Technical Reference
Peptide Reconstitution Guide
This guide covers the standard reconstitution procedure for lyophilised peptides and reference compounds supplied by NMChem. It is intended for trained laboratory personnel working in appropriately equipped research environments and does not constitute medical advice or guidance for human or veterinary use.
Equipment required
Before starting, assemble all required equipment within reach of your work area. Working with everything to hand reduces the risk of contamination and avoids interruptions once the vial is open.
- Sterile vials, if reconstituting volumes for medium-term storage
- Appropriate solvent — bacteriostatic water, sterile water for injection, or DMSO depending on the compound
- Sterile syringes and needles, or a calibrated micropipette with sterile tips
- Laminar flow hood or dedicated clean bench
- Nitrile gloves, lab coat, and safety eyewear as a minimum PPE standard
- Sterile microtubes for aliquoting, pre-labelled where possible
- The product Certificate of Analysis (COA) for compound-specific notes
Choosing your solvent
Bacteriostatic water (sterile water containing 0.9% benzyl alcohol) is appropriate for most peptides intended for multiple-use vials, as the benzyl alcohol inhibits bacterial growth between uses. Sterile water for injection is appropriate for single-use reconstitution where the entire reconstituted volume will be used within a single working session.
DMSO is required for some SARMs and small molecules that are not water soluble. When DMSO is required, it should be used at the minimum effective volume to dissolve the compound, then diluted into the final aqueous working buffer. Never use tap water, deionised water that is not certified sterile, or any solvent that has been opened for an extended period.
Always check the product-specific COA for solvent recommendations. If the product insert specifies a different solvent or a specific solvent grade, follow it in preference to the general guidance above.
Calculating concentration
Decide your target working concentration before adding any solvent. The simple formula is:
Volume of solvent (mL) = Mass of peptide (mg) ÷ Target concentration (mg/mL)
For example, 5 mg of peptide reconstituted to a target concentration of 1 mg/mL requires 5 mL of solvent. The reference table below shows common combinations.
| Mass (mg) | Target concentration (mg/mL) | Volume to add (mL) |
|---|---|---|
| 5 mg | 1 mg/mL | 5.0 mL |
| 5 mg | 2 mg/mL | 2.5 mL |
| 10 mg | 1 mg/mL | 10.0 mL |
| 10 mg | 2 mg/mL | 5.0 mL |
| 10 mg | 5 mg/mL | 2.0 mL |
| 2 mg | 1 mg/mL | 2.0 mL |
Reconstitution technique
Allow the lyophilised vial to reach room temperature before opening. Cold vials can develop condensation that interferes with dissolution and introduces contamination risk. Add solvent slowly by injecting or pipetting it down the inside wall of the vial — never directly onto the lyophilised pellet, as direct impact can damage peptide structure and create insoluble aggregates.
Do not vortex. Gently swirl or roll the vial between your palms until the pellet is fully dissolved. If the pellet does not dissolve within five minutes, allow the vial to stand at room temperature for a further ten minutes before checking again. For stubborn pellets, sonication in a temperature-controlled water bath (not an ultrasonic cleaner) at low power for 30 seconds can assist dissolution without damaging the peptide.
Visual inspection
The reconstituted solution should be clear and free of visible particulates. A slight pale yellow tint or a colourless appearance is normal for many peptides. Do not use a solution that is cloudy, contains visible particulates, or shows an unexpected colour change compared to previous batches.
Cloudiness most often indicates incomplete dissolution rather than degradation — allow additional time at room temperature with gentle agitation before discarding any vial. If cloudiness persists after 30 minutes at room temperature, contact our technical team with the batch number before using the solution in any experiment.
Aliquoting and storage
If the full reconstituted volume will not be used within the working session, divide the solution into single-use aliquots in sterile microtubes immediately after reconstitution. This avoids repeated freeze-thaw cycles, which are the single largest cause of avoidable peptide degradation in research settings.
Label each aliquot clearly with the compound name, batch number (taken from the original vial label), concentration, date of reconstitution, and the initials of the researcher performing the work. Store according to the product COA — most peptides are stable at -20°C for up to six months after reconstitution, though specific stability data varies by compound and should always be confirmed against the COA.
Freeze-thaw cycles
Repeated freeze-thaw cycles degrade peptide integrity through both physical aggregation and chemical hydrolysis at the cycling interface. Use single-use aliquots wherever possible. Thaw aliquots at 4°C or at room temperature — never in a microwave, hot water bath, or boiling water.
Once thawed, use the aliquot within the working session and discard any remainder rather than refreezing. The maximum recommended number of freeze-thaw cycles for most peptides is three. Compounds containing disulfide bridges or with critical secondary structure may degrade significantly faster and should be treated as single-use only.
Record keeping
Good documentation practice requires a complete record of each reconstitution. For every vial reconstituted, record the date, compound name and CAS number, batch number from the vial label, solvent used (including grade and lot), volume added, calculated concentration, storage location of the resulting aliquots, and the name of the researcher performing the reconstitution.
NMChem can provide a reconstitution log template on request — please contact our technical team directly through the request form.
Product-specific guidance
Each product Certificate of Analysis contains compound-specific reconstitution notes including the recommended solvent, maximum advisable concentration, known stability issues, and storage conditions validated against that batch. Where the COA differs from the general guidance in this document, the COA takes precedence. Request a COA through the request form on the relevant product page or via our documentation request channel.