Do Peptides Actually Work?
Short answer: Some do, some don't, most are somewhere in between. Below is an evidence-based effectiveness rating for popular peptides across different use cases.
Effectiveness Ratings by Peptide & Use Case
Peptide | Primary Claim | Human Evidence | Animal Evidence | Effectiveness Rating | Confidence Level |
---|---|---|---|---|---|
Tesamorelin | Visceral fat reduction | ✓✓✓ FDA approved, multiple RCTs | ✓✓✓ | 9/10 - Proven | Very High |
Ipamorelin | GH release, recovery | ✓✓ Clinical trials show GH elevation | ✓✓✓ | 8/10 - Strong | High |
CJC-1295 No DAC | GH release (pulsatile) | ✓✓ Multiple human studies | ✓✓✓ | 8/10 - Strong | High |
GHRP-2 | GH release, appetite | ✓✓ Clinical data exists | ✓✓✓ | 7/10 - Good | Moderate-High |
GHRP-6 | GH release, appetite | ✓✓ Clinical studies | ✓✓✓ | 7/10 - Good | Moderate-High |
BPC-157 | Injury healing, gut health | ✗ Zero published human trials | ✓✓✓ Extensive positive data | 6/10 - Probable | Moderate (animal + anecdotal) |
TB-500 | Tissue repair, inflammation | ✗ Very limited | ✓✓ Some evidence | 5/10 - Possible | Low-Moderate |
GHK-Cu | Skin/wound healing | ✓ Small trials, mostly topical | ✓✓ | 6/10 - Moderate | Moderate (topical better than injectable) |
Gonadorelin | Testosterone support | ✓✓ Clinical use for hypogonadism | ✓✓✓ | 7/10 - Good | High (for specific indication) |
Kisspeptin | Reproductive hormone regulation | ✓ Emerging research | ✓✓✓ | 5/10 - Emerging | Low-Moderate |
LL-37 | Immune/antimicrobial | ✓ Limited clinical data | ✓✓ | 5/10 - Possible | Low-Moderate |
MGF | Muscle growth | ✗ No human trials | ✓ Limited | 3/10 - Questionable | Low |
PEG-MGF | Muscle growth (extended) | ✗ No human data | ✓ Minimal | 3/10 - Questionable | Low |
CJC-1295 DAC | Sustained GH elevation | ✓ Limited trials, side effect concerns | ✓✓ | 5/10 - Works but risky | Moderate (concerns about prolactin) |
Thymosin Beta-4 (full) | Immune, healing | ✗ Very limited | ✓✓ | 5/10 - Expensive TB-500 | Low-Moderate |
Evidence Quality Breakdown
Evidence Tier | Criteria | Peptides in This Tier | Trust Level |
---|---|---|---|
Tier 1: Proven | FDA approved OR multiple published human RCTs | Tesamorelin | Can trust effectiveness for labeled use |
Tier 2: Strong Evidence | Multiple human clinical studies showing efficacy | Ipamorelin, CJC-1295 No DAC, GHRP-2, GHRP-6 | High confidence in mechanism; results expected |
Tier 3: Moderate Evidence | Some human data OR strong animal + anecdotal | BPC-157, GHK-Cu, Gonadorelin, LL-37 | Likely works but gaps in human data |
Tier 4: Weak Evidence | Limited animal data, mostly anecdotal human reports | TB-500, Kisspeptin, CJC-DAC, Thymosin Beta-4 | May work; significant uncertainty |
Tier 5: Insufficient Evidence | Minimal or no credible research | MGF, PEG-MGF, exotic blends | Buyer beware; likely marketing > reality |
Specific Use Case Effectiveness
Goal | Best Peptide(s) | Does It Work? | Expected Results | Timeline |
---|---|---|---|---|
Increase GH levels | Ipamorelin, CJC-1295, GHRP-2/6 | Yes (proven) | 2-4x GH elevation post-dose | Immediate (acute), weeks for downstream effects |
Reduce visceral fat | Tesamorelin | Yes (FDA approved) | 10-15% reduction over 6 months | 12-26 weeks |
Heal tendon injuries | BPC-157, TB-500 | Probably (no human trials) | Faster recovery reported anecdotally | 2-8 weeks |
Improve sleep quality | Ipamorelin (bedtime) | Maybe (indirect) | Deeper sleep from GH pulse | 1-2 weeks |
Build muscle directly | MGF, PEG-MGF | Questionable | No proven human results | Unknown |
Improve skin appearance | GHK-Cu (topical) | Moderately (some studies) | Improved texture, minor wrinkle reduction | 4-12 weeks |
Heal gut issues | BPC-157 (oral or subQ) | Likely (strong animal data) | Reduced symptoms reported | 1-4 weeks |
Boost testosterone | Gonadorelin, Kisspeptin | Yes for hypogonadism | Modest T increase if LH-responsive | 2-6 weeks |
Enhance immune function | LL-37, Thymosin Alpha-1 | Possibly | Unclear clinical benefit | Unknown |
Accelerate fat loss (general) | GH secretagogues (Ipa, CJC, GHRP) | Modest effect | Improved body comp over months | 8-16 weeks |
What Determines If Peptides Work For You
Factor | Impact on Effectiveness | Why It Matters |
---|---|---|
Age | High | Older users may see bigger improvements from GH peptides (lower baseline); younger users have less room for improvement |
Baseline GH levels | High | If your natural GH is already optimal, peptides won't do much |
Dosing accuracy | Very High | Underdosing = no effect; overdosing = diminishing returns or sides |
Product purity | Critical | Degraded or fake peptides obviously don't work |
Diet quality | Moderate-High | Peptides enhance good nutrition; can't fix terrible diet |
Training status | Moderate | Peptides amplify training stimulus; don't replace it |
Sleep quality | High (for GH peptides) | GH release peaks during deep sleep; poor sleep blunts effects |
Genetics | High | Receptor sensitivity varies; 20-30% of people are non-responders to certain peptides |
Consistency | Very High | Sporadic dosing = minimal results; most peptides require consistent use |
Expectations | Moderate (psychological) | Realistic expectations lead to better assessment of actual effects |
The Placebo Problem
Peptides are particularly susceptible to placebo effects because:
Placebo Factor | Why It's Strong for Peptides |
---|---|
Injection ritual | Daily injections create strong psychological commitment |
Cost | Spending $100-300/month creates pressure to believe it's working |
Community hype | Social reinforcement from forums/groups |
Subjective measures | Most effects (recovery, pain, sleep) are self-reported and hard to quantify |
Lifestyle changes | People often improve diet/training when starting peptides, attributing all gains to peptides |
No immediate feedback | Weeks-long timelines make it hard to separate peptide effects from natural variation |
Bottom Line: Effectiveness Hierarchy
Definitely Work (Human Proof):
- Tesamorelin - visceral fat reduction
- Ipamorelin, CJC-1295, GHRP-2/6 - GH elevation
- Gonadorelin - LH/FSH stimulation
Probably Work (Strong Indirect Evidence):
- BPC-157 - injury healing, gut health (based on animal data + massive anecdotal support)
- GHK-Cu - topical skin/wound healing (some human trials)
Maybe Work (Weak Evidence):
- TB-500 - tissue repair (limited data, anecdotal)
- LL-37 - immune/antimicrobial (emerging research)
- Kisspeptin - reproductive hormones (early stage)
Questionable (Insufficient Evidence):
- MGF, PEG-MGF - muscle growth (no human data)
- Exotic blends - usually marketing gimmicks
- Most "new" peptides with zero research - wait for data
Related Pages
- Best Value Peptides
- Peptide Myths Busted
- BPC-157 Real Talk
- Side Effects Truth
- Community Results Logs