GLP-1, Mounjaro, weight loss & periods: everything you need to know

GLP-1 medications like Ozempic, Mounjaro and Wegovy are EVERYWHERE right now. Your best mate’s sister is on it. The woman at Pilates swears it’s “changed her life”. And honestly? For many people, the changes experienced have certainly been transformational.

Over the past year I’ve seen first-hand how these drugs can genuinely help with weight loss and reduce that relentless ‘food noise’…especially for women battling binge eating or food addiction.

BUT (and yes, it’s a BIG but)... there are some side effects I really wish more people were being warned about.

And here’s the part no one says loudly enough: these medications aren’t designed to be a lifelong solution.

Research consistently shows that most people regain up to two-thirds lost weight within 1 year of stopping diet-led or medication-based weight loss approaches. Which is why learning how to change the way you eat (not just how to eat less) is where real, sustainable results live.

After continually being asked about my thoughts on GLP-1s as a registered Nutritionist, I wanted to break down everything you need to know about GLP-1s, the side effects, what they mean for PCOS, your hormones and fertility, how to support your body while taking them, PLUS how to naturally encourage GLP-1 production through lifestyle and nutrition...

Let's dive in!

So… what actually is GLP-1?

GLP-1 (glucagon-like peptide-1) is a hormone naturally produced in your intestines when you eat. GLP-1 receptor agonists (GLP-1 RAs) are medications that mimic this hormone and work by:

• Stimulating insulin secretion to regulate blood sugar

• Slowing stomach emptying

• Suppressing appetite by signalling fullness to the brain

Think of it as your body’s internal portion-control manager helping to reduce blood sugar spikes, improve satiety and curb cravings… hence the weight loss.

Common GLP-1 medications include:

1.     Semaglutide: Ozempic, Wegovy, Rybelsus

2.    Tirzepatide: Mounjaro, Zepbound

3.    Liraglutide: Victoza

4.    Exenatide: Byetta

Originally developed for Type 2 diabetes, these medications are now widely prescribed both on the NHS and privately for weight loss due to their powerful effects on appetite and blood sugar regulation.

 

Potential benefits may include:

• Significant weight loss

• Improved blood glucose control

• Improved cardiovascular health

• Improved insulin sensitivity

• Reduced food noise (especially helpful for addictive eating patterns)

Sounds dreamy, right? I’m not 100% convinced just yet…

The not-so-glam side effects nobody puts on Instagram

Here’s what doesn’t make it onto the highlight reel:

• GI symptoms (nausea, vomiting, constipation, diarrhoea, reflux) — affects up to 1 in 10 users

• Gallstones, pancreatitis and dehydration

• Rapid weight regain once medication stops

• Low blood sugar episodes

• Muscle loss: studies suggest 25–39% of weight lost may come from muscle mass

• Nutrient deficiencies (including vitamin D, B12, iron, omega-3s) linked to fatigue, hair thinning, cycle disruption and fertility issues.

• Protein insufficiency impacting hormone production (oestrogen & progesterone)

• Food intolerances, which are more likely to develop when digestive capacity is altered for long periods (BDA, 2023)

When digestion slows and calorie intake is decreased long-term, the risk of nutrient deficiencies and absorption increases. That’s when symptoms like bloating, skin issues, brain fog and that “why do I feel 87?” energy slump creep in.

Not exactly what you signed up for. 

GLP-1s & your reproductive years

Yes, “Ozempic babies” are now a thing.

• Rapid weight loss can trigger unexpected ovulation and surprise pregnancies

• Contraception is essential during treatment – especially non-oral methods for those on tirzepatide

• GLP-1s should be avoided during pregnancy and breastfeeding due to potential risks shown in animal studies

Can GLP-1 medications help PCOS?

There is a growing body of research suggesting GLP-1s may improve weight, insulin resistance and hormone profiles in women with PCOS. Some studies also show improved cycle regularity and even increased pregnancy rates. However, you won’t be able to get GLP-1s prescribed by your NHS Doctor, based on this diagnosis alone.

However (and this is crucial) nowhere in the science does it say medication alone is enough.

Without tailored nutritional support, women risk nutrient deficiencies, muscle loss, worsening hormone imbalance and side effects that can undo long-term progress. In my experience, supporting those with PCOS requires a whole-body approach, not just appetite suppression.

If you ARE taking GLP-1 meds, here’s what matters most

This is NOT the time for beige food and rice crackers.

• Prioritise nutrient-dense, protein-rich meals (at least 1.6g of protein per kg of body weight)

• Support digestion and gut health by eating a rainbow of vegetables

• Consider targeted supplementation to address nutrient deficiencies caused by calorie reduction

• Monitor side effects closely

• Work with a qualified practitioner (or nutritionist!)

With the right approach, GLP-1 medications can be a safe, effective tool, but only when combined with a personalised programme.

Can you boost GLP-1 naturally?

Yes! And without the side effects. Here's how to do it:

1. Chew your food

I know, sounds basic. Almost insulting. But effective chewing directly stimulates GLP-1 release. Aim for 20–30 chews per mouthful until food resembles mashed potato. Glamorous? No. Impactful? MASSIVELY. Even I have to remind myself when juggling family and work life!

2. Up your fibre intake!

   If you want to naturally boost GLP-1, fibre is your best friend. It slows down digestion (in a good way), keeps blood sugar steady and helps trigger the release of fullness hormones so you actually feel satisfied after eating, not rummaging in the cupboards 20 minutes later for a sugary treat. Fibre also feeds your good gut bacteria, which then release compounds that further support GLP-1 production. Basically? It’s doing the most behind the scenes. Aim to include fibre-rich foods daily like oats, legumes (think beans and lentils), fruits such as apples, pears and berries, and plenty of leafy greens and cruciferous veggies like broccoli, kale and Brussels sprouts. These foods help tame cravings, support your gut and keep you feeling fuller for longer. without relying on injections or extreme restriction. Sustainable, simple and far more kind to your hormones.

3. Support your gut microbiome

Your gut bacteria directly influence GLP-1 production. A balanced microbiome supports efficient digestion and hormone signalling. Support your gut health by eating REAL, nutrient dense foods such as vegetables, fruit, lentils, wholegrains, animal protein and health fats (think olive oil, nuts and salmon). You might also want to consider increasing fermented foods such as kombucha, kefir and and kimchi to increase your 'good' gut bacteria. If you're having gut issues, you might also want to consider a gut microbiome test, more info on that here.

5. Meal ingredient sequence

   The order in which you eat the different foods on your plate may also influence the stimulation of GLP-1 and post-meal insulin and blood sugar responses. For example, eating the fibre, fat and protein before the carbohydrate component of your meal can help with better GLP-1 secretion.

4. Lifestyle tweaks that naturally boost GLP-1

   Your daily habits have a huge impact on your hormones, and GLP-1 is no exception. The goal isn’t perfection or living like a wellness influencer… it’s simple, realistic shifts that support your body instead of fighting it. Here's how to do it:

   
   

   - Move regularly. Brisk walks (ideally after eating), swimming or regular strength training help improve insulin sensitivity and encourage GLP-1 release (also key for protecting muscle and metabolism).

   
   

   - Sleep like it matters (because it does). Poor sleep messes with hunger hormones and cravings. Aim for 7–9 hours and keep your sleep routine as consistent as possible.

   
   

   - Stress less, crave less. Chronic stress lowers GLP-1 and pushes your body towards comfort food mode. Deep breathing, time outdoors and being around people who calm your nervous system genuinely help.

   
   

So what’s the verdict?

There's no doubt that GLP-1s can be an important tool for weight loss. However, without good nutrition and long-term behaviour change, the results rarely stick. Sustainable weight loss isn’t about eating less, it’s about supporting your hormones, metabolism and nervous system so your body feels safe enough to let go of weight.

How nutrition support changes the game

Whether you're considering GLP-1s, already using them, or stuck in weight loss limbo, personalised nutrition support helps you:

• Build sustainable eating habits for life after GLP-1 medication

• Prioritise nutrient-dense foods that matter the most when eating less

• Protect muscle mass & metabolism

• Minimise side effects and support digestion

  
  

Ready to get some personalised support whilst on GLP-1s?

As a Registered Nutritional Therapist, I support women using GLP-1 medications to make sustainable changes for long-term health and vitality My approach is holistic and personalised, covering the vital pillars of health, including nutrition, lifestyle, sleep, and movement. Book your free discovery call or get in touch today to chat about how I can support you.