase the risk of blood clots.  

Pituitary gland 

The pituitary gland is a pea-sized organ attached to the part of the brain called the hypothalamus. It lies at the base of the brain above the back of the nose. The hypothalamus sends signals to the pituitary gland, which then makes hormones that control other glands and many of the body’s functions, including growth and fertility. 


Prediabetes is a health condition whereby blood sugar levels are higher than they should be but not quite high enough to be considered diabetes. Without intervention, prediabetes may progress to type 2 diabetes, but this isn’t inevitable.  

Primary hypogonadism 

Primary hypogonadism happens due to a problem with the testes (or ovaries in females) where the body doesn’t produce enough sex hormones (testosterone in males). The testes still receive the message to produce hormones from the brain but can’t produce them.  


Prohormone is a substance that is converted into another hormone, sometimes with a weak hormonal effect itself.  


Prolactin is a hormone made by the pituitary gland. Prolactin causes a women’s breasts to make milk during and after pregnancy and has many other effects on the body. In males, the specific function of prolactin is less well known, but it plays a role in reproductive health. High levels of prolactin can cause erectile dysfunction, reduced libido, and infertility.  

Prostate-specific antigen (PSA) 

PSA is an enzyme secreted by the prostate. High PSA levels can point toward many conditions including prostate cancer, an enlarged or inflamed prostate, or a urine infection.  

Secondary hypogonadism 

In secondary hypogonadism, the testes are normal but don’t produce enough testosterone due to a problem with the pituitary gland or hypothalamus in the brain. Normally, these parts of the brain send signals to the testes to produce testosterone. 

Sex hormone-binding globulin (SHBG) 

SHBG is a protein produced by the liver that binds to certain hormones in the blood reducing their effect (such as testosterone).  


Testosterone is a hormone that stimulates the development of male sexual characteristics produced mainly in the testes, but also the ovaries and adrenal glands. 

Testosterone deficiency syndrome (TDS) 

TDS is a condition in which not enough testosterone is produced in the body. It’s sometimes termed male hypogonadism.  

Testosterone replacement therapy (TRT) 

TRT is a form of hormone therapy in which testosterone is supplemented or replaced. It’s usually given as a treatment option for hypogonadism/testosterone deficiency syndrome to improve symptoms.  

Total testosterone 

Total testosterone is a measure of the testosterone concentration in the blood that includes both free testosterone and testosterone that is bound to proteins (such as albumin and sex hormone-binding globulin).