Dual GIP/GLP-1 receptor agonist

Tirzepatide

aka Mounjaro · Zepbound

Evidence grade
Grade A: Strong human evidence
for weight management and type 2 diabetes
User score everyone · n = 23
US FDA Approved checked 2026-11-13
WADA 2026 Not prohibited monitored · checked 2026-11-13
EU Mounjaro authorised for T2D age 10 years and older and adult weight management; OSA/HFpEF results appear in clinical evidence, not separate indications in the reviewed EPAR. · checked 2026-11-13

Goals: Fat loss Compare with another peptide →

User reports

approximate — combined from two independent Reddit reads

Men 45–60

8 men aged 45–60

small sample · n = 8

Outcome positive 5 of 8 · mixed 3 of 8

Benefits fat loss 8 of 8 · less appetite 4 of 8 · blood sugar 1 of 8 · joints / tendons 1 of 8 · other 1 of 8

Side effects insomnia 2 of 8 · other 2 of 8 · headache 1 of 8 · nausea 1 of 8

Stopped 0 of 8 Used with other compounds 0 of 8

All men

9 men

small sample · n = 9

Outcome positive 6 of 9 · mixed 3 of 9

Benefits fat loss 8 of 9 · less appetite 4 of 9 · blood sugar 1 of 9 · joints / tendons 1 of 9 · muscle 1 of 9 · other 1 of 9

Side effects insomnia 2 of 9 · other 2 of 9 · headache 1 of 9 · nausea 1 of 9

Stopped 0 of 9 Used with other compounds 1 of 9

Everyone

23 people

  • Positive: 17 of 23 (74%)
  • Mixed: 5 of 23 (22%)
  • Negative: 1 of 23 (4%)
Benefits reported of 23
Benefits reported (n = 23)
ItemReports
Fat loss18 of 23 (78%)
Less appetite8 of 23 (35%)
Blood sugar3 of 23 (13%)
Joints / tendons2 of 23 (9%)
Inflammation1 of 23 (4%)
Muscle1 of 23 (4%)
Other1 of 23 (4%)
Side effects reported of 23
Side effects reported (n = 23)
ItemReports
GI upset3 of 23 (13%)
Insomnia3 of 23 (13%)
Nausea3 of 23 (13%)
Other2 of 23 (9%)
Headache1 of 23 (4%)

Stopped 0 of 23 (0%) Used with other compounds 1 of 23 (4%)

User reports are anecdata, not evidence: self-selected, unverified, often combined with other compounds.

In their words

  • “Now 12 weeks later, I'm down just over 30lbs. Health wise I feel the best I've felt in 30 years.”

  • “Not measured inflammation but I have reduced pain in my joints by 90% in my estimation.”

  • “It has been a complete world changer. All excess hunger and food noise disappeared”

  • “Like I said, a near miracle… BUT, sleep deterioration was terrible.”

  • “(58m) Down 53lbs since April, Feeling Good & Feeling Healthy. Before/After Pics.”

  • “I have been doing sermorin with Tirzepetide, TRT, BPC-157, GHK-Cu and have seen a very fast change in my body.”

Read summaries and method notes

Read 1. The strongest target-age sample: seven men aged 50–55, 4 positive and 3 mixed; all lost substantial weight, appetite/food-noise reduction was common, and one 52M saw major glucose-lab and joint-pain improvement. Target-group side effects: nausea, headache, insomnia — one 52M had excellent weight loss but severe lasting sleep deterioration and muscle loss. Across 21 users: 15 positive, 5 mixed, 1 negative. Appetite effects sometimes within hours to two days of a dose step; target men used it ten weeks to about a year. No target user stopped.

Read 2. One man aged 45–60: a 58M on Zepbound lost 53 lb in about 6 months and feels healthy. A second man (on TRT) saw rapid recomposition and muscle gain within weeks stacking tirzepatide with sermorelin, TRT, BPC-157 and GHK-Cu. No side effects or stops reported. Only two accessible threads.

Note 1. Largest usable men-45-60 subset; still self-selected and success-heavy. Compounded and branded tirzepatide combined. Weight-loss outcomes often included diet/exercise changes.

Note 2. Only two accessible threads had firsthand reports; one man stacked five compounds.

Each read counted people independently. Overlap between the two reads is estimated from shared threads and removed; counts are approximate. How we count.

Summary

GLP-1/GIP dual agonist. 39-amino acid peptide. MW: ~4,813 Da. Once-weekly SubQ injection.

Proposed mechanism

Tirzepatide is a dual incretin agonist — it activates both:

  1. GLP-1 receptor — suppresses appetite, delays gastric emptying, enhances insulin secretion, reduces glucagon
  2. GIP receptor — enhances beta-cell function, modulates fat metabolism, may improve lipid handling and energy expenditure

The GIP component is what differentiates it from semaglutide (GLP-1 only). GIP receptor activity does not establish superior lean-mass preservation. A DXA substudy found about one-quarter of lost weight was lean tissue and did not compare semaglutide. Body-composition study.

Safety

  • Gastrointestinal reactions, sometimes severe; not recommended with severe gastroparesis
  • Pancreatitis, gallbladder disease, dehydration-related kidney injury and anaesthetic aspiration warnings
  • MTC/MEN2 and serious hypersensitivity contraindications
  • Hypoglycaemia with insulin/secretagogues; retinopathy monitoring in susceptible patients
  • Pregnancy precautions and reduced effectiveness of oral hormonal contraceptives around initiation/escalation
  • Potential NAION warning required by FDA November 9, 2026
  • Weight loss includes lean tissue loss

From labels, regulators and trials. No signal in small studies ≠ safe.

Evidence A weight management and type 2 diabetes

A stands. Approved for the marketed use, with multiple large RCTs (SURMOUNT-1, SURMOUNT-5, SURMOUNT-OSA, SURPASS-CVOT).

Human trials · 6

  1. PMID 356580242022RCT, double-blind 2,539 people

    Adults with overweight/obesity without diabetes (SURMOUNT-1)

    At 72 weeks, weight change -15.0%, -19.5% and -20.9% with 5, 10 and 15 mg versus -3.1% placebo. Source

  2. PMID 403535782025RCT, open-label, active-controlled 751 people

    Adults with overweight/obesity without diabetes (SURMOUNT-5)

    Weight change -20.2% versus -13.7% with semaglutide at 72 weeks, using maximum tolerated trial doses. Source

  3. PMID 389126542024Two RCTs, double-blind 469 people

    Adults with obesity and moderate-to-severe OSA, with or without baseline PAP (SURMOUNT-OSA)

    Placebo-adjusted AHI reductions of 20.0 and 23.8 events/hour at 52 weeks. Source

  4. PMID 414064442025RCT, double-blind, active-controlled noninferiority 13,299 people

    T2D and atherosclerotic cardiovascular disease; 13,165 included in modified intention-to-treat analysis (SURPASS-CVOT)

    MACE 12.2% versus 13.1% with dulaglutide; HR 0.92; noninferior, not statistically superior. Source

  5. PMID 395558262025RCT, double-blind 731 people

    Obesity and HFpEF (SUMMIT; first published online 2024)

    Reduced composite of cardiovascular death or worsening heart failure and improved health status. Source

  6. PMID 395362382025RCT, double-blind, extended subgroup follow-up 1,032 people

    SURMOUNT-1 participants with obesity and prediabetes (online report 2024)

    At 176 weeks, T2D diagnosed in 1.3% versus 13.3% placebo; weight reduction maintained during treatment. Source

Bar length = trial size on a log scale.

Dose ranges

Reported ranges from labels and studies, with context. Not a recommendation.

  • approved label
    Adult Mounjaro: 2.5 mg weekly initiation, then 5-15 mg weekly; paediatric T2D maximum 10 mg weekly. Source
  • approved label
    Zepbound: 2.5 mg weekly initiation; weight-management maintenance 5, 10 or 15 mg weekly; OSA maintenance 10 or 15 mg weekly; label escalation intervals at least four weeks. Source

Editorial ratings EDITORIAL

Editors’ judgement, 0–5. Opinion, not data; separate from grade and user score.

Not rated yet.

Sources

  1. pubmed.ncbi.nlm.nih.gov/35658024/
  2. pubmed.ncbi.nlm.nih.gov/40353578/
  3. pubmed.ncbi.nlm.nih.gov/38912654/
  4. pubmed.ncbi.nlm.nih.gov/41406444/
  5. pubmed.ncbi.nlm.nih.gov/39555826/
  6. pubmed.ncbi.nlm.nih.gov/39536238/
  7. accessdata.fda.gov/drugsatfda_docs/label/2025/215866s041lbl.pdf
  8. wada-ama.org/sites/default/files/2025-09/2026_list_monitoring_program_en_final_clean_septe
  9. ema.europa.eu/en/medicines/human/EPAR/mounjaro
  10. dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776
  11. fda.gov/drugs/drug-safety-communications/fda-requires-safety-labeling-changes-glucagon-pep
  12. pubmed.ncbi.nlm.nih.gov/39996356/
  13. fda.gov/news-events/press-announcements/fda-approves-first-medication-obstructive-sleep-ap
  14. fda.gov/drugs/drug-safety-communications/fda-requests-removal-suicidal-behavior-and-ideati
  15. fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-
  16. fda.gov/drugs/drug-alerts-and-statements/fda-clarifies-policies-compounders-national-glp-1
  17. fda.gov/news-events/press-announcements/fda-proposes-exclude-semaglutide-tirzepatide-and-l
  18. fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-c
  19. pmc.ncbi.nlm.nih.gov/articles/11598664/
  20. pmc.ncbi.nlm.nih.gov/articles/PMC11598664/

Reddit threads read · 9

1 further source on commercial or non-primary hosts not listed.

Research checked 2026-11-13.