GHK-Cu

What is GHK-Cu?

The 50mg vial is the smaller of the two presentations of GHK-Cu, the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine, molecular formula C₁₄H₂₄CuN₆O₄, molecular weight 403.9 g/mol, CAS 89030-95-5. It holds half the lyophilised mass of the 100mg vial and contains approximately 124 µmol of complex. The compound is identical in both presentations, and the copper-shuttle model, the near-parity of the GHK-Cu stability constant with the albumin copper transport site, the matrikine classification and the extracellular matrix and transcriptomic literatures are all documented on the main GHK-Cu page rather than repeated here. This page documents what is specific to the 50mg format: why a shorter in-use window is a technical advantage for a photolabile copper complex, and the molar-mass error that is easy to make when calculating against a smaller vial. Supplied as lyophilised powder for in-vitro research use only.

GHK-Cu 50mg vs 100mg: Which Vial Size to Choose

The two vials contain the same complex, so this is a handling and logistics comparison rather than a chemical one, and unusually for a size comparison the smaller vial has a genuine technical argument in its favour. GHK-Cu is a photolabile copper(II) complex, and freeze-thaw cycling can disrupt the copper coordination sphere independently of any degradation of the peptide backbone, which means cumulative in-use exposure is a real variable and not a generic caution. A 50mg vial is consumed across a shorter working life, so one reconstituted stock takes fewer stopper penetrations, less light exposure and fewer freeze-thaw cycles before it is finished. That makes it the better choice for pilot studies, method development, spectrophotometric characterisation work, or any protocol that will not consume 100mg inside a sensible window. The 100mg vial answers with a lower cost per milligram and with batch continuity across a larger body of work, since one batch and one certificate of analysis cover twice as much. Molar content differs accordingly, roughly 124 µmol against roughly 248 µmol.

GHK-Cu Research Applications

Applications are those documented for the 100mg vial, since the compound is the same: copper transport and delivery to copper-dependent enzymes, extracellular matrix biology including collagen and glycosaminoglycan synthesis and matrix metalloproteinase-2 expression, matrikine signalling, and transcriptomic profiling. Where the 50mg presentation is specifically useful is in work whose scale is small but whose sensitivity to complex integrity is high. Spectrophotometric characterisation of the Cu(II) centre, stability studies across buffer compositions, competition experiments against other chelators, and method development for HPLC or ICP analysis all consume modest amounts of material while depending heavily on the complex not having degraded in storage. A vial that is opened, used and finished quickly serves that better than half a large vial held across months.

Reconstitution Guide

Allow the vial and the bacteriostatic water to reach room temperature, then swab both rubber stoppers with alcohol. Inject the diluent slowly down the inner glass wall rather than onto the powder, and swirl gently until the blue colour is uniform. Never shake or vortex. Carry out reconstitution away from direct light, since copper(II) peptide complexes are photolabile, and transfer any aliquots into amber or foil-wrapped vessels. Use glass or high-grade polypropylene labware and avoid prolonged contact with stainless steel or other chelating surfaces that can strip Cu(II) from the tripeptide. The solution will be blue to blue-violet, from the d-d transition of the Cu(II) centre, and this is expected. A colourless or green-tinged solution indicates the complex has been disrupted rather than simply diluted, and visible absorption spectrophotometry around 500-600 nm is the standard bench check on complex integrity. When converting a fill volume into molarity, use 403.9 g/mol for the complex, not 340.4 g/mol for the free tripeptide.

See our full peptide reconstitution guide and reconstitution calculator for step-by-step protocol.

Storage Instructions

Lyophilised vials should be stored at -20°C, protected from light and moisture, and remain stable for up to 24 months. Once reconstituted, hold the solution at 2-8°C in a light-protected container. Freeze-thaw cycling can disrupt the copper coordination sphere as well as degrade the peptide backbone, so single-use aliquots in amber or foil-wrapped vessels are preferable to repeated access of one stock. The shorter working life of a 50mg vial is part of what makes it the safer choice for sensitive work, so there is little value in extending that window unnecessarily. Keep both lyophilised material and reconstituted solution away from UV and fluorescent light throughout, and handle under sterile laboratory conditions.

Frequently Asked Questions

Research References

• Growth-modulating plasma tripeptide may function by facilitating copper uptake into cells (Nature, 1980)
• GHK-Cu stimulates matrix metalloproteinase-2 expression by fibroblast cultures (Life Sci, 2000)
• GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration (Biomed Res Int, 2015)

Related Research Compounds

• → GHK-Cu 100mg (main product page)
• → BPC-157 5mg
• → Bacteriostatic Water 10ml