Tirzepatide dosage and evidence

What is Tirzepatide?

How does Tirzepatide work?

It switches on two receptors at once, GIP and GLP-1. Both answer gut hormones after a meal. Together they make the body release insulin when blood sugar is high, hold back glucagon, slow how fast the stomach empties and turn down hunger. The GIP part is thought to add its own effect on how the body handles sugar and fat.

What have studies in people found about Tirzepatide?

Tirzepatide has been tested in tens of thousands of people. One set of trials was in diabetes and another in obesity. They include two trials of stopping the drug, a sleep apnea trial, a heart failure trial and one head-to-head against semaglutide. There is one big catch. The heart trial compared it with another drug, not with a dummy shot. It only asked whether tirzepatide was no worse.

• Heart trial: 13,299 people with type 2 diabetes and clogged arteries. Heart attacks, strokes and heart deaths hit 12.2% on tirzepatide and 13.1% on dulaglutide, an older drug already known to protect the heart. That showed tirzepatide was no worse. It was not compared with a dummy shot.
• Obesity without diabetes: 2,539 adults lost 15.0% of body weight on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg over 72 weeks. On the dummy shot they lost 3.1%.
• Against insulin: 2,002 people with type 2 diabetes and raised heart risk were split between tirzepatide and insulin glargine, and 1,995 were treated. After 52 weeks, three-month average blood sugar fell 2.43 points on 10 mg and 2.58 on 15 mg, against 1.44 on insulin. Major heart events happened to 109 people in all. The numbers leaned toward tirzepatide, but there were too few events to be sure.
• Against semaglutide in type 2 diabetes: 1,879 people over 40 weeks. Every tirzepatide dose lowered blood sugar more than semaglutide 1 mg. On 15 mg, people lost up to 5.5 kg more.
• Obesity with type 2 diabetes: 938 adults lost 12.8% on 10 mg and 14.7% on 15 mg over 72 weeks, against 3.2% on the dummy shot. Two people died in the 10 mg group. The doctors running the trial judged the deaths unrelated to the drug.
• Stopping the drug: 783 people took it openly for 36 weeks and lost 20.9% on average. Then 670 were split: some kept going and some switched to a dummy shot. From week 36 to week 88, those who kept going lost another 5.5%. Those who switched gained back 14.0%, a gap of 19.4 points. 89.5% of those who kept going held on to at least 80% of their loss, against 16.6% of those who switched.
• Head-to-head against semaglutide: 751 adults with obesity and no diabetes lost 20.2% on tirzepatide and 13.7% on semaglutide over 72 weeks. Waists shrank 18.4 cm against 13.0 cm. Everyone knew which drug they were on.
• Heart failure: 731 people with obesity and a stiff heart that fills poorly were followed for about 104 weeks. Heart death or worse heart failure hit 9.9% on the drug and 15.3% on the dummy shot. Nearly all of that came from fewer heart failure events, 8.0% against 14.2%. Heart deaths alone were 2.2% against 1.4%, too few to read either way. A symptom and quality-of-life score improved 6.9 points more on the drug. 6.3% quit over side effects, against 1.4% on the dummy.
• Sleep apnea: two large final-stage trials in people with obesity and moderate to severe sleep apnea found about 25 fewer breathing pauses per hour of sleep at 52 weeks than on a dummy shot.

What this does not tell you: No trial has compared tirzepatide with a dummy shot for heart attacks and strokes, and there probably never will be one. It would now be wrong to hold back a working blood sugar drug from these patients for years. The heart trial answers a smaller question: tirzepatide is no worse than dulaglutide. The heart failure trial was not big enough to judge deaths, and its heart death numbers are small either way. The stopping trial shows the weight comes back: two thirds of the people switched to a dummy shot regained weight by week 88. The longest weight-loss study ran 88 weeks. And none of this used compounded or 'research' tirzepatide, which is what many readers of this page are actually injecting.

What do people who took Tirzepatide report?

This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.

• Most of the practical discussion is about which product someone actually has. Brand and generic naming causes constant confusion, and a large share of threads are people establishing that the branded diabetes product, the branded obesity product and a compounded vial all contain the same molecule.
• A rate of loss of roughly half a percent to one percent of body weight per week is repeatedly described as the normal pace, and slower loss is commonly recommended by other users as the way to limit loose skin. People who lose faster than that describe being uneasy about it.
• Reduced appetite is usually described not as hunger going away but as the constant mental chatter about food going quiet, which is the single most consistent positive report in the whole sample and is frequently described as the thing that made the difference rather than the weight itself.
• Sharply reduced desire to drink alcohol comes up often and unprompted, from people who were not using it for that.
• The compounded versus branded argument is the most heated recurring topic. People report differences in how compounded product feels dose for dose, disagreement about whether that is real, questions about storage and freezing, and references to the manufacturer publishing data claiming more side effects with compounded versions. Dosing errors by compounding pharmacies are raised as a specific worry.
• It is widely described as a long-term medication rather than a course, with weight returning after stopping, and cost and insurance coverage are the most common reasons people describe stopping or being unable to start.
• Negative reports centre on stomach and gut effects and on people who did better on a different GLP-1 than this one, in both directions. Access problems through pharmacy benefit managers generate as much frustration in these threads as side effects do.

Sources: Public discussion in r/Zepbound, r/tirzepatidecompound, r/TirzepatideRX, r/glp1, r/Semaglutide, r/PCOS and general subreddits where these drugs come up, read through the PullPush Reddit archive on 2026-09-13 because Reddit's own endpoints are unreachable from this environment. 84 comments reviewed. Nothing above is attributed to any specific post and no comment is reproduced.

The state of the research

The evidence, in charts

The studies we cite

• Study in people2022
  Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)

  It worked, and the dose mattered. Around 2,500 adults with obesity and no diabetes took a weekly tirzepatide shot at one of three strengths, or a dummy shot, for about seventeen months. The dummy group finished about 3% lighter. On tirzepatide people finished 15%, 20% or 21% lighter, rising with the dose. Everyone here was free of diabetes, so this is a weight result and not a blood sugar one.

  2,539 adults without diabetes: mean weight change at 72 weeks of -15.0% (5 mg), -19.5% (10 mg) and -20.9% (15 mg) versus -3.1% with placebo.

  PMID 35658024 New England Journal of Medicine
• Study in people2021
  Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2)

  Tirzepatide beat semaglutide head to head on blood sugar. Nearly 1,900 people with type 2 diabetes took one drug or the other for about nine months. Every tirzepatide dose brought average blood sugar down further than semaglutide did. People on the strongest tirzepatide dose also lost up to 5.5 kg more, which is about 12 pounds. One thing matters here. The semaglutide dose used was 1 mg, lower than the 2.4 mg dose people take for weight loss.

  1,879 patients over 40 weeks: all tirzepatide doses were noninferior and superior to semaglutide 1 mg for HbA1c, with greater weight loss (up to -5.5 kg more at 15 mg).

  PMID 34170647 New England Journal of Medicine
• Study in people2025
  Cardiovascular Outcomes with Tirzepatide versus Dulaglutide in Type 2 Diabetes (SURPASS-CVOT)

  Tirzepatide guarded the heart about as well as a drug already known to do it. More than 13,000 people with type 2 diabetes and hardened, narrowed arteries took either tirzepatide or dulaglutide. Heart attacks, strokes and deaths from heart disease happened to 12.2% of the tirzepatide group and 13.1% of the dulaglutide group. The trial was built to show tirzepatide was not worse, rather than to show it was better. It was not worse. That is what the 2026 heart licence rests on.

  13,299 patients with type 2 diabetes and atherosclerotic disease: primary MACE in 12.2% on tirzepatide vs 13.1% on dulaglutide (HR 0.92), meeting noninferiority against an active comparator with proven benefit; basis of the August 2026 cardiovascular indication.

  PMID 41406444 New England Journal of Medicine
• Study in people2024
  Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity (SURMOUNT-OSA)

  It worked for sleep apnea, and the change was big. Adults with obesity and moderate to severe sleep apnea took tirzepatide or a dummy injection for a year, across two trials. Breathing interruptions during sleep dropped by roughly 25 an hour more than on the dummy. That count is the measure doctors use to grade how severe sleep apnea is, so a fall that size moves many people down a grade. These two trials are why the drug carries a sleep apnea licence.

  Two phase 3 trials in moderate-to-severe OSA with obesity: apnea-hypopnea index fell by about 25 events per hour at 52 weeks versus placebo, supporting the Zepbound sleep apnea indication.

  PMID 38912654 New England Journal of Medicine
• Study in people2023
  Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial

  Tirzepatide produced large weight loss in people who also had type 2 diabetes. 938 adults took the weekly shot or a dummy one for 72 weeks, and nobody involved knew which. Those on the drug lost about 12.8% of their body weight at the middle dose and 14.7% at the top dose. The dummy group lost 3.2%. Around eight in ten on the drug lost at least 5% of their weight, against three in ten on the dummy.

  938 adults with obesity and type 2 diabetes over 72 weeks: least-squares mean weight change -12.8% (10 mg) and -14.7% (15 mg) versus -3.2% on placebo; 79% to 83% versus 32% lost at least 5%.

  PMID 37385275 The Lancet
• Study in people2024
  Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial

  Stopping tirzepatide undoes most of the weight loss. Everyone took the drug openly for 36 weeks first and lost about 20.9% of their body weight. Then 670 people were split by chance to keep going or to switch to a dummy shot. Over the next year those who kept taking it lost another 5.5%. Those who switched gained 14.0% back. The gap of 19.4 percentage points came from stopping, and from nothing else.

  670 participants randomized after a 36-week lead-in in which they lost a mean 20.9%: weight change from week 36 to 88 was -5.5% on continued tirzepatide versus +14.0% on placebo, a difference of 19.4 percentage points.

  PMID 38078870 JAMA
• Study in people2025
  Tirzepatide as Compared with Semaglutide for the Treatment of Obesity

  Tirzepatide beat semaglutide head to head, in a trial run by the company that sells tirzepatide. 751 adults with obesity and no diabetes took one drug or the other for 72 weeks. Everyone knew which they were getting. Tirzepatide took off 20.2% of body weight and semaglutide 13.7%. Waists shrank 18.4 cm against 13.0 cm. Eli Lilly funded it, and no comparable trial funded by the other side has been published.

  SURMOUNT-5, open-label head to head in 751 adults with obesity and without diabetes: -20.2% on tirzepatide versus -13.7% on semaglutide at 72 weeks, and waist circumference -18.4 cm versus -13.0 cm. Funded by Eli Lilly.

  PMID 40353578 New England Journal of Medicine
• Study in people2021
  Tirzepatide versus insulin glargine in type 2 diabetes and increased cardiovascular risk (SURPASS-4): a randomised, open-label, parallel-group, multicentre, phase 3 trial

  Tirzepatide controlled blood sugar better than insulin and caused far fewer dangerous sugar lows. 1,995 people with type 2 diabetes and raised heart risk were treated for a year, everyone knowing which drug they got. Average blood sugar over three months fell about 2.5 points on tirzepatide and 1.44 on insulin glargine. Serious low blood sugar hit 6% to 9% on tirzepatide against 19% on insulin. Heart attacks and strokes leaned tirzepatide's way, on too few events to call.

  1,995 treated participants: HbA1c change at 52 weeks -2.43% (10 mg) and -2.58% (15 mg) versus -1.44% on glargine, with severe or clinically significant hypoglycaemia in 6% to 9% versus 19%. Adjudicated four-point MACE hazard ratio 0.74 (95% CI 0.51 to 1.08).

  PMID 34672967 The Lancet
• Study in people2025
  Tirzepatide for Heart Failure with Preserved Ejection Fraction and Obesity

  Tirzepatide cut heart failure flare-ups in people with a stiff heart and obesity. 731 patients were followed for about two years on the drug or a dummy shot. Death from heart causes or worsening heart failure hit 9.9% on the drug and 15.3% on the dummy, about 54 fewer such events for every 1,000 people. Almost all of that came from fewer heart failure events. Deaths from heart causes alone ran slightly higher on the drug, 2.2% against 1.4%, on numbers too small to read either way.

  SUMMIT, 731 patients over a median 104 weeks: cardiovascular death or worsening heart failure in 9.9% versus 15.3% (HR 0.62). Cardiovascular deaths alone were 2.2% versus 1.4% (HR 1.58, 95% CI 0.52 to 4.83), so the composite was driven by heart-failure events.

  PMID 39555826 New England Journal of Medicine
• Study in people2025
  Once-Monthly Maridebart Cafraglutide for the Treatment of Obesity - A Phase 2 Trial

  A drug that blocks the receptor tirzepatide switches on caused big weight loss too, which leaves the textbook story about GIP unsettled. 592 people took a monthly shot or a dummy one for a year. Weight fell between 12.3% and 16.2% depending on dose, against 2.5% on the dummy. This is a mid-stage trial of a different drug. It sits on this page because two drugs doing opposite things at one receptor both work, and nobody can yet say why.

  592 participants: a GIP receptor antagonist combined with GLP-1 agonism produced -12.3% to -16.2% at 52 weeks versus -2.5% on placebo. Relevant here because it blocks the receptor tirzepatide activates, which leaves the role of GIP genuinely disputed.

  This study gave people maridebart cafraglutide, not Tirzepatide. It is here because it belongs on the record, and it is excluded from every count on this page.

  PMID 40549887 New England Journal of Medicine
• Study in people2025
  Efficacy and Safety of Cagrilintide 2.4 mg s.c. in Combination With Semaglutide 2.4 mg s.c. (CagriSema s.c. 2.4 mg/2.4 mg) Once-weekly Compared to Tirzepatide 15 mg s.c. Once-weekly in Participants With Obesity (NCT06131437)

  The comparison of tirzepatide against CagriSema has finished and published nothing. 809 people with obesity took part, and the registry records the trial as completed on 8 December 2025. No results have been posted and no paper has appeared. This trial gave people CagriSema or tirzepatide. Until it publishes, nobody can honestly say which of the two takes off more weight.

  REDEFINE 4, 809 participants, listed as completed with primary completion December 8, 2025. No results posted and no publication indexed at review. It is a CagriSema trial that included tirzepatide as the comparator, so it is excluded from every tirzepatide count on this page.

  This study gave people CagriSema (cagrilintide plus semaglutide), not Tirzepatide. It is here because it belongs on the record, and it is excluded from every count on this page.

  NCT06131437 ClinicalTrials.gov, Novo Nordisk