Best peptides for weight loss
For GLP-1 drugs, appetite control, body fat, metabolic health.
Reviewed by the amino101 editorial team. , first published .
This is the one category where the evidence is strong, because the leading compounds are approved drugs with tens of thousands of trial participants. The list runs from most proven to most speculative. If you are new to this, start at the top.
- 1Full guideTirzepatideExtensively studied
The current best balance of results and evidence. Approved, about 20 percent body weight in trials, gentler on the stomach than semaglutide.
Dosage2.5 to 15 mgFrequencyonce weeklyRouteSubcutaneous - 2Full guideSemaglutideExtensively studied
The most used and longest studied. Slightly less weight loss than tirzepatide, more nausea, cheapest per mg.
Dosage0.25 to 2.4 mgFrequencyonce weeklyRouteSubcutaneous, Oral - 3Full guideRetatrutideExtensively studied
The biggest trial numbers, about 24 percent, but unapproved, phase 3 only, and heavily faked on the grey market.
Dosage1 to 12 mgFrequencyonce weeklyRouteSubcutaneous - 4Full guideCagrilintideExtensively studied
An amylin analog, not a GLP-1. Adds a second appetite pathway and is being tested combined with semaglutide.
Dosage0.3 to 4.5 mgFrequencyonce weeklyRouteSubcutaneous - 5Full guide
A small molecule, not a peptide, that blocks NNMT in fat cells. Rodent data only. Speculative.
Dosage5 to 25 mgFrequencyonce dailyRouteSubcutaneous, Oral - 6Full guide
An exercise mimetic that raises fat oxidation in mice. No human data at all. Last on the list for a reason.
Dosage250 to 1000 mcgFrequencyonce to three times dailyRouteSubcutaneous, Oral
The GLP-1 class works and the rest of the list is guessing. Between the three GLP-1 options, pick on evidence and tolerance, not on trial percentages. And whichever one you choose, follow the titration schedule. Fast escalation is the source of nearly every bad story.
Dosage at a glance
What appears in research and community protocols for each pick. Every number links to the full protocol table and calculator on the compound page.
| Peptide | Dosage | Frequency | Route | Cycle | First effects |
|---|---|---|---|---|---|
| Tirzepatide | 2.5 mg (starting dose) | once weekly | Subcutaneous | ongoing, increase by 2.5 mg every 4 weeks as tolerated | appetite drops within the first 1 to 2 weeks, weight loss builds from about week 4, plateau around 12 to 18 months |
| Semaglutide | 0.25 mg (starting dose) | once weekly | Subcutaneous, Oral | ongoing, step up every 4 weeks through 0.5, 1.0, 1.7 and 2.4 mg | appetite drops within 1 to 2 weeks, steady weight loss from about week 4 once past 0.5 mg, plateau around 12 to 18 months |
| Retatrutide | 1 to 2 mg (starting dose) | once weekly | Subcutaneous | ongoing in trials, escalated every 4 weeks toward 4, 8 or 12 mg | appetite drop within 1 to 2 weeks, resting heart rate rise in the first month, weight loss builds from about week 4 and was still going at 48 weeks in phase 2 |
| Cagrilintide | 0.3 mg (starting dose) | once weekly | Subcutaneous | ongoing, stepped every 4 weeks through 0.6, 1.2, 2.4 and 4.5 mg | reduced hunger and smaller portions within 1 to 2 weeks, weight loss builds over 4 to 12 weeks, still trending down at 26 weeks in phase 2 |
| 5-Amino-1MQ | 5 to 25 mg subcutaneous, or 50 to 150 mg oral | once daily | Subcutaneous, Oral | 4 to 8 weeks | no human data; mouse fat loss appeared over 11 days, and any human effect would be subtle over 4 to 8 weeks |
| SLU-PP-332 | 250 mcg | once to three times daily | Subcutaneous, Oral | 4 to 8 weeks | no human data; mouse endurance and fat changes appeared over 4 weeks of daily injections |
Side effects to expect
- ▲Nausea and reduced appetite, worst right after each dose increase
- ▲Diarrhea or constipation
- ▲Burping, reflux and indigestion
- ▲Nausea, especially the first few days after each dose increase
- ▲Constipation or diarrhea
- ▲Burping, reflux and early fullness
- ▲Nausea, vomiting and diarrhea, rougher than semaglutide in the early weeks
- ▲Resting heart rate up by several beats per minute for the first months
- ▲Skin tingling or heightened skin sensitivity (dysesthesia)
- ▲Nausea and vomiting, worst after each dose increase
- ▲Injection site redness, itching or lumps, more common than with semaglutide
- ▲Appetite reduced to the point of under-eating and low energy
- ▲No human safety data exist, so this list is anecdotal
- ▲Mild stomach upset or nausea with capsules
- ▲Headache
- ▲No human safety data exist, so this list is anecdotal
- ▲Faster resting heart rate or palpitations
- ▲Trouble sleeping with evening doses
Where to buy
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Best peptides for weight loss: frequently asked
What is the best peptide for weight loss?
Tirzepatide, on the balance of results and evidence. It is approved, produced about 20 percent weight loss in SURMOUNT-1, and beat semaglutide head to head in SURMOUNT-5. Semaglutide is the cheaper, longer studied alternative. Retatrutide posts bigger numbers but is unapproved until at least late 2027.
Which peptide is best for weight loss without nausea?
None of the GLP-1 drugs is nausea free, but tirzepatide is generally reported as the gentlest at equivalent weight loss, which is attributed to its GIP component. More important than the molecule is the titration: holding each step at least 4 weeks prevents most of the nausea people blame on the drug. See semaglutide vs tirzepatide.
Is retatrutide better than tirzepatide for weight loss?
On trial averages, yes: about 24 percent at 48 weeks in phase 2 and a sponsor reported 28 percent at 80 weeks in TRIUMPH-1, versus about 20.9 percent for tirzepatide. It is not approved, has a heart rate signal, and is the most faked product on the grey market. See retatrutide vs tirzepatide.
Do peptides for weight loss cause muscle loss?
The GLP-1 drugs do, to a degree. Reviews estimate 30 to 40 percent of weight lost may be fat free mass, and the STEP 1 DEXA substudy of semaglutide found roughly 39 percent was lean mass. Resistance training and protein are the proven counters; no peptide has been shown in a human trial to prevent it. See GLP-1 muscle loss.
Does microdosing GLP-1 peptides work for weight loss?
No controlled trial supports it. Common descriptions are 25 to 50 percent of the labeled maintenance dose. A Lancet commentary in early 2025 said there is no evidence it works for obesity, and the SURMOUNT-MAINTENANCE trial of reduced tirzepatide doses is expected to report late 2026. See GLP-1 microdosing.
Related reading
Weight loss beyond semaglutide alone
Weight loss while limiting muscle loss
Three generations of GLP-1 drugs. What actually separates them?
The triple agonist beats the dual agonist on paper. Is it worth waiting for, or buying early?
The two approved GLP-1 drugs went head to head. What does the result mean for you?
First generation versus third. How big is the gap, and what do you give up to close it?
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