Foundayo side effects
Most Foundayo (orforglipron) side effects involve the stomach and gut, and most are mild or moderate. This guide gives the rates from the ATTAIN-1 trial, when effects tend to appear, what eases each one and which symptoms need urgent help.
In short: The most common Foundayo side effects are nausea, constipation, diarrhoea, vomiting, indigestion and stomach pain. In the 72-week ATTAIN-1 trial, nausea affected 28.9% to 35.9% of people on Foundayo against 10.4% on placebo, and 5.3% to 10.3% stopped treatment because of side effects. Gut effects are most frequent while the dose is rising. Severe stomach pain reaching the back needs urgent medical help because pancreatitis is a rare risk.
How common each side effect was in ATTAIN-1 #
ATTAIN-1 followed 3,127 adults with obesity or overweight, without diabetes, for 72 weeks. Everyone received diet and activity support. The trial used capsules at 6 mg, 12 mg and 36 mg, which match the 5.5 mg, 9 mg and 17.2 mg Foundayo tablets.
| Side effect | 5.5 mg tablet dose | 9 mg tablet dose | 17.2 mg tablet dose | Placebo |
|---|---|---|---|---|
| Nausea | 28.9% | 35.9% | 33.7% | 10.4% |
| Constipation | 21.7% | 29.8% | 25.4% | 9.3% |
| Diarrhoea | 21.0% | 22.8% | 23.1% | 9.6% |
| Vomiting | 13.0% | 21.4% | 24.0% | 3.5% |
| Stopped due to any side effect | 5.3% | 7.9% | 10.3% | 2.7% |
Across the weight management trials in the UK product information, 60.1% to 68.7% of people on Foundayo reported at least one gut effect, against 36.3% on placebo. Of those gut effects, 61.8% were mild, 34.3% moderate and 3.9% severe.
The full list by frequency #
The UK patient leaflet groups side effects by how often they occur.
| Frequency | Side effects |
|---|---|
| More than 1 in 10 people (the most common group) | Nausea, constipation, diarrhoea, vomiting, indigestion, stomach pain. Low blood sugar when taken with insulin. |
| Up to 1 in 10 people (common) | Dizziness, headache, fast pulse, low blood pressure, bloating, burping, reflux or heartburn, wind, gallstones, hair loss, tiredness, raised lipase and amylase on blood tests. Low blood sugar with a sulfonylurea. |
| Up to 1 in 100 people (uncommon) | Acute pancreatitis, an unusual taste, an unpleasant feeling when the skin is touched. Low blood sugar without insulin or a sulfonylurea. |
| Frequency not known | Sudden vision changes, bowel obstruction, severe constipation, serious allergic reactions, kidney problems, food or liquid entering the lungs during an anaesthetic. |
Some figures from the product information put the common effects in context. Gallstones occurred in 1.3% of people on Foundayo against 0.6% on placebo. Hair loss occurred in 3.7% against 1.8%, was temporary and was linked to weight loss. Aero Clinic has guides on hair loss and gallstones. A fast heartbeat was reported in 2.7% against 0.8%.
When side effects start and how long they last #
Nausea, vomiting and diarrhoea are most frequent during dose escalation and decline over time. Escalation on Foundayo lasts at least 150 days when you climb all the way to 17.2 mg, with a new strength every 30 days or more.
When symptoms have not settled by your monthly check-in, the prescriber can keep you on the same strength for another 30 days. The step schedule is set out in the Foundayo doses guide.
What helps with each side effect #
The advice below follows NHS self-care guidance for each symptom. Message the clinical team when a symptom lasts, gets worse or stops you eating and drinking.
Nausea
- Eat smaller, more frequent meals and eat slowly.
- Avoid hot, fried or greasy food and strong-smelling food.
- Take regular sips of a cold drink. Avoid a large drink with meals.
- Try ginger or peppermint tea, or foods containing ginger.
Vomiting and diarrhoea
- Drink plenty of fluids such as water or squash, in small sips when you feel sick.
- Avoid fruit juice and fizzy drinks, which can make diarrhoea worse.
- Watch for dehydration: dark, strong-smelling urine or passing urine less often than usual.
Constipation
- Drink plenty of water and other fluids, and cut back on alcohol.
- Raise your fibre intake gradually. Add oats, wheat bran or linseed to meals.
Dehydration from vomiting or diarrhoea can harm the kidneys, a risk named in the product information. The hydration guide and the eating guide give practical help.
Urgent warning signs #
Call 111 urgently in these situations:
- You keep being sick and cannot keep fluids down.
- Vomiting lasts more than 2 days or diarrhoea lasts more than 7 days.
- You show signs of dehydration after trying to rehydrate.
- You have severe constipation with a swollen, painful stomach.
People taking insulin or a sulfonylurea have a higher risk of low blood sugar on Foundayo. Test your blood glucose as your diabetes team instructs and tell them about any low readings. Before any operation, tell the anaesthetist you take Foundayo.
Who should not take Foundayo #
The only absolute bar in the UK product information is an allergy to orforglipron or any other ingredient in the tablet. The label also says Foundayo is not for use, or not recommended, in these groups:
- Anyone pregnant or breastfeeding. Stop at least 3 weeks before trying for a baby.
- Anyone under 18. Foundayo has not been studied in this age group.
- People with severe liver impairment.
- People with severe heart failure (NYHA class IV).
Tell the prescriber before starting when you have had pancreatitis, have severe stomach or gut disease including severe gastroparesis, have kidney problems, gallbladder problems or diabetic eye disease, or take blood pressure medicines, insulin or a sulfonylurea. Aero Clinic treats adults aged 18 to 75 who meet the criteria on the eligibility page.
Reporting a side effect through Yellow Card #
You can report any suspected side effect to the MHRA Yellow Card scheme, including effects not listed in the leaflet. Report online at mhra.gov.uk/yellowcard or through the Yellow Card app. Foundayo was authorised in the UK on 10 August 2026, so reports from patients are especially useful. Tell the Aero Clinic clinical team as well.
Foundayo side effects: questions #
What is the most common side effect of Foundayo?
Nausea. In the 72-week ATTAIN-1 trial, 28.9% to 35.9% of people taking Foundayo reported nausea, depending on dose, against 10.4% on placebo. Constipation, diarrhoea and vomiting came next. Most gut effects were mild or moderate, and they were most frequent while the dose was being increased.
How long do Foundayo side effects last?
Duration varies; gastrointestinal symptoms are more frequent during dose escalation. The UK product information describes a decline over time, but persistent or worsening symptoms need advice. Tell your prescriber before increasing your dose and follow the leaflet’s urgent warning instructions.
Does Foundayo cause hair loss?
Hair loss is listed as a common side effect. In the weight management trials, 3.7% of people on Foundayo reported hair loss against 1.8% on placebo. The product information describes the hair loss as temporary and linked to weight reduction. Tell the clinical team when hair shedding worries you.
Can Foundayo cause pancreatitis?
Acute pancreatitis is an uncommon side effect, affecting up to 1 in 100 people. The main sign is severe stomach pain which does not go away and may spread to your back, sometimes with vomiting. Get urgent medical help and stop the tablets. Foundayo is not restarted after confirmed pancreatitis.
How many people stop Foundayo because of side effects?
In ATTAIN-1, discontinuation because of side effects increased across the studied doses. The figures were 5.3%, 7.9% and 10.3% for doses matching the 5.5 mg, 9 mg and 17.2 mg tablets, respectively, versus 2.7% with placebo. Individual tolerability varies.
Foundayo pill plan price to be confirmed
Aero’s treatment prices and service inclusions will be confirmed before booking opens. Ask which prescribing, dispensing, delivery and follow-up costs are included in your quote.
Page information
- Summary
- Nausea affected up to 35.9% of people taking Foundayo in ATTAIN-1. See rates by dose, when effects peak, what helps and the urgent warning signs.
- Publisher
- Aero Clinic, operated by AERO HEALTHCARE LTD.
- Editorial update
- Clinical review
- Pending. An editorial update is not a clinical sign-off.
Cite as: Foundayo side effects, Aero Clinic (https://www.cagri.co.uk), AERO HEALTHCARE LTD. https://www.cagri.co.uk/foundayo-side-effects. Editorial update: 4 November 2026. Clinical review pending.