Body & health

Testosterone

Alsoandrogenlow Ttestosterone levels

Not yet reviewed by a clinician. This health entry was written from the public-health sources listed below and is general information only. It is not medical advice.

Definition

Testosterone is a hormone, the main androgen, produced mostly by the testicles and in smaller amounts by the ovaries and adrenal glands. It influences sex drive, muscle, bone, hair growth and sperm production.

At a glance

  • Testosterone is the main androgen, made mostly by the testicles and in smaller amounts by the ovaries and adrenal glands.
  • It influences sex drive, muscle, bone, hair growth and sperm production.
  • It plays a role in libido and energy for people of all sexes.
  • Levels vary through the day and gradually decline with age.
  • Low testosterone symptoms have many other possible causes, so a blood test and assessment are needed.

In detail

Testosterone drives many of the body changes of puberty in people assigned male, such as a deeper voice and facial hair, and it plays a role in libido and energy for people of all sexes. Levels vary through the day and gradually decline with age.

Symptoms of low testosterone can include low sex drive, erectile problems, tiredness and low mood, but these have many other possible causes, so a blood test and medical assessment are needed before treatment. Testosterone is also used as gender-affirming hormone therapy for some trans and non-binary people.

In a sentence

  • His doctor ordered a blood test to check his testosterone level.
  • He started testosterone as part of his gender-affirming care.

Where the word comes from

The hormone was isolated and named in the mid-1930s. The name combines testis, sterol and the chemical suffix -one.

Common questions

Do women and people with ovaries have testosterone?

Yes. The ovaries and adrenal glands produce smaller amounts, and testosterone plays a role in libido and energy for people of all sexes.

How do I know if I have low testosterone?

Symptoms such as low sex drive, erectile problems, tiredness and low mood can have many causes, so they are not enough on their own. A doctor can arrange a blood test and medical assessment before any treatment is considered.

Related terms

Sources

  1. MedlinePlusTestosterone Levels Test
  2. MedlinePlusHormones