Best Peptide for Weight Loss
Semaglutide, Tirzepatide, Retatrutide & More — Ranked by Fat Loss Efficacy (2026)
Weight loss peptides split into two categories: GLP-1/GIP receptor agonists (semaglutide, tirzepatide, retatrutide) with FDA-reviewed clinical trial data showing 15–29% body weight reduction, and research peptides targeting fat metabolism (AOD-9604, ipamorelin, 5-Amino-1MQ). GLP-1 medications are the most effective weight loss peptides ever studied in humans. Research peptides offer complementary mechanisms — but without equivalent clinical evidence. Track any of them in Shotlee.
Top Weight Loss Peptides — Ranked by Efficacy
| Peptide | Type | Best Clinical Result | FDA Status | Evidence Level |
|---|---|---|---|---|
| Retatrutide | GIP + GLP-1 + Glucagon | 28.7% mean loss (68 wks, Phase 3) | Investigational | ⭐⭐⭐⭐⭐Best |
| Tirzepatide | GIP + GLP-1 dual agonist | 20.9% mean loss (72 wks) | Approved (Mounjaro/Zepbound) | ⭐⭐⭐⭐⭐ |
| Semaglutide | GLP-1 agonist | 14.9% mean loss (68 wks) | Approved (Ozempic/Wegovy) | ⭐⭐⭐⭐⭐ |
| Cagrisema | Amylin + GLP-1 combo | ~15.6% (Phase 2) | Phase 3 | ⭐⭐⭐⭐ |
| AOD-9604 | hGH fragment (176-191) | Modest fat reduction (Phase 2) | Not approved | ⭐⭐ |
| Ipamorelin | GHRP (GH secretagogue) | GH pulse increase, indirect fat loss | Research only | ⭐⭐ |
| 5-Amino-1MQ | NNMT inhibitor | Preclinical fat loss data | Research only | ⭐ |
| Tesamorelin | GHRH analogue | Visceral fat reduction in HIV lipodystrophy | Approved (Egrifta, limited) | ⭐⭐⭐ |
#1 Category: GLP-1 / Dual / Triple Agonists (FDA-Reviewed)
Retatrutide (Triple Agonist)
GIP + GLP-1 + glucagon. Phase 3 TRIUMPH-4: 28.7% mean weight loss at 68 weeks. Not yet FDA approved. The highest weight loss result ever reported in a Phase 3 obesity trial.
Tirzepatide (Mounjaro/Zepbound)
GIP + GLP-1 dual agonist. SURMOUNT-1: 20.9% mean weight loss at 72 weeks. FDA approved for obesity (Zepbound) and T2D (Mounjaro). Currently the most effective approved weight loss medication.
Semaglutide (Ozempic/Wegovy)
GLP-1 agonist. STEP-1: 14.9% mean weight loss at 68 weeks. FDA approved for obesity (Wegovy) and T2D (Ozempic). Longest real-world data and strongest CV outcome evidence (SELECT trial).
#2 Category: Research Peptides Targeting Fat Metabolism
AOD-9604 (hGH Fragment 176-191)
A fragment of human growth hormone targeted at fat cell metabolism. Phase 2 human trials showed modest visceral fat reduction without HGH's anabolic effects or blood sugar impact. Phase 3 for osteoarthritis failed. Used by biohackers for mild fat loss support, not weight management replacement.
Ipamorelin (GHRP)
Growth hormone releasing peptide. Stimulates GH pulses, which promotes lipolysis indirectly. No direct Phase 3 fat loss data in humans. Used in combination protocols (often with CJC-1295) for body composition. Effects are moderate and indirect compared to GLP-1 class.
Tesamorelin (GHRH Analogue)
FDA-approved for HIV-associated lipodystrophy (visceral fat accumulation). In non-HIV adults: Phase 2 showed 10–15% visceral fat reduction. Requires daily injections. Off-label use for biohacking body composition is emerging but evidence base is narrower than GLP-1s.
5-Amino-1MQ (NNMT Inhibitor)
Inhibits nicotinamide N-methyltransferase (NNMT), an enzyme active in adipose tissue. Preclinical animal data shows fat cell shrinkage and metabolic improvements. No published human Phase 2/3 data. Very early-stage compound with theoretical fat loss mechanism.
How to Choose the Right Weight Loss Peptide
If your goal is meaningful, medically supervised weight loss with the strongest evidence base, the answer is clear: start with an approved GLP-1 receptor agonist. Tirzepatide gives you the best currently-approved weight loss result. Semaglutide has the strongest cardiovascular outcome data. Both are covered by insurance for eligible patients.
If you are a biohacker interested in body composition optimisation on top of a GLP-1 protocol, complementary research peptides like tesamorelin (visceral fat) or ipamorelin (GH-axis support) may have theoretical additive benefits — but the evidence base is significantly weaker and these are research-use only in most jurisdictions.
Retatrutide represents the next generation — early Phase 3 data shows 28.7% mean weight loss, the highest ever reported in a Phase 3 trial. It is not yet available, but tracking your current protocol in Shotlee builds the baseline data you will need to compare outcomes when it launches.
How to Track Your Weight Loss Protocol
Frequently Asked Questions
By clinical trial data, retatrutide (Phase 3: 28.7% mean weight loss) is the most effective weight loss compound ever tested, though it is not yet FDA approved. Among approved medications, tirzepatide (20.9% mean weight loss, SURMOUNT-1) outperforms semaglutide (14.9%, STEP-1). Track your progress with whichever compound you use in Shotlee.
No. AOD-9604 showed modest fat reduction in Phase 2 human trials and failed to show joint benefit in Phase 3. Semaglutide in the STEP-1 trial showed 14.9% mean weight loss — a magnitude that AOD-9604 has never demonstrated in human studies. They serve different purposes and are not comparable.
Some biohackers combine GLP-1 medications with GHRPs like ipamorelin for body composition goals. There is no clinical trial data on this combination. GLP-1s act on appetite and metabolism directly; ipamorelin acts on GH pulsatility. If you experiment with stacking, track both compounds carefully in Shotlee and discuss with your prescriber.
GLP-1 agonists (semaglutide, tirzepatide): measurable weight loss starts within 4–8 weeks, with maximum effect over 6–12 months. Research peptides like ipamorelin: GH effects are immediate but fat loss benefits — if any — are gradual and mild over weeks to months. Track weekly weight from day one in Shotlee to see your personal response curve.
In most countries, research peptides (AOD-9604, ipamorelin, BPC-157, etc.) are not FDA-approved for human use and cannot be legally marketed for weight loss. They exist in a regulatory grey area as "research chemicals." Approved medications (semaglutide, tirzepatide) require a prescription and are the only legally sanctioned weight management peptide therapies in the US.
Track Your Weight Loss Protocol in Shotlee
Whatever peptide you use, Shotlee gives you clean dose logs, weekly weight trends, and side effect tracking — free.