Noopept

1 Identity

Non-peptide small molecule. A capped dipeptide ethyl ester: neutral crystalline solid with no basic center, therefore no salt form and no counterion. Not a racetam, despite the INN ending and despite the shelf it is sold on. Not a peptide product in any operating sense. Not a synonym for piracetam, phenylpiracetam or aniracetam.

Sequence

No peptide sequence in the operating sense. The structure is N-phenylacetyl-L-prolylglycine ethyl ester: a proline-glycine dipeptide backbone bearing an N-terminal phenylacetyl cap and a C-terminal ethyl ester. In peptide shorthand, PhAc-Pro-Gly-OEt. Exactly one stereocenter, the L-proline alpha carbon, and that single center carries the entire identity burden that no achiral method can discharge. There is no 2-oxopyrrolidine-1-acetamide core anywhere in the structure, so the molecule is not a racetam; that class label is a consumer-channel marketing convention and not a chemical fact. No basic center, so no acetate or trifluoroacetate salt exists and none can be reported.

Molecular formula

C17H22N2O4

Average mass

318.373 Da from C17H22N2O4 on IUPAC 2021 abridged conventional atomic weights. Older atomic-weight tables return 318.368 for the same formula, so both figures are defensible; this catalog standardizes on 318.373. Three institutional monographs print 318.37, which is consistent with either.

Monoisotopic mass

318.1580 Da neutral monoisotopic from C17H22N2O4. [M+H]+ 319.1652; [M+Na]+ 341.1472; [M-H]- 317.1507. The two deltas that govern the impurity table: the de-esterified free acid sits at exactly -28.0313 and the methyl ester analogue at exactly -14.0157.

Salt / variant note

A single molecule by formula, but the substitution risk here is the one no mass measurement can catch. (1) the D-proline epimer is isobaric - identical formula, identical average 318.373, identical monoisotopic 318.1580, identical [M+H]+ 319.1652 - and no reversed-phase chromatogram resolves it. Only chiral HPLC on a polysaccharide stationary phase detects it, so a certificate with no chiral result has not excluded an epimeric lot. (2) The reversed-order regioisomer, N-phenylacetylglycyl-L-proline ethyl ester, is also C17H22N2O4 at 318.1580 monoisotopic and is separable only by NMR or by a qualified resolving method. (3) The de-esterified free acid, N-phenylacetyl-L-prolylglycine, C15H18N2O4, avg 290.316 / mono 290.1267, [M+H]+ 291.1339 - exactly 28.031 Da lighter, and a specified degradant here rather than a separate article, because the ethyl ester is the hydrolysis-labile handle. (4) The methyl ester analogue, C16H20N2O4, avg 304.345 / mono 304.1423, [M+H]+ 305.1496 - exactly 14.016 Da lighter, a plausible synthesis variant and an easy mislabel. (5) Wholesale substitution by cheaper racetams sold under the same marketing class label, all with masses nowhere near 318: piracetam C6H10N2O2, avg 142.158 / mono 142.0742; phenylpiracetam C12H14N2O2, avg 218.254 / mono 218.1055; aniracetam C12H13NO3, avg 219.240 / mono 219.0895. (6) A structural check any reader can run without an instrument: the molecule has no basic center, so it forms no salt. A certificate reporting acetate or trifluoroacetate counterion content, or a net peptide content, is a peptide laboratory's template applied to a molecule it does not fit.

2 Class & testing panel

Form

Single article

Testing panel

P6 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Identifiers by study type. Analytical and physicochemical characterization: Araj et al., J Pharm Biomed Anal 2025, PMID 39298839. Review by the originating group: Ostrovskaia et al., Eksp Klin Farmakol 2002, PMID 12596521. Metabolism, animal (rat): Gudasheva et al., Eur J Drug Metab Pharmacokinet 1997, PMID 9358206. Animal (rat): Ostrovskaya et al., Bull Exp Biol Med 2008, PMID 19240853. Animal (rat, mouse) behavioral paradigms: Ostrovskaya et al., Behav Pharmacol 1999, PMID 10780261; Ostrovskaya et al., J Psychopharmacol 2007, PMID 17092975; Belnik et al., PMID 18214292. In vitro, human cells: Pelsman et al., Int J Dev Neurosci 2003, PMID 12711349. In vitro cell-line proliferation: Zainullina et al., Bull Exp Biol Med 2019, PMID 30788746. Human, open prospective, n=60, post-stroke mild cognitive impairment: Amelin et al., Zh Nevrol Psikhiatr Im S S Korsakova 2011, PMID 22500312. Human clinical study, anesthesia recovery: Belenichev et al., Georgian Med News 2019, PMID 31687967. Comparative animal/human pharmacokinetics: Boyko et al., Eksp Klin Farmakol 2004, PMID 15079908. Pipeline reviews: PMID 12690708, PMID 16395422. Analytical study of marketed consumer products: Cohen et al., Neurol Clin Pract 2021;11(3):e303-e307, PMID 34484905, which found "75 percent (9 of 12) of declared quantities inaccurate, declared drugs sometimes absent and undeclared unapproved drugs present". No systematic human safety dataset and no published acute, repeat-dose, genotoxicity, reproductive/developmental or carcinogenicity toxicology program was identified in the accessible literature.

4 Storage & specification

Storage

No material is received, quoted or ordered until both clearances are in hand. The condition written into the specification, effective from that point: white to off-white crystalline solid, stored at -20 degrees C plus or minus 5 degrees C in the sealed original container with desiccant, protected from light and moisture. The moisture control is not boilerplate - the ethyl ester is the hydrolysis-labile handle and water is the reagent that opens it. Containers are equilibrated to room temperature before opening. Ship frozen or at 2 to 8 degrees C with a validated shipper and a temperature logger.

Shelf life

Provisional 24-month retest interval at -20 degrees C plus or minus 5 degrees C, desiccated and light-protected, with the de-esterified acid designated as the stability-indicating attribute rather than assay. Provisional pending the company's own stability data: three lots on real-time storage with pull points at 0, 3, 6, 12, 18, 24 and 36 months, an accelerated arm at 40 degrees C / 75 percent RH, and an open-dish moisture-challenge arm specifically to characterize ester hydrolysis, since that is the pathway that will decide the interval. Chiral purity is re-measured at the terminal point. No stability program is initiated unless and until those clearances are in place.