Yes, testosterone is an androgen. It is the primary androgen in the human body and the most clinically significant one. Androgens are a group of hormones responsible for developing and maintaining male sex characteristics, though they play important roles in all sexes. The body produces five androgens in total, and testosterone is the most potent of the group.
The Five Androgens in the Human Body
Your endocrine glands produce five androgenic hormones: testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), and androstenedione. Of these five, only testosterone and DHT can directly activate androgen receptors in your cells. The other three (DHEA, DHEAS, and androstenedione) are precursor hormones, meaning your body converts them into testosterone before they have androgenic effects.
DHT is actually the most biologically active androgen. It binds to androgen receptors with about twice the strength of testosterone and detaches five times more slowly. Your body creates DHT from testosterone using a family of enzymes in tissues like the skin, prostate, and hair follicles. Testosterone can also be converted into estradiol, a form of estrogen, through a different enzyme called aromatase. So testosterone sits at a metabolic crossroads, serving as both an active hormone and a raw material for two other important hormones.
Where Testosterone Is Made
In males, the Leydig cells in the testes produce the majority of circulating testosterone by converting cholesterol through a series of enzymatic steps. In females, testosterone comes from two sources: the ovaries and the adrenal glands. The ovaries produce testosterone in specialized cells called theca cells, while both sexes produce weaker androgens (DHEA and androstenedione) in a layer of the adrenal glands called the zona reticularis. These weaker androgens can be converted into testosterone in peripheral tissues if produced in high enough amounts.
The adrenal glands are responsible for all circulating DHEAS, about 80% of DHEA, and roughly half of androstenedione. The ovaries contribute the other half of androstenedione and about 20% of DHEA. Some of this conversion to testosterone happens in the skin itself.
How Testosterone Works Inside Cells
Testosterone produces its effects through two distinct pathways. The slower, classical pathway works through gene regulation. When testosterone enters a cell, it binds to an androgen receptor that’s sitting in the cell’s cytoplasm, attached to chaperone proteins. Binding triggers the receptor to change shape, release those chaperone proteins, and travel into the cell nucleus. Once there, it pairs up with another receptor and attaches to specific sections of DNA, turning certain genes on or off. Helper proteins called coregulators fine-tune this process, either amplifying or dampening the gene’s activity.
The faster pathway doesn’t involve DNA at all. Within seconds to minutes of testosterone reaching a cell, it can activate signaling cascades through receptors on the cell membrane. These rapid effects are too quick to involve gene transcription and translation, so they represent a completely separate mechanism. Testosterone can also influence gene activity indirectly by grabbing onto transcription factors that other genes need, essentially blocking those genes from being activated without ever touching DNA itself.
Androgenic vs. Anabolic Effects
Testosterone’s effects fall into two overlapping categories. Its androgenic effects are the ones that develop and maintain male sex characteristics: facial and body hair growth, voice deepening, and genital development. Its anabolic effects involve building skeletal muscle and increasing bone density. In practice, these two categories are hard to separate because the same hormone and the same receptor drive both. The distinction matters mostly in pharmacology, where synthetic steroids have been designed to emphasize muscle-building effects while minimizing masculinizing ones, though no compound has ever fully separated the two.
Normal Testosterone Levels
Testosterone is measured through a blood test, with results reported in nanograms per deciliter (ng/dL). Normal ranges differ significantly by sex and can vary between labs.
For adult males (18 and older), the typical range is 193 to 824 ng/dL. For adult females, normal levels fall below 40 ng/dL. During male puberty (ages 11 to 15), levels can climb as high as 830 ng/dL, which explains the rapid physical changes during those years. In children under 10 of either sex, testosterone is generally below 25 ng/dL.
The American Urological Association considers a total testosterone level below 300 ng/dL as the threshold for low testosterone in males, but the number alone isn’t enough for a diagnosis. Two separate blood draws taken in the early morning are required, and symptoms must be present. Testosterone levels naturally fluctuate throughout the day, peaking in the morning, which is why timing matters.
Testosterone’s Role in Female Health
Though testosterone is often framed as a “male hormone,” it plays meaningful roles in women. It contributes to the sexual maturation of vulvar and vaginal tissues and influences sexual desire and arousal through effects on the brain. Serum testosterone levels are considered the best single marker of overall androgen status in women. Low levels are found in women with pituitary disorders or after surgical removal of the ovaries. Mildly elevated levels are associated with acne and excess hair growth, while markedly elevated levels can cause more pronounced masculinizing changes.
What Happens When Androgen Levels Are Low
Androgen deficiency produces different symptoms depending on when it occurs. In children, it can delay or prevent puberty entirely. Boys may not develop enlarged testes, a deeper voice, or facial hair. Girls may not develop breasts or begin menstrual periods. In some cases, short stature or an inability to smell can accompany the condition.
In adults, low androgen levels typically cause decreased sex drive, loss of energy, mood changes, weight gain, and infertility. Men may also lose muscle mass. Women may stop menstruating. Low testosterone is also a recognized risk factor for cardiovascular disease, and screening is recommended for men with unexplained anemia, bone density loss, diabetes, chronic opioid use, or a history of chemotherapy or testicular radiation, even if they don’t yet have obvious symptoms.