Ac-SDKP vs CGRP

Inhibits hematopoietic stem cell entry into S-phase. Blocks TGF-β1-mediated fibroblast activation, reducing collagen deposition. Promotes angiogenesis via VEGF upregulation. Regulated in vivo by ACE enzyme.

Ac-SDKP (N-acetyl-seryl-aspartyl-lysyl-proline) is an endogenous tetrapeptide generated from the N-terminus of thymosin beta-4 by the enzyme prolyl oligopeptidase, with further regulation by angiotensin-converting enzyme (ACE), and is characterized by roles in hematopoietic progenitor regulation and anti-fibrotic signaling in renal, cardiac, and vascular tissue. Ac-SDKP inhibits collagen synthesis and fibroblast proliferation, reduces TGF-beta-1-mediated fibrotic signaling, and promotes anti-inflammatory macrophage polarization in preclinical models, suggesting a role in tissue homeostasis downstream of the thymosin beta-4 pathway. Preclinical studies in rodent models of renal fibrosis and systemic lupus erythematosus — predominantly from the NIH-funded Rhaleb and Carretero laboratory at Henry Ford Health — have demonstrated that exogenous Ac-SDKP reduces collagen deposition and inflammatory infiltrate; no human clinical trials have been completed or indexed in PubMed. Ac-SDKP has no FDA approval and no approved indication in any jurisdiction; it is studied as a research compound with a plausible anti-fibrotic mechanism and consistent preclinical evidence, but extrapolation of rodent findings to human therapeutic outcomes has not been validated by any clinical investigation.

Binds CLR/RAMP1 receptor complex. Causes vasodilation via cAMP/PKA/nitric oxide pathway. Modulates nociceptive signaling in the trigeminal system. Promotes bone healing and has anti-inflammatory effects in peripheral tissues.

CGRP (calcitonin gene-related peptide) is a 37-amino-acid endogenous neuropeptide produced by alternative splicing of the calcitonin gene, expressed predominantly in sensory neurons of the trigeminal system and peripheral vasculature, where it functions as a potent vasodilator and pain neuromodulator central to migraine pathophysiology. CGRP activates its receptor complex (CLR/RAMP1) to mediate vasodilation and nociceptive signal amplification; during migraine attacks, trigeminal activation releases CGRP at elevated plasma concentrations, and blockade of this pathway has been established as the primary validated pharmacological target for modern preventive migraine therapy. Phase 3 randomized controlled trials published in the New England Journal of Medicine and the Lancet — including the STRIVE trial (Goadsby et al. 2017) and a Phase 3b study in treatment-refractory patients — demonstrated that anti-CGRP monoclonal antibodies significantly reduced monthly migraine days versus placebo, validating the pathway and supporting FDA approval of erenumab, fremanezumab, and galcanezumab. CGRP itself is an endogenous neuropeptide and is not a therapeutic agent that is compounded or administered by providers; the FDA-approved interventions are monoclonal antibody and small-molecule receptor antagonists available by prescription, and exogenous CGRP peptide is exclusively a research tool compound used in vasodilatory and pain signaling pharmacology studies.