Peptide Stability & Shelf Life

Understanding how long peptides remain stable and what factors affect their potency is crucial for valid research results.

Factors Affecting Peptide Stability

Temperature

Temperature is the most critical factor for peptide stability:

Higher temperatures accelerate degradation exponentially
Room temperature (20-25°C) suitable only for short periods
Refrigeration (2-8°C) significantly extends stability
Freezing (-20°C or below) provides maximum long-term stability

Light Exposure

Light, especially UV light, can damage peptides:

Causes oxidation and structural changes
Effects are cumulative over time
Amber vials or opaque storage provide protection
Store away from windows and direct lighting

Moisture

Water exposure is particularly damaging to lyophilized peptides:

Humidity can rehydrate freeze-dried powder
Moisture promotes chemical reactions and degradation
Keep unreconstituted peptides sealed until use
Consider desiccant packets for storage

Oxygen

Oxidation degrades many peptides:

Methionine and cysteine residues are particularly vulnerable
Sealed vials maintain inert atmosphere
Minimize air exposure when drawing doses

pH

For reconstituted peptides, pH affects stability:

Bacteriostatic water maintains appropriate pH for most peptides
Acidic or basic conditions can accelerate degradation
Some peptides require specific pH ranges

Shelf Life Guidelines

Lyophilized (Unreconstituted) Peptides

Storage Condition	Typical Shelf Life	Notes
Room Temperature	1-3 months	Not recommended for storage
Refrigerated (2-8°C)	6-12 months	Good for medium-term storage
Frozen (-20°C)	1-2+ years	Ideal for long-term storage
Deep Frozen (-80°C)	2-3+ years	Maximum stability

Reconstituted Peptides

Diluent	Storage	Typical Shelf Life
Bacteriostatic Water	Refrigerated	4-6 weeks
Sterile Water	Refrigerated	48-72 hours
Bacteriostatic Water	Room Temp	Not recommended

Important: These are general guidelines. Specific peptides may have different stability profiles. When in doubt, prioritize fresher preparations.

Peptide-Specific Stability Notes

BPC-157

Relatively stable peptide
Reconstituted: 4-6 weeks refrigerated
Sensitive to extreme pH

TB-500

Good stability profile
Reconstituted: 3-4 weeks refrigerated
Protect from light

Growth Hormone Secretagogues (Ipamorelin, GHRP-6, CJC-1295)

Moderate stability
Reconstituted: 3-4 weeks refrigerated
CJC-1295 DAC has longer stability than non-DAC version

Semaglutide

Relatively stable in solution
Reconstituted: 4-6 weeks refrigerated
Commercially formulated versions have longer stability

Melanotan II

Sensitive to light
Reconstituted: 3-4 weeks refrigerated
Store in amber vial or wrapped in foil

Signs of Peptide Degradation

Visual Indicators

Check reconstituted peptides before each use:

Cloudiness: Solution should be clear
Discoloration: Most peptides should remain colorless
Precipitation: Particles or sediment indicate problems
Gel formation: Some peptides form gels when degraded

Reduced Effectiveness

If research results suddenly become inconsistent or diminished, peptide degradation may be the cause.

What To Do With Suspect Peptides

Do not use visibly degraded peptides
When in doubt, discard and reconstitute fresh
Document any issues for future reference

Maximizing Peptide Stability

Best Practices

Store lyophilized peptides frozen until ready to use
Only reconstitute what you'll use within 4-6 weeks
Refrigerate immediately after reconstitution
Protect from light using amber vials or covering
Minimize temperature cycling - don't repeatedly warm and cool
Use proper sterile technique to prevent contamination
Label with dates - reconstitution date and expiration

Avoid These Mistakes

❌ Leaving reconstituted peptides at room temperature
❌ Storing near windows or under lights
❌ Repeated freeze-thaw cycles
❌ Using beyond recommended timeframe
❌ Contaminating with non-sterile equipment

Freeze-Thaw Considerations

Can You Freeze Reconstituted Peptides?

Generally not recommended because:

Ice crystal formation can damage peptide structure
Repeated freeze-thaw accelerates degradation
Better to reconstitute smaller amounts more frequently

If Freezing is Necessary

Aliquot into single-use portions before freezing
Thaw completely before use - don't refreeze
Flash freezing (liquid nitrogen) is less damaging than slow freezing
Expect some potency loss

Testing Peptide Potency

For critical research, consider:

Third-party testing: Send samples to analytical labs
HPLC analysis: Can detect degradation products
Bioassays: Test biological activity directly

For routine use, following proper storage and visual inspection is usually sufficient.