Orforglipron

Is orforglipron safe?

Based on the trials, orforglipron looks about as safe as the injectable GLP-1 drugs, but nobody can be sure yet. Sold as Foundayo, it is Eli Lilly's daily tablet for weight loss, approved by the FDA on 1 April 2026 for adults with obesity, or overweight with at least one weight-related condition. By October 2026 it had been on sale for about six months.

In two 72-week trials with 3,155 people taking it, the side effects were the familiar GLP-1 pattern: nausea, vomiting, constipation and diarrhoea, mostly while the dose was going up. We score it 65, below semaglutide (72) and tirzepatide (70), for two reasons: a much shorter track record and more drug interactions. Confidence is low, because rare harms often appear only after hundreds of thousands of people have used a drug.

What makes it different from Wegovy or Zepbound?

Orforglipron acts on the same GLP-1 receptor, but it is a small molecule rather than a peptide. In practice that means a tablet taken once a day, with or without food, instead of a weekly injection or a pill that needs an empty stomach. It is broken down by the liver enzyme CYP3A4CYP450 enzymesA family of liver enzymes that break down many medicines. When another drug or supplement speeds them up or slows them down, drug levels change.More in the glossary, which is where its extra interactions come from.

It is also somewhat less powerful in the trials. At the top dose of 17.2 mg, people without diabetes lost 11.1% of their body weight after 72 weeks, against 2.1% on placebo. People with type 2 diabetes lost 9.6% vs 2.5%.

What are the side effects?

The FDA label pools the two weight trials:

Side effect	Orforglipron 5.5 to 17.2 mg	Placebo
Nausea	26% to 35%	10%
Constipation	20% to 27%	9%
Diarrhoea	21% to 25%	11%
Vomiting	13% to 24%	4%
Indigestion	12% to 16%	4%
Hair loss	4% to 5%	2%

Overall, 60% to 69% had a stomach side effect, against 37% on placebo, and 8% stopped the drug because of side effects, against 3%. Severe stomach reactions were reported in about 3% vs 1%.

The serious risks on the label are shared with the rest of the class:

• Pancreatitis: reported with orforglipron; fatal and necrotising cases have occurred with other GLP-1 drugs.
• Gallbladder disease: gallstones in 1% vs 0.7% on placebo.
• Kidney injury, usually from dehydration after vomiting or diarrhoea.
• Low blood sugar: 2% vs 0.2% in people with diabetes, rising to 7% in those also taking a sulfonylurea.
• Aspiration under anaesthesia, because food stays in the stomach longer. Tell any surgery or endoscopy team.

The boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary covers thyroid C-cell tumours, as on every GLP-1 drug, though orforglipron itself caused none in rodents.

Doses on the label

Treatment starts at 0.8 mg once a day. After at least 30 days it goes to 2.5 mg, then after another 30 days to 5.5 mg. From there the dose can rise, at least 30 days apart, to 9 mg, 14.5 mg and a maximum of 17.2 mg, depending on response and side effects. Tablets are swallowed whole, and the label says never to take more than one a day.

Interactions to check before starting

This is where orforglipron differs most from the injections:

Medicine	What the label says
Strong CYP3A4CYP450 enzymesA family of liver enzymes that break down many medicines. When another drug or supplement speeds them up or slows them down, drug levels change.More in the glossary inhibitors (for example clarithromycin, itraconazole)	Maximum dose 9 mg
Ritonavir and similar drugs that also block OATP1B	Avoid
Strong CYP3A4 inducers (for example rifampicin, carbamazepine)	Avoid; they cut the effect
Simvastatin	Do not exceed 20 mg a day
Insulin or sulfonylureas	Their dose may need lowering
Contraceptive pill	Non-oral or back-up method for 30 days after starting and after each dose step

St John's wort induces CYP3A4 and may also weaken it. Blood-sugar supplements such as berberine can add to the glucose-lowering effect. Show your pharmacist everything you take, including supplements.

Who should be careful

Talk to your doctor or pharmacist before starting if you have had pancreatitis, gallbladder disease, diabetic eye disease, kidney problems, severe gastroparesis or severe liver disease, or if you take any of the drugs above. Stop and seek help for severe, persistent stomach pain. The label says to stop the drug when a pregnancy is recognised, and to use effective contraception while taking it. Buy only with a prescription from a registered pharmacy; the MHRA has warned that GLP-1 medicines from unregulated sellers carry serious risks. In an overdose, call Poison Help on 1-800-222-1222 in the US or NHS 111 in the UK.

How we scored it

Dependence (95) is strong: there is no misuse or withdrawal. Track record (35) is the weakest factor, after six months on sale, and regulatory warnings (48) reflect the class boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary. Interactions (65) lose points for the CYP3A4CYP450 enzymesA family of liver enzymes that break down many medicines. When another drug or supplement speeds them up or slows them down, drug levels change.More in the glossary, simvastatin and pill rules. Serious side effects (62) carry the most weight and match the class. A lower score does not mean you should stop a prescribed medicine; talk to your prescriber first.