The Peptide
Starter Guide

Peptides are short chains of amino acids — the same building blocks that make up proteins. The difference: peptides are smaller (typically 2–50 amino acids), which means they can signal cells more precisely and act as targeted messengers in the body.

Your body already produces thousands of peptides naturally. They regulate everything from growth and repair to immune function, appetite, and skin elasticity. When researchers talk about "therapeutic peptides," they're referring to synthetic versions of these naturally occurring chains — designed to mimic, amplify, or direct specific biological processes.

Why the Research Interest?

Over the past two decades, peptide research has accelerated dramatically. The appeal is specificity — because peptides mimic natural signaling molecules, they tend to have targeted effects with fewer off-target interactions than small-molecule drugs. This has made them attractive for healing, longevity, metabolic research, and skin science.

Important Framing

Most peptides discussed in this guide are research compounds — they are studied in laboratory and clinical settings, but many are not FDA-approved medications. This guide is educational. It explains the science. It does not constitute medical advice. See the disclaimer at the end of this document.

Peptides generally cannot be taken orally as pills — stomach acids break down the amino acid chains before they can absorb. This is why most research peptides are either injected or administered topically (for skin applications).

Equipment You Need for Injections

• Insulin syringes (28–31 gauge, 0.5cc or 1cc capacity)
• Bacteriostatic water (BAC water) — not sterile water, which doesn't preserve the reconstituted peptide
• Alcohol swabs for vial tops and injection sites
• Sharps container for safe needle disposal
• Refrigerator storage for reconstituted peptides (most are stable 2–4 weeks refrigerated)

Quality varies enormously across research peptide suppliers. The checklist below covers what separates reputable research-grade suppliers from low-quality operations that can result in contaminated, mislabeled, or ineffective compounds.

• Third-Party Certificate of Analysis (COA) — Every reputable supplier provides a CoA from an independent lab (not their own) showing purity levels (look for ≥98% by HPLC), identity confirmation, and absence of heavy metals or microbial contamination. If a supplier doesn't publish CoAs, walk away.
• HPLC Testing (High-Performance Liquid Chromatography) — This is the gold standard for purity testing. It measures actual purity percentage. Some suppliers use mass spectrometry alone (which confirms identity but not purity). Both is ideal.
• Accurate labeling with molecular weight — The vial should clearly state the peptide name, molecular weight, and peptide content. Some suppliers use "salt form" peptides — which means the actual peptide content is lower than the stated mg (acetate salt adds mass). Look for suppliers who report the peptide content, not total weight.
• Lyophilized powder in sealed glass vials — Properly stored peptides should be freeze-dried powder, not liquid. Liquid peptide products have much shorter shelf lives and are more prone to degradation. Vials should be vacuum-sealed.
• US-based synthesis or verified overseas manufacturing — US-synthesized peptides are subject to stricter quality standards. Overseas peptides (commonly China) can be high quality but require more scrutiny of the CoA. Always verify the lab testing is from an independent US or EU-accredited facility.
• No medical claims in marketing — Legitimate research peptide suppliers do not market their products as treatments for any disease or condition. If a vendor says their BPC-157 "heals tendons" or their Semaglutide "melts fat," that's a red flag — it violates FDA marketing rules for non-approved substances.
• Responsive customer support + clear return policy — Quality suppliers stand behind their products. Test their support before buying. If they don't respond promptly or dodge questions about their testing, choose a different vendor.
• Reasonable pricing — Quality peptides have real synthesis costs. Suspiciously cheap peptides (e.g., BPC-157 at <$15/vial for 5mg) are almost always low-purity or mislabeled. Research current market rates before purchasing and be skeptical of deep discounts.

This guide is your starting point. WellSourced exists to take you further — with deeper dives into each peptide, tools to make research safer, and courses that turn this foundational knowledge into expertise.