At the most basic level, a hormone is a chemical made in one part of a living thing that travels around and affects other parts of that thing. Hormones are as old as the hills, and probably evolved when life on Earth was nothing but cells bobbing in the primordial seas. The special organs in human bodies that make hormones–including ovaries and testicles–came much later.
What are a typical woman’s hormone levels?
When you say “raging hormones,” most people think about those awkward teenage year–complete with sprouting hair, inconveniently timed periods, and zits. This makes sense since it’s during the change from childhood to adulthood that women’s ovaries start making the sex hormones estrogen and progesterone in large amounts. (By the way, “large amounts” of a hormone are actually very tiny amounts, since we measure hormones in our blood in billionths or trillionths of a gram.)
For the average woman between ages 15 and 40 who isn’t using hormonal birth control, here’s what the sex hormones estradiol (a type of estrogen) and progesterone do each day of a menstrual cycle.
Both hormones increase about 10-fold over a few days around the time an egg is released from the ovary. (FYI, estrogen and progesterone aren’t the only hormones involved in coordinating the whole menstrual cycle, but they’re the two that cause either a period or a pregnancy.) The amount and timing of estrogen and progesterone an individual woman makes changes from cycle to cycle depending on lots of factors–including age, health, stress level, and whether her body will release an egg that cycle or not. Between different women, there can be even bigger variations in the amount of these hormones they produce and when.
How do hormones affect mood?
It’s a challenge to make any general statements about how hormones impact women since every woman is different. Studies about the relationship between women’s hormones and mood have had mixed results. The most scientifically sound studies show that stress and overall health had a much greater–and steadier–impact on mood than hormones did.
But some women have serious depression that comes and goes with their periods–about 1% have a medically recognized condition known as premenstrual dysphoric disorder (PMDD). These mood changes are not caused by higher levels of hormones–studies of women with PMDD show they have normal levels of estrogen and progesterone. The actual cause isn’t well understood, but it may be related to differences in the way women’s bodies process hormones. Women with a mental health condition like bipolar or anxiety disorder may also process hormones differently, leading to different experiences of hormone changes during menstrual cycles.
Because there are as many ways to react to hormones as there are human beings, each woman will be the best judge of how her mood changes during the menstrual cycle.
How do hormones in birth control work?
The hormones in some methods of birth control are similar to the ones women’s bodies make–close enough that the body recognizes them as estrogen and progesterone. There are multiple kinds of hormonal birth control, each with unique ingredients that are released differently.