Most reconstituted peptides last 28-30 days when properly refrigerated, but it varies by peptide type, water used, storage conditions, and preservative content.

GLP-1 peptides like semaglutide may last longer (30-45 days).

Growth hormone peptides typically last 28-30 days.

Some peptides without preservatives degrade faster.

Understanding these differences prevents wasted money and ensures effective treatment.

This guide breaks down exact shelf life for each major peptide category, what factors affect longevity, how to recognize degradation, optimal storage practices, and when to mix fresh batches.

You'll know precisely how long your specific reconstituted peptide lasts refrigerated.

Let's start with the general rule, then dive into peptide-specific timelines.

General rule: 28-30 days for most reconstituted peptides

When peptides are reconstituted with bacteriostatic water and properly refrigerated, the standard shelf life is approximately one month.

Why 28-30 days is the standard

Bacteriostatic water preservation: Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth. This preservative remains effective for about 28 days after opening or mixing. After that, bacterial contamination becomes more likely even with refrigeration.

Peptide stability in solution: Once dissolved in water, peptide bonds can slowly hydrolyze. Temperature slows but doesn't stop this process. After 30 days, even refrigerated peptides begin losing potency measurably.

Conservative recommendation: Manufacturers and clinics typically recommend 28-30 days because it balances safety (bacterial growth risk) with peptide stability. Most peptides retain 90-95% potency at 28 days, dropping to 80-85% by 60 days.

FDA guidelines for reconstituted medications: Pharmacy standards for reconstituted injectable medications typically cite 28 days as maximum when using bacteriostatic water, even with refrigeration.

Factors that extend or shorten shelf life

Extends shelf life:

• Proper refrigeration (consistent 2-8°C)

• Minimal light exposure

• Sterile reconstitution technique

• Quality bacteriostatic water

• Sealed vial (rubber stopper intact)

Shortens shelf life:

• Temperature fluctuations

• Light exposure

• Contamination during drawing

• Low-quality water

• Damaged vial seal

Bottom line: 28-30 days is safe, conservative timeline for nearly all peptides when stored properly. Some peptides tolerate slightly longer, but 30 days is the reliable maximum.

Shelf life by peptide category

Different peptides have different stability profiles.

Healing peptides (BPC-157, TB-500, KPV)

These are among the most stable peptides after reconstitution.

BPC-157:

• Standard shelf life: 28-30 days refrigerated

• Maximum (if necessary): 45 days, expect 10-15% potency loss

• Very stable peptide due to short sequence

• Shows minimal degradation in first month

TB-500 (Thymosin Beta-4):

• Standard shelf life: 28-30 days refrigerated

• Maximum: 45-60 days, expect 15-20% potency loss

• Relatively stable in solution

• Longer peptide chain but still maintains structure well

KPV:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 30-40 days

• Tripeptide (very short), highly stable

• Minimal degradation within first month

Recommendation: Follow 28-30 day rule for these healing peptides. They remain effective throughout this window.

See our BPC-157 guide and TB-500 guide for complete protocols. Use our BPC-157 dosage calculator and TB-500 dosage calculator.

Growth hormone peptides (CJC-1295, Ipamorelin, GHRP-6, GHRP-2)

Growth hormone releasing peptides are moderately stable.

CJC-1295 (with or without DAC):

• Standard shelf life: 28-30 days refrigerated

• Maximum: 35-40 days, expect some potency loss

• Stable peptide, no special concerns

Ipamorelin:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 35 days

• Very stable GHRP

GHRP-6 and GHRP-2:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 30-35 days

• Similar stability to Ipamorelin

IGF-1 LR3:

• Standard shelf life: 28 days refrigerated

• Maximum: 30 days (do not push longer)

• More sensitive to degradation than other peptides

• Loses potency faster after 28 days

Hexarelin:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 35 days

Recommendation: Stick to 28-30 days for all growth hormone peptides. IGF-1 LR3 should not exceed 28 days.

Learn more in our best peptides for muscle growth guide.

GLP-1 agonists (Semaglutide, Tirzepatide)

These FDA-approved medications have longer shelf life data.

Semaglutide:

• Standard shelf life: 30-45 days refrigerated

• Maximum: 56 days (some clinical protocols allow)

• More stable than research peptides

• Pharmaceutical-grade formulations include additional stabilizers

Tirzepatide:

• Standard shelf life: 30-45 days refrigerated

• Maximum: 56 days

• Similar stability to semaglutide

Important note: Research chemical versions of semaglutide/tirzepatide may be less stable than pharmaceutical versions. Follow 28-30 day rule if using research peptides.

Recommendation: Pharmaceutical semaglutide/tirzepatide can last 30-45 days. Research versions should follow 28-30 day rule.

See our semaglutide vs tirzepatide guide and use our semaglutide dosage calculator.

Fat loss peptides (AOD 9604, Tesamorelin)

AOD 9604 (HGH Fragment 176-191):

• Standard shelf life: 28-30 days refrigerated

• Maximum: 35 days

• Fragment of growth hormone, reasonably stable

Tesamorelin:

• Standard shelf life: 30 days refrigerated

• Maximum: 45 days (pharmaceutical formulations)

• FDA-approved, includes stabilizers

Recommendation: Follow 28-30 days for research versions, 30-45 days for pharmaceutical Tesamorelin.

Anti-aging and longevity peptides

Epithalon:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 30-35 days

• Short peptide sequence, stable

Thymosin Alpha-1:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 45 days (pharmaceutical grade)

• Relatively stable peptide

Semax and Selank:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 30-35 days

• Short peptides, stable

Sexual health peptides

PT-141 (Bremelanotide):

• Standard shelf life: 28-30 days refrigerated

• Maximum: 45 days (pharmaceutical Vyleesi)

• Stable peptide

Melanotan II:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 35-40 days

• Relatively stable

Copper peptides (GHK-Cu)

GHK-Cu injectable:

• Standard shelf life: 28-30 days refrigerated

• Maximum: 30 days (copper can catalyze oxidation)

• More sensitive than other peptides due to copper ion

Special note: Copper peptides may show visible degradation (color change to greenish/blue) if stored too long. Discard if color changes.

See our copper peptides storage guide and GHK-Cu complete guide.

Reconstituted peptide shelf life table

Quick reference for all major peptides:

Key:

• Standard shelf life = Safe, reliable timeline with minimal potency loss

• Maximum shelf life = Upper limit before significant degradation (expect 10-20% potency loss)

What happens to peptides after 30 days in fridge

Understanding degradation helps you make informed decisions.

Gradual potency loss

Days 1-28: Minimal degradation. Peptides retain 95-100% potency. This is the safe zone.

Days 28-45: Gradual decline. Most peptides retain 85-95% potency. Still effective but losing strength.

Days 45-60: Noticeable degradation. Peptides may retain only 70-85% potency. Results become inconsistent.

Beyond 60 days: Significant degradation. Potency drops below 70%. Not recommended to use.

Bacterial contamination risk

Bacteriostatic water's preservative effect diminishes over time.

Weeks 1-4: Bacterial inhibition strong. Contamination risk minimal with proper handling.

Weeks 4-6: Preservative weakening. Contamination possible if poor handling or temperature abuse.

Beyond 6 weeks: Preservative largely ineffective. Bacterial growth likely if any contamination occurred during reconstitution or drawing doses.

Signs of bacterial contamination:

• Cloudiness (should be clear)

• Particles or floating material

• Unusual odor

• Color change

Physical degradation signs

Visual changes indicating degradation:

• Clear solution becomes cloudy

• Color change (especially copper peptides)

• Precipitation or crystals forming

• Separation of layers

When in doubt: Discard. Don't risk injecting degraded or contaminated peptides.

Factors that affect refrigerated shelf life

Several variables influence how long your reconstituted peptides last.

Storage temperature consistency

Optimal: 2-8°C (36-46°F) constant

Temperature fluctuations shorten shelf life:

• Frequent door opening warms vials temporarily

• Power outages or fridge malfunctions

• Storing in fridge door (warmest, most variable location)

Best practice:

• Store in main fridge section (not door)

• Middle or back of shelf (most stable temperature)

• Away from freezer section (avoid freezing)

• Avoid frequent removal for extended periods

Light exposure

Peptides degrade faster with light exposure, especially UV light.

Protection strategies:

• Keep vial in original box

• Wrap in aluminum foil

• Store in opaque container

• Refrigerator naturally limits light, but protect during removal

Amber vials: Some peptide suppliers use amber glass vials for light protection. This extends shelf life slightly.

Water quality and preservative content

Not all bacteriostatic water is equal.

Quality bacteriostatic water (0.9% benzyl alcohol):

• Inhibits bacterial growth effectively

• Standard for peptide reconstitution

• 28-30 day shelf life reliable

Sterile water (no preservative):

• MUCH shorter shelf life: 3-7 days maximum

• Bacterial growth risk high

• Only use if consuming entire vial within days

Lower quality bacteriostatic water:

• Preservative concentration may be lower

• Contamination during manufacturing

• Shorter shelf life than premium water

Recommendation: Always use pharmaceutical-grade bacteriostatic water from reputable suppliers.

See our bacteriostatic water guide for sourcing quality water.

Reconstitution technique and sterility

Contamination during mixing shortens shelf life dramatically.

Proper sterile technique:

• Clean hands thoroughly

• Wipe vial tops with alcohol before every needle insertion

• Use sterile needles and syringes

• Don't touch needle to any non-sterile surface

• Inject water slowly down side of vial (not directly onto powder)

• Don't shake, swirl gently

Poor technique consequences:

• Bacterial contamination introduced during mixing

• Peptide degradation from vigorous shaking

• Shorter shelf life even with proper refrigeration

Learn complete reconstitution technique in our how to reconstitute peptides guide.

Vial seal integrity

Once vial seal is compromised, shelf life decreases.

Multi-dose vials:

• Each needle puncture creates potential entry point for contaminants

• After 10-15 punctures, seal integrity weakens

• Recommendation: Use vial within 28 days even if seal appears intact

Single-dose draws:

• If drawing entire vial in one session, seal integrity not an issue

• Can preload syringes for convenience (store in fridge, use within week)

Extending shelf life: tips and tricks

While 28-30 days is standard, these practices maximize longevity.

Mix smaller batches more frequently

Strategy: Instead of reconstituting entire 10mg vial to last 8 weeks, reconstitute 5mg to last 4 weeks.

Benefits:

• Always using fresh peptides

• No worry about degradation

• Can adjust doses without wasting partially-used vials

Trade-off: Slightly more frequent mixing (minor inconvenience for better quality).

Freeze individual doses (controversial)

Some users pre-load syringes and freeze them individually.

Potential benefits:

• Extends beyond 30 days

• Convenient pre-measured doses

Significant risks:

• Ice crystal formation can damage peptide structure

• Unknown potency loss during freezing/thawing

• No clinical data supporting this practice

Recommendation: Not advised. Better to mix fresh batches than freeze reconstituted peptides.

Store in original packaging

Vials that come in boxes or protective packaging should remain there.

Why it helps:

• Protects from light

• Adds insulation against temperature fluctuations

• Keeps vials organized with reconstitution dates

Label with reconstitution date

Essential practice: Write reconstitution date on vial or box immediately after mixing.

Why it matters:

• Easy to track 28-day window

• No guessing when peptides expire

• Multiple peptides? Never confuse which was mixed when

Use waterproof marker or label: Refrigerator condensation can smudge ink.

Minimize vial removal time

Each time you remove vial to draw dose:

• Take out vial

• Draw dose quickly (1-2 minutes)

• Return to fridge immediately

Don't:

• Leave vial on counter for 30+ minutes

• Warm to room temperature before drawing (unnecessary for most peptides)

• Forget to return to fridge (happens more than you'd think)

How to tell if your reconstituted peptides have gone bad

Recognition prevents using ineffective or unsafe peptides.

Visual inspection

Clear solution should remain clear:

• Any cloudiness = discard

• Particles floating = discard

• Color change = discard (especially important for copper peptides)

• Separation or layers = discard

Exception: Some peptides may have slight natural color. What matters is CHANGE from when first mixed.

Smell test

Normal: Faint medicinal smell or no smell at all.

Warning signs:

• Sour smell

• Rancid odor

• Any unusual smell different from when first mixed

If smells off: Discard. Don't risk injecting.

Effectiveness loss

Subjective but important indicator:

• Peptide stopped working as well

• Need higher doses for same effect

• Complete loss of expected benefits

Example: BPC-157 was reducing pain, but suddenly stops helping. Peptide may be degraded.

Date check (most reliable)

Simplest method: If it's been more than 30 days since reconstitution, discard regardless of appearance.

Why: Degradation may not be visible. Bacterial contamination may not show obvious signs. Better safe than sorry.

Special cases: peptides that differ from standard timeline

Peptides reconstituted with sterile water (no preservative)

Shelf life: 3-7 days maximum, refrigerated

Why so short: No bacteriostatic preservative. Bacterial growth can occur despite refrigeration.

When this happens:

• Pharmacy compounds without bacteriostatic water

• User mistakenly uses sterile water instead

• Specific medical reason to avoid benzyl alcohol preservative

Recommendation: Only use sterile water if consuming entire vial within 3-5 days. Otherwise, always use bacteriostatic water.

Pharmaceutical-grade pre-filled pens (Ozempic, Wegovy, Mounjaro, Zepbound)

Different rules apply for pharma products:

• Ozempic pen: 56 days after first use (per FDA label)

• Wegovy pen: 28 days after first use

• Mounjaro/Zepbound pen: 28 days after first use

Why longer: Pharmaceutical formulations include additional stabilizers not present in research peptides. FDA-tested stability data supports longer timelines.

Important: These timelines only apply to authentic pharmaceutical products, NOT research chemical versions.

Peptides with added preservatives or stabilizers

Some compounding pharmacies add extra preservatives or stabilizers.

May extend shelf life to:

• 45-60 days depending on formulation

• Pharmacy should provide specific expiration guidance

If unsure: Follow standard 28-30 day rule.

Cost-benefit analysis: using peptides near expiration

Should you use peptides at day 35? Day 40? Day 50?

Financial consideration

Scenario: You have expensive peptide vial at day 35. Half remains. Discard or continue?

Option 1: Discard and mix fresh

• Cost: Price of new vial

• Benefit: Guaranteed full potency

• Risk: None (besides cost)

Option 2: Continue using

• Cost: None (already paid for)

• Benefit: Don't waste remaining peptide

• Risk: 10-15% potency loss means 10-15% less effectiveness

Calculation: If vial costs $50 and you're at day 35 with half remaining, you're deciding whether to waste $25 to guarantee full potency, or accept 10-15% reduced effectiveness.

When to extend timeline

Consider using beyond 30 days when:

• Peptide is very expensive (TB-500, pharmaceutical GLP-1s)

• You're close to finishing vial (only 2-3 doses remain)

• Peptide appears perfect (clear, no smell, stored optimally)

• You're using for non-critical purpose (anti-aging vs acute injury)

• Financial hardship makes wasting difficult

Maximum extension: 45 days for most stable peptides (BPC-157, TB-500, semaglutide). Not recommended beyond this.

When to strictly follow 28-30 days

Always discard at 30 days when:

• Using for critical healing (serious injury, surgical recovery)

• Peptide shows any signs of degradation

• Storage conditions were suboptimal (power outage, left out, etc.)

• Peptide is sensitive (IGF-1 LR3, copper peptides)

• You can afford fresh vial without financial strain

Reconstituted peptide shelf life FAQs

Can I refreeze reconstituted peptides?

No. Never freeze reconstituted peptides. Ice crystals damage peptide structure. If you must travel without refrigeration, use insulated cooler with ice packs, but avoid freezing.

Can I store reconstituted peptides at room temperature?

Only very briefly. Room temperature dramatically accelerates degradation. Refrigeration is mandatory for shelf life beyond a few days.

Short-term room temp tolerance:

• 15-30 minutes: Fine (drawing dose)

• 2-4 hours: Acceptable if necessary (traveling short distance)

• 24+ hours: Significant degradation, bacterial risk increases

Never intentionally store reconstituted peptides at room temperature.

Does freezing peptides before reconstitution extend shelf life?

Yes. Lyophilized (freeze-dried) powder can be frozen for 24-36 months before reconstitution. This is different from freezing AFTER reconstitution (which is harmful).

Freezing powder:

• Safe and effective

• Extends shelf life beyond room temp or refrigerated storage

• Thaw completely before reconstituting

What if my refrigerator lost power?

Timeline matters:

Power outage <4 hours: Peptides likely fine if fridge stayed closed. Continue using if they appear normal.

Power outage 4-12 hours: Peptides may have warmed significantly. If they still look clear and normal, can probably use but consider discarding soon.

Power outage >12 hours: Discard. Temperature abuse significantly shortens shelf life and increases contamination risk.

Can I mix peptides from same vial over time?

Question: Reconstitute half vial now, add more water to other half later?

Answer: No, don't do this. Once vial is opened and exposed to air/moisture, the entire contents begin degrading. Reconstitute full vial or transfer unused powder to new sterile vial immediately (difficult to do properly).

How you can use SeekPeptides for optimal peptide storage and protocols

Maximizing peptide effectiveness requires more than just knowing shelf life - you need personalized protocols, accurate dosing, and expert guidance on storage.

SeekPeptides provides everything you need to use reconstituted peptides safely and effectively.

Personalized peptide protocols with optimal reconstitution schedules: SeekPeptides creates custom protocols showing exactly when to reconstitute each peptide based on your dosing frequency.

Know whether to mix a full 10mg vial to last 6 weeks or split into two 5mg reconstitutions for maximum freshness. Get precise timelines for your specific peptide stack, so you're never guessing whether your month-old BPC-157 is still effective or if it's time to mix fresh.

AI peptide advisor for storage questions: Wondering if your semaglutide that's been in the fridge for 35 days is still good? Need to know if you can travel with reconstituted TB-500 for a week? Curious whether that slightly cloudy BPC-157 is safe or should be discarded? Get instant expert answers about storage, shelf life, degradation signs, and whether to continue using or mix fresh.

Ask about optimal reconstitution timing, batch sizing, or troubleshooting storage issues - anytime you need help.

Complete research library for peptide stability: Access comprehensive guides on peptide degradation mechanisms, bacteriostatic water chemistry, optimal storage conditions, and stability data for specific peptides.

Understand exactly why temperature matters, how preservatives work, and what factors accelerate or prevent degradation.

See the science behind shelf life recommendations and make informed decisions about extending timelines when necessary.

Reconstitution calculators and tracking: Our peptide reconstitution calculator shows exactly how much bacteriostatic water to add for your target concentration, how many doses you'll get from each vial, and when you'll need to reconstitute fresh batches. Track your reconstitution dates, get reminders when peptides approach expiration, and never waste money on forgotten vials that sat too long.

Storage optimization guidance: Learn proper refrigeration techniques, how to identify quality bacteriostatic water, sterile reconstitution methods that prevent contamination, and travel storage solutions. Know exactly how to maximize shelf life through optimal storage practices while maintaining safety and effectiveness.

Cost-benefit analysis tools: Our peptide cost calculator helps you determine whether mixing full vials or smaller batches more frequently makes financial sense for your protocol. Calculate the true cost of discarding partially-used vials versus the risk of reduced potency from extended storage.

Protocol adjustments for reconstitution timing: SeekPeptides optimizes your dosing schedule around reconstitution windows. If you're stacking BPC-157, TB-500, and CJC-1295, get a schedule showing when to reconstitute each peptide to minimize waste while ensuring maximum potency. Know whether to sync reconstitution dates or stagger them for convenience.

SeekPeptides takes the guesswork out of peptide storage and reconstitution timing. Instead of worrying whether your peptides are still effective or wasting money discarding good peptides too early, you get personalized protocols with clear timelines, storage guidance, and expert AI support whenever questions arise.

Stop losing sleep over shelf life concerns, just know exactly when your peptides expire and when to mix fresh batches.

Final thoughts

How long do reconstituted peptides last in the fridge? For most peptides, 28-30 days is the safe, reliable answer.

Some peptides tolerate slightly longer - BPC-157, TB-500, and pharmaceutical GLP-1s can last 35-45 days. Others require stricter timelines - IGF-1 LR3 and copper peptides should stay within 28-30 days.

The critical factor is using bacteriostatic water and maintaining consistent refrigeration at 2-8°C.

Beyond 30 days, you're accepting gradual potency loss and increased contamination risk.

For most users, mixing fresh batches every 28-30 days provides peace of mind and guaranteed effectiveness.

The cost of occasionally discarding partially-used vials is small compared to the cost of using degraded peptides that don't work.

Store in main fridge section, protect from light, maintain sterile technique, label with reconstitution date, and discard at 30 days unless you have specific reason to extend.

These simple practices ensure your reconstituted peptides remain safe and effective throughout their use.

Your peptides are an investment in your health. Proper storage and timely replacement protect that investment and ensure you get the results you're paying for.

Helpful resources for peptide storage

• Peptide storage guide: complete protocols - Comprehensive storage information

• How to reconstitute peptides: step-by-step - Proper mixing technique

• Peptide reconstitution calculator - Calculate water amounts and doses

• Bacteriostatic water guide - Choose quality water

Related guides worth reading

• Should copper peptides be refrigerated: storage guide - Copper peptide specifics

• BPC-157 complete guide: healing protocols - BPC-157 information

• TB-500 guide: recovery protocols - TB-500 details

• Semaglutide vs tirzepatide: GLP-1 comparison - Weight loss peptides

• Best peptides for muscle growth - Growth hormone peptides

• How to inject peptides safely: complete tutorial - Injection technique

• Getting started with peptides: beginner roadmap - New to peptides?

In case I don’t see you, good afternoon, good evening, and good night.