Menopause and GLP-1s: what actually changes

The thing most coverage gets backwards

If you have read that menopause makes you gain weight faster, that is not what the best data shows.

The Study of Women's Health Across the Nation followed women through the transition and measured them with DXA scans, not just a scale. Weight climbed in a straight line through the years before menopause. It did not speed up when the transition began¹.

What changed was the fat itself. At the start of the transition the rate of fat gain doubled, and lean mass started to fall¹.

A later analysis of the same cohort looked at where that fat went. Android fat — the fat around your middle — grew 1.21% a year before menopause and 5.54% a year during the transition. Visceral fat, the deep kind, only began climbing at the transition, at 6.24% a year².

So the scale can be almost quiet while your body rearranges itself. That is worth knowing before you decide nothing is happening.

That second analysis is 380 women, observed rather than assigned to anything. It describes a pattern. It does not prove a cause.

Perimenopause and postmenopause are two different bodies

Perimenopause means you are still cycling, even if the cycles have gone strange. You can still ovulate. You can still get pregnant. If that is what you are hoping for rather than avoiding, I wrote about it separately in GLP-1s and fertility.

Postmenopause means twelve months have passed with no period at all. By then the fat trajectory has settled too — the curves flatten once the transition ends¹.

Almost everything written treats these as one topic. They are not, and the practical advice differs.

What the trials actually show

No trial has been designed for women in menopause. What exists is a look back at trials that happened to enrol them.

Researchers took the SURMOUNT tirzepatide trials and sorted the women by reproductive stage. In SURMOUNT-1, weight fell 26% before menopause, 23% in perimenopause and 23% after menopause. Placebo in those same three groups was 2%, 3% and 3%³.

Between 97% and 98% of the women on tirzepatide lost at least 5% of their weight. On placebo it was 29% to 33%³.

Read that as reassurance rather than precision. The stages were assigned after the fact, and the manufacturer funded the analysis.

Hormone therapy, with the denominator attached

One retrospective study compared postmenopausal women on semaglutide who were also taking menopause hormone therapy with those who were not. At twelve months the hormone therapy group had lost 16% of their body weight against 12%⁴.

That group was sixteen women. Ninety were in the comparison group, and nobody was randomised. Sixteen is a question someone should answer properly, not an answer.

A 2025 review of this whole area says the same thing more formally: there is little data specific to peri and postmenopausal women, and more research is needed⁵.

The perimenopause detail almost nobody mentions

If you are still cycling, contraception matters, and one of these medicines interferes with it.

The Zepbound label tells patients on oral hormonal contraceptives to switch to a non-oral method, or add a barrier method. It says to do that for four weeks after starting, and for four weeks after every dose increase⁶.

The Wegovy label carries no such instruction. Its own interaction studies found no clinically significant change in ethinyl estradiol or levonorgestrel⁷.

Both labels say the medicine should be stopped when a pregnancy is recognised⁶⁷.

What to do with all this

• Measure your waist as well as your weight. Here the scale is the less sensitive instrument.
• If you are perimenopausal and on the pill, ask about backup contraception before your first dose.
• If you take hormone therapy, say so. It may matter, and you may not be asked.
• Dryness and urinary changes belong more to the transition than to the injection; I go through that overlap in Ozempic vagina.
• Take new or worsening symptoms to your clinician rather than to a forum.

The medicines work at every stage of this. What to stop expecting is that the transition alone explains the number on the scale.