Peptides for weight loss range from FDA-approved GLP-1 drugs that produce 15-24% body weight reduction to research compounds with more modest but complementary effects. This guide covers the most evidence-backed peptide combinations for fat loss, from the straightforward (semaglutide alone) to the complex (multi-compound stacks for maximum effect).
Tier 1: GLP-1 Monotherapy (Best Evidence)
Semaglutide (Wegovy/Ozempic): The current clinical gold standard. 14.9% average weight loss at 68 weeks (STEP 1, n=1,961). FDA-approved for obesity. Once weekly injection.
Tirzepatide (Zepbound/Mounjaro): Currently the most effective approved option. 20-22% average weight loss at 72 weeks (SURMOUNT-1, n=2,539). Dual GLP-1/GIP mechanism. FDA-approved.
Who should start here: Anyone for whom GLP-1 therapy is appropriate. These compounds produce fat loss outcomes that no other research peptide can match at the clinical scale.
Tier 2: GLP-1 + GH Stack (Fat Loss + Muscle Preservation)
The major concern with GLP-1 monotherapy is lean mass loss (35-40% of total weight lost is muscle + bone). Adding a GH secretagogue stack counteracts this:
Semaglutide or Tirzepatide + CJC-1295 (Mod GRF 1-29) + Ipamorelin:
- GLP-1 compound: handles appetite suppression and fat mobilization
- CJC-1295 + Ipamorelin: elevates GH/IGF-1, promoting lean mass preservation and fat oxidation
Protocol:
- GLP-1 compound: per standard escalation protocol
- CJC-1295 No DAC: 100mcg before bed
- Ipamorelin: 100-200mcg before bed (same injection)
Evidence basis: The combination is not studied together in clinical trials, but the mechanisms are complementary. GH elevation during caloric restriction from GLP-1 therapy should theoretically preserve lean mass better than GLP-1 alone.
Tier 3: GH-Only Protocol (No GLP-1)
For researchers who want to avoid GLP-1 compounds or are using GH optimization as their primary fat loss approach:
CJC-1295 + Ipamorelin: The most popular GH stack. Produces fat loss through elevated GH/IGF-1, particularly visceral fat reduction. Effects are significantly more modest than GLP-1 drugs but with less side effect burden.
Expected fat loss: 3-8% body fat reduction over 3-6 months. Less than GLP-1 drugs but meaningful for body recomposition.
Best for: Athletes or researchers who want improved body composition without the GI side effects of GLP-1 drugs, or those who want to optimize GH/IGF-1 for recovery and anti-aging in addition to fat loss.
Muscle Preservation: Critical for All Weight Loss Protocols
Regardless of which fat loss protocol you use, preserving lean mass requires:
Resistance training: Minimum 3x per week. Specifically, compound movements (squat, deadlift, bench, row, shoulder press). This is non-negotiable during aggressive caloric restriction.
Protein intake: 1.6-2.2g per kilogram of LEAN body mass. On aggressive GLP-1 protocols, appetite suppression can make adequate protein intake challenging — protein shakes help.
BPC-157 + TB-500 adjunct: For researchers dealing with injury limitations that prevent full training, the healing stack allows faster return to activity — critical for muscle preservation during fat loss.
Key Takeaways
For maximum fat loss, tirzepatide is the most effective approved option. Adding CJC-1295 + Ipamorelin preserves lean mass and adds GH optimization benefits. GH-only protocols (without GLP-1) are significantly less potent but have fewer side effects and broader applicability.