Fat Loss Peptides: Best Peptides for Burning Fat and Optimizing Body Composition

Overview: Three Categories of Fat Loss Peptides

Fat loss peptides work through three distinct mechanisms, each with unique advantages and ideal use cases:

GLP-1 Agonists (Semaglutide, Tirzepatide): These injectable peptides trigger dramatic appetite suppression by activating GLP-1 receptors in the brain. They produce the most substantial weight loss (15-25% body weight loss) by reducing food intake. They\'re the current gold standard for pharmaceutical weight loss.

Growth Hormone Secretagogues (CJC-1295, Ipamorelin, GHRP-6, GHRP-2): These peptides stimulate pituitary release of endogenous growth hormone. Elevated GH promotes fat breakdown while preserving muscle mass. Results are more modest than GLP-1s (1-3 kg fat loss) but body composition improvements are superior.

Metabolic and Direct Lipolysis Peptides (AOD-9604, MOTS-c, 5-amino-1MQ, Tesamorelin): These peptides target specific metabolic pathways. AOD-9604 directly activates fat cell lipolysis. MOTS-c enhances mitochondrial function. 5-amino-1MQ increases thermogenesis. These produce variable results but offer targeted mechanisms independent of appetite suppression.

The optimal choice depends on your primary goal: maximum weight loss favors GLP-1s; body composition improvement with muscle preservation favors GH peptides; metabolic optimization favors direct lipolysis or mitochondrial peptides.

GLP-1 Peptides: Semaglutide and Tirzepatide for Appetite Suppression

GLP-1 receptor agonists are the most powerful weight-loss tools available, producing unprecedented appetite suppression and resulting fat loss. GLP-1 (glucagon-like peptide-1) is a hormone naturally secreted by intestinal L-cells in response to food intake, signaling satiety to the brain.

Mechanism of Action

Semaglutide and tirzepatide are synthetic GLP-1 agonists that activate GLP-1 receptors throughout the brain (particularly in the hypothalamus and brainstem) and peripheral nervous system. This activation triggers multiple satiety signals: reduced hunger sensations, increased fullness perception, slowed gastric emptying, and improved blood glucose regulation. The net result is profound appetite suppression—users typically lose interest in food and naturally eat 25-40% less without conscious effort.

Semaglutide is a GLP-1 agonist that elevates GLP-1 levels. Tirzepatide goes further, acting as a dual GLP-1/GIP receptor agonist, activating both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptors. This dual action produces stronger appetite suppression and weight loss compared to pure GLP-1 agonism.

Clinical Efficacy and Weight Loss Results

Semaglutide clinical trials (STEP program) showed approximately 15% body weight loss at the 2.4 mg weekly dose over 68 weeks. Tirzepatide trials (SUMO program) showed 20-25% body weight loss at the 15 mg weekly dose over 72 weeks, significantly exceeding semaglutide efficacy.

Real-world results are substantial: users consistently report losing 10-25% of starting body weight. The weight loss continues as long as the peptide is used, with most weight regain occurring after discontinuation if lifestyle changes aren\'t maintained. This makes GLP-1s powerful tools for breaking through weight loss plateaus and achieving substantial body composition improvements.

Dosing Protocols

Semaglutide is dosed at 0.25 mg weekly for 4 weeks, then titrated by 0.25 mg increments weekly until reaching 2.4 mg weekly (the maximum recommended dose). The typical maintenance dose for weight loss is 2.4 mg weekly via subcutaneous injection. Some users respond well to lower doses (1.7-2.0 mg); others require the maximum.

Tirzepatide follows a similar titration: starting at 2.5 mg weekly, increasing by 2.5 mg increments every 4 weeks until reaching 15 mg weekly (maximum). Most users achieve weight loss at 10-15 mg weekly.

Side Effects and Tolerability

GLP-1 side effects are well-documented from clinical trials. Common early side effects include nausea (particularly upon dose escalation), vomiting, constipation, diarrhea, and general gastrointestinal discomfort. These typically peak during the first 1-2 weeks after dose increases, then improve as the body adapts. Most users develop excellent tolerance by 4-6 weeks at a stable dose.

Less common but significant side effects include pancreatitis (rare but serious), dehydration, and thyroid C-cell proliferation in animal studies (though human relevance is debated). GLP-1s should be avoided in individuals with personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2.

After discontinuation, appetite typically returns over 2-4 weeks. Some users report residual appetite suppression for months, suggesting lasting changes in hunger signaling. However, without lifestyle maintenance, weight regain commonly occurs.

Growth Hormone Secretagogues: CJC-1295, Ipamorelin, and GHRP Peptides

GH secretagogues stimulate the pituitary gland to release endogenous growth hormone. Unlike exogenous GH injection, secretagogues trigger the body\'s own GH production, preserving natural hormonal control. This approach produces modest fat loss alongside beneficial body composition changes.

CJC-1295 (Growth Hormone Releasing Hormone Analog)

CJC-1295 is a synthetic analog of GHRH (growth hormone-releasing hormone), the brain peptide that naturally stimulates pituitary GH secretion. CJC-1295 binds GHRH receptors and directly stimulates GH release. It produces strong GH elevation—studies show GH levels increase 2-10 fold above baseline. The result is enhanced fat mobilization, improved body composition, and increased muscle protein synthesis.

Dosing typically ranges from 250-500 mcg administered 1-2 times weekly via subcutaneous or intramuscular injection. CJC-1295 has a long half-life (approximately 6-8 days), allowing less frequent dosing than other GH peptides. Many users inject once or twice weekly for convenience.

A critical concern: CJC-1295 can elevate cortisol alongside GH elevation. Elevated cortisol is catabolic (breaks down muscle), promotes fat storage (especially visceral fat), and increases stress-related side effects. This is why many users pair CJC-1295 with Ipamorelin or other GHRP peptides to moderate cortisol elevation.

Ipamorelin and GHRP Peptides

Ipamorelin is a selective GH secretagogue that acts through growth hormone secretagogue receptors (GHSR), stimulating GH release without elevating cortisol or prolactin—the main advantage over CJC-1295. This makes Ipamorelin the "cleaner" GH secretagogue option.

GHRP-6 and GHRP-2 are older GH secretagogues with similar mechanisms to Ipamorelin but less selective pharmacology. GHRP-6 strongly stimulates appetite (sometimes desirable during bulk phases); GHRP-2 has milder appetite stimulation. Both also increase GH but less cleanly than Ipamorelin.

Typical dosing for Ipamorelin: 100-200 mcg once or twice daily via subcutaneous injection. GHRP-6 and GHRP-2: 100-200 mcg daily or a few times weekly.

Stacking CJC-1295 + Ipamorelin for Synergy

Many users combine CJC-1295 (GHRH agonist) with Ipamorelin or GHRP peptides (GHSR agonists) because they work through complementary mechanisms. GHRH drives GH release directly; GHSR amplifies the GH pulse and potentiates GHRH\'s effect. The result is greater GH elevation than either alone. Additionally, Ipamorelin\'s cortisol-sparing properties offset CJC-1295\'s cortisol elevation.

A common stack: CJC-1295 at 300 mcg twice weekly plus Ipamorelin at 150 mcg daily. This produces robust GH elevation with minimal cortisol elevation and excellent tolerability. Fat loss from this combination is modest (1-3 kg over 8-12 weeks) but body composition improvements are substantial due to muscle preservation.

Mechanism of Fat Loss with GH Peptides

Growth hormone promotes fat loss through multiple mechanisms. First, GH is a potent lipolytic hormone—it stimulates hormone-sensitive lipase in adipose tissue, breaking down triglycerides into free fatty acids. Second, GH increases fatty acid oxidation in mitochondria, promoting fat burning for energy. Third, GH slightly increases metabolic rate and energy expenditure. Fourth, GH enhances insulin sensitivity, improving metabolic efficiency.

Critically, GH also preserves and builds muscle during fat loss. This is why body composition improvements from GH peptides are superior to appetite suppressants alone. A user losing fat while preserving muscle looks dramatically better than someone losing the same weight with muscle loss.

Realistic Fat Loss Expectations

GH secretagogues produce more modest fat loss than GLP-1s. Typical results: 1-3 kg fat loss over 8-12 weeks of use with proper diet and exercise. This is significantly less than the 15-25% weight loss from GLP-1s. However, the preserved muscle mass and improved body composition make the visual results often superior. A person losing 2 kg fat while gaining 0.5 kg muscle looks far better than someone losing 5 kg total body weight with 1 kg muscle loss.

AOD-9604: Direct Lipolysis Peptide

AOD-9604 is a 15-amino acid fragment of human growth hormone that specifically targets fat cell lipolysis via beta-3 adrenergic receptor activation. Unlike GLP-1s (which suppress appetite) or GH secretagogues (which elevate systemic GH), AOD-9604 directly triggers fat cell breakdown independent of appetite or systemic hormones.

Mechanism and Beta-3 Receptor Activation

AOD-9604 binds beta-3 adrenergic receptors on adipocytes (fat cells), activating a cascade of intracellular signaling. This triggers adenylyl cyclase production of cyclic AMP (cAMP), which activates protein kinase A (PKA). PKA activates hormone-sensitive lipase (HSL), the enzyme that breaks triglycerides into free fatty acids and glycerol. The fat cells literally drain their stored fat into the bloodstream where it can be oxidized for energy.

The elegant aspect: this is the same fat-burning mechanism that growth hormone uses, but AOD-9604 activates it directly without the systemic effects of full GH. No carpal tunnel syndrome, joint swelling, or insulin resistance—just targeted fat mobilization.

Dosing and Administration

AOD-9604 is typically dosed at 100-300 mcg per injection, usually administered once or twice daily via subcutaneous injection. Common protocols: 100-150 mcg once daily in the morning (capitalizing on daytime lipolysis), or 100-150 mcg twice daily for sustained fat mobilization. Higher doses (200-300 mcg) are used by some but carry increased risk of side effects and tachyphylaxis.

Injection frequency: 5-7 days per week with 1-2 rest days to maintain receptor sensitivity. Cycles typically last 8-16 weeks with potential 2-4 week breaks to prevent tolerance development.

Clinical Evidence and Realistic Expectations

AOD-9604 has stronger animal data than human data. Animal studies consistently show dose-dependent fat loss without muscle loss or organ growth. Human clinical studies are limited and small-scale. A notable 2014 Phase 2 trial showed improved body fat percentage in healthy adults, though absolute weight loss was modest. Real-world reports suggest 1-3 kg fat loss over 8-12 weeks with proper diet.

AOD-9604 is best viewed as a fat-loss enhancer—it mobilizes fat but doesn\'t guarantee it gets burned. Caloric deficit and exercise are still essential. AOD-9604 works better as part of a comprehensive program than as a standalone intervention.

MOTS-c: Mitochondrial Function and Metabolic Optimization

MOTS-c is a mitochondrial-derived peptide that enhances cellular energy production, improving metabolic efficiency and fat oxidation. Rather than directly burning fat like AOD-9604, MOTS-c optimizes the metabolic machinery to burn fat more efficiently.

Mechanism: Mitochondrial and Metabolic Effects

MOTS-c activates the SIRT4 pathway in mitochondria, enhancing oxidative phosphorylation (the process that converts fat into ATP energy). It improves mitochondrial function, increases fatty acid oxidation capacity, and enhances glucose metabolism. The result is improved metabolic rate and body composition—more calories burned, fat loss accelerated, and metabolic health improved.

Unlike appetite suppressants (which reduce intake) or direct lipolytic agents (which mobilize fat), MOTS-c improves the intrinsic efficiency of fat burning. This makes it valuable in metabolic optimization protocols.

Dosing and Results

MOTS-c is typically administered at 100-200 mcg daily or several times weekly via subcutaneous injection. Limited human data exists; most evidence comes from animal studies and preliminary human trials. Results appear modest but consistent: improved metabolic markers, modest fat loss acceleration (typically 10-20% improvement in fat loss rate when combined with diet/exercise), and improved insulin sensitivity.

MOTS-c is best used as part of a stack with more potent fat-loss agents rather than as a standalone peptide. Its primary value is metabolic optimization and insulin sensitivity improvement.

5-Amino-1MQ: Thermogenic Fat Loss Accelerator

5-amino-1MQ is a novel metabolic regulator that increases thermogenesis (heat production), accelerating fat loss through increased energy expenditure. It works by inhibiting nicotinamide N-methyltransferase (NNMT), an enzyme that reduces NAD+ availability in cells.

Mechanism: NAD+ and Thermogenic Metabolism

By inhibiting NNMT, 5-amino-1MQ increases intracellular NAD+ levels. NAD+ is critical for mitochondrial function, SIRT1 activation (which enhances metabolism), and thermogenic processes. Higher NAD+ drives brown adipose tissue (BAT) thermogenesis—essentially converting stored energy to heat.

The result: increased metabolic rate, improved fat oxidation, and accelerated energy expenditure. Users report noticeable thermogenic effects (feeling warm, increased sweating at rest), which directly translate to increased calorie burn independent of activity.

Dosing and Results

5-amino-1MQ is administered at 100-300 mcg daily via subcutaneous injection. Early human data suggests consistent thermogenic effects and modest fat loss acceleration (approximately 10-15% improvement in fat loss rate). Side effects include excessive thermogenesis (feeling too warm), sweating, and potentially paradoxical appetite increase in some users.

Notably, 5-amino-1MQ is newer than other peptides listed here with less human data. It shows promise but should be considered experimental. Combining 5-amino-1MQ with GLP-1 agonists (appetite suppression) can provide complementary mechanisms: reduced intake from GLP-1s and increased expenditure from 5-amino-1MQ.

Tesamorelin: Targeted Visceral Fat Reduction

Tesamorelin is a GHRH analog similar to CJC-1295 but with specific efficacy for visceral (belly) fat reduction. While less commonly used than CJC-1295, tesamorelin has compelling clinical evidence for selectively reducing dangerous visceral adiposity.

Mechanism and Visceral Fat Targeting

Tesamorelin stimulates GH release, enhancing lipolysis and metabolic rate generally. However, visceral fat cells (which line the abdomen and surround organs) appear disproportionately sensitive to GH-mediated lipolysis. Clinical studies show tesamorelin preferentially reduces visceral fat—the most metabolically damaging fat depot—while sparing subcutaneous fat to a greater degree.

Clinical Evidence

Tesamorelin has substantial clinical evidence. A key study in HIV-positive patients with lipodystrophy showed visceral fat reduction of 15-25% with tesamorelin therapy over 6 months. Metabolic markers including insulin sensitivity improved alongside fat loss. This makes tesamorelin particularly valuable for individuals with central obesity or metabolic syndrome.

Dosing and Practical Considerations

Tesamorelin is administered at 2 mg daily via subcutaneous injection, or 1 mg twice daily. It follows a similar mechanism and side effect profile to CJC-1295 but appears to have slightly better visceral fat selectivity. For those specifically targeting belly fat and metabolic health, tesamorelin may be superior to other GH secretagogues.

Stacking Fat Loss Peptides: Synergistic Approaches

Advanced users combine multiple fat-loss peptides for enhanced results. Common stacks leverage complementary mechanisms:

GLP-1 + GH Secretagogue Stack

This combination pairs appetite suppression (GLP-1) with fat mobilization and muscle preservation (GH peptides). The theoretical benefit: GLP-1 reduces caloric intake while GH peptides accelerate fat loss and preserve muscle mass. Real-world reports suggest this combination produces faster and better body composition improvements than either peptide alone.

Example protocol: Semaglutide 2.4 mg weekly + CJC-1295 300 mcg twice weekly + Ipamorelin 150 mcg daily. This combines strong appetite suppression with robust GH elevation and excellent tolerability.

GLP-1 + AOD-9604 Stack

GLP-1 suppresses appetite; AOD-9604 directly burns fat. The combination leverages both approaches: reduced food intake from GLP-1 and enhanced lipolysis from AOD-9604. Some users report superior fat loss from this combination than either alone. The main consideration: ensure adequate caloric intake for health, as combined appetite suppression and enhanced lipolysis could theoretically lead to excessive fat loss.

Metabolic Optimization Stack

For those focused on metabolic health rather than aggressive fat loss: MOTS-c + 5-amino-1MQ + Tesamorelin. This combination targets mitochondrial function (MOTS-c), thermogenesis (5-amino-1MQ), and visceral fat reduction (Tesamorelin). Results are more modest than GLP-1s but provide comprehensive metabolic improvement.

Cautions with Stacking

Stacking amplifies both benefits and side effects. Combining multiple appetite-suppressing or metabolic-stressing compounds requires careful monitoring. Always work with a healthcare provider, start with conservative doses, and conduct regular bloodwork. Realistic expectations matter—stacking peptides is not a substitute for disciplined diet and consistent exercise. The best results come from combining effective peptides with sustainable lifestyle practices.

Complete Dosing Guide for Fat Loss Peptides

Optimal dosing varies based on compound, individual factors, and goals:

Semaglutide (GLP-1): 0.25 mg weekly for 4 weeks, then titrate by 0.25 mg weekly every 4 weeks until reaching 2.4 mg weekly. Maintenance: 2.4 mg weekly via subcutaneous injection. Some respond to lower doses (1.7-2.0 mg).

Tirzepatide (GLP-1/GIP): 2.5 mg weekly for 4 weeks, then titrate by 2.5 mg weekly every 4 weeks until reaching 15 mg weekly. Maintenance: 10-15 mg weekly via subcutaneous injection.

CJC-1295: 250-500 mcg once or twice weekly via subcutaneous or intramuscular injection. Long half-life allows weekly or bi-weekly dosing.

Ipamorelin: 100-200 mcg daily (or split into 100 mcg twice daily) via subcutaneous injection. Some protocols use 3-5 days per week dosing.

GHRP-6 or GHRP-2: 100-200 mcg daily or a few times weekly via subcutaneous injection.

AOD-9604: 100-300 mcg daily (once or twice daily) via subcutaneous injection, 5-7 days per week. Typical cycle: 8-16 weeks.

MOTS-c: 100-200 mcg daily or several times weekly via subcutaneous injection.

5-amino-1MQ: 100-300 mcg daily via subcutaneous injection.

Tesamorelin: 2 mg daily or 1 mg twice daily via subcutaneous injection.

Realistic Expectations and Limitations

Fat loss peptides are powerful tools but not magic solutions. Critical realistic expectations:

Diet Still Matters: Peptides enhance diet; they don\'t replace it. GLP-1s suppress appetite but don\'t prevent overeating if consumed post-injection. GH peptides mobilize fat but can\'t burn it without caloric deficit. AOD-9604 accelerates lipolysis but requires reasonable diet. Caloric deficit, protein intake, and whole-food focus remain foundational.

Results Are Variable: Individual response to peptides varies significantly based on genetics, metabolic health, diet quality, exercise, sleep, and stress. Two people on identical protocols may experience 50% difference in results. Realistic mindset: peptides improve your individual baseline, not guarantee specific outcomes.

Sustainability is Critical: Weight loss is only meaningful if sustained long-term. GLP-1s typically cause weight regain after discontinuation if lifestyle changes aren\'t maintained. GH peptides and other approaches have similar sustainability challenges. Combine peptide use with lifestyle changes that become permanent.

Combination Effects Are Less Understood: While individual peptides are relatively well-studied, combinations are poorly understood. Always approach stacking cautiously, start conservatively, and monitor carefully.

Side Effects and Safety Considerations

GLP-1 Side Effects: Nausea (particularly upon dose escalation), vomiting, constipation or diarrhea, reduced appetite (usually desired), fatigue, dehydration, and rare pancreatitis. Most GI side effects improve within 1-2 weeks at a stable dose.

GH Secretagogue Side Effects: Injection site reactions, mild headaches, transient dizziness, potential cortisol elevation (with CJC-1295), slight prolactin elevation in some users, and rarely carpal tunnel symptoms if causing water retention. Generally well-tolerated compared to exogenous GH.

AOD-9604 Side Effects: Injection site reactions (redness, swelling), occasional mild headaches, dizziness, and fatigue in some users. Notably absent: carpal tunnel, joint swelling, and insulin resistance (unlike full GH).

MOTS-c and 5-amino-1MQ Side Effects: Local injection reactions, thermogenic effects (5-amino-1MQ especially), and limited long-term safety data due to novelty. Monitor closely.

General Safety Notes: All peptides require sourcing from reputable suppliers with third-party testing. Manufacturing quality directly impacts safety. Work with healthcare providers familiar with peptide therapies. Bloodwork monitoring is essential for long-term use. Pregnant women, nursing mothers, and those with personal or family history of medullary thyroid carcinoma should avoid these peptides.

Sourcing Quality Fat Loss Peptides

Because most fat loss peptides are not FDA-approved in the United States (except pharmaceutical GLP-1s like branded semaglutide), sourcing quality products is critical:

Third-Party Testing: Always source from suppliers providing HPLC or mass spectrometry testing confirming peptide purity and potency. Certificates of Analysis (CoA) should be available from independent labs.

Reputable Suppliers: Established peptide suppliers with years of track record, customer reviews, and verified testing are significantly safer than newer, unknown sources.

Pharmaceutical Channels: GLP-1 agonists prescribed through legitimate healthcare providers offer maximum quality assurance. Compounded peptides from licensed pharmacies provide intermediate assurance. Research chemical suppliers offer lowest assurance.

Price Red Flags: Significantly cheaper peptides than market averages are often underdosed, contaminated, or mislabeled. Reasonable pricing correlates with quality in most cases.

Comparing Fat Loss Approaches: Peptides vs Alternatives

Fat loss peptides exist within a broader landscape of weight management tools. How do they compare to alternatives?

Peptides vs Pharmaceutical Medications: GLP-1 peptides (semaglutide, tirzepatide) are themselves pharmaceutical medications when prescribed through healthcare providers. Other peptides discussed here are less established pharmaceutically. Prescription medications provide quality assurance and healthcare provider oversight that research-grade peptides don\'t.

Peptides vs Traditional Diet/Exercise: Disciplined diet and consistent exercise are the foundation. Peptides enhance these approaches but don\'t replace them. Most experts recommend building solid nutrition and training habits first, then adding peptides as adjuncts.

Peptides vs Other Compounds: Peptides often outperform oral SARMs or non-peptide secretagogues for fat loss specifically. GLP-1 peptides particularly outperform most oral agents for appetite suppression. GH peptides compare favorably to exogenous GH for fat loss with preserved muscle and better tolerability.