Hormones and weight loss: what oestrogen does and does not do

Hormones and weight loss work differently than the adverts tell you. Oestrogen does not make you fatter, it moves your fat. During the transition, belly fat climbs from 1.21% to 5.54% per year, and visceral fat by 6.24% per year (PMID 34061966). Your total weight does not accelerate.

The internet is full of powders and pills that promise to "balance your hormones" and melt the fat away. That is a profitable story. It is simply not true.

The honest version is less exciting and far more useful.

What oestrogen does: it moves your fat

When your oestrogen falls, what mainly changes is where your fat sits. Fat moves toward your belly and into the space around your organs. Belly fat goes from 1.21% per year before the transition to 5.54% per year during it. Visceral fat was flat, then rises by 6.24% per year (PMID 34061966).

At the same time your muscle mass flips. Before the transition you were still gaining a little, during the transition you slowly lose (PMID 30843880).

Fat up, muscle down. On the scale those two largely cancel out. That is exactly why the number barely moves while your clothes clearly fit differently.

And your total weight? It climbs steadily through midlife, with no acceleration at the moment of the transition (PMID 30843880).

Karvonen-Gutierrez put it precisely (PMID 27417630). Your weight changes because of chronological ageing. Your body composition and fat distribution change because of the ageing of your ovaries.

That distinction is the whole story. Where the fat actually goes is covered in menopause belly.

What oestrogen does not do: make you insulin resistant

This is the claim that gets inflated everywhere. The best long-running study we have, SWAN, tracked glucose, insulin, blood pressure and CRP across the whole transition. All four followed the pattern of ordinary ageing, not the pattern of menopause (PMID 20082925).

What did jump around menopause: cholesterol, LDL and apoB. Those three shift in a way that age alone does not explain.

Glucose and insulin did not.

Does that mean your insulin sensitivity never changes? No. But the effect runs through the detour of that visceral fat, not through a direct hormonal switch (PMID 34061966, PMID 33651741).

That difference sounds technical and it matters. No hormone repairs your insulin directly. There is a route you can act on, and that route is the fat itself.

What insulin resistance really looks like in women, and which values to measure, is covered in insulin resistance in women.

The cortisol belly does not exist

The "cortisol belly" and "adrenal fatigue" are not medical concepts. Cadegiani ran a systematic review of 58 studies and titled the result exactly that way: adrenal fatigue does not exist (PMID 27557747). No endocrine society recognises it. An entire supplement market has still been built on it.

So what has actually been found? Woods saw cortisol rise in some women in the late transition (PMID 19322116). That is all that study shows.

It does not show that cortisol drives your belly fat. And it supports no treatment at all.

There is no trial in which a cortisol-lowering supplement or an adaptogen reduced abdominal fat in menopause.

If someone sells you a "cortisol support" formula for your menopause belly, they are selling you a story.

And no, your metabolism does not slow down

"Your metabolism crashes when menopause starts." You hear it everywhere and it is folklore. There is no solid evidence that the transition itself slows your metabolism. What changes is your muscle mass and where your fat sits, not some mysterious brake on your engine.

That is good news. A problem that does not exist does not need solving.

The claims next to the evidence

Five stories show up on every supplement page. Below they sit next to what the research actually says. One of them is about hormone therapy, and it lands the opposite way round from what you expect.

What does work is boring, and it works

No diet beats another diet. In the DIETFITS study, low-carb and low-fat differed by 0.7 kg after a year, and that was not significant (PMID 29466592). There was not even a link with how much insulin you produce. What counts is whether you keep it up.

So pick the form that fits your life. Not the form someone online defends the loudest.

Three things do something measurable:

• Protein. More protein while losing weight retains on average 0.43 kg more fat-free mass and takes off 0.87 kg more fat (PMID 23097268). Combined with training, one study saw 1.2 kg of lean mass gained and 4.8 kg of fat lost (PMID 26817506).
• Resistance training. In postmenopausal and older women, resistance training went together with more lean body mass (PMID 33880736). Read the small print: this is a meta-analysis of observational studies, graded C. It shows that training builds lean mass. It does not prove that it prevents menopausal muscle loss.
• A calm pace. Losing 0.5 to 1.0% of your bodyweight per week is the rate at which your muscle mass comes along best (PMID 21558571).

That is the whole list. There is no supplement on it.

What about hormone therapy?

In short: hormone therapy does not make you fatter. In pooled data from 107 randomised trials, abdominal fat actually fell by 6.8% (PMID 16918589). Many women still turn down effective treatment out of fear of the scale. That fear is not warranted, and it is a shame.

The full picture, with all the caveats, is in does hormone therapy cause weight gain.

What a blood test does and does not tell you

Here is the honest version. A blood test will not tell you why the scale is stuck. For most women, your oestrogen simply comes back as normal for your age. Testing your hormones to explain your weight is, for most women, not a useful step.

That is also what Thuisarts and the Dutch GP guideline (NHG) hold. Menopause is diagnosed on your symptoms and your cycle. Not on a single hormone value.

What a metabolic blood panel does is something else entirely. It shows what the redistribution of fat is doing to your health underneath: your blood sugar, your lipids and your liver.

And that is not theory. Visceral fat rises 8.2% per year around your final period, and it tracks with thickening of your carotid artery, independent of your BMI (PMID 33651741). In 13.7% of women, a new metabolic syndrome develops by that final period (PMID 18663170).

That is a real reason to look. It is simply a different reason than the one most women arrive with.

You do not test to learn why you are heavier. You test to learn what the move of that fat is doing to your heart, your blood sugar and your liver.

That is what the complete metabolic panel is for: your glucose, your lipid profile and your liver values in one go, so you can follow them.

When this article is not for you

Weight loss is not a healthy goal for everyone. Do not follow this article if you have or have had an eating disorder, are pregnant or breastfeeding, are underweight, use insulin, or have had bariatric surgery. Speak to your GP first.

If thoughts about food or your body start to take over, talk to your GP or contact an eating disorder helpline. That is not weakness. That is sense.

What to do now

Do not start with a hormone test and do not start with a supplement.

Pick two things this week: two resistance training sessions, and a protein source at every meal. Keep that up for eight weeks and judge it on your strength and your energy, not on the number on the scale.

If you want to know what the redistribution of fat is doing under the bonnet, measure your glucose, your lipids and your liver values. The wider overview of what works and what does not is in weight loss in menopause.