Cheat sheet: What do female sex hormones do, exactly?

Even before we’re born, our hormones work hard to take care of us. They help our brains to develop and our bodies to grow. They help us to breathe and eat, and traveling in our bloodstream, they play a vital role in the transformation of our body as we reach puberty.

They’re special chemical messengers that affect our fertility and lead us into old age through menopause. When we have a hormone imbalance, they can create really common conditions like PCOS (polycystic ovarian syndrome), amenorrhea (the absence of periods), and hirsutism (extra hair growth that’s darker, coarser, and appears in areas that it normally wouldn't for you).  

Our hormones can change our bodies in ways we love, and some we don’t—think glowing skin or acne breakouts, greasy hair or tons of volume. They affect how we digest our food, how strong we feel in the gym, how well we sleep, our sex drive, and our mental health. 

They are the bits behind the scenes, silently working to keep our bodies and minds working together in a constant loop—and although we can’t see them, we can see the results of their hard work. 

Read on to find out about your female sex hormones and all the powerful things they do under the skin to make you, you. 

Editor’s note: Throughout the article, we refer a lot to ‘your’. We say ‘your body', ‘your uterus', ‘your eggs'. We know everyone is different and these terms may not apply to everyone. We also want to go beyond the science to speak to every one of you in a non-detached, human way. Please get in touch if you’d like to talk this through with the team.

Estrogen

Where is it made?

Mainly in your ovaries (also in fat cells and adrenal glands).

What does it do?

• Helps to boost your mood(1) 

• It’s important for bone growth(2), especially during puberty. During this time, it also signals for breasts(3) and pubic hair to begin to grow(4)

• Plays an important role in regulating your libido (aka sexual desire)(5)

• When you have low estrogen, your ovaries release an egg(6)
  

High estrogen = sexy times 

Estrogen levels peak mid-cycle, which is when sexual desire tends to peak(5). It’s also when we’re most fertile.

Low estrogen = sad times

There’s a reason why you may feel sad during your period. Estrogen boosts your mood, so when your estrogen levels drop around your period, you may experience PMS symptoms like feeling low, lethargic, or irritable(7).

Progesterone

Where is it made?

In your ovaries.

What does it do?

• Plays an important role in regulating your libido(5)

• When your levels are high, progesterone helps to maintain the thickness of your uterus lining in preparation for an egg to be implanted(8)

• If the egg isn’t fertilized, your progesterone levels decrease which triggers your uterus to shed its lining (aka you have your period)(8)
  

Progesterone = not so sexy times  

Unlike estrogen and testosterone, progesterone tends to decrease sexual desire(5).

Testosterone

Where’s it made? 

In your ovaries, adrenal glands, fat cells, and skin cells. 

What does it do? 

• Improves wellbeing, reduces anxiety and depression(9,10)

• Higher levels around your period can increase oil production, which can cause spots (yay)(11)

• Important for fertility and for regulating your menstrual cycle(12,13)

• Plays an important role in regulating your libido(5)

• Helps to maintain bone and muscle strength(14)

Testosterone = for everyone

Those who are assigned females at birth produce less testosterone than men (about 1/10th to 1/20th of male testosterone production)(15,16), but the sex hormone still plays many important roles in our bodies. 

Testosterone = soars during puberty

When we go through puberty, those of us with cycles have the highest levels of testosterone that we’ll ever have (it dips again after puberty)(17). The hormone acts differently in women than men and is more readily converted into estrogen(18). Young women with lower testosterone levels may also start puberty earlier(17).

Follicle stimulating hormone (FSH)

Where’s it made? 

In your pituitary gland (in your brain). 

What does it do? 

• Causes follicles to mature in your ovaries(19)(your follicles contain immature eggs, so it’s important if you want to have kids)

• Plays a key role in puberty(19)

• Boosts the production of estrogen in your ovaries(20) 

FSH = the sex/reproduction hormone

FSH is vital for sexual development and reproduction in both men and women(19). 

Luteinizing hormone (LH)

Where’s it made? 

In your pituitary gland.   

What does it do? 

• In the first half of your menstrual cycle, triggers your ovaries to produce estrogen(20)

• A second surge of LH around day 14 of your cycle causes an egg to be released from your ovaries(21)

LH = crucial for healthy reproductive systems

LH is important for the normal function of both the testes and ovaries. It stimulates cells in the testes to produce testosterone and in the ovaries to produce estradiol (estrogen)(21).

As you can see, our hormones are complex, brilliant, things that do so much. If you take one thing away from our cheat sheet, remember that every moment of the day, they’re working super hard behind the scenes to bring about important changes in our bodies. 

Our next cheat sheet will explain how your hormones influence your menstrual cycle, with more info about how your hormones work together to make some really cool stuff happen.

Written by

Hermione Wright (she/her)

An NCTJ-qualified journalist, Hermione writes for national and local publications in addition to creating thought leadership for brands with a purpose. Passionate about telling the stories that matter, she helps our community make their own clued-up choices about their healthcare.

Medically reviewed by

Dr. Alejandra Elder Ontiveros, MD, PHD (she/her)

Ale is a PhysicianScientist with a doctoral degree in Development Biology and Embryology and is currently a Postdoctoral Scholar at UCSF. Ale believes that the union of academia and business can lead to transformative discoveries for women’s health.

Scientifically researched by

Hannah Durrant (she/her)

Hannah is a Biomedical Content Writer at Tuune, with a BSc in Biomedical Sciences from University College London. She is passionate about bringing together the scientific community and the general public by disseminating modern science via digestible, engaging and thought-provoking content.