Hexarelin (5mg)

Hexarelin Peptide

Hexarelin (also known as Examorelin) is a synthetic analog of ghrelin and shares a high degree of structural similarity to GHRP-6. Both are research peptides made of six amino acids that mimic the function of the endogenous hormone ghrelin and stimulate the release of growth hormone (hGH) from anterior pituitary gland cells. The only difference between Hexarelin and GHRP-6 is the inclusion of a methyl group in the structure of Hexarelin. Like other ghrelin analogs, this peptide is reported by researchers to display a relative selectivity in its mode of action. However, researchers have commented that Hexarelin is also associated with an elevation in prolactin, adrenocorticotropic hormone (ACTH), and consequently cortisol.^[1][2] It has been extensively studied in relation to cardiac cell survival after ischemia and nutrient deprivation.

Specifications

Molecular Formula: C₄₇H₅₈N₁₂O₆

Molecular Weight: 887.05 g/mol

Sequence: His-2-Me-D-Trp-Ala-Trp-D-Phe-Lys-NH2

Hexarelin Research

Hexarelin and Growth Hormone Secretagogue Receptors
It is theorized that Hexarelin functions by activating growth hormone secretagogue receptors (GHS-Rs), specifically targeting the GHSR-1a subtype.^[3] The activation of these receptors is thought to potentially trigger the release of growth hormone (GH), suggesting Hexarelin’s role as a potential growth hormone secretagogue (GHS). GHS-Rs mediate the actions of ghrelin, an endogenous hormone that typically promotes GH release during fasting periods. It is conceivable that Hexarelin may mimic the role of ghrelin by engaging ghrelin receptors, particularly those located in key areas such as the pituitary gland and hypothalamus, to stimulate hGH secretion.

GHSR-1a receptors are distributed throughout the hypothalamus and pituitary gland as well as across various regions of the nervous system and other bodily tissues. Therefore, it is suggested that Hexarelin’s mechanisms might involve both direct and indirect stimulation of GH release. Direct actions might occur via actions on the GHS-Rs within the pituitary, while indirect actions could involve modulation of the hypothalamus. Upon binding to GHS-Rs, it is speculated that Hexarelin may induce a structural modification in the receptor, potentially initiating signaling cascades reliant on G-proteins. This might lead to the activation of pathways such as those involving protein kinase C (PKC), which might enhance the signaling required for GH secretion from pituitary cells. Nonetheless, it is also hypothesized that Hexarelin exposure could result in transient receptor desensitization, a state that could persist for several days or weeks.^[4] Overall, the activation of the GHSR-1a might represent an alternative route by which Hexarelin regulates hGH synthesis in the anterior pituitary cells, differing from the direct actions mediated by the native growth hormone-releasing hormone (GHRH) on the GHRH receptors in the pituitary gland cells.

Hexarelin and Muscle Cell Protection
The peptide has been suggested to protect cells inside and outside the heart muscle. Studies in Hexarelin and GHRP-6 observe how the peptides may control calcium flow and mitochondrial dysfunction in the muscles of rats suffering from cachexia (extreme weight loss due to illness or chemotherapy).^[5] The researchers report that the secretagogue may potentially “protect skeletal muscle from mitochondrial damage and improve lean mass recovery.” It also appears to keep muscle cells viable by maintaining mitochondrial integrity. Through its energy supply, Mitochondria help muscles carry out day-to-day functions. It has been suggested that calcium ion regulation is often disturbed due to chemotherapy and may be one of the principal causes of altered muscle and lean body mass. Researchers suggest the potential for Hexarelin and GHRP-6 to potentially support the reestablishment of proper calcium regulation. Additional studies have indicated that Hexarelin, a synthetic hexapeptide, might positively reduce muscle degradation in experimental settings that simulate catabolism and cachexia. Cachexia is a complex syndrome associated with severe muscle atrophy and weight loss. For instance, research involving experimental models exposed to catabolic agents showed a 12% decrease in muscle mass.^[6] However, introducing Hexarelin may have reduced this loss to approximately 7%. Another related study proposed that Hexarelin might have helped mitigate the decline in muscular strength typically observed when experimental models are subjected to catabolic agents.^[7]

Hexarelin and Cardiac Functions
Hexarelin appears to affect the heart through its association with the CD36 receptor and the GHSR. Research conducted on murine models suggests that the peptide appears to protect cardiac cells from injury in the backdrop of cardiac arrest.^[8] The scientists even note that Hexarelin “may be a promising [research] agent for some cardiovascular conditions.” Researchers suggest that the peptide may interact with the aforesaid receptors and potentially prevent apoptosis of the cardiac cells. The peptide may act to improve cardiac function, increasing the number of surviving cardiac cells and reducing the levels of malondialdehyde (cardiac cell death marker). Interestingly, the study also suggested GHRP-6 to be partially superior in function compared to ghrelin. Hexarelin has also been observed to ameliorate oxidative stress in cardiac cells during cardiac failure as well as to prevent myocardial remodeling in rats.^[9] Cardiac remodeling is characterized by a decrease in cardiac function and may be fatal. However, GHRP-6 or Hexarelin-exposed rats appeared to show significant improvement in their cardiac function compared to the controls. The molecular mechanisms underlying the function of the peptide have been suggested to involve an increase of phosphatase and tensin homolog (PTEN) activity and subsequent reduction in protein kinase B levels. While PTEN is considered to regulate cellular regeneration, protein kinase B appears to help modulate cell survival. GHRP-6 and Hexaralin may mediate cardiac remodeling by switching the nervous system response from sympathetic (includes increased blood pressure, heart rate, etc.) to parasympathetic. This regulation may help to improve short-term function. Moreover, when exposed to the peptide following cardiac arrest, studies with rat models observed a significant decrease in scar tissue arising from cardiac tissue healing. The peptide may have the potential for assisting in numerous cardiac damages as its mode of action is not hypothesized to be specific to protection against heart attack. Studies in rat models of diabetes have also observed Hexarelin to potentially improve cardiac function by altering the processing of calcium and potassium by cardiac muscle cells.^[10]

Hexarelin and Fat Cells
Dyslipidemia is the physiological condition of elevated fat levels in the blood. Interestingly, it also is considered to be an independent contributing factor for the onset of diabetes. GHRP-6 and Hexarelin studies have observed the peptides’ potential to correct dyslipidemia in the backdrop of insulin resistance (considered the first step in the pathway to diabetes).^[11] The peptide may also help to reduce blood sugar and insulin resistance as reported in rat models.

Hexarelin and Appetite
It has been suggested that Hexarelin might broadly stimulate ghrelin receptors beyond just targeting the pituitary gland, which might possibly impact appetite and hunger.^[12] When activated in certain areas of the nervous system, Ghrelin receptors may initiate cellular activities, leading to an increased release of hunger-promoting neuropeptides such as Neuropeptide Y (NPY) and Agouti-related peptide (AgRP). These neuropeptides play a pivotal role in the regulation of energy balance and the modulation of appetite. It is also hypothesized that Hexarelin could potentially decrease the production of melanocyte-stimulating hormone (α-MSH), an appetite-suppressing hormone, thereby possibly shifting the physiological balance toward enhanced hunger and promoting increased food consumption. Additionally, there is a possibility that Hexarelin may interact with the mesolimbic reward system, which is integral to the regulation of cravings for palatable food, through the potential activation of the GHSR-1a receptor. Such interaction might lead to the activation of cyclic adenosine monophosphate (cAMP) pathways, which may theoretically heighten the motivation to eat, thereby implying a potential influence of Hexarelin on altering feeding behaviors and reward-based eating patterns.

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