Zepbound (Tirzepatide) Constipation: Alternatives Without This Side Effect

Does any weight-loss medicine avoid constipation?

In a JAMA review of obesity medications, the incretin-based drugs liraglutide, semaglutide and tirzepatide were associated with nausea in 28% to 44% of patients, diarrhea in 21% to 30% and constipation in 11% to 24%. The centrally acting pair phentermine-topiramate and naltrexone-bupropion were associated with constipation in about 20% [3]. A network meta-analysis of 39 articles covering 33,354 people with overweight or obesity and no diabetes found that semaglutide and liraglutide were associated with increased constipation risk [2].

Orlistat works differently from the incretins, as a reversible inhibitor of gastrointestinal lipases [5], but its bowel profile is not quiet either. The Xenical label lists oily spotting, flatus with discharge, fecal urgency, fatty/oily stool, oily evacuation, increased defecation and fecal incontinence among the most common adverse reactions, meaning those occurring in at least 5% of patients and at least twice the placebo rate [5]. The JAMA review reports that orlistat causes gastrointestinal adverse effects such as oily fecal spotting and urgency in more than 25% of patients [3].

What the Zepbound label actually reports

The label's pooled weight-management trials (SURMOUNT-1 and SURMOUNT-2, up to 72 weeks, 958 people on placebo and 630, 948 and 941 on 5, 10 and 15 mg) list constipation in 5% of placebo patients, 17% at 5 mg, 14% at 10 mg and 11% at 15 mg [1]. The rate was highest at the lowest dose and lowest at the highest dose.

Constipation is one part of a broader pattern. Any gastrointestinal adverse reaction was reported in 56% of patients on every Zepbound dose versus 30% on placebo, and treatment was discontinued for a GI reason in 1.9%, 3.3% and 4.3% of the 5, 10 and 15 mg groups versus 0.5% on placebo [1]. Severe GI reactions occurred in 1.7%, 2.5% and 3.1% versus 1% [1].

The label also cautions that adverse reaction rates observed in one drug's trials cannot be directly compared with rates from another drug's trials and may not reflect the rates seen in practice [1].

Is semaglutide gentler on the bowel?

Semaglutide has been associated with increased constipation risk [2], and the JAMA review groups semaglutide with the other incretin drugs across an 11% to 24% constipation range rather than separating it out [3].

The head-to-head trial in adults with obesity and no diabetes, SURMOUNT-5, randomized 751 adults to maximum tolerated tirzepatide (10 or 15 mg) or maximum tolerated semaglutide (1.7 or 2.4 mg) for 72 weeks. Weight fell 20.2% with tirzepatide and 13.7% with semaglutide [6]. Gastrointestinal events were the most common adverse events in both groups, and most were mild to moderate [6].

Do the non-incretin pills avoid it?

Phentermine-topiramate (Qsymia) and naltrexone-bupropion (Contrave) regulate appetite in the brain rather than acting on incretin receptors, and constipation is still associated with both, at roughly 20% of patients in the review [3].

What orlistat does instead

Orlistat is taken as one 120 mg capsule three times a day with each main meal containing fat [5]. Its most common adverse reactions are bowel-related, including oily spotting and fecal urgency [5][3].

What does the Zepbound label say about dose steps?

The label builds the dose slowly: 2.5 mg once weekly for 4 weeks, then 5 mg, then increases of 2.5 mg after at least 4 weeks on the current dose, and it states that this escalation schedule is followed to reduce the risk of gastrointestinal adverse reactions [1]. The 2.5 mg dose is for initiation and is not approved as a maintenance dose [1].

For the maintenance dose itself, the label says to consider treatment response and tolerability, and to consider a lower maintenance dose if the current one is not tolerated [1]. Maintenance options for weight reduction are 5, 10 or 15 mg weekly, with 15 mg the maximum [1].

What does guidance say about treating constipation?

The joint American Gastroenterological Association and American College of Gastroenterology guideline on chronic idiopathic constipation strongly recommends polyethylene glycol, sodium picosulfate, linaclotide, plecanatide and prucalopride, and conditionally recommends fiber, lactulose, senna, magnesium oxide and lubiprostone [4]. That guideline covers chronic idiopathic constipation in adults, not constipation caused by a weight-loss drug, so it offers a framework rather than a tested Zepbound routine [4].

When constipation is more than a nuisance

The Zepbound label warns about severe gastrointestinal adverse reactions, states that the drug is not recommended in people with severe gastroparesis, and warns about acute kidney injury from volume depletion, advising that renal function be monitored in patients reporting reactions that could cause it [1]. A 2026 review of GLP-1 receptor agonist safety notes that nausea, vomiting, diarrhea and constipation generally emerge during dose escalation and resolve over time, but that other GI complications, including gastroparesis and bowel obstruction, have been reported with these drugs and tirzepatide [7].