Five Things I Got Wrong About My Hormones in My 20s (And What I Know Now)

I have been working in pharmacy for over 12 years. I trained with Dr Louise Newson, one of the UK's leading menopause specialists. I am completing my Independent Prescriber Trainee qualification, and I now spend a large part of my time educating women about their hormonal health.

And yet. When I look back at my 20s, I held some spectacularly wrong ideas about how my own hormones worked.

I am not embarrassed by that. These are not obscure mistakes. They are the same beliefs I hear from women every week, in consultations, in comments, in messages. They were taught, or implied, or simply never corrected. If you have believed any of them, you are in very good company. Here are five I would like to set straight.

1. The pill fixes hormonal symptoms

Like most women in their 20s, I assumed the combined oral contraceptive pill (a tablet taken daily that contains synthetic versions of oestrogen and progesterone to prevent pregnancy) was genuinely solving hormonal problems. Painful periods? Pill. Acne? Pill. Mood swings? Pill.

Here is what the pill actually does: it overrides your natural hormonal cycle entirely. It does not regulate your hormones; it replaces your cycle with a flat synthetic one. The symptoms it appears to treat are, in many cases, simply paused rather than resolved. When women stop the pill after years of use, the original symptoms often return, sometimes more intensely than before.

That is not a reason to avoid it. The pill is genuinely useful for contraception, and for managing conditions like endometriosis it has a real role. But if a GP (general practitioner) prescribed it primarily to "sort out" your hormones without investigating what was happening underneath, that conversation was incomplete. The root cause is still there, waiting.

2. Progesterone does not matter until you are older

When I was in my 20s, progesterone barely registered. Oestrogen got all the attention: fertility, femininity, the menopause conversation. Progesterone (the hormone produced after ovulation that prepares the uterine lining and has calming effects on the brain and nervous system) felt like a supporting character.

It is not.

Progesterone is the hormone women tend to lose first, often a decade or more before oestrogen starts to decrease. Low progesterone in your late 30s is common, and it does not announce itself with a clear label. It looks like anxiety that has no obvious cause. Difficulty sleeping, particularly waking in the early hours. Heavier periods. Feeling more irritable in the second half of your cycle. PMS (premenstrual syndrome, symptoms that occur in the days before your period) that gets worse every year.

These are not signs that you are stressed, hormonal in an unhelpful way, or not coping. They are signs that progesterone may have started to decrease, and that is a clinical question, not a character failing.

Related reading: Progesterone is the hormone most women know least about, and it has an unfairly bad reputation. Progesterone: What It Actually Does (and Why It Gets Such a Bad Reputation).

3. Cortisol is just your stress hormone

I studied cortisol at university. I knew it was released during stress. I had no idea it was doing quite so much else besides.

Cortisol (the hormone produced by your adrenal glands that regulates your stress response) is a whole-body hormone. It helps control blood sugar, affects immune function, influences thyroid activity, affects how your body stores fat, and plays a direct role in sleep and mood. It also interacts with sex hormones: when cortisol stays high for extended periods, the body tends to produce less progesterone and oestrogen in response.

The reason this matters is not to make you anxious about your cortisol levels. It is to point out that "I am just stressed" and "my hormones are off" are often the same conversation. Chronic stress (the kind that many high-achieving women are running on for years, not the acute kind that resolves quickly) has a genuine, measurable impact on hormonal balance. It is not in your head. It is in your blood.

Free and low-cost guides for the hormones in this post

If cortisol, iron, or blood sugar are part of your own pattern, these clinic guides are a plain-English place to start before you change anything:

4. If your blood tests are normal, your hormones are fine

This one I held onto for years, probably because the medical framework I worked within reinforced it. Normal blood test equals no problem. Move on.

The issue is that standard blood tests have a wide reference range. A woman can sit at the bottom of the "normal" range for oestradiol or progesterone, experience real and debilitating symptoms, and be told her results are fine. From a population statistics point of view, they are fine. From the perspective of how she feels, they are not.

There is also the question of timing. Female hormones change throughout the cycle. Testing on the wrong day gives you data that does not reflect what is actually happening.

The current guidance from NICE (the National Institute for Health and Care Excellence, the UK body that sets clinical standards) is clear: perimenopause (the transition into menopause, which can begin a decade before periods stop) is a clinical diagnosis. It is based on symptoms, not on a single blood test. If you have been told your hormones are fine because your bloods were normal, that test tells one part of the story. Your symptoms tell the rest.

5. Fatigue in your 30s is just being busy

This is the one I find most common, and honestly, the most frustrating to unpick.

There is a particular kind of tiredness that comes from being a high-achieving woman in her 30s. It is not fixed by a holiday. It does not improve after a full night's sleep, and often the full night's sleep does not come anyway. It sits behind your eyes and makes everything slightly harder. The prevailing wisdom, delivered by GPs and well-meaning friends alike, is that this is just life. Just being busy. Just a lot on your plate.

In some cases, that is true. In others, it is a sign that something hormonal is going on and has been for a while. Brain fog and bone-deep fatigue can come with hormonal changes, and many women are running with lower progesterone and some cortisol disruption for years before anyone has the clinical knowledge to name it. Fatigue with no clear cause, brain fog, a persistent sense of running on empty despite doing everything right: these are worth looking into rather than simply accepting.

A reasonable starting point: thyroid function, iron levels (ferritin, the stored form of iron, not just haemoglobin), oestradiol, progesterone, and cortisol. Not all in one test, not necessarily all at once, but these are the markers worth looking at when fatigue is the presenting complaint.

Keep reading: Low progesterone is one of the most missed pieces of the perimenopause picture, and it often shows up long before periods change. Low Progesterone: The Symptoms Your GP Might Miss.

What to take from all of this

These are not obscure, specialist-only insights. They are gaps in the standard information that women receive about their own bodies, and they have consequences. Women spend years tolerating symptoms they do not need to tolerate, or accepting reassurance that does not match how they actually feel.

The fact that you believed any of this is not a failing. It is what happens when the conversation about women's hormonal health has been incomplete for so long that even healthcare professionals were trained inside the same gaps.

If you are in your 30s or 40s and something feels off, the questions in this post are a reasonable starting point. You do not have to wait until things are severe, until menopause is imminent, or until someone takes you seriously on the third appointment. You are allowed to start the conversation now.

Shop the products in this post

These are the clinic guides and resources that map onto the five hormones and patterns covered above:

Browse the full range at deboratentis.com. To talk through your own symptoms properly, book a Health and Wellness Consultation at Debora Tentis Clinic (£60).

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Debora Tentis is a Women's Health Pharmacist and Independent Prescriber Trainee at Debora Tentis Clinic, Milton Keynes. This post is for educational purposes only and does not constitute medical advice.