Testosterone booster supplements are designed to support healthy T levels by acting upon several different endocrine system pathways. This glossary page defines some of the hormones, hormone precursors, enzymes, body structures, and health concerns related to testosterone production and T-booster supplements.
5-Alpha-reductase
This enzyme is involved in sex hormone production and in men is secreted primarily by the testes. 5-Alpha-reductase is best known as being responsible for converting testosterone into its more potent version – dihydrotestosterone (DHT). Deficiency of 5-alpha-reductase inhibits the conversion of testosterone into DHT, which can result in decreased libido and overall sexual function.
Anabolic Steroids
Also called anabolic-androgenic steroids (AAS), anabolic steroids are synthetic versions of testosterone. These steroids are used in medicine to treat delayed puberty and significant muscle loss. However, they are far better known for being widely used by bodybuilders and athletes seeking to improve muscle performance and appearance. Anabolic steroids have a wide range of health risks, and are banned in competitive sports.
Androstenedione
While it is a relatively ineffectual androgen hormone by itself, androstenedione is vital in aiding the production of more important sex hormones, such as testosterone. Too much androstenedione results in excess testosterone and low estrogens, whereas too little has the reverse effect.
Androgen
This word is a blanket term that refers to all male sex hormones. Androgens are primarily synthesized within the testes, with the pituitary gland playing a key role in signaling for their production. Androgen hormones include androstenedione, dihydrotestosterone, epitestosterone, and testosterone.
Andropause
Also known as the “male menopause,” andropause refers to the decline of male sex hormones in aging men. Despite its informal nickname, andropause is markedly different from menopause. Whereas menopause refers to the sudden drop in female sex hormones, andropause is a much more gradual decline in testosterone and other androgens in aging men. Andropause begins around 30 years of age with roughly a 1% reduction in testosterone per year.
Aromatase
Aromatase is an enzyme responsible for converting androgens into estrogens. Aromatase deficiencies in men cause health problems associated with low estrogen levels, whereas too much aromatase triggers issues related to low testosterone.
Aromatase Inhibitor
An aromatase inhibitor (AI) is a compound that suppresses aromatase activity. AIs are already widely used to treat hormonal disorders in men, and also hold promise of increasing testosterone levels in older men by preventing its conversion into estrogen.
Benign Prostatic Hyperplasia (BPH)
BPH is a condition where the prostate becomes larger in older men. The causes of BPH are not yet entirely known, although it seems to be related to the changes in the testosterone: estrogen ratio in aging men. BPH can push against the urethra and reduce the flow of urine, but is otherwise harmless.
Cortisol
Cortisol is a steroid hormone produced in the adrenal glands that is vital for dealing with stress and low blood sugar. Too much cortisol in the body can lead to muscle weakness, osteoporosis, and high blood pressure. Not enough cortisol can likewise result in muscle weakness as well as fatigue and dizziness. Some studies have linked an increase in cortisol levels after exercise to reduced testosterone levels in men.
Dehydroepiandrosterone (DHEA)
Most commonly called DHEA, this hormone is the most widely circulating steroid hormone in humans. DHEA mainly serves as a precursor in the synthesis of both androgens and estrogens. It was once used by bodybuilders and athletes to enhance performance but has long been banned for competitive use by various health agencies. More on DHEA.
Dihydrotestosterone (DHT)
Testosterone converts into this powerful androgen, otherwise known as DHT. Although only about ten percent of testosterone gets converted into DHT, it is considerably more potent than testosterone at developing male genitalia and promoting male sex characteristics, such as facial hair. More on dihydrotestosterone.
Endocrine System
This system comprises of a number of glands that secrete hormones into the bloodstream. The endocrine system includes the pineal gland, pituitary gland, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands. A well-functioning endocrine system is essential to the reproductive system and the production of all hormones, testosterone included.
Epitestosterone
Epitestosterone is a male sex hormone that regulates body hair distribution and prostate growth. Despite its similar chemical structure to testosterone, its function is different. The concentration of epitestosterone in relation to testosterone is called the epitestosterone: testosterone ratio.
Erectile Dysfunction (ED)
Also known as impotence, ED is the inability to maintain an erect penis. Among the various causes and hundreds of proposed solutions, research suggests that testosterone plays a central role in ED.
Estradiol
This form of estrogen is produced not only in the testes, but also in the adrenal glands of men. Since this hormone is a type of estrogen, high levels in males can cause certain health problems. Low sperm count, high body fat, and increased osteoporosis risk have been linked with abnormal estradiol levels in men.
Estrogen
Estrogens are the female sex hormones. Contrary to popular belief, estrogens are also produced in small quantities in men, and their levels increase with age. Although a certain level of estrogen is necessary for proper sperm function, libido, and other processes in males, high levels have been associated with impotence and low sex drives. Common forms of estrogen include estrone, estradiol, estriol, and 7-oxo-DHEA.
Follicle Stimulating Hormone (FSH)
Otherwise known as FSH, this is one of two important hormones produced in the pituitary gland that act on the male reproductive system. FSH is sent from the brain and signals to the testes to produce testosterone. If the testes are not producing enough testosterone, FSH levels will spike. Low FSH levels can result in infertility and insufficient sperm production. More on FSH.
Gonadotropin-Releasing Hormone (GnRH)
This hormone is released in the brain in order to stimulate the release of FSH and LH in the pituitary gland. Because FSH and LH then regulate the production of testosterone and sperm, GnRH is a key part of the male reproductive system. Low GnRH levels can result in infertility and reduced testosterone production.
Human Growth Hormone (HGH)
As the name implies, HGH stimulates growth, cell regeneration, and cell reproduction in humans. It is produced in the pituitary gland, and plays an important role in maintaining muscle mass, bones, and many other aspects of health. Because of these effects, healthy HGH levels are arguably as important as testosterone for maintaining muscle mass and other manly characteristics.
Hyperprolactinemia
This medical condition occurs when an individual has too much prolactin in their bloodstream. The effects of hyperprolactinemia in men include erectile dysfunction, decreased libido, infertility and osteoporosis. This condition is usually characterized by some sort of issue with the hypothalamic-pituitary-gonadal axis and an overall insufficiency of testosterone.
Hypothalamic-Pituitary-Gonadal Axis
This refers to the trifecta of the gonads (testes), hypothalamus, and pituitary gland and their combined effects on the reproductive and immune systems. The HPG axis regulates the flow of FSH, LH, and GnRH in males, which are all crucial in the production of testosterone and other sex hormones.
Insulin-like Growth Factor-1
Produced in the liver, insulin-like growth factor-1 (IGF-1) is a hormone structurally similar to insulin, which mediates most of the effects of human growth hormone. Abnormally low levels have been linked to dwarfism, and extremely high levels are believed to promote unwanted cellular growth. Several studies have reported a significant connection between levels of testosterone and IGF-1.
Leydig Cells
These cells are present in the testes and produce various androgens, including testosterone, androstenedione, and DHT. Testosterone is also converted into DHT in leydig cells. Certain toxins and contaminants, such as BPA (present in many plastics used to store food) and DEHP (a plastic additive that is present in IV tubing, children’s toys, and many other household items), are known to damage leydig cells. Our top-ranked T-booster compound, D-aspartic Acid (DAA), notably stimulates testosterone production in leydig cells.
Luteinizing Hormone (LH)
LH is an important hormone for the male reproductive system that is secreted by the pituitary gland. Like FSH, it travels from the brain to the testes, but instead of stimulating the production of sperm, it aids in the synthesis and production of testosterone. Testosterone cannot be produced without LH, and insufficient levels can result in infertility. Very high levels of LH surprisingly trigger a negative feedback loop that ultimately reduces testosterone.
Ovaries
These female sexual organs are analogous to the testes in males. They not only produce and release eggs, but also various hormones, such as estrogen, to trigger menstruation, and testosterone. Excess production of testosterone in the ovaries can lead to the development of male characteristics in women.
Oxidative Stress
A state in which the body’s antioxidant defenses are unable to effectively neutralize reactive oxygen species (ROS) – compounds that can cause damage to cells. In the context of male reproductive health, oxidative stress can negatively impact both testosterone levels and overall fertility.
Performance-Enhancing Drugs (PED)
Performance-enhancing drugs (PEDs) are substances used to improve any kind of physical or mental activity. PEDs are banned for competitive use, but that hasn’t stopped many – and arguably the majority – of professional athletes from using these substances. They are also taken by military personnel to optimize combat performance and by students to improve academic performance.
Pituitary Gland (PED)
This small endocrine gland is responsible for regulating such physiological processes as stress, growth, blood pressure, and reproduction. Its primary role is to synthesize and release hormones, including HGH, LH, FSH, and PRL.
Priapism
This health condition is defined by a continuous and painful penile erection that appears even outside of sexual stimulation. It is most commonly faced by men in their 30s and those with sickle cell anemia, although research has also identified uncontrolled testosterone or GnRH intake as a likely cause.
Prolactin (PRL)
This hormone gets its name from its role in stimulating lactation in females, although it has countless additional roles in both men and women. Abnormally high levels of prolactin can lead to a condition called hyperprolactinemia, which is characterized by lowered levels of testosterone in men. Prolactin is present in most dairy products.
Progesterone
Although this hormone is most commonly associated with regulating the female reproductive system, it also serves as a precursor to testosterone. Progesterone levels drop as men age, which can result in lowered libido, reduced muscle mass, and impotence.
Resistance Training
Also popularly referred to as strength or weight training, this form of exercise involves any activity where a resisting force is applied during muscle contraction, such as weights or your own body weight. Resistance training is undergone by athletes and bodybuilders hoping to increase muscle strength, tone, mass, or endurance. Regular resistance training is one of the most effective ways to naturally increase testosterone levels.
Sertoli Cells
These cells are essential for the production of sperm, and are located in the seminiferous tubules within the testes. FSH increases the number of sertoli cells, whereas testosterone signals for their production of sperm.
Sex Hormone-Binding Globulin (SHBG)
Sex hormone-binding globulin (SHBG) is a protein that sex hormones bind to in the bloodstream. Androgens and estrogens bound to SHBG are biologically inactive, and only 1-2% of total testosterone (“free” testosterone) is not bound to this protein, which allows it to be biologically active. More on SHBG.
Sperm Count
This phrase refers to the concentration of spermatozoa in a man’s ejaculate, and is used as a measure of fertility. Since testosterone is vital to sperm production, a low sperm count may be an indicator of lower than normal testosterone. On the other hand, sperm count can also be reduced if a man is taking anabolic steroids, because this causes the body to stop producing its own natural testosterone.
Sperm Motility
Sperm motility refers to the ability of a man’s sperm to move. Men who have high levels of testosterone are often observed as also having good sperm motility, while high levels of FSH and LH are linked with low sperm motility.
Steroidogenesis
This biological processes refers to the conversion of cholesterol into different steroids, each of which has its own pathway.
Testes
Also known as gonads, these are the primary sex organs in which sperm, testosterone, and other androgens are produced. The testes’ leydig cells produce testosterone in the presence of LH. The testes are also responsible for erectile function. Anabolic steroid use can shrink the testes.
Testosterone
Testosterone is the most common androgen found in men. Testosterone has a key role in many aspects of male health, including muscle mass, hair growth, and sexual function. Only about 1-2 % of all testosterone is “free” in the bloodstream, meaning that it is not bound to SHBG and thus capable of exerting its effects. By contrast, total testosterone refers to the whole amount of testosterone, be it attached or unattached to SHBG.
Testosterone Replacement Therapy
Testosterone replacement therapy (TRT) is the administration of synthetic testosterone to men with low testosterone levels. Benefits of TRT include improvements in muscle mass, energy, mood, libido, and quality of erections, although the effects can vary. The use of TRT to counter the natural age-related decrease in testosterone is a controversial area of study that continues to be debated, especially considering the lack of scientific research.
Testosterone-to-Estrogen Ratio
This refers to the concentration of testosterone in relation to the concentration of estrogen in men. A healthy T:E ratio is important for various aspects of male health, and changes in this ratio have been particularly implicated in prostate issues in aging men.
