RG3vsSermorelin

Ginsenoside Rg3 is a dammarane-type triterpene saponin found in Panax ginseng, with significantly higher concentrations in red (steamed) ginseng compared to white (dried) ginseng, as the steaming process converts other ginsenosides into Rg3 through sugar moiety deglycosylation. It exists as two stereoisomers: 20(S)-Rg3 and 20(R)-Rg3, which have overlapping but distinct biological activities.

Rg3's anti-inflammatory mechanism centers on inhibition of the NF-κB signaling pathway. It prevents phosphorylation and degradation of IκBα, keeping the NF-κB p65/p50 complex sequestered in the cytoplasm and blocking transcription of pro-inflammatory genes including TNF-α, IL-1β, IL-6, COX-2, and iNOS. This broad anti-inflammatory effect is complemented by modulation of the MAPK pathways (ERK, JNK, p38), further reducing inflammatory mediator production.

The anti-angiogenic and anti-tumor properties involve multiple mechanisms. Rg3 suppresses VEGF expression and VEGF receptor signaling (VEGFR2/KDR), inhibiting the formation of new blood vessels that tumors require for growth beyond a few millimeters (tumor angiogenesis). It modulates the PI3K/Akt/mTOR pathway — inhibiting Akt phosphorylation to reduce cell survival signaling and promote apoptosis in cancer cells. It enhances innate immune surveillance by increasing NK cell cytotoxic activity and promoting dendritic cell maturation and antigen presentation, improving the immune system's ability to detect and eliminate abnormal cells. Rg3 also inhibits epithelial-to-mesenchymal transition (EMT) — the process by which cancer cells acquire migratory and invasive properties for metastasis — by modulating TGF-β signaling and maintaining E-cadherin expression. The combination of anti-inflammatory, anti-angiogenic, pro-apoptotic, and immune-enhancing properties has led to Rg3's approval as a cancer adjunct therapy in China and South Korea, though it is not recognized as a drug in Western regulatory frameworks.

Sermorelin is a synthetic peptide consisting of the first 29 amino acids of endogenous growth hormone-releasing hormone (GHRH 1-44). These 29 residues contain the full biological activity domain required for GHRH receptor activation — the remaining 15 amino acids of native GHRH are not necessary for receptor binding or signal transduction.

Sermorelin binds to the GHRH receptor on anterior pituitary somatotrophs, activating the Gs/adenylyl cyclase pathway to increase intracellular cAMP. This triggers PKA-mediated phosphorylation of CREB and stimulates both GH gene transcription and the release of pre-formed GH vesicles. Because sermorelin works through the body's own regulatory system, GH release occurs in a physiological pulsatile pattern governed by the interplay between GHRH stimulation and somatostatin inhibition — the hypothalamic-pituitary feedback loop remains intact.

This preservation of feedback regulation is sermorelin's primary safety advantage over exogenous GH administration. The pituitary gland can only release as much GH as it has synthesized, providing a natural ceiling effect that prevents supraphysiological GH levels. Somatostatin feedback still functions normally, ensuring appropriate pulse spacing. Additionally, because the pituitary itself is being stimulated rather than bypassed, sermorelin may help maintain or even restore pituitary somatotroph function over time. It was the first GHRH analogue to receive FDA approval (as Geref), specifically for evaluating pituitary GH reserve and treating pediatric GH deficiency, giving it one of the longest clinical track records among GH-stimulating peptides.