Lyophilised peptides are fragile. Improper storage or sloppy reconstitution degrades the active compound before it ever reaches a research subject. This guide covers what you need to know — with South African climate considerations included.
South African climate warning
South Africa's summer ambient temperatures frequently exceed 30 °C in Gauteng, the Western Cape, and KwaZulu-Natal. Lyophilised peptides left in a car, postal depot or courier warehouse during a heatwave can degrade significantly within hours. Always specify temperature-controlled courier options and confirm your delivery won't sit in a hot depot over a weekend.
Most lyophilised (freeze-dried) peptides arrive as a white powder sealed under nitrogen or vacuum in a glass vial. In this form they are far more stable than once reconstituted — many can be stored at fridge temperature (2–8 °C) for 12–24 months without significant degradation. A freezer (−20 °C) extends this further and is mandatory for peptides with a shorter stability window.
Once reconstituted with water, peptides degrade significantly faster. The bacteriostatic agent in BAC water (0.9% benzyl alcohol) prevents microbial contamination but does not stop chemical hydrolysis, oxidation or aggregation of the peptide chains. This is why reconstituted vials should always be stored in the fridge, used within the window specified per peptide, and never refrozen (freeze-thaw cycles degrade peptides rapidly).
| Peptide | Lyophilised | Reconstituted | Notes |
|---|---|---|---|
| BPC-157 | 2–8 °C (fridge), up to 24 months | 4 °C, use within 30 days | Keep away from light; stable at RT for short transit |
| TB-500 | −20 °C preferred, fridge acceptable short-term | 4 °C, use within 30 days | More stable than most peptides; tolerates brief RT |
| Semaglutide | −20 °C | 4 °C, use within 28 days | Pharmaceutical pens keep at RT up to 56 days once in use |
| Tirzepatide | −20 °C | 4 °C, use within 28 days | Same class as semaglutide; similar stability profile |
| GHK-Cu | −20 °C, light-protected | 4 °C, use within 14 days | Copper chelate is sensitive to oxidation; amber vial strongly recommended |
| Epithalon | −20 °C | 4 °C, use within 21 days | Tetrapeptide; relatively stable but degrade faster than larger peptides at RT |
| PT-141 | −20 °C | 4 °C, use within 21 days | Melanocortin peptide; light-sensitive |
| MOTS-c | −20 °C | 4 °C, use within 14 days | Mitochondrial peptide; treat like GHK-Cu — light and heat sensitive |
Bacteriostatic water (BAC water) is the standard diluent for most research peptides. It contains 0.9% benzyl alcohol, which suppresses microbial growth in multi-use vials. Sterile water for injection is used for single-dose applications but is not suitable for vials that will be accessed multiple times. Do not use saline for peptide reconstitution — the ionic environment can accelerate degradation in some peptides.
Gather supplies
You need: bacteriostatic water (BAC water), 1 mL insulin syringe (27–31G), a larger-bore 18–21G needle or blunt-tip for drawing from the BAC water vial, alcohol swabs (70% isopropyl), and the peptide vial. Keep everything on a clean, flat surface.
Calculate your target concentration
Decide how concentrated you want the solution. A common choice is 1 mg/mL — for a 5 mg vial this means adding 5 mL BAC water. Some researchers prefer 2 mg/mL (add 2.5 mL for a 5 mg vial) to reduce injection volume. Use a peptide reconstitution calculator to confirm maths before drawing.
Reconstitute — technique matters
Swab both vial septa with an alcohol wipe. Draw the calculated volume of BAC water. Insert the needle into the peptide vial at a 45° angle and let the water run slowly down the glass wall — do not jet it directly onto the lyophilised powder. This minimises mechanical disruption of peptide chains. Swirl gently for 10–20 seconds until clear. Never vortex, shake vigorously, or heat.
Label and store
Label the vial with the peptide name, concentration, reconstitution date, and expiry date (based on the peptide-specific window from the table above). Store capped in the fridge at 2–8 °C away from light. If you used a standard insulin vial that was not amber-tinted, wrap it in foil.