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Chapters

0:00 Introduction
0:28 What is testosterone
0:58 What is testosterone supplement
1:08 Why a person needs testosterone supplement
2:02 How to know if you are low on testosterone
3:22 is it safe to use testosterone supplements
3:47 Side effects

.Testosterone is the primary sex hormone and anabolic steroid in males.[3] In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.[4] In addition, testosterone in both sexes is involved in health and well-being, including moods, behaviour, and in the prevention of osteoporosis.[5][6] Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss.

Testosterone is a steroid from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites.[7] It exerts its action through binding to and activation of the androgen receptor.[7] In humans and most other vertebrates, testosterone is secreted primarily by the testicles of males (see Biosynthesis) and, to a lesser extent, the ovaries of females. On average, in adult males, levels of testosterone are about seven to eight times as great as in adult females.[8] As the metabolism of testosterone in males is more pronounced, the daily production is about 20 times greater in men.[9][10] Females are also more sensitive to the hormone.[11]

In addition to its role as a natural hormone, testosterone is used as a medication in the treatment of hypogonadism in men and breast cancer in women.[12] Since testosterone levels decrease as men age, testosterone is sometimes used in older men to counteract this deficiency. It is also used illicitly to enhance physique and performance, for instance in athletes.[13] The World Anti-Doping Agency is listing it as S1 Anabolic agent substance "prohibited at all times".[14] In general, androgens such as testosterone promote protein synthesis and thus growth of tissues with androgen receptors.[15] Testosterone can be described as having virilising and anabolic effects (though these categorical descriptions are somewhat arbitrary, as there is a great deal of mutual overlap between them).[16]

Anabolic effects include growth of muscle mass and strength, increased bone density and strength, and stimulation of linear growth and bone maturation.
Androgenic effects include maturation of the sex organs, particularly the penis, and the formation of the scrotum in the fetus, and after birth (usually at puberty) a deepening of the voice, growth of facial hair (such as the beard) and axillary (underarm) hair. Many of these fall into the category of male secondary sex characteristics.

Testosterone effects can also be classified by the age of usual occurrence. For postnatal effects in both males and females, these are mostly dependent on the levels and duration of circulating free testosterone.[citation needed]
Before birth

Effects before birth are divided into two categories, classified in relation to the stages of development.

The first period occurs between 4 and 6 weeks of the gestation. Examples include genital virilisation such as midline fusion, phallic urethra, scrotal thinning and rugation, and phallic enlargement; although the role of testosterone is far smaller than that of dihydrotestosterone. There is also development of the prostate gland and seminal vesicles.[citation needed]

During the second trimester, androgen level is associated with sex formation.[17] Specifically, testosterone, along with anti-Müllerian hormone (AMH) promote growth of the Wolffian duct and degeneration of the Müllerian duct respectively.[18] This period affects the femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult's own levels. Prenatal androgens apparently influence interests and engagement in gendered activities and have moderate effects on spatial abilities.[19] Among women with CAH, a male-typical play in childhood correlated with reduced satisfaction with the female gender and reduced heterosexual interest in adulthood.[20]
Early infancy







Chapters

0:00 Introduction
0:27 What is testosterone
0:57 What is testosterone supplements
2:02 How to know if you are low on testosterone
3:23 Is it safe to use testosterone supplements
3:47 Side effects of testosterone supplements