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Human RCTfat lossblood sugarinflammationcardiovascular

Survodutide

Boehringer and Zealand's weekly glucagon and GLP-1 dual agonist, giving about 16.6% weight loss in phase 3 alongside some of the strongest liver-fibrosis data in the class.

Also known as GLP-1/glucagon dual agonist, BI 456906

Human RCT — Randomised controlled trials in humans, but not an approved product for this use.

SYNCHRONIZE-1 reported up to 16.6% mean weight loss at 76 weeks, with SYNCHRONIZE-2 in type 2 diabetes and SYNCHRONIZE-MASLD reading out in 2026, on top of positive phase 2 MASH histology data published in NEJM in 2024. Genuinely strong phase 3 evidence, but not yet approved anywhere.

How it works

Survodutide is built on the glucagon backbone with modifications giving potent activity at both GCGR and GLP-1R, plus a fatty-acid chain for weekly dosing. The GLP-1 arm supplies satiety and glucose-dependent insulin secretion; the glucagon arm acts on hepatocytes to increase fatty-acid oxidation, deplete hepatic triglyceride and raise resting energy expenditure, and also has direct antifibrotic signalling effects in the liver. This is why survodutide's most distinctive results are in MASH - a phase 2 trial showed histological improvement in a majority of treated patients including fibrosis regression - rather than in raw weight loss, where it sits below tirzepatide and retatrutide.

Targets: Glucagon receptor, GLP-1 receptor

Dosing

ProtocolDoseFrequencyRoute
SYNCHRONIZE phase 3 dosingSame day each week.3.6 mg – 6 mgonce weeklysubcutaneous
  • · Phase 3 used maintenance doses of 3.6 mg or 6.0 mg weekly after a long stepped escalation. The 6.0 mg arm gave up to 16.6% mean weight loss at 76 weeks versus 3.2% for placebo.

Titration

The escalation is deliberately slow - typically 16 weeks or more to reach maintenance - because the glucagon arm drives nausea, vomiting and heart-rate increases if pushed.

Cycling

Chronic therapy; no cycling rationale.

Work out your exact syringe units →

Pharmacology

Half-life
Supports once-weekly dosing, roughly 5-7 days.
Onset
Appetite effects within weeks; liver fat and fibrosis endpoints measured over 48 weeks or more.
Routes
subcutaneous
Molecule
Acylated glucagon-based GLP-1/glucagon receptor dual agonist peptide

Handling

Diluent
Bacteriostatic water for research-grade material
Typical mix
1 or 2 mL
Lyophilised
Refrigerate at 2-8 C.
Reconstituted
Refrigerated, use within about 28 days.
Light sensitive
Yes — keep it out of the light

Mixing

Trial material is supplied as a pen solution; anything lyophilised is grey-market.

Side effects

  • very commonNausea and vomiting— Higher than pure GLP-1 agents; the main reason for the slow titration.
  • very commonDecreased appetite
  • commonIncreased heart rate— Glucagon-receptor effect, typically 5-10 bpm.
  • commonDiarrhoea and constipation

Do not use if

  • Pregnancy.
  • History of pancreatitis - class caution.
  • Uncontrolled tachyarrhythmia.
  • Type 1 diabetes without specialist supervision.

Combining it

  • redundantsemaglutide — GLP-1 agonism is already present.
  • redundantretatrutide — Overlapping GLP-1 and glucagon agonism.
  • cautioninsulin-analogues — The glucagon arm can raise glucose while the GLP-1 arm lowers it; monitor closely.

What to monitor

  • · Resting heart rate during escalation.
  • · Liver enzymes and, where MASH is the target, imaging or elastography.
  • · Fasting glucose and HbA1c.
  • · Weight and body composition.

Legal status

Investigational; not approved in any jurisdiction as of mid-2026.

References

  • Sanyal et al. 2024, survodutide phase 2 in MASH, NEJM (trial)
  • Boehringer Ingelheim 2026, SYNCHRONIZE-1 phase 3 topline results (trial)
  • le Roux et al. 2024, survodutide phase 2 obesity dose-finding, The Lancet Diabetes & Endocrinology (trial)

Mechanism in depth

Survodutide is built on the glucagon scaffold rather than the incretin scaffold, and that lineage shows in what it is good at. The glucagon receptor arm drives hepatic fatty-acid oxidation, raises resting energy expenditure and mobilises hepatic triglyceride, and survodutide has the strongest published liver histology data of any dual agonist - the phase 2 MASH trial showed improvement in steatohepatitis with improvement in fibrosis, which is a much harder endpoint than a liver-fat imaging reduction and is the endpoint regulators care about. The GLP-1 arm supplies satiety, delayed gastric emptying and glucose-dependent insulin secretion, and it also counterbalances the glucagon arm's tendency to raise hepatic glucose output. SYNCHRONIZE-1 gave 16.6% mean weight loss at 76 weeks, which places it below tirzepatide and retatrutide on weight but well above semaglutide's liver credentials. The clinical trade-offs are the same ones retatrutide has, in milder form: heart rate rises, and glycaemic control needs watching early because the glucagon arm pushes in the wrong direction before weight loss overtakes it. The programme is unusually broad - SYNCHRONIZE-1 in obesity, SYNCHRONIZE-2 in obesity with type 2 diabetes, SYNCHRONIZE-MASLD in liver disease, a Japanese trial and a cardiovascular outcomes trial - which is what a sponsor does when it thinks the differentiator is organ-specific rather than scale-weight.

What usually goes wrong

The escalation is long - eight steps from 0.3 to 6.0 mg in the phase 2 design - and people compress it, which produces vomiting and tachycardia. The glucagon-arm fasting-glucose rise in the first weeks is misread as the drug causing diabetes when it is a known transient effect. And because there is no approved product, everything sold to consumers is research-grade material of unverifiable identity, which for a drug whose selling point is liver safety is a particular irony.

Titration ladder

  1. 300 mcgWeeks 1-2 — The phase 2 dose-finding trial escalated from 0.3 mg through 0.6, 1.2, 1.8, 2.4, 3.6, 4.8 to 6.0 mg weekly. Step durations varied by arm and were not verified in detail here.
  2. 1.2 mgEscalation
  3. 2.4 mgEscalation
  4. 3.6 mgEscalation
  5. 6 mgMaintenance — The top studied dose in phase 2 and the basis for the phase 3 maintenance dosing.

Bloodwork worth running

MarkerWhenWhy it matters
ALT, AST and non-invasive fibrosis scores (FIB-4, ELF, or transient elastography)Baseline, 6 months, 12 months.This is the marker set that matters most on survodutide, because liver is where it differentiates. Fibrosis improvement on biopsy is what the phase 2 showed.Act if: A FIB-4 above 2.67 or elastography above 8 kPa at baseline means you should be under specialist hepatology care regardless of what drug you are on.
Resting heart rateDaily during escalation.Glucagon receptor agonism is chronotropic. Milder than retatrutide but present.Act if: A rise of more than 15 bpm from baseline, or a sustained resting rate above 100, means stop escalating.
Fasting glucose and HbA1cBaseline, then every 2-4 weeks through escalation.The glucagon arm can raise hepatic glucose output early. In diabetes the net effect is still downward, but the first weeks can look wrong.Act if: A sustained rise in fasting glucose during escalation means hold the dose rather than climbing.
Body composition by DEXABaseline and every 3-4 months.Glucagon-containing agents are sometimes claimed to spare lean mass through increased energy expenditure rather than reduced intake; that claim needs measuring rather than assuming.Act if: No established threshold.
Potassium and magnesiumBaseline and 3 months.Vomiting during escalation plus increased energy expenditure is an electrolyte risk, and low magnesium amplifies the tachycardia.Act if: Potassium under 3.5 mmol/L needs correcting before escalating.

Pharmacokinetics

Time to steady state
35 days
Crosses blood-brain barrier
partial
Accumulates
Yes — doses stack before steady state
Metabolism
Presumed proteolytic backbone cleavage plus beta-oxidation of the acyl chain.
Elimination
Presumed catabolic. Notably, a dedicated study in cirrhosis found the pharmacokinetics acceptable in that population, which matters for a drug being developed for liver disease.

Receptor targets

  • Glucagon receptor (GCGR) — Not verified; the molecule is described as a balanced dual agonist

    Hepatic fatty-acid oxidation, increased resting energy expenditure, mobilisation of hepatic triglyceride, and the improvement in fibrosis seen in the phase 2 MASH histology. Also the source of the heart-rate rise and the early glycaemic drift.

  • GLP-1 receptor (GLP1R) — Not verified

    Satiety, delayed gastric emptying, glucose-dependent insulin secretion, and the counterweight to the glucagon arm's hyperglycaemic push.

Trials

  • SYNCHRONIZE-1 Phase 3 · 76 weeks · 2026

    Mean weight reduction of up to approximately 16.6% with survodutide once weekly in adults with obesity.

  • Survodutide phase 2 MASH trial Phase 2 · n=293 · 48 weeks · 2024

    Improvement in metabolic dysfunction-associated steatohepatitis without worsening of fibrosis, on biopsy, in a substantially higher proportion than placebo.

  • SYNCHRONIZE-MASLD Phase 3 · 2026

    Survodutide in adults with obesity and metabolic dysfunction-associated steatotic liver disease.

  • Survodutide phase 2 obesity dose-finding Phase 2 · n=387 · 46 weeks · 2024

    Dose-dependent weight loss up to approximately 18.7% at 6.0 mg weekly.

What to expect, and when

Weeks 1-4: appetite effects begin; heart rate starts climbing. Weeks 4-5: steady state. Weeks 8-24: liver fat falls fast, and this is the endpoint that moves earliest. Weeks 48+: fibrosis endpoints measured on biopsy. Weeks 76: 16.6% mean weight loss in SYNCHRONIZE-1.

Stacking and comparisons

Survodutide already contains a full GLP-1 arm, so semaglutide, tirzepatide and retatrutide are redundant with it. The mechanistically non-overlapping addition would be an amylin analogue, and there is no data for that pairing. If the goal is liver disease specifically, the things that actually stack with survodutide are not peptides - alcohol cessation, weight loss, and where appropriate a licensed MASH agent. Watch the heart rate rather than adding a beta-blocker to mask it.

Against retatrutide: both carry a glucagon arm, retatrutide adds GIP and delivers more weight loss, survodutide has the stronger biopsy-confirmed liver evidence. Against tirzepatide: tirzepatide wins on weight and has SYNERGY-NASH histology data of its own; survodutide's fibrosis result is the more direct claim. Against semaglutide: survodutide beat it on weight in the diabetes dose-response study and is the better liver drug. Against pemvidutide: the same GLP-1-plus-glucagon concept with different balance - pemvidutide is positioned on lean-mass preservation, survodutide on fibrosis.

Rough cost

Not approved anywhere as of mid-2026, so there is no legitimate price. Grey-market research vials exist at roughly 100-300 per month equivalent. Market observation, not verified pricing.

Genuinely uncertain

  • No verifiable human pharmacokinetic parameters - volume of distribution, clearance, protein binding, tmax and bioavailability are all unresolved.
  • The SYNCHRONIZE-1 primary outcome figure of 16.6% is as reported in the Core record and matches published summaries, but the exact primary-analysis value and participant number were not extracted from the paper in this session.
  • Titration step durations in phase 2 varied by arm and were not verified.
  • Receptor affinities and the GCGR-to-GLP1R potency ratio are not published in verifiable form.
  • Long-term cardiovascular safety of chronic glucagon receptor agonism is uncharacterised; the SYNCHRONIZE cardiovascular outcomes trial has not read out.
  • Cost figures are market observations, not verified pricing.

Papers