Epitalon FAQ: Storage, Mixing and Stability

The questions below are the ones researchers ask most about storing, mixing and handling Epitalon. Each answer reflects the peptide’s sequence, Ala-Glu-Asp-Gly, and links to the fuller page where there is one.

How long does Epitalon last in the fridge after mixing?

Mixed with bacteriostatic water and kept at 2 to 8 °C in the dark, Epitalon lasts 8 to 12 weeks under Vistara Labs’ handling guidance, with quality slowly fading from around week 6 to 8. No published study covers Epitalon in solution, so the window is general guidance that its chemistry supports. The full table is on how long Epitalon lasts.

How long does unmixed Epitalon powder last?

One supplier rates the sealed powder, kept away from moisture and light, at 1 year at minus 20 °C and 2 years at minus 80 °C (MedChemExpress, HY-P1149). No supplier fridge figure was found, so the fridge is for vials in near-term use. Days at room temperature in transit do not harm the dry cake, so it ships without an ice pack.

Are Epitalon and Epithalon the same?

Yes. Epitalon, Epithalon and Epithalone are spellings of the same synthetic tetrapeptide, Ala-Glu-Asp-Gly, and PubChem lists them as synonyms of one compound (CID 219042). Epithalamin is different: it is the older pineal gland extract that Epitalon was designed from.

What is the weak point of Epitalon in solution?

The bond between its aspartic acid and glycine. Aspartate can form a ring with the next residue’s backbone and reopen as isoaspartate, and glycine, with no side chain, lets that ring form most easily. In a model peptide with the same pair, acid also cleaved the bond (Oliyai and Borchardt, Pharmaceutical Research, 1993). The details are on the Epitalon stability page.

What do you mix Epitalon with?

Bacteriostatic water, which is sterile water with 0.9% benzyl alcohol so a refrigerated vial can be accessed more than once. Epitalon is small and acidic, and a supplier rates its water solubility at 50 mg/mL or more, so it dissolves fully without acid or other solvents. The reasons are on the Epitalon solubility guide.

How much bacteriostatic water goes in a 10 mg Epitalon vial?

There is no single correct volume. With 2 mL a 10 mg vial gives 5 mg/mL; with 1 mL it gives 10 mg/mL. More water spreads the same amount of peptide through a larger volume, so write the chosen concentration on the vial. The tables and calculator are on the Epitalon reconstitution page.

Should Epitalon be dissolved in acetic acid?

No. Dilute acetic acid is used in labs for hydrophobic or basic peptides that resist water, but Epitalon dissolves readily without it. Acid also cleaves its Asp-Gly bond, which in model work was the main reaction at very acidic pH, and it strips the negative charges that keep the molecules apart.

Why is my Epitalon cloudy after mixing?

Brief cloudiness that clears within 10 to 15 minutes is usually trapped air from adding water too fast or shaking. A tetrapeptide this soluble does not cloud on its own, so haze, particles or a tint that appear later point to contamination, warm storage or freezing, and the solution is discarded. More in why peptides gel or go cloudy.

Can you freeze mixed Epitalon?

Not a vial that will be opened again, because repeated freezing and thawing promotes aggregation in peptide solutions and warms the solution each time. Laboratories that need frozen solution divide it into single-use aliquots and thaw each one once; one supplier gives such stock 1 month at minus 20 °C and 6 months at minus 80 °C. Sealed powder can be frozen without concern.

Does Epitalon need to be kept out of the light?

Light is a minor factor for Epitalon. It has no tryptophan, tyrosine or phenylalanine, the residues that absorb ultraviolet light and start photo-oxidation, and no methionine. The supplier still specifies storage away from light, so the vial is kept boxed in the main body of the fridge, which also keeps it away from warmth.