Major Weight-Loss Peptides Compared: How They Stack Up
Weight-loss peptide research has moved quickly over the last few years.
What started mainly with GLP-1 research has now expanded into dual-agonist, triple-agonist, amylin and combination approaches. This means that not all weight-loss peptides work in the same way. Some focus mainly on appetite. Some influence glucose and insulin pathways. Others are being studied because they may affect multiple metabolic signals at once.
The most important point is this: weight-loss peptides are not all the same.
Each compound has its own pathway, research status, strength of evidence, safety profile and regulatory position. Some are approved medicines in certain countries and contexts. Others are still investigational. Some are sold as research compounds and are not registered as approved treatments.
This guide compares the major peptides and peptide-related compounds currently being discussed in weight-loss and metabolic research.
Quick Comparison Table
| Compound | Main Pathway | Research Interest | Simple Summary |
|---|---|---|---|
| Semaglutide | GLP-1 | Appetite, glucose, body-weight regulation | Best-known GLP-1 option |
| Tirzepatide | GLP-1 + GIP | Dual incretin pathway research | Stronger multi-pathway profile |
| Retatrutide | GLP-1 + GIP + glucagon | Triple-agonist metabolic research | Next-generation investigational compound |
| Cagrilintide | Amylin analogue | Satiety and appetite research | Often studied with semaglutide |
| AOD-9604 | GH fragment | Fat-metabolism research | Older, mixed evidence |
| Tesofensine | Non-peptide small molecule | Appetite and neurotransmitter research | Not a peptide, but often compared |
1. Semaglutide: The GLP-1 Benchmark
Semaglutide is one of the best-known compounds in modern weight-loss and metabolic research.
It acts on the GLP-1 receptor, a pathway involved in appetite signalling, gastric emptying, glucose regulation and insulin response. GLP-1 stands for glucagon-like peptide-1, a natural hormone released by the gut after eating.
Semaglutide became famous because it helped move GLP-1 science from diabetes research into mainstream weight-management research.
In the STEP 1 trial, adults with overweight or obesity who received once-weekly semaglutide had an average body-weight change of -14.9% at 68 weeks, compared with -2.4% in the placebo group.
Simple research summary
Semaglutide is often viewed as the “benchmark” GLP-1 compound because it has strong published clinical research behind it and helped establish GLP-1 receptor agonists as a major category in metabolic research.
Main research areas
- Appetite regulation
- Satiety signalling
- Glucose response
- Body-weight regulation
- Metabolic health
- Long-term obesity research
How it stacks up
Semaglutide is strong, well studied and widely recognised. Compared with newer multi-pathway compounds, it is simpler because it mainly focuses on the GLP-1 pathway.
2. Tirzepatide: The Dual-Pathway Option
Tirzepatide is different from semaglutide because it targets two pathways:
- GLP-1
- GIP
GIP stands for glucose-dependent insulinotropic polypeptide. Like GLP-1, it is involved in incretin hormone signalling and metabolic regulation.
Because tirzepatide works through both GLP-1 and GIP receptor pathways, it is often described as a dual agonist.
In the SURMOUNT-1 trial, adults with obesity who received tirzepatide had average weight reductions of 15.0%, 19.5% and 20.9% at 72 weeks, depending on dose, compared with 3.1% for placebo.
Simple research summary
Tirzepatide expanded the conversation beyond GLP-1 alone. It showed researchers that combining incretin pathways could produce stronger metabolic and weight-related effects in clinical studies.
Main research areas
- Appetite and fullness
- Glucose regulation
- Insulin sensitivity
- Body-weight reduction
- Metabolic syndrome research
- Dual incretin pathway research
How it stacks up
Tirzepatide generally shows stronger weight-loss results than semaglutide in major studies, although study design, dose, population and duration all matter. It is one of the most important compounds in modern metabolic research.
3. Retatrutide: The Triple-Agonist Research Compound
Retatrutide is one of the most talked-about next-generation compounds in obesity and metabolic research.
It is being studied because it targets three receptor pathways:
- GLP-1
- GIP
- Glucagon
This makes it a triple-agonist compound.
The addition of glucagon receptor activity is important because glucagon is involved in energy balance, liver metabolism and fat-related metabolic pathways. Researchers are studying whether combining these three pathways may produce stronger effects than GLP-1 or GLP-1/GIP approaches alone.
In a phase 2 obesity trial published in the New England Journal of Medicine, retatrutide produced dose-dependent body-weight reductions at 24 and 48 weeks. Lilly reported that the highest studied dose showed mean weight reduction of up to 24.2% at 48 weeks as a secondary endpoint.
Simple research summary
Retatrutide is one of the most exciting investigational compounds in this category, but it is still under research and should not be described as a fully approved treatment where it has not received regulatory approval.
Main research areas
- Triple receptor metabolic signalling
- Appetite regulation
- Energy balance
- Body-weight reduction
- Fat metabolism
- Next-generation obesity research
How it stacks up
Retatrutide may be one of the strongest compounds from a research-results perspective so far, but it is also newer and still investigational. That means the research is exciting, but long-term safety, approval status and real-world use still need careful evaluation.
4. Cagrilintide: The Amylin Pathway
Cagrilintide is not a GLP-1 compound. It is an amylin analogue.
Amylin is a hormone involved in satiety and appetite regulation. Because it works through a different pathway, cagrilintide is often studied in combination with semaglutide.
The combination of cagrilintide + semaglutide is often referred to as CagriSema.
Recent phase 3 results showed that CagriSema produced significant weight loss compared with placebo, with reported results around 20.4% body-weight reduction at week 68 in REDEFINE trial reporting.
Simple research summary
Cagrilintide is interesting because it does not simply copy GLP-1. It works through the amylin pathway, which may complement GLP-1-based approaches.
Main research areas
- Satiety signalling
- Appetite reduction
- Amylin pathway research
- Combination metabolic research
- GLP-1 + amylin research
How it stacks up
Cagrilintide is especially interesting as a combination partner. On its own, it is less famous than semaglutide or tirzepatide, but in combination research it may become very important.
5. AOD-9604: Older Fat-Metabolism Research
AOD-9604 is a peptide fragment based on part of human growth hormone.
It has been discussed for many years in fat-metabolism and body-composition research. The idea behind AOD-9604 was to study whether a specific fragment could influence fat metabolism without the broader effects of full growth hormone.
However, compared with semaglutide, tirzepatide and retatrutide, the evidence around AOD-9604 is much less convincing.
Some early research suggested possible effects, but later studies were mixed. One review notes that effects on weight loss were seen in initial trials but not in the later study that included an intensive diet and exercise programme.
Simple research summary
AOD-9604 is often discussed in peptide communities, but it does not have the same level of modern clinical weight-loss evidence as GLP-1, GIP or triple-agonist compounds.
Main research areas
- Fat metabolism
- Lipolysis research
- Growth hormone fragment research
- Body-composition research
How it stacks up
AOD-9604 is weaker from an evidence point of view. It may still appear in research discussions, but it should not be placed in the same category as semaglutide, tirzepatide or retatrutide for strong clinical weight-loss results.
6. Tesofensine: Important, But Not a Peptide
Tesofensine is often mentioned in weight-loss discussions, but it is important to understand that it is not a peptide.
It is a small-molecule compound originally studied in neurological conditions before researchers became interested in its effects on appetite and body weight. It acts mainly through neurotransmitter pathways, including dopamine, noradrenaline and serotonin reuptake inhibition.
Because it affects appetite and food intake differently from GLP-1 compounds, it is sometimes compared in weight-loss research discussions. But it belongs in a different category.
Simple research summary
Tesofensine may be relevant to weight-loss research, but it is not a peptide and does not work like semaglutide, tirzepatide or retatrutide.
Main research areas
- Appetite suppression
- Central nervous system pathways
- Neurotransmitter signalling
- Obesity research
How it stacks up
Tesofensine is interesting, but it should be separated from true peptide compounds. It may have appetite-related research value, but it is not part of the GLP-1 peptide category.
Visual Ranking: Simple Research Comparison
| Compound | Pathway Complexity | Strength of Weight-Loss Research | Research Maturity |
|---|---|---|---|
| Semaglutide | Medium | High | High |
| Tirzepatide | High | Very High | High |
| Retatrutide | Very High | Very High | Developing |
| Cagrilintide | Medium | High in combination | Developing |
| AOD-9604 | Low-Medium | Weak to Mixed | Older / Mixed |
| Tesofensine | Non-peptide | Moderate | Separate category |
Which One Looks Strongest in Research?
Based on published study results, the strongest modern weight-loss research currently sits around:
- Retatrutide — very strong early results, but still investigational
- Tirzepatide — very strong published results and more developed than retatrutide
- Semaglutide — strong evidence and the most widely recognised GLP-1 benchmark
- Cagrilintide combinations — promising, especially when combined with semaglutide
- AOD-9604 — mixed evidence and weaker clinical support
- Tesofensine — not a peptide, but relevant in appetite research
This is not a recommendation or medical ranking. It is a simple research-based overview of how the compounds are currently discussed in the scientific and metabolic-research space.
GLP-1 vs Dual-Agonist vs Triple-Agonist
A useful way to understand this category is by pathway count.
GLP-1 only
Example: Semaglutide
This targets the GLP-1 receptor pathway, which is involved in appetite, glucose and satiety signalling.
Dual agonist
Example: Tirzepatide
This targets GLP-1 and GIP pathways, making it broader than GLP-1 alone.
Triple agonist
Example: Retatrutide
This targets GLP-1, GIP and glucagon pathways, making it one of the most advanced multi-pathway research compounds.
Amylin combination
Example: Cagrilintide with semaglutide
This approach combines GLP-1 research with amylin-related satiety signalling.
Why Pathways Matter
The pathway matters because weight regulation is not controlled by one signal.
The body uses many overlapping systems, including:
- Hunger signals
- Fullness signals
- Blood sugar response
- Insulin signalling
- Gastric emptying
- Fat metabolism
- Energy expenditure
- Brain reward pathways
- Hormonal feedback loops
This is why modern obesity research has moved toward multi-pathway approaches. Researchers are not only asking whether a compound reduces appetite. They are studying how different systems interact.
Final Thoughts
Weight-loss peptide research is no longer only about one compound or one pathway.
Semaglutide helped establish GLP-1 as a major research category. Tirzepatide expanded the field into dual incretin pathway research. Retatrutide is pushing interest toward triple-agonist metabolic science. Cagrilintide brings the amylin pathway into the conversation, especially in combination studies.
At Health-Tech, our view is simple: this field is exciting, but it must be discussed honestly. Many of these compounds are currently being researched and are not automatically registered as approved treatments, but early studies have shown promising potential in selected areas of metabolic investigation.
The best approach is education first, transparency always, and no exaggerated claims.
