The Evidence-Based Guide to Peptides
No hype. No sales. Just research-backed information on every peptide that matters -- from FDA-approved GLP-1 medications to emerging research compounds.
What Are Peptides?
Peptides are short chains of amino acids -- the same building blocks that make up proteins. Your body naturally produces thousands of peptides that regulate everything from appetite to tissue repair to immune function.
Therapeutic peptides are lab-synthesized versions of these natural molecules. Some have completed rigorous clinical trials and received FDA approval. Others are still being studied or available only for research purposes.
Three categories you need to understand
FDA-approved medications. Semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound), tesamorelin (Egrifta), and PT-141 (Vyleesi) have completed full clinical trials. They are available by prescription and covered by some insurance plans. These have the strongest safety and efficacy data.
Clinical trial compounds. Retatrutide, survodutide, orforglipron, and CagriSema are in Phase 2 or Phase 3 trials. Early results are promising, but they are not yet approved or available by prescription. We track their progress in our research section.
Research-only compounds. BPC-157, TB-500, ipamorelin, CJC-1295, GHK-Cu, and many others have preclinical data (mostly animal studies) but have not completed the FDA approval process. They are available from research peptide suppliers and are not approved for human therapeutic use. Every compound on this site clearly states its FDA status.
The GLP-1 Revolution
GLP-1 receptor agonists are the biggest development in obesity medicine in decades. Clinical trials consistently show 15-26% body weight reduction -- numbers that were unheard of before these medications existed.
These are not supplements. They are powerful medications that fundamentally change how your body regulates appetite and metabolism. Semaglutide and tirzepatide are both FDA-approved for chronic weight management, with different mechanisms: semaglutide targets GLP-1 receptors only, while tirzepatide targets both GLP-1 and GIP receptors.
The next generation -- retatrutide (triple agonist targeting GLP-1, GIP, and glucagon receptors) -- showed 24.2% weight loss in Phase 2 trials. Multiple new compounds are racing through clinical trials.
See our weight loss peptide guide, GLP-1 deep dive, or semaglutide vs tirzepatide comparison for detailed analysis.
Explore the Site
Everything is free. No accounts, no paywalls, no upsells.
Pillar Guides
Weight Loss Guide
Complete weight loss peptide overview
GLP-1 Peptides
GLP-1 agonist deep dive
Healing Peptides
BPC-157, TB-500, GHK-Cu
How-To Guides
Dosing, reconstitution, injection
Research & Science
Clinical trials and new compounds
Comparisons
Head-to-head peptide analysis
Safety Guide
Side effects and harm reduction
Free Tools
Frequently Asked Questions
What are peptides?
Peptides are short chains of amino acids -- the same building blocks that make up proteins. Your body naturally produces thousands of peptides that regulate appetite, tissue repair, immune function, and more. Therapeutic peptides are lab-synthesized versions of these natural molecules.
Are peptides safe?
FDA-approved peptides (semaglutide, tirzepatide) have extensive clinical safety data from multi-year trials. Research-only peptides (BPC-157, TB-500) have less human safety data. Side effects vary by compound. Always consult a healthcare provider before starting any peptide.
Are peptides legal?
FDA-approved peptides are legal with a prescription. Research-only peptides exist in a gray area -- they are legal to purchase for research purposes but not FDA-approved for human therapeutic use. Regulations vary by country and are evolving in 2026.
What is the best peptide for weight loss?
Based on clinical trial data, tirzepatide (Zepbound) has shown the highest average weight loss at 22.5% in SURMOUNT-1. Semaglutide (Wegovy) showed 16.9% in STEP 1. Retatrutide showed 24.2% in Phase 2 but is not yet approved. Individual results vary significantly.
What is the difference between FDA-approved and research peptides?
FDA-approved peptides (semaglutide, tirzepatide, tesamorelin) have completed full clinical trials and are available by prescription. Research-only peptides (BPC-157, TB-500, ipamorelin) have not completed the approval process and are sold for laboratory research purposes only.
Do peptides require injections?
Most therapeutic peptides are administered via subcutaneous injection. Some are available in oral form (oral semaglutide as Rybelsus), nasal spray (semax, selank), or topical application (GHK-Cu creams). Injectable forms generally have higher bioavailability.
How much do peptides cost?
Costs vary widely. FDA-approved GLP-1 medications range from $900-1,500/month without insurance. Compounded versions are typically $200-500/month. Research peptides range from $30-100 per vial. Insurance coverage is expanding for FDA-approved weight loss medications.
Is this site selling peptides?
No. PeptideNerds is an educational reference site. We do not sell peptides, supplements, or medications. We provide evidence-based information to help you make informed decisions with your healthcare provider.
Our Standards
Evidence-based content
Every claim links to published research with PubMed IDs. We distinguish between strong evidence (large RCTs) and preliminary data (animal studies, case reports).
Editorial independence
We do not sell peptides or accept sponsored content. Affiliate relationships are disclosed.
Regular updates
Content is reviewed and updated as new research publishes. Last site-wide review: March 2026.
Medical disclaimer
This is not medical advice. Always consult a qualified healthcare provider. Full disclaimer.