If you stop taking your GLP-1, rebound effects are possible
Although both classes of drug have shown significant benefit versus placebo control in phase 3 clinical trials, the residual risk remains high after treatment with either of these drug classes in CKD and T2D (Table 1) [12,13,14,15,16]
If you have previously used a branded product and are switching to a compounded version, the transition from a pre-filled pen to a vial and syringe can feel different
Moreover, atorvastatin treatment led to downregulation of co-stimulatory molecules for T-cell stimulation, for example, CD80, and enhanced the number of regulatory T cells in mononuclear cell lymph nodes [66]
Summary: Mixing retatrutide with GHK-Cu is not supported by any published clinical evidence, pharmacokinetic data, or regulatory guidance, and carries significant unknown risks