Why Cu²⁺ : Peptide Ratio Matters — A 90-Second Quality Check for Formulators. Read our briefing →
Why Cu²⁺ Ratio Matters — a field guide. Read →
On the Cu²⁺ ratio. Read →
Copper coordinated by pyrrolidone carboxylic acid (5-oxoproline)
Overview
Copper PCA is a copper(II) coordination active in which the metal is carried by pyrrolidone carboxylic acid — INCI Copper PCA, the copper salt of L-5-oxoproline written by CosIng as "L-Proline, 5-Oxo-, Copper Salt (2:1)," CAS 15454-74-7, C10H12CuN2O6, MW 319.8. It earns a place in Cupratec's copper line as the small-ligand end of the coordination range: where GHK-Cu wraps copper in a tripeptide and Copper Lysinate/Prolinate uses an amino-acid pair, Copper PCA delivers Cu(II) through a single, compact, well-characterised PCA ligand. PCA is itself a familiar cosmetic humectant moiety, so this active doubles as a copper carrier whose ligand is already at home in skin-care chemistry. For a formulator it is a copper source with a distinct ligand field and a high water solubility — a useful contrast point against the peptide and amino-acid complexes when mapping how ligand choice shapes a copper active's behaviour. Cupratec supplies it strictly as a cosmetic active; efficacy and any cosmetic claim a finished product makes are the brand's responsibility under its destination-market rules. Cupratec releases Copper PCA on the copper bench used for the peptide complexes. Each lot carries a copper-content figure by atomic absorption with the copper-to-PCA relationship reported as-found against the 2:1 ligand-to-metal stoichiometry, a UV-Vis trace logging the Cu(II) d-d signature for the PCA ligand field, identity confirmation against the C10H12CuN2O6 / MW 319.8 expected value, and a CIELAB ΔE colour reading against an internal Copper PCA master so incoming lots have a colour anchor. As with every copper active in the range, the visible signature is logged against this material's own reference rather than the GHK-Cu band near 622 nm. Fills are 50 mg and 100 mg lyophilized vials, with gram-scale lots on the same documentation pack for contract-monograph development. The copper-content and colour discipline mirrors the peptide complexes — see our Cu²⁺ : peptide ratio field note.
Who buys this, and why
Cosmetic-peptide buyers fall into two groups: established beauty / med-aesthetic brands extending an existing line, and private-label clients building a catalog from scratch. The first group usually wants lyophilized peptide material plus stability data in their existing carrier matrix; the second usually wants a finished formulation under their label. Both need INCI naming verified, regulator-specific safety files (CPNP for EU, FDA OTC monograph for US where relevant), and packaging-compatibility data.
Primary buyer fit: medical aesthetic clinics and med spas, regional distributors and re-sellers, and academic and contract research laboratories.
Specifications
Documentation available on request
Regulatory note
Copper PCA is supplied as a cosmetic-grade INCI ingredient (Copper PCA), a copper-PCA coordination active, not for compounded human-use preparations. Cosmetic-grade material available for beauty private-label brands and finished-product formulators worldwide; INCI name supplied on SDS for cosmetic-notification workflows (CPNP in EU, equivalent registries elsewhere). Finished-product cosmetic claims are the brand's to substantiate under its destination-market rules.
Frequently asked questions
At the small-ligand end of the same coordination range. GHK-Cu carries Cu(II) in a tripeptide pocket; Copper Lysinate/Prolinate uses an amino-acid pair; Copper PCA uses a single compact pyrrolidone-carboxylic-acid ligand at a 2:1 PCA-to-copper stoichiometry. Reading the three together is a clean way to see how ligand size and donor set change a copper active's colour, solubility, and stability — which is exactly the coordination-chemistry question Cupratec is set up to document. The PCA moiety is also a well-known cosmetic humectant, so the ligand is already familiar in skin-care formulation, but Cupratec frames the material as a copper carrier and leaves finished-product claims to the brand.
By assay against the known stoichiometry. Each lot is read by atomic absorption for total copper on the PCA ligand, with the copper-to-PCA relationship reported as-found against the expected 2:1 ligand-to-metal ratio, and identity is confirmed against the C10H12CuN2O6 / MW 319.8 value. A UV-Vis trace logs the Cu(II) d-d signature for the PCA ligand field — distinct from the copper-peptide band near 622 nm — and a CIELAB ΔE reading under D65 anchors the colour against an internal Copper PCA master. The reference matters: each copper active in the range is logged against its own master swatch and its own spectral feature, so the QC signal is specific to the ligand actually present.
The same copper-coordination guardrails that govern the whole range: no strong chelators (EDTA, DTPA) that could strip the copper from the ligand, a near-neutral working pH held through shelf life, reductants kept on a separate phase, and clean process water. Copper PCA's high water solubility makes it straightforward to place in aqueous systems, but a formulator should still confirm the coordination has held through a finished base with copper-content and colour readouts across shelf life rather than assuming stability from the starting material. Use level and finished-product behaviour are formulation choices for the brand to develop and substantiate; the lot-release logic is the one described in our Cu²⁺ : peptide ratio field note.
Related peptides