In general, the shorter the needle, the lower the risk of injecting into muscle by accident, especially in people with minimal fat
Ma J, Rayner CK, Jones KL, Horowitz M
However, during clinical trials, researchers observed a notable side effect: significant weight loss
(Eur J Endocrinol 1998) reported that ipamorelin stimulated GH release from anterior pituitary somatotrophs via GHSR-1a (Gq/11PLCIP pathway) at doses up to 200-fold its GH-effective dose without significantly elevating ACTH, cortisol, FSH, LH, prolactin, or TSH above GHRH-stimulated controls in rats
2 Otoprotection in Zebrafish Lateral Line Hair Cells Uribe et al., Frontiers in Cellular Neuroscience (2015) This paper from the Coffin laboratory (with WSU co-authors) tested whether Dihexa could protect zebrafish lateral line hair cells (homologous to mammalian inner ear hair cells) from aminoglycoside-induced ototoxicity