Your GLP-1 is doing its job. Your gut is paying for it.
Bloating, nausea, constipation: you're not the only one. Your medication changes how your gut digests, so nb1 builds a daily formula around what your gut needs now.
1. Less food in changes your gut too
The medication is doing what it's meant to: your appetite drops and you eat around a third less. But your gut bacteria live on what you eat. Less food in means a different supply for them, and that's part of why your gut feels different now.
GLP-1 medication also slows how quickly your stomach empties, so food spends longer in your gut. Fewer meals, smaller portions and often less fibre mean the bacteria that live on fibre have less to work with. Researchers are still mapping exactly how this shifts the microbiome, and it varies a lot from person to person.
Calories eaten at a free-choice lunch after 20 weeks, 72 adults (1,736 vs 2,676 kJ). Friedrichsen et al., Diabetes, Obesity and Metabolism, 2021.2. You're not the only one
Nausea, constipation, diarrhoea and bloating are the most commonly reported side effects of GLP-1 medication. In the trials, most were mild to moderate and eased as people adjusted to each dose.
None of this means the medication isn't right for you. It means your gut is working harder than before. If side effects are severe or don't settle, speak to your prescriber.
3. Off-the-shelf supplements assume your gut hasn't changed
Probiotics and multivitamins off the shelf are built for an average gut. Yours has moved.
A shop-bought probiotic gives everyone the same strains at the same dose. A multivitamin is set for an average diet, not one where you're eating a third less. Neither knows which bacteria you have, which you're short of, or how your medication has changed things. nb1 starts from a reading of your gut, so your formula is built around what's actually there.
4. Your dose keeps moving. A formula made once doesn't.
Your gut reading is a snapshot of your gut on the dose you're on today. As the dose climbs, your appetite and eating change again, and so does what your gut bacteria have to work with. With nb1 Advanced we read your gut again at month 4 and rebuild your formula from what changed.
Most GLP-1 plans raise the dose every four weeks until you reach the one that works for you. Each step can change your appetite, your portions and how your gut feels, so a supplement picked in week one may not suit week sixteen.
{{ drugSource }}5. How nb1 works
Three steps, and we do most of the work. You send a small stool sample from home. We read which bacteria live in your gut and what they're doing, and turn that into a health report scored out of 100. Our scientists then build your daily formula from it. With Advanced, we read your gut again at month 4 and adjust the formula to match.
6. Built by our scientists. Checked by independent ones.
Our in-house science team builds every formula from your results. Two of Europe's leading microbiome researchers, who don't work for us, review the method behind it.
Every ingredient and dose is chosen from published microbiome research. The independent reviewers check how we read your gut and build formulas; they don't review or advise on GLP-1 medication.
From people on GLP-1 medication
Charlotte BennettLondon · nb1 memberFinally feel normal after meals again
I started semaglutide in March and the weight loss was great, but the bloating and queasiness after eating were wearing me down. I was sceptical about a gut test, but seeing my actual results made sense of a lot. About 5–6 weeks into my NB1 formula, the post-meal heaviness is noticeably less. It’s not gone completely, but I no longer plan my day around it.
James MitchellManchester · nb1 memberThe side effect nobody talks about
Nobody warned me how much GLP-1 would slow everything down. I’d tried fibre powders and magnesium with mixed results. What I liked about NB1 is that it’s based on my own microbiome, not a generic blend. After a month or so I was much more regular. The report was also interesting reading in its own right.
Sarah ThompsonBristol · nb1 memberWanted to do GLP-1 the smart way
I’m eating far less on tirzepatide, so I worried about what that does to my gut long term. NB1 felt like a proactive step rather than a fix for a problem. Energy is steadier and digestion is calmer. I’m taking one star off because the kit return took a bit of effort, but the onboarding was really clear.
David ParkerBirmingham · nb1 memberI expected nothing, honestly
My doctor put me on Wegovy and my partner bought me NB1. I assumed it was another wellness gimmick. The test results were surprisingly specific, and the dosage ramp-up was explained well. Two months in, my stomach is calmer than it’s been since starting the injections. I’ve now renewed it myself.
Emily ClarkeLeeds · nb1 memberGradual, but real
Don’t expect overnight results. The first two weeks I noticed nothing. By week 4–6 the bloating and cramps from my GLP-1 had eased quite a bit. I can’t say how much is NB1 and how much is my body adjusting, but I’m sticking with it. The personalisation and the science behind it are what sold me.
7. “I don’t want another routine”
You already have enough to keep track of. We've done the thinking, so your part is opening the pack.
What you get each month
One rolling monthly plan. Add retesting and blood markers to track what changes as your dose moves.
GMP certifiedQuestions people on a GLP-1 ask
nb1 is a food supplement built from your gut reading. It isn't a medicine and doesn't replace or change your prescription. Some supplement ingredients can interact with medication, so tell us you're on a GLP-1 in your questionnaire, and talk to your GP or prescriber before you start.
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Give your gut a formula built for where it is now
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