Peptide stability & storage reference
Every row states whether its number is measured, extrapolated or merely conventional — because most storage advice in this field is the second or third and is presented as the first.
Filter
| State | Condition | Usable window | Basis | Note |
|---|---|---|---|---|
| Lyophilised solid | −20 °C, sealed, desiccated | 24–36 months | measured Supplier guidance | Long-term storage default. Below the glass transition; hydrolysis effectively stopped. |
| Lyophilised solid | −80 °C, sealed | 36+ months | extrapolated Extrapolated | No practical advantage over −20 °C for a dry solid, and a real disadvantage in condensation risk on removal. |
| Lyophilised solid | 2–8 °C, sealed | 12–24 months | measured Supplier guidance | Perfectly adequate for material you will use inside a year. |
| Lyophilised solid | 25 °C, sealed | 4–8 weeks | extrapolated Arrhenius extrapolation | Each 10 °C roughly doubles to triples the rate. This is the transit case. |
| Lyophilised solid | 30 °C, sealed | 2–4 weeks | extrapolated Arrhenius extrapolation | A summer transit lane. Survivable; worth testing after. |
| Lyophilised solid | 40 °C, sealed | 7–14 days | extrapolated Arrhenius extrapolation | An August letterbox. Test before use. |
| Lyophilised solid | 25 °C, opened, humid air | Days | extrapolated Inference | Residual moisture is the dominant variable. Do not open a cold vial in a humid room. |
| Solution, preserved (0.9% benzyl alcohol) | 2–8 °C | 28 days | convention USP microbiological convention | The number is a microbiological risk-category default, not a chemical stability result. |
| Solution, preserved | 25 °C | 3–7 days | extrapolated Extrapolation + label analogy | Licensed pens carry multi-week room-temperature in-use periods, but they are buffered and contain a surfactant. |
| Solution, preserved | 37 °C | Under 48 hours | extrapolated Extrapolation | Aggregation overtakes chemical degradation at this temperature. |
| Solution, unpreserved (sterile water) | 2–8 °C | 24 hours | convention USP microbiological convention | Single-withdrawal presentation only. The limit is bioburden, not chemistry. |
| Solution, any | Repeated freeze-thaw | 2–3 cycles | extrapolated Inference from formulation science | Damage occurs at the moving ice front and via freeze-concentration, not during the cold hold. |
| Solution, any | Agitation / vortexing | Immediate | measured Formulation science | Interfacial denaturation. Swirl; do not shake. A research vial has no surfactant to protect it. |
| Solution, any | Direct sunlight | Days | extrapolated Residue-dependent | Matters for tryptophan, tyrosine and methionine. Amber glass is cheap insurance. |
| Licensed semaglutide pen | In use, ≤30 °C | Several weeks | measured Label | Buffered, surfactant-containing, preserved. Do not transfer this figure to a reconstituted research vial. |
| Licensed tirzepatide vial | In use, refrigerated | Weeks per label | measured Label | As above. The formulation is doing work your vial is not. |
Which degradation pathway dominates when
| Pathway | Residues at risk | Dominant when | How it presents analytically | Note |
|---|---|---|---|---|
| Deamidation | Asn, Gln | Solution, neutral to alkaline pH | +1 Da; new earlier-eluting peak | Strongly sequence-dependent — the n+1 residue dominates the rate |
| Oxidation | Met, Trp, Cys | Light, trace metals, peroxides | +16 Da per oxygen | Amber glass and metal-free diluent help |
| Hydrolysis | Backbone amides | Solution, pH extremes, heat | Fragment masses | The reason a dry solid outlasts a solution by orders of magnitude |
| Aspartimide formation | Asp-Gly, Asp-Ser | Synthesis and solution | −18 Da; often reversible | A synthesis impurity as often as a degradation product |
| Aggregation | Whole molecule | Agitation, interfaces, high concentration | Often invisible on RP-HPLC; visible on SEC | The failure mode your purity test is worst at detecting |
| Fibrillation | Whole molecule | Prolonged warm storage | Visible haze, then precipitate | Effectively irreversible |
| Racemisation | His, Cys, Asp | Synthesis; alkaline conditions | Same mass, shifted retention | Needs peptide mapping or a chiral method to localise |
| Freeze-concentration damage | Whole molecule | Freeze-thaw of buffered solution | Loss of recovered content | Buffer components crystallising at different rates shift local pH |
The temperature arithmetic, briefly
Over the range that matters, degradation follows Arrhenius kinetics closely enough to reason with. A useful shorthand is Q10 ≈ 2 to 3: every ten degrees of increase multiplies the rate by two to three.
So ten days at 30 °C is equivalent to roughly 10 × 2.5((30−4)/10) ≈ 10 × 2.52.6 ≈ 110 days at 4 °C, using the middle of that range. Bad, and not the catastrophe it feels like when you open a warm parcel — provided the material was a dry solid, in which case the absolute rates are so low that a hundred equivalent refrigerated days is nothing. Run the same calculation on a reconstituted solution and the conclusion inverts, because the baseline rate in solution is orders of magnitude higher.
That asymmetry is the single most useful thing on this page: a warm transit is a problem for solutions and mostly a non-problem for solids.
Related tags: peptide-stability832 The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,… Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the… Keeping material within a temperature window from manufacture to use: phase-change packs versus dry ice, thermal mass, transit-lane temperature… What repeated freezing does to a peptide in solution: ice-crystal shear at the growing front, freeze-concentration of solutes, pH shifts as buffer… How long a preparation remains within specification: labelled expiry for a sealed lyophilised vial, beyond-use dating after reconstitution, and…peptide-stability
storage
cold-chain
freeze-thaw
shelf-life
Sigma-Aldrich - Certified Reference Materials
Analytical standards and reagents with traceable certificates. Every quantitative result you read inherits the accuracy of the standard behind it.
Shop standards