Posted by Marcus Chen | Pinned If you're here, you probably have a vial of lyophilized peptide sitting on your desk and you're staring at it like it's a bomb. It's not. But you can absolutely ruin it if you don't know what you're doing. So let's fix that. This is the guide I wish existed when I started. No fluff, no bro-science — just the exact steps. What You Need • Your lyophilized peptide vial • Bacteriostatic water (BAC water) OR sterile water • Alcohol swabs • An insulin syringe (1mL / 100 units) • A clean, flat workspace BAC Water vs. Sterile Water — When to Use Which Bacteriostatic water contains 0.9% benzyl alcohol, which prevents bacterial growth. Use this when you plan to draw from the vial multiple times over days or weeks. This is what you'll use 95% of the time. Sterile water has no preservative. Use it only for single-use reconstitution — meaning you're drawing the entire vial at once. The moment you puncture that vial, the clock starts ticking on contamination. The rule: If the vial will sit in your fridge and get poked more than once, BAC water. Period. Step-by-Step Reconstitution Step 1: Let it warm up. If your peptide was stored in the freezer, let the vial reach room temperature. Don't rush this. Cold vials + water = condensation issues. Give it 10-15 minutes. Step 2: Decide your volume. You need to decide how much water you're adding. This determines your concentration. More water = more dilute = easier to measure small doses. Less water = more concentrated = fewer injections per vial. I recommend 2mL for most peptides as a starting point. It makes the math clean. Step 3: Swab everything. Alcohol swab the top of the peptide vial. Alcohol swab the top of the BAC water vial. Every. Single. Time. This isn't optional — it's the difference between a sterile preparation and an infection. Step 4: Draw your water. Using your syringe, draw your chosen volume of BAC water. For 2mL, that's the full 100 units on an insulin syringe (1mL = 100 units), done twice. Or use a larger syringe.

Posted by Marcus Chen | Pinned A Certificate of Analysis is the single most important document you'll never read — until now. It's the lab report card for your peptide, and if you're not checking it, you're flying blind. Think of it this way: you wouldn't buy a used car without a Carfax report. A COA is the Carfax for your peptide. It tells you what's actually in that vial, how pure it is, and whether it's going to do what you think it's going to do. What a COA Is A COA is a document provided by the manufacturer or a third-party lab that details the testing results for a specific batch of peptide. Every batch should have one. If you can't get a COA for the specific batch you purchased, that's problem number one. Key Sections to Look At 1. Peptide Identity / Sequence Confirmation This confirms the peptide is actually what the label says it is. Methods used are typically mass spectrometry (MS) or HPLC-MS. You're looking for the molecular weight to match the expected value for that peptide sequence. If the molecular weight is off by more than 1-2 daltons, something's wrong. Either it's the wrong peptide, or there are significant impurities. 2. Purity (HPLC) This is the big number everyone looks at. It's expressed as a percentage, determined by High-Performance Liquid Chromatography. • >98% — Pharmaceutical/research grade. This is what you want. • 95-98% — Acceptable for most research purposes. • <95% — Ask questions. What's the other 5%+? Degradation products? Synthesis byproducts? • <90% — Walk away. A vendor advertising "99% purity" but the COA says 96%? That's not a rounding error. That's dishonesty. 3. Endotoxin Testing (LAL Test) Endotoxins are bacterial toxins that can cause fever, inflammation, and worse. The Limulus Amebocyte Lysate (LAL) test measures these. You want to see: • <5 EU/mg — Standard acceptable level • <1 EU/mg — Even better If there's no endotoxin data on the COA, that's a yellow flag. For injectable peptides especially, this test is non-negotiable.

Save this. Screenshot it. Tape it to your fridge. Whatever works. BEFORE RECONSTITUTION (Lyophilized Powder) • Short-term (under 1 month): Refrigerator (2-8°C / 36-46°F) • Long-term (1+ months): Freezer (-20°C / -4°F) • Extended storage (6+ months): Deep freezer (-20°C or colder) • Shelf life: 12-24 months if stored properly • Light exposure: Keep in original packaging or wrap in foil • Humidity: Keep sealed; desiccant packs help Lyophilized peptides are surprisingly stable when kept cold and dry. AFTER RECONSTITUTION (In Solution) • Storage: Refrigerator ONLY (2-8°C / 36-46°F) • With BAC water: Good for 28-30 days • With sterile water: Use within 24-48 hours • Freezing: Do NOT freeze reconstituted peptides • Light exposure: Keep in box or wrap vial in aluminum foil • Between uses: Return to fridge immediately after drawing Never leave a reconstituted vial out at room temperature for more than the time it takes to draw your dose. THE 5 RULES 1. Cold. Always. 2. Dark. Always. 3. Dry. Before reconstitution. 4. Sterile. After reconstitution. 5. Don't freeze reconstituted peptides. Ever. When in doubt: colder and darker is better. — Marcus