Guide
Copper-peptide stability and storage: the vials, the powder and what changes GHK-Cu in solution
Published October 9, 2026 · Facts checked October 9, 2026
Short answer
Every copper peptide and copper blend in our catalogue is a freeze-dried powder in a sealed vial, stored at 2–8 °C and protected from light and moisture. The published chemistry of GHK-Cu concerns solutions: the 1:1 complex forms above about pH 3.6 and changes structure near pH 9.2 and 11.4, and other molecules — histidine, imidazole, glutathione — can join or reduce the copper. For the blends, no published stability study of the fixed combinations was found.
How our catalogue stores them
| Product | Vial strengths | As supplied | Storage |
|---|---|---|---|
| GHK-Cu | 50, 100 mg | Blue lyophilized powder | 2–8 °C, protected from light and moisture |
| AHK-Cu | 20, 50, 100 mg | Blue lyophilized powder | 2–8 °C, protected from light and moisture |
| GLOW | 42, 70 mg | Lyophilized powder; 70 mg blue to blue-green | 2–8 °C, protected from light and moisture |
| KLOW | 80 mg | Blue to blue-green lyophilized powder | 2–8 °C, protected from light and moisture |
| GHK-Cu + TB-500 + BPC-157 | 50 mg | Lyophilized powder | 2–8 °C, protected from light and moisture |
Why the peptides ship as a dry powder
Lyophilized means freeze-dried: the water is removed and the peptide is sealed in its vial as a powder. Every product above ships that way, as a kit of ten vials of one strength. The storage line on the label and on the batch COA is the one to follow; the water content of a batch can be requested before the quote if you need it on paper.
pH and the GHK–copper complex in solution
Once dissolved, GHK and copper(II) form a 1:1 complex above about pH 3.6, and the complex changes structure again near pH 9.2 and 11.4. Across pH 3.5–10.6 several copper–GHK species have been described. A solution's colour and its UV-Vis band are therefore read at a stated pH.
Sources: Freedman et al., Biochemistry 1982 · Lau & Sarkar, Biochem J 1981
Other molecules that change the copper
These are findings about solutions. They matter when a laboratory dissolves a sample for analysis, because what is measured depends on what else is in that solution.
- Histidine joins copper and GHK in ternary complexes.
- Imidazole binds to the copper as an extra ligand and moves the d–d band from about 606 nm to 565 nm.
- Glutathione reduces the copper(II) in Cu(II)GHK.
Sources: Lau & Sarkar, Biochem J 1981 · Bossak-Ahmad et al., Int J Mol Sci 2020 · Ufnalska et al., Inorg Chem 2021
What changes in a blend
In GLOW, KLOW and the 50 mg blend, GHK-Cu shares the vial with peptides that hold no copper. Our catalogue's literature review found no published stability or compatibility study of these fixed combinations. What a batch has is its release data: identity confirmed for each declared peptide, and an assay of each against its own label claim in our specification.
Checking a kit when it arrives
- Product and strength on the vials against your order and the COA.
- Appearance against the COA: blue for GHK-Cu and AHK-Cu, blue to blue-green for GLOW 70 mg and KLOW 80 mg.
- The storage line, so the kit goes straight to 2–8 °C away from light.
Questions
- How should GHK-Cu vials be stored?
- As supplied — lyophilized powder in sealed vials — at 2–8 °C, protected from light and moisture. That is how our catalogue lists every copper peptide and copper blend.
- Does pH change GHK-Cu?
- In solution, yes: the 1:1 GHK–copper complex forms above about pH 3.6 and changes structure near pH 9.2 and 11.4.
- Is there stability data for GLOW or KLOW?
- Our catalogue's literature review found no published stability study of these fixed blends. Each batch has release data: identity for each declared peptide and an assay of each against its label claim.
- What can change the copper in GHK-Cu?
- In solution, other ligands such as histidine or imidazole can join the copper, and glutathione reduces copper(II) in the complex.
References
- Freedman et al., Biochemistry 1982 — structure of the GHK–copper(II) complex in solution — mononuclear 1:1 complex at neutral pH; pH transitions at pK 3.6, 9.2 and 11.4
- Lau & Sarkar, Biochem J 1981 — interaction of copper(II) and GHK — multiple species across pH 3.5–10.6; ternary complexes with histidine
- Bossak-Ahmad et al., Int J Mol Sci 2020 — ternary Cu(II) complex with GHK — d–d band of Cu(GHK) at 605–606 nm; aqua copper absorbs near 816 nm
- Ufnalska et al., Inorg Chem 2021 — reduction of Cu(II)GHK by glutathione — Cu(II)GHK d–d band at 606 nm; imidazole adduct at 565 nm; glutathione reduces the complex
Products and related guides
- GHK-Cu vials and fact table
- GLOW: GHK-Cu, BPC-157 and TB-500
- KLOW: GHK-Cu, BPC-157, TB-500 and KPV
- Batch data and COAs