Tirzepatide 5 mg: What to Expect (Results, Side Effects, Cost)

Written by Nataliia Bondarchuk. Updated November 6, 2026.

Tirzepatide 5 mg is the first real dose after the 4-week 2.5 mg starter dose, and it can also be a long-term maintenance dose: in the SURMOUNT-1 trial, people with obesity who stayed on 5 mg lost an average of 15.0% of their body weight at 72 weeks, and 25% had nausea, according to the Zepbound label. Tirzepatide is the drug sold as Zepbound for weight management and as Mounjaro for type 2 diabetes; it is a once-weekly injection that acts on two gut hormone receptors (GIP and GLP-1) to reduce appetite and improve blood sugar. This guide covers 5 mg only: results, side effects, how long to stay on it, missed doses and cost as of November 2026. For a side-by-side look at every strength, see our tirzepatide dosage guide comparing 2.5, 5, 10 and 15 mg.

Both Zepbound and Mounjaro start the same way. You inject 2.5 mg once a week for 4 weeks, then move to 5 mg. The 2.5 mg dose exists to let your stomach and gut get used to the drug; the Zepbound label says it is for starting treatment and is not a maintenance dose, and Lilly's medical information says the Mounjaro 2.5 mg dose is not intended to control blood sugar. That makes 5 mg the first dose that is expected to do real work.

From 5 mg, your prescriber can increase the dose in 2.5 mg steps (7.5, 10, 12.5, then 15 mg), with at least 4 weeks on each dose before the next increase. The maximum is 15 mg a week for adults. Injection sites stay the same at every dose; see where to inject tirzepatide for the abdomen, thigh and upper arm options.

It can be either. The Zepbound label names three maintenance doses for weight reduction: 5 mg, 10 mg and 15 mg. (For obstructive sleep apnea, the label lists only 10 or 15 mg.) The label also says that if a dose is not tolerated, a lower maintenance dose may be considered, which means someone who struggles on a higher dose may be moved back to 5 mg.

Whether you stay on 5 mg or go up depends on how much benefit you get and how well you tolerate side effects; there is no rule that you must go higher. For Mounjaro in type 2 diabetes, the decision is usually based on blood sugar targets rather than weight. The two brands contain the same drug but are approved for different uses, which we explain in Mounjaro vs Zepbound.

The best evidence comes from SURMOUNT-1, a 72-week trial in adults with obesity, or with overweight plus a weight-related health problem, who did not have diabetes. The 630 people assigned to 5 mg weighed about 102.9 kg (227 lb) on average at the start.

At 72 weeks, the 5 mg group lost an average of 15.0% of body weight, compared with 3.1% on placebo. That figure counts everyone assigned to the dose, including people who stopped (the treatment-regimen estimand). Looking only at people who kept taking the drug as planned (the efficacy estimand), the average loss was 16.0%, or about 16.1 kg (35.5 lb), according to the trial report in the New England Journal of Medicine. Waist size fell by an average of 14.0 cm at 5 mg compared with 4.0 cm on placebo.

Roughly half of people on 5 mg lost 15% or more, while about one in seven did not reach 5%. Responses vary widely.

The trials report the week-by-week weight curve for each dose only as graphs, not as numbers, and neither the Zepbound label nor the NEJM paper gives a 5 mg-specific figure for any point before week 72. What the graphs show is a steady decline that slows over time. The NEJM authors wrote that the 72-week length was enough for the 5 mg group to reach a weight plateau, meaning a point where weight levelled off.

Longer-term data exist for one group. Among SURMOUNT-1 participants who had prediabetes and were followed for about 3 years (176 weeks), the 5 mg group's average loss was 12.3%, against 1.3% on placebo (15.4% for people who kept taking the drug as planned). Lilly noted that this 5 mg result was not controlled for statistical error from multiple comparisons, so treat it as supportive rather than definitive. For a general picture of how results build over the first months across all doses, see tirzepatide weight loss by week.

In people with type 2 diabetes, 5 mg was tested in the SURPASS trials, which lasted 40 to 52 weeks. A1c is a blood test that reflects average blood sugar over about three months. Starting from average A1c levels of roughly 8.0% to 8.5%, the 5 mg dose lowered A1c by 1.87 to 2.24 percentage points, and 81% to 93% of participants reached an A1c below 7%, depending on the trial. Average weight loss at 5 mg ranged from 6.2 to 7.8 kg. These figures, from Lilly's medical information, count people who kept taking the drug as planned.

The SURPASS trials enrolled people with diabetes and were shorter than SURMOUNT-1, so their weight numbers should not be compared directly with SURMOUNT-1. In SURPASS-2, where 5 mg was compared with semaglutide 1 mg, the share of people on 5 mg reaching an A1c below 7% was not significantly different from semaglutide when everyone assigned to the drug was counted.

Stomach and gut side effects are the most common at every dose. The table below shows the rates from the Zepbound label (weight-management trials) and from Lilly's medical information restating the Mounjaro label (pooled type 2 diabetes trials). The two sets of trials enrolled different people and lasted different lengths of time, so the Zepbound and Mounjaro columns are not directly comparable.

In the Zepbound trials, 4.8% of people on 5 mg stopped treatment because of any side effect, compared with 3.4% on placebo. The NEJM report described the gut events as mostly mild to moderate and temporary, occurring mainly while the dose was being increased. Lilly's Mounjaro information likewise says most nausea, vomiting and diarrhea happened during dose escalation and decreased over time.

Smaller meals and less greasy food may help; see foods to eat and avoid on tirzepatide for details. For how long these effects usually last, read how long Mounjaro side effects last.

The label sets a minimum, not a maximum. You need at least 4 weeks on 5 mg before any increase, but there is no point at which you are required to move up. Because 5 mg is an approved maintenance dose for weight reduction, some people stay on it for as long as they continue treatment. Others move up after 4 weeks or later because their prescriber wants more effect, and some move back down to 5 mg because a higher dose caused too many side effects.

If your weight has stopped falling on 5 mg, that alone does not prove the dose is wrong. Sleep, diet changes, fluid shifts and other medicines can all play a part, as explained in why you may not be losing weight on tirzepatide. Stopping the drug altogether is a different question; see what happens when you stop tirzepatide.

The rule is the same for both brands and for every dose. If you miss a dose, take it as soon as possible within 4 days (96 hours) of the missed day. If more than 4 days have passed, skip the missed dose and take the next one on your usual day. Do not take two doses to make up for it.

You can change your weekly injection day, as long as the last dose was at least 3 days (72 hours) earlier. If you have missed several weeks in a row, do not simply restart at 5 mg on your own; ask your prescriber how to restart, since side effects can return after a break.

As of November 2026, LillyDirect, Lilly's self-pay pharmacy program, lists Zepbound 5 mg at $399 per 28 days, according to its Zepbound page last updated October 30, 2026. The price is the same whether you get single-dose vials (four 0.5 mL vials) or one KwikPen. The program is self-pay only, eligibility rules and limits apply, prices can change, and needles for the vials are sold separately.

The 5 mg vial price was cut from $499 to $399 on December 1, 2025, and the multi-dose KwikPen launched on February 23, 2026 at the same price as the vials. One 5 mg KwikPen holds four weekly doses, and each 5 mg dose from the KwikPen or multi-dose vial is 0.6 mL. Our Zepbound KwikPen guide explains how the pen works.

Tirzepatide 5 mg is where treatment really starts, and for many people it is also where it stays. In SURMOUNT-1, people on 5 mg lost an average of 15.0% of their body weight at 72 weeks, nearly half lost 15% or more, and people with prediabetes still averaged a 12.3% loss at 3 years. In type 2 diabetes, 5 mg lowered A1c by about 2 points. Nausea, diarrhea and constipation are common, mostly early and during dose increases. Whether you stay on 5 mg or move up is a decision to make with your prescriber based on your results and how you feel.

This article summarizes published research and prescribing information for general information and is not medical advice. The SURMOUNT and SURPASS trials were funded by Eli Lilly, the maker of Zepbound and Mounjaro.