Hormones play a critical role in the body. Humans have around 50 different types of hormones produced by the endocrine system, and each help control specific aspects of bodily function, including sexual reproduction, metabolism and more.

Hormones also play a role in the way your hair grows and looks. The hair cycle is affected by a group of hormones—largely the sex hormones testosterone, estrogen and progesterone. To understand some of the most important hair changes, you’ll want to take a deeper look at the hormones produced by your body.

Finding chemical balance

Various glands in your body produce hormones every day. These hormones send messages to different parts of the body through the bloodstream. A single hormone may affect some parts of the body differently than others.

Balance in hormone levels is critical to maintaining proper health. A problem with your endocrine system, such as a tumor on hormone-producing glands, may cause hormone levels to skyrocket or plummet, resulting in a wide variety of negative consequences.

The level of each hormone present in your body can also vary throughout the day or over a period of time. Two examples of this are how melatonin (a hormone that gets your body ready for sleep) is more abundant every night, and how the sex hormones (which help bodies mature during puberty and regulate a women’s menstrual cycle) can vary based on the time of the month. These shifting hormone levels can produce alternating symptoms in the body.

It is because of these hormonal imbalances or cycles that both men and women experience hair-related problems. The hormones most closely related to hair growth can cause hair loss if balance is not maintained, as well as changes in the way hair looks and feels.

Hormonal hair loss

Hair loss is a problem that affects thousands of people each day. While there are many causes of hair loss, one of them is rooted in hormones and how they interact with the body.

Androgenic alopecia is one of the most common forms of hair loss in both men and women. The hair loss condition affects the two sexes differently, with each having its own distinct hair loss pattern. Male pattern hair loss begins at the hair line and causes bald spots to occur, while female pattern hair loss causes wide-spread thinning and a widening part.

Androgenic alopecia is caused by the interactions between your hair follicles and androgens—male sex hormones that regulate hair growth and contribute to male sexual development and function. Specifically, testosterone and a derivative product called dihydrotestosterone (DHT) are at work here.

If you have the genetic predisposition to androgenic alopecia, your hair follicles will be extremely sensitive to DHT and testosterone. This sensitivity causes hair follicles to shrink, and it also results in longer times between the shedding and new growth stages of hair. Between these two effects, hair is lost over time.

Having androgenic alopecia does not necessarily mean you have abnormal levels of testosterone or DHT in your body; it merely means that the gene for the sensitivity is present. However, some endocrine disorders may also cause a hormonal imbalance that leads to the overproduction of these androgens and hair loss.

Women’s hormonal cycles

The hormones that regulate a woman’s reproductive cycle also have an effect on hair loss and hair appearance. Estrogen and progesterone are two hormones that are closely linked with hair and follow a pattern of highs and lows throughout a woman’s entire life.

Pregnancy is one of the times that women may experience a natural period of hair loss. After a child is born, estrogen levels drop dramatically. Estrogen increases the hair’s resting phase, or time the hair stays on your head before falling out. Thus, when the drop occurs, women may notice they are shedding much more than before. This hair loss is usually temporary, though, and will regulate after a few months.

Another significant hair loss period is during and after menopause. During this time, estrogen levels drop again because the ovaries stop producing it. Hair loss might occur if the adrenal glands, which also produce estrogen, cannot pick up the slack right away. This drop in estrogen also paves the way for DHT to affect the hair follicles more, which is why women often experience androgenic alopecia during this time.

Finally, menstruation can have an effect on a woman’s hair. During menstruation, hair is not lost, but can change in feeling and appearance due to oil. Before you period, progesterone levels rise, which comes with an increase in oil on the scalp called sebum. During the period, progesterone levels drop, but testosterone levels rise, which also increases sebum production.

This excess sebum is what causes hair to be extra-oily during your period, which results in that flat, lifeless and “bad hair day” type of look.

Watch your hormones

Your lifestyle plays a role in maintaining hormone balances, so the best way to avoid frustrating hair loss or excessively oily hair is to stay away from crash diets, exercise, eat well and find ways to manage stress. If you notice that your hair is starting to change or thin out, visit a doctor to see if something is going on with your hormone levels.