In this post, I will be highlighting the basics to understanding your hormones. I believe this information is valuable because, as we know, hormones are involved in everything from birth control to fertility to when you choose to have sex. Understanding their role is a great way to become more self-aware, and if you struggle with hormonal imbalance or take synthetic hormones, better advocate for yourself as a patient. 

Sex Hormones 101

A quick breakdown

The “holy trinity” of sex hormones are estrogen, testosterone, and progesterone (3). And while they all have different names and functions, they’re more similar than not: They can all be found in the bloodstream, and are derived from a hormonal precursor known as DHEA-S (1).

Estrogen:

Estrogen comes in three main types: estradiol, estrone, and estriol (2). It is typically thought of as a “feminine” hormone because people assigned female at birth experience drastic changes in estrogen throughout their lifetime. Estrogen is essential for fertility, which helps explains why a drop in estrogen are associated with menopause. But estrogen isn’t girls-only: Men also require estrogen for sexual development.

Given its crucial role in a number of processes, there are ways to artificially receive estrogen if your body isn’t producing enough. The gold standard of estrogen delivery is a topical treatment for application on the vagina and vulva, such as the brands Estrace, Premarin, Vagifem, Imvexxy, and Estring. However, estrogen supplementation has been associated with a few types of cancers, including breast cancer. If you have a history of these conditions in your family, then other options are available to you, including Intrarosa and a hyaluronic acid-based topical.

Testosterone:

The counterpart to estrogen, testosterone is often thought of as a “male hormone.” At its peak, those assigned male at birth can have up to 100 times the testosterone levels of their female counterparts, until levels gradually decline at around 40 years old (3). However, women also require testosterone for sexual function, especially given that the hormone is associated with feelings of lust and heightened sex drive (3).

Testosterone is produced in both the testes and the ovaries, which means that no matter what you’re born with, you’ll likely produce testosterone over the course of your lifetime. Unlike estrogen, which can fluctuate on a monthly basis, testosterone levels cycle throughout the day. Given the volatility of testosterone levels, there is no exact “healthy” standard for everyone, but it is possible to suffer from too much or too little. Too much leads to hair growth, male-patterned hair loss, or acne; too little leads to loss of libido and sexual function for those assigned male at birth (1).

Just like with estrogen, there are ways to supplement your body’s natural testosterone levels, primarily in the form of pellets, injections, or topical creams. Oral testosterone is not legal in the U.S. as it can cause liver damage. Despite the fact that women also require testosterone, all FDA-approved products are indicated specifically for men, so your doctor might write an off-label prescription if you are a woman experiencing low testosterone (1).

Progesterone:

Progesterone is the key hormone for all things fertility: the menstrual cycle, pregnancy, embryogenesis, and spermiogenesis, to name a few (1). While experts are still studying how progesterone directly affects sexual activity, they do know that it’s very important for women to balance estrogen with progesterone levels. Think of progesterone spikes as a green light for your period: That’s what tells the uterus to shed its lining, thus preventing a potentially dangerous buildup of blood. Too much estrogen and not enough progesterone can prevent a normal period from occurring, so doctors will often prescribe progesterone and estrogen simultaneously.

How Hormones Contribute to Sexual Differences by Gender

Men and women experiences have drastically different levels of key sex hormones. But what is the overall impact of this difference?

John and Julia Gottman sum it up in two words: rhythm and fear (1). In this post, I focus mainly on rhythm, but if you want to learn more about their hypothesis, you should read Sex and World Peace.

When the Gottmans discuss rhythm, they are talking about something very specific: the female menstrual cycle, given that levels of female sex hormones — and, as a result, fertility — vary drastically throughout each month. Hormonal changes can lead to fluctuations in your sex drive, as well as “altered needs and emotions” throughout a 20- to 40-day cycle (1). For more information on changes to expect throughout the menstrual cycle, see my post here.

Short-term periods of low sex drive are to be expected and are likely hormonally-driven for women who aren’t asexual. However, long-term loss of desire to have sex is more likely attributable to other factors, such as depression, anxiety, stress, or trauma (2).

 Hormones as Birth Control

When it comes to hormonal birth control, there are two forms: systemic and local. 

• Systemic birth control, such as an oral contraceptive pill, is processed and distributed throughout your entire body. That’s how birth control can affect both fertility and, say, acne production at the same time. 

• Local birth control, on the other hand, is placed deliberately where the intended effect is needed: say, in your uterus, as is the case with a hormonal IUD. 

Most hormonal birth controls use synthetic estrogen, which suppresses your body’s natural production of both estrogen and testosterone. This can contribute to some of the side effects associated with birth control use. If you’re particularly sensitive to these, there are alternatives, such as the copper IUD. Talk to your doctor about which one might be right for you — your needs might be more complex than simply trying to avoid a pregnancy.

And remember: this article is just the tip of the iceberg. I would encourage you to check out Alissa Vitta’s Book In the Flo to learn more!

 References

1. Marcus, Bat Sheva. Sex Points: Reclaim Your Sex Life with the Revolutionary Multi-Point System. Hachette Go, 2021.

2. Vitti, Alisa. In the FLO: A 28-day plan working with your monthly cycle to do more and stress less. HarperCollins UK, 2020.

3. Gottman, John, et al. The Man's Guide to Women: Scientifically Proven Secrets from the" love Lab" about what Women Really Want. Rodale, 2016.