The ovaries and testes each produce a mix of sex hormones that go far beyond just “estrogen” and “testosterone.” Both organs release several hormones that regulate reproduction, shape physical development during puberty, and influence bone, muscle, and fat throughout life. While the ovaries are best known for estrogen and progesterone, and the testes for testosterone, each organ also produces smaller quantities of other signaling molecules that play surprisingly important roles.
Hormones Produced by the Ovaries
The ovaries are the primary source of three categories of hormones in the female body: estrogens, progesterone, and a handful of regulatory peptides. These hormones don’t work in isolation. They rise and fall in a coordinated cycle each month, and their balance shifts dramatically across life stages like puberty, pregnancy, and menopause.
Estrogens
The ovaries produce three forms of estrogen, and which one dominates depends on your stage of life. Estradiol is the most potent form and the primary estrogen during the reproductive years. Estrone takes over after menopause, when the ovaries produce far less estradiol and the body relies more on fat tissue and the adrenal glands for estrogen. Estriol becomes the dominant form during pregnancy, produced mainly by the placenta.
Estrogen production involves teamwork between two types of ovarian cells. Theca cells on the outside of a developing follicle produce androgens, which are then transported inward to granulosa cells. The granulosa cells convert those androgens into estradiol. This two-step process is why both cell types need to function properly for normal estrogen levels.
Estrogens do far more than regulate the menstrual cycle. During puberty, they drive the growth of the uterus, breasts, and vagina, shape the pattern of fat distribution that creates a typically female body shape, trigger the growth spurt, and eventually signal the bones to stop growing. Throughout adulthood, estrogens help regulate carbohydrate and lipid metabolism, protect the cardiovascular system, and maintain bone density. In both sexes, estrogen is one of the most essential hormones for keeping bones strong.
Progesterone
After ovulation each month, the empty follicle transforms into a structure called the corpus luteum, which produces progesterone. This hormone prepares the uterine lining for a potential pregnancy and helps maintain early pregnancy if fertilization occurs. If no pregnancy happens, the corpus luteum breaks down, progesterone drops, and menstruation begins. During pregnancy, the placenta eventually takes over progesterone production.
Inhibin and AMH
The ovaries also produce two important regulatory peptides. Inhibin comes in two forms: inhibin A and inhibin B, both made by granulosa cells. Their job is to put the brakes on a brain signal called FSH (follicle-stimulating hormone) that would otherwise keep pushing the ovaries to develop more follicles. Inhibin B rises during the early part of the menstrual cycle as small follicles develop, while inhibin A peaks later, around ovulation.
Anti-Müllerian hormone (AMH) is also secreted by granulosa cells. It helps regulate how many follicles mature at once, and clinicians often use AMH levels as a marker of ovarian reserve, essentially a snapshot of how many eggs remain available.
Hormones Produced by the Testes
The testes are the primary source of androgens in men, but they also produce peptide hormones and even small amounts of estrogen. Two main cell types handle hormone production: Leydig cells in the tissue between the sperm-producing tubes, and Sertoli cells inside those tubes.
Testosterone
Testosterone is the headline hormone. Produced by Leydig cells, it drives the development of male secondary sexual characteristics like a deeper voice, increased muscle mass, and facial hair. It’s also essential for sperm production, playing a direct role in the cell divisions that create mature sperm and protecting developing sperm cells from premature death. Normal adult male testosterone levels range from about 291 to 1,100 ng/dL, compared to 18 to 54 ng/dL in women.
Beyond reproduction, testosterone has direct effects on muscle, fat distribution, and bone. Androgens maintain bone strength in men through mechanisms partly independent of estrogen, giving male bones a sort of double layer of hormonal protection.
Dihydrotestosterone (DHT)
Some testosterone gets converted into a more powerful form called DHT at specific target tissues throughout the body. DHT binds to the same receptor as testosterone but roughly twice as strongly, and it hangs on about five times longer. This makes it the more potent androgen where it acts.
During fetal development, DHT is responsible for forming the male external genitalia, including the penis, scrotum, and prostate. Later in life, DHT drives prostate growth, oil gland activity in the skin, and the growth of facial, body, and pubic hair. It’s also the primary androgen behind male pattern baldness. Unlike testosterone, DHT cannot be converted into estrogen, which is why it’s sometimes called a “pure” androgen.
Inhibin B and AMH
Sertoli cells in the testes secrete inhibin B, which functions the same way it does in the ovaries: it signals the pituitary gland to dial back FSH production. In men, inhibin B levels serve as a useful biomarker for how well spermatogenesis is working and how healthy the Sertoli cell population is.
Sertoli cells also produce anti-Müllerian hormone, which plays a critical role during fetal development. AMH causes the regression of structures that would otherwise develop into a uterus and fallopian tubes. Without AMH during the right window of fetal development, those female reproductive structures would form regardless of the baby’s genetic sex.
INSL3
Insulin-like peptide 3 is a lesser-known hormone produced by Leydig cells alongside testosterone. Its most important job happens before birth: INSL3 drives the descent of the testes from the abdomen into the scrotum by acting on the ligament that connects the fetal testis to the inguinal wall. Later in life, INSL3 also helps protect developing sperm cells from programmed cell death.
How the Brain Controls Both Organs
The ovaries and testes don’t operate independently. They’re part of a feedback loop with the brain called the hypothalamic-pituitary-gonadal axis. It starts in the hypothalamus, a small region at the base of the brain, which releases gonadotropin-releasing hormone (GnRH) in rhythmic pulses. These pulses tell the pituitary gland to release two signaling hormones: LH (luteinizing hormone) and FSH.
In women, FSH stimulates ovarian follicles to grow and mature, while LH triggers ovulation and the formation of the corpus luteum. In men, LH stimulates Leydig cells to produce testosterone and INSL3, while FSH works together with testosterone to sustain sperm production. The sex hormones produced by the gonads then feed back to the brain, generally telling the hypothalamus and pituitary to ease off. The exception is a brief window before ovulation, when rising estrogen levels actually amplify the signal instead of suppressing it, creating the surge that triggers egg release.
Hormones Both Organs Share
One of the more surprising facts about gonadal hormones is how much overlap exists. The testes produce small amounts of estrogen, and the ovaries produce small amounts of testosterone. Men typically have estradiol levels between 20 and 50 pg/mL, while women’s levels fluctuate dramatically through the menstrual cycle, from as low as 10 pg/mL in the early follicular phase to 100 to 300 pg/mL at the mid-cycle peak, then dropping below 10 pg/mL after menopause.
Both organs also produce inhibin to regulate FSH, AMH to manage reproductive development, and INSL3. In women, INSL3 is synthesized by theca cells in the ovary rather than Leydig cells, and its levels reflect overall gonadal function. This shared hormonal toolkit reflects the fact that ovaries and testes develop from the same embryonic tissue and retain many of the same cellular machinery, just tuned to different settings.