DSIP: Delta Sleep-Inducing Peptide, Identity and Analysis

DSIP is one of those compounds where the abbreviation has almost entirely replaced the name. It stands for delta sleep-inducing peptide, and that full name is worth knowing for one practical reason: it is what the older literature indexes it under, so searching the abbreviation alone will miss a good deal of the published work.

The identity

Published on the DSIP 5 mg page:

• Compound: DSIP
• Sequence: Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE)
• Molecular formula: C35H48N10O15
• Molecular mass: 848.8 g/mol
• CAS registry number: 62568-57-4

Nine residues, no modifications, no cyclisation, no terminal caps. As peptides go it is structurally plain, and that plainness has consequences worth understanding before you compare two certificates.

The tryptophan at position one

The sequence opens with tryptophan, and that single residue changes how the compound is measured. Tryptophan is one of the three aromatic amino acids, which means DSIP absorbs meaningfully at 280 nm as well as at 214 nm.

Most peptides do not. A sequence with no aromatic residues is close to invisible at 280 nm, which is why purity figures are normally reported at 214 nm where the peptide bond itself absorbs. For DSIP you can legitimately get a figure at either wavelength, and they will not be the same number — 214 nm sees nearly everything in the vial, while 280 nm sees only what contains tryptophan, tyrosine or phenylalanine.

So if two certificates for DSIP disagree, check the detection wavelength before assuming one is wrong. It is a common and entirely innocent source of variation, covered in more detail in why certificates of analysis disagree on purity.

Asparagine, aspartate and what ages in the vial

The sequence contains aspartate at position five and glutamate at position nine. Acidic residues make the molecule polar and weakly retained on reversed phase, which again means early elution and a method that has to be set up for it.

Deamidation — the loss of an amide group that adds roughly one dalton to observed mass — is the usual slow degradation route for peptides carrying asparagine or glutamine. DSIP carries neither, which is a genuine point in its favour for storage stability, though hydrolysis and moisture uptake still apply to any lyophilised powder. The general case is covered in storage and stability of lyophilised research peptides.

What the certificate establishes

Observed mass against the calculated 848.8 g/mol settles identity. RP-HPLC area percent settles uniformity, subject to the wavelength question above. Endotoxin, sterility and residual solvents are not covered by either and require their own tests.

Where a lot has been tested, the certificate is published on the product page or on the certificates page, matched to your vial by cap and crimp colour. Not every lot has one posted; ask and we will send what we hold for yours. The purity guarantee refunds product and test if an independent laboratory disagrees.

Buying DSIP in Canada

The 5 mg vial dispatches from inside Canada, so no border step and no brokerage appearing after the fact. Cost per milligram is on the price index, quantity pricing applies from two vials in the cart, and shipping is free and tracked over $200 CAD. The wider class sits under neuropeptides.

All compounds referenced here are supplied by ExoLabz for laboratory research use only. They are not for human or veterinary use, are not authorised by Health Canada as a drug or natural health product, and nothing on this page is guidance on preparation, administration or use.