try to dissolve your complex in different solvents such as acetonitrile, ethanol etc and leave the solution to evaporate at room temperature. if you are lucky u will get crystals after some days.

It is not easy to prepare crystals especially from aqueous solutions. But I woul apply  the general method: prepare a concentrated solution of the title compound,  adjuste the pH value to the desired value of the maximum formation and wait, wait, wait up to the formation of the first microcrystals (do not touch them e let them to become bigger).

I recommend to use Amonia solution ( concentrated). But pH and geting enough time is so important.

Dear Ahmed Hammouda 

Copper peptides are naturally occurring small protein fragments that have high affinity to copper ions. In human plasma, the level of GHK-Cu is about 200 µg/ml at age 20. By the age of 60, the level drops to 80 µg/ml. In humans, tripeptide GHK-Cu can promote activation of wound healing, attraction of immune cells, antioxidant and anti-inflammatory effects, stimulation of collagen and glycosaminoglycan synthesis in skin fibroblasts and promotion of blood vessels growth. Recent studies revealed its ability to modulate expression of a large number of human genes, generally reversing gene expression to a healthier state. Synthetic GHK-Cu is used in cosmetics as a reparative and anti-aging ingredient.

I advise you to dissolve your compound completely in a suitable solvent and leave it to cool very slowly at RT for long time (few days) keeping small vent on the neck of the vessel to permit very very small rate of evporation avoiding any dust to come in.

Best wishes