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    Understanding your hormones: Everything you need to know

    Updated 19 January 2023 |
    Published 20 December 2022
    Fact Checked
    Medically reviewed by Dr. Jenna Flanagan, Academic generalist obstetrician and gynecologist, Beth Israel Deaconess Medical Center, Massachusetts, US
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    From mood swings to acne, your hormones play a pretty major role in how you change during puberty, but do you know what they actually are and where they come from? Here, a Flo expert breaks down why your hormones affect you so much. 

    Thanks to the power of hormones, it might feel like your boobs have appeared overnight, your period has started, and discharge has suddenly become part of your everyday life. The changes can seem sudden, but your body will actually have been impacted by hormones for some time now. 

    Between the ages of 9 and 10, people assigned female at birth experience a surge in hormones in preparation for all the changes your body needs to make over the following few years. This means that hormones have shaped the way your body, brain, and behavior have developed since you were pretty young. You just might not have spotted it.

    While you might point to your hormones when you’re feeling particularly annoyed with your parents, you’d be forgiven for not actually knowing what they are. So, to get to the bottom of it, a Flo expert demystifies everything you need to know. Prepare to become a pro!

    Hormones definition

    You’ll have probably heard the word “hormone” used a lot but might not be totally sure what it means. It’s not like you can see them or anything. But fear not — we’re here to help you out. 

    Associate professor of obstetrics, gynecology, and reproductive endocrinology Dr. Amanda Kallen, Connecticut, US, explains that hormones are chemicals that are created in glands called endocrine glands. Keep reading to learn more about what these glands are and why they’re important. 

    These chemicals (that’s your hormones, remember) are transported around your body in your bloodstream and act as messages or commands to other organs or cells to make sure they do their jobs. They’re the bodily equivalent of a green light telling you to cross the road. Clever, huh?

    What are hormones made of?

    Amazingly, research has found that humans produce around 50 different types of hormones. They control every biological process that goes on in your body — from how long your menstrual cycle is to how easily you can build muscles.

    Each hormone has a slightly different chemical structure, depending on what its job is. Getting a bit more scientific (we told you you’ll be a pro on the subject!), Dr. Kallen explains that all hormones are made of microscopic proteins and fats. You can’t actually see hormones, as their chemical makeup is so tiny. However, they’re small but mighty. A slight change in your hormone levels can impact your mood, growth, and how easily you fall asleep.

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    What do hormones do? 

    Now that you know that hormones are the chemicals that keep the rest of your body in line, you might be curious about how they actually affect you.

    “They organize, coordinate, and control different functions throughout the body,” explains Dr. Kallen. Your hormones are sent to different cells and organs to trigger processes

    Your hormones are also responsible for: 

    • Your mood 
    • Your metabolism 
    • Your menstrual cycle
    • Your sleep cycle and how easily you fall and stay asleep
    • Your physical growth and development 
    • The way you can balance your internal temperature, blood pressure, and blood sugar levels

    As you’ll know, your teen years are a time of some pretty major physical and mental changes. While you’re figuring out what you want to study at college or who you might want to date, your brain is developing rapidly, helping you to become who you will be as an adult. If you feel like you’re on a roller coaster with your emotions, then try not to worry. This is totally normal, and it might be helpful to talk to an adult you trust or your doctor. 

    Hormones that impact you during puberty 

    So, let’s get into it. If hormones control every process in your body, which ones are responsible for the changes you experience during puberty? 

    Hormones that cause changes to your reproductive cycle

    One of the major changes during your teen years is starting your period. Many people start to experience the first signs of puberty between the ages of 8 and 13. And these changes are triggered by your hormones, which increase during puberty. Here are some of the key ones to remember: 

    • Gonadotropin-releasing hormone (GnRH): When it comes to starting puberty, GnRH is the initiator. It acts as a green light that sets all your other hormonal changes in motion. Keep reading to find out which hormones are affected by GnRH. 
    • Follicle-stimulating hormone (FSH): FSH is a hormone produced in a tiny portion of your brain (called your pituitary gland.) It targets your ovaries and sends the message for them to start to nurture your eggs to be released during ovulation, which tends to happen once every cycle.
    • Luteinizing hormone (LH): LH works with FSH to keep your menstrual cycle going. After your ovaries have developed an egg ready for ovulation, LH will trigger its release. If the egg isn’t fertilized by a sperm, then it will break down within 24 hours. You can learn more about your menstrual cycle using an app like Flo
    • Estrogen and progesterone: Your ovaries produce the hormones estrogen and progesterone that help to regulate your cycle (establishing when you’ll ovulate and when you’ll have your period).  

    The menstrual cycle is pretty amazing, right? 

    Hormones that affect your mood 

    Your period isn’t the only change you’ll notice during puberty. Have you been feeling a little bit tense about schoolwork lately? You might be able to blame that on your hormones. They can play a really key role in the way you feel about the people closest to you and the way you manage stressful situations. 

    When you’re feeling happy or close to a friend, you might be experiencing a boost in: 

    • Oxytocin: Oxytocin is sometimes called the bonding hormone. It can help you build trust and affection for other people, give you an overall sense of happiness and peace, and help to regulate your sleeping. 
    • Dopamine: Dopamine is often called the happy hormone or your brain’s reward system. It may give you an overall sense of pleasure or happiness when you’re doing something you enjoy.

    Alternatively, if you’re not feeling your best, you might have a surge in: 

    • Adrenaline: You’ve probably heard someone say they’re running on adrenaline after being in a stressful situation. This is because adrenaline helps you to function in tense or dangerous times, sometimes referred to as “fight or flight”. When you enter “fight or flight” mode, your muscles become tense, and your heart rate gets faster. This is to prepare you to run away or fight if you need to. Adrenaline tells your blood vessels to redirect blood to your major muscles (like your lungs and heart) so you can make a speedy getaway. 
    • Cortisol: This is the stress hormone that helps you in “fight or flight” situations. This might have been useful if you were readying yourself to go to battle with your ancestors many centuries ago, but less so when you’re preparing for a big test. 

    Hormones that help you to grow and sleep 

    You might have heard your teachers preaching the importance of getting a good night’s sleep, but your hormones are also working overtime to help you get your full eight hours. 

    Melatonin is a hormone that is released at nighttime to help your body know when to sleep. It enables it to recognize that it’s dark outside and time to rest. So, if your parent is arguing with you that the blue light of your phone is interrupting your sleep, they’re probably actually just concerned about how much melatonin your body is able to produce. 

    Your friends may have experienced major growth spurts over the last few years, and this could be due to hormonal changes. 

    • Growth hormone-releasing hormone (GHRH): In the same way that GnRH triggers the hormonal changes that lead to your menstrual cycle, GHRH also prompts your body to produce growth hormones, helping you to build strength and energy.
    • Growth hormone (GH): Growth hormone targets your bones and muscles and does exactly what its name suggests: It helps you grow taller and build strength. GH also impacts where fat is sent in your body and how your body turns food into energy.

    What hormone causes female arousal?

    OK, so we’ve covered a lot. But hormones can be pretty science heavy, so you might still have some questions — and that’s totally understandable. 

    One area your biology teacher might not have touched on is hormones and sex. You might have found yourself thinking more about sex as you get older. This is totally normal and has a simple explanation. Dr. Kallen explains that the hormones produced in your ovaries — estrogen and progesterone (remember those?) — play a key role in when you feel more turned on. The higher your hormone levels, the spicier you might feel. 

    Is serotonin a hormone?

    You might have heard of dopamine and oxytocin being linked with serotonin, but you may not be entirely sure what that is. Serotonin isn’t actually a hormone (it’s a “neurotransmitter”).

    It sends messages to the nervous system in your brain and throughout your body, and it has lots of different jobs. Among other things, serotonin helps you to: 

    • Feel happy 
    • Heal wounds
    • Regulate your anxiety 

    What is hormone balance?

    Your teen years are naturally a time when you might feel like things are changing at a million miles an hour. From managing your schoolwork and relationships to changes in your mood and body, there’s a lot going on. And your newfound hormones only contribute to this. 

    It’s totally normal to feel confused or annoyed. Reach out to your friends. They’re likely going through the same thing. Similarly, a trusted adult may be able to share a few bits of wisdom. 

    You might have heard people talk about “hormonal balance” in reference to remaining calm or happy. However, Dr. Kallen explains that it actually means that “there are optimal levels of hormones.” Your body generally knows how much of each hormone you need, and if you produce too much or too little of a certain hormone, it could be described as an imbalance. 

    How to know if your hormones are unbalanced

    Hormone imbalance might sound dramatic, but there are a number of things that can throw your levels off, including: 

    • Stress
    • Gaining or losing a lot of weight
    • Extreme lack of sleep 
    • Pregnancy
    • Puberty 

    If you feel that something isn’t quite right, it could be worth speaking to someone that you trust and paying a visit to your health care provider. You might be curious if there’s a way you can balance your own hormones, but the best thing to do is get the advice of your doctor. They will be able to talk to you about what’s going on. 

    They might also take a blood test or provide a pelvic exam or ultrasound to figure out the root of your concerns. This could be to check your hormones and general health. While hormones can have a massive impact on the way you think and feel, your doctor will likely want to chat through all of your symptoms to make sure they suggest the right next step.

    Understanding hormones: The takeaway

    As a teenager, you’ll probably be feeling the effects of hormone changes. They can have a massive impact.

    As you grow into an adult, the brain sends out lots of new stress hormones, sex hormones, and growth hormones around your body. This means that you’re experiencing a lot of changes that may feel completely out of your control. Chances are, your friends will be experiencing the same thing, so don’t be afraid to talk to them about it. Simply knowing someone else is experiencing the same thing can offer a huge sense of relief. 

    There’s no doubt that puberty is a challenging time for many reasons, but if you’re feeling overwhelmed by surging hormones, remember that all of these changes are molding you into the adult you’ll be for the rest of your life — and that’s really exciting!


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    History of updates

    Current version (19 January 2023)

    Medically reviewed by Dr. Jenna Flanagan, Academic generalist obstetrician and gynecologist, Beth Israel Deaconess Medical Center, Massachusetts, US

    Published (20 December 2022)

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