Best Peptides for Fat Loss: A Research Comparison

The fat-loss research landscape has changed fundamentally in the last five years. Before 2017, peptide research in this area was dominated by hGH-fragment compounds like AOD-9604 and off-label appetite-suppression work. Since then, three GLP-1-class compounds have produced weight-loss endpoints that previously required bariatric surgery, and one small molecule (5-Amino-1MQ) has opened a separate metabolic axis via NNMT inhibition. This article compares the five compounds most relevant to current body-composition research.

The honest positioning: semaglutide, tirzepatide, and retatrutide are the serious compounds here. AOD-9604 and 5-Amino-1MQ are valid research tools but not direct substitutes for the GLP-1 class. The Alkhezi 2023 network meta-analysis in Obesity Reviews is the cleanest external framing for the comparative GLP-1 landscape ¹.

Comparison at a glance

How to choose between them

The first question is the research axis. Are you investigating appetite-driven energy intake (where GLP-1 signalling dominates) or lipolysis and adipocyte energetics (where AOD-9604 and 5-Amino-1MQ are the relevant tools)?

For the appetite and body-weight axis, the hierarchy is clear from head-to-head data:

1. Retatrutide produces the largest weight-loss endpoints in Phase 2 research ⁵, but the long-term safety profile is still being characterised.
2. Tirzepatide produces larger HbA1c and weight reductions than semaglutide in the SURPASS-2 head-to-head trial in T2DM ², and SURMOUNT-1 demonstrated ~21% weight loss at 72 weeks in obesity without diabetes ³.
3. Semaglutide has the deepest evidence base (STEP, SUSTAIN, SELECT programmes) and is the research-literature baseline ⁴.

For the lipolysis and NAD+ axis:

• AOD-9604 for classical fat-mobilisation research without the IGF-1 elevation that full-length hGH carries.
• 5-Amino-1MQ for NNMT-inhibition research and NAD+ metabolism.

Semaglutide

Semaglutide is the foundation of the modern GLP-1 research literature. Its mechanism is well-characterised: glucose-dependent insulin secretion from pancreatic β-cells, α-cell glucagon suppression, delayed gastric emptying, and hypothalamic GLP-1 receptor activation that reduces appetite and energy intake. A fatty-acid side-chain enables albumin binding, extending the half-life to approximately 165 hours and supporting once-weekly dosing.

Where the literature stands: the STEP programme established the obesity endpoints. Wilding and colleagues’ STEP 1 trial demonstrated ~15% weight loss at 68 weeks in adults with overweight or obesity ⁴. SUSTAIN-6 established the cardiovascular-outcome benefit in type 2 diabetes. SELECT extended the CV benefit to obesity without diabetes.

Why a researcher picks semaglutide: broadest literature, longest safety tail, reference standard for any new GLP-1 class comparison. The Alkhezi 2023 network meta-analysis positions it at the lower end of weight-loss efficacy within the GLP-1 class ¹, but at the highest level of evidence-base depth.

Tirzepatide

Tirzepatide is a single-molecule dual agonist at the GIP and GLP-1 receptors. The mechanism difference matters: co-activation of both incretin receptors amplifies insulin secretion beyond GLP-1 alone, and GIP activity at adipocytes appears to contribute additional body-weight reduction. Clinical head-to-head data (SURPASS-2) show larger A1c and weight reductions than semaglutide in T2DM ².

Where the literature stands: SURPASS-2 is the head-to-head vs semaglutide ². SURMOUNT-1 is the obesity-without-diabetes trial showing up to ~21% weight loss at 72 weeks ³.

Why a researcher picks tirzepatide: dual-agonist pharmacology research, or when the comparison requires the stronger weight-loss endpoint per milligram than semaglutide produces. The half-life (~5 days) is shorter than semaglutide’s but still supports once-weekly dosing.

Retatrutide

Retatrutide is the first triple-agonist peptide to reach published Phase 2 data. It activates GLP-1, GIP, and glucagon receptors in a single molecule. The glucagon component is the novelty: glucagon receptor activation increases hepatic glucose output and energy expenditure, which, combined with the appetite-reducing GIP/GLP-1 effect, produces dose-dependent weight reductions greater than any earlier compound in the class.

Where the literature stands: Jastreboff and colleagues’ 2023 Phase 2 obesity trial is the published endpoint ⁵. Dose-dependent weight reduction up to approximately 24% at 48 weeks, with the highest-dose arm still descending at trial end (i.e., the weight-loss curve had not plateaued).

Why a researcher picks retatrutide: research questions specifically about triple-agonist pharmacology, glucagon-receptor contribution to energy expenditure, or the upper bound of GLP-1-class weight-loss research. The long-term safety profile is still being characterised in ongoing Phase 3 work.

AOD-9604

AOD-9604 is a synthetic analogue of the C-terminal residues 176–191 of human growth hormone. Unlike full-length hGH, it produces lipolytic activity in preclinical models without the IGF-1 elevation, insulin-sensitivity changes, or tissue growth effects that limit the research utility of hGH for body-composition work. The lipolytic pathway appears independent of classical β-adrenergic receptors in several published studies.

Where the literature stands: the evidence base is thinner than for the GLP-1 class and mostly preclinical. Human clinical trials have produced more modest body-composition endpoints than the GLP-1 compounds.

Why a researcher picks AOD-9604: research questions specifically about adipocyte lipolysis pathways, or protocols that require a compound without the endocrine ceiling imposed by GLP-1-driven satiety. It is not a substitute for semaglutide in weight-loss research; it is a different research tool for a different question.

5-Amino-1MQ

5-Amino-1MQ (5-amino-1-methylquinolinium) is a small-molecule selective inhibitor of nicotinamide N-methyltransferase (NNMT). Not a peptide, catalogued here alongside other metabolic research compounds. NNMT methylates nicotinamide to 1-methylnicotinamide, consuming SAM and redirecting nicotinamide away from NAD+ salvage. Inhibiting NNMT preserves cellular NAD+ pools and SAM availability, with preclinical readouts in adipocyte lipolysis, muscle energy metabolism, and metabolic flexibility.

Where the literature stands: preclinical, primarily in adipocyte and hepatocyte models. No published large human clinical trials comparable to the GLP-1 class. Oral bioavailability distinguishes it from the injectable peptides in the catalogue.

Why a researcher picks 5-Amino-1MQ: NNMT biology is the research question, not body weight per se. The compound fits research protocols where NAD+ and SAM availability matter pharmacologically.

Where to order

All five compounds are supplied by Thailand Peptides from the Bangkok research desk. Same-week Thailand delivery, lab reports on request, WhatsApp ordering with no account required.

• Buy Semaglutide: multi-mg vials, ≥98% HPLC purity
• Buy Tirzepatide: multi-mg vials, ≥98% HPLC purity
• Buy Retatrutide: research-grade, ≥98% HPLC purity
• Buy AOD-9604: 5 mg vials, ≥98% HPLC purity
• Buy 5-Amino-1MQ: oral research powder, ≥98% HPLC purity

Semaglutide and tirzepatide are the most-ordered compounds in this category. Retatrutide availability varies with research-supply conditions; confirm in chat before committing a protocol to it.