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Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
A synthetic hexapeptide that stimulates growth hormone secretion by mimicking ghrelin and binding to GHS receptors in the pituitary gland.
Shati. Ali A AA; El-Kott. Attalla F AF
In rats, giving a tiny dose of the hormone ghrelin helped protect kidneys from damage caused by a chemotherapy drug. It did this by lowering inflammation and scar‑building proteins, boosting antioxidant defenses, and turning on a longevity‑related protein called SIRT1. When the ghrelin signal was blocked, the protection disappeared.
Li. Xinying X; Ji. Qun Q; Zhong. Chunrong C; Wu. Congyin C; Wu. Jinchan J; Yuan. Caihong C; Ran. Jia...
In pregnant mice with diabetes, giving the hormone ghrelin lowered blood sugar, cholesterol, triglycerides and insulin levels, protected the pancreas, and reduced cell stress and death. Blocking ghrelin with a GHRP-6 variant cancelled these benefits, showing ghrelin’s role in easing cellular stress.
Frégeau. Geneviève G; Sarduy. Roger R; Elimam. Hanan H; Esposito. Cloé L CL; Mellal....
In a mouse model of high cholesterol, two modified versions of the peptide GHRP-6 (called MPE-001 and MPE-003) were given daily and they slowed down or even reversed plaque buildup in the arteries. The benefit seemed to come from shifting immune cells toward a healing (M2) type and lowering overall inflammation, and it only worked when the CD36 receptor was present.
de la Nuez Veulens. Ania A; Rodríguez Fernández. Rolando E RE; Álvarez Ginarte. Yoann...
Scientists used computer models to see how two new cyclic peptides (A228 and A233) stick to the ghrelin receptor, comparing them to the natural hormone ghrelin and the known peptide GHRP‑6. They found the new peptides bind in a similar way, mainly using a positively charged start (N‑terminal) and an aromatic side‑chain that lines up with a specific pocket on the receptor. From this they suggested a simple design rule (pharmacophore) for making effective ghrelin‑like compounds.
Islam. Md Nurul MN; Zhang. Weidong W; Sakai. Katsuya K; Nakazato. Yuki Y; Tanida. Ryota R; Sakoda. H...
A study in mice found that giving the natural ghrelin blocker LEAP2 doesn’t stop hungry mice from eating, but when mice are on a low‑calorie diet, LEAP2 makes them lose more weight, drop blood sugar, get colder, and turn on some inflammation genes in the liver. These effects happen even in mice that lack the ghrelin receptor, meaning LEAP2 works through other pathways too.
Nisembaum. Laura G LG; de Pedro. Nuria N; Delgado. María J MJ; Isorna. Esther E
In goldfish, giving ghrelin (the hunger hormone) changed the activity of clock genes in the brain and liver and boosted orexin, a wake‑up signal. Blocking ghrelin with a GHRP‑6‑based antagonist stopped the fish’s normal pre‑feeding activity, suggesting ghrelin helps drive the body’s food‑anticipation clock. While the work is in fish and uses injections, it hints that ghrelin can influence circadian rhythms and appetite timing.
Xu. Geyang G; Hong. Xiaosi X; Tang. Hong H; Jiang. Sushi S; Liu. Fenting F; Shen. Zhemin Z; Li. Ziru...
The study shows that ghrelin, the hormone that GHRP‑6 mimics, can lower the gut hormone GLP‑1, which helps control blood sugar, by turning off a cell pathway called mTOR. Mice that can’t sense ghrelin have more GLP‑1, and blocking the ghrelin receptor with a related peptide (D‑Lys‑3‑GHRP‑6) raises GLP‑1 levels in gut cells. Giving ghrelin or GHRP‑6 reduces GLP‑1 production.
Cao. Chun C; Zhang. Yijie Y; Zuo. Shi S; Zhao. Wei W; Wu. Yingxia Y; Ma. Xiaoming X
In rats with sepsis, feeding them through a tube (enteral nutrition) boosted the hormone ghrelin and turned on a brain pathway that reduced the breakdown of muscle and other tissues. When the researchers blocked the ghrelin receptor with a peptide (D‑Lys³‑GHRP‑6) or blocked a cell‑clean‑up process (autophagy), the protective effect disappeared. This shows that ghrelin signaling is needed for the anti‑catabolic benefits of nutrition in this severe illness model.
Smith. R G RG; Leonard. R R; Bailey. A R AR; Palyha. O O; Feighner. S S; Tan. C C; Mckee. K K KK; Po...
Scientists mapped the growth‑hormone secretagogue receptor (GHS‑R) and found that the peptide GHRP‑6 can turn it on, just like the natural hormone ghrelin. They also discovered that other molecules like adenosine and motilin can partially activate related receptors, and that this system has been unchanged for hundreds of millions of years.
Gong. Yating Y; Guo. Yaoyao Y; Jiang. Yiming Y; Xing. Zhiyang Z; Zhang. Heng H; Wang. Hongbo H; Gong...
In rats with diet‑induced fatty liver, blocking the brain's ghrelin receptor with a compound called D‑Lys‑3‑GHRP‑6 lowered blood fats, liver enzymes, and insulin resistance, and it reduced fat buildup in the liver. The effect seemed to come from improved insulin signaling in the hypothalamus.
Azimzadeh. Mansour M; Beheshti. Siamak S
In rats that had already developed epilepsy, blocking the brain's ghrelin receptors with the compound D‑Lys‑3‑GHRP‑6 made seizures last longer and even triggered continuous seizure activity (status epilepticus). This suggests that the natural hormone ghrelin may help keep seizures in check.
Kimura. Risa R; Kondo. Daisuke D; Takemi. Shota S; Fujishiro. Miyuki M; Tsukahara. Shinji S; Sakai....
In mice on a very low‑calorie diet, the brain's stress‑hormone system (CRF receptors) boosts the sympathetic nervous system, which makes the stomach release more ghrelin. That extra ghrelin helps keep blood sugar stable. Blocking ghrelin receptors with a compound called [d‑Lys3]‑GHRP‑6, or blocking the brain stress receptors, drops blood sugar, but giving ghrelin back rescues it.
Bailey. A R AR; Honda. K K; Smith. R G RG; Leng. G G
In male rats, drugs that boost growth hormone (like GHRP-6) light up certain brain cells, but giving morphine or another hormone (GHRH) before the boost cuts down that brain activity. The reduction isn’t total, meaning some brain cells still respond. This shows the body’s own feedback loop can dampen the effect of growth‑hormone‑releasing peptides.
Rodríguez-Viera. Leandro L; Caderno. Anyell A; Martinez. Rebeca R; Martinez-Rodríguez. Gon...
Researchers added the ghrelin‑like peptide GHRP‑6 to the feed of sea bream and found that, after an immune challenge, the fish kept stable blood sugar, fat and stress hormone levels, showed higher antibody numbers, and turned on several immune‑related genes, all without any damage to their gut or spleen. This suggests GHRP‑6 can safely boost immune resilience in fish, but it doesn’t directly tell us how it works in humans.
Howard. A D AD; Feighner. S D SD; Cully. D F DF; Arena. J P JP; Liberator. P A PA; Rosenblum. C I CI...
Scientists identified and cloned the receptor in the pituitary and hypothalamus that GHRP-6 and similar growth‑hormone‑releasing compounds bind to, confirming how these peptides trigger a burst of growth hormone.
Giustina. A A; Bresciani. E E; Bugari. G G; Bussi. A R AR; Deghenghi. R R; Imbimbo. B B; Giustina. G...
In a small study of people with acromegaly, the peptide hexarelin caused a massive jump in growth hormone levels even when cortisol (a stress hormone) was high, showing it can fight the usual cortisol‑induced drop in GH. However, the research used IV doses in a disease group, so it isn’t a ready‑to‑use guide for healthy self‑experimenters.
Poppi. L L; Dixit. V D VD; Baratta. M M; Giustina. A A; Tamanini. C C; Parvizi. N N
The study shows that hexarelin, a peptide similar to GHRP‑6, can make immune cells from pigs and cows release more growth hormone in a lab dish, but it doesn't test this in people or give dosing advice.
Schiöth. H B HB; Muceniece. R R; Wikberg. J E JE
The study shows that GHRP‑6 can stick to two of the melanocortin receptors (MC1 and MC5) but only very weakly, and a modified version (D‑Lys3‑GHRP‑6) sticks to all four receptors. Because the binding is so weak, the peptide probably doesn’t do anything useful through these receptors at the doses people normally use.
Carmignac. D F DF; Bennett. P A PA; Robinson. I C IC
In normal male and female rats, the peptide GHRP‑6 does not raise prolactin levels, but in growth‑hormone‑deficient dwarf rats it can increase prolactin, especially when estrogen is present. This effect seems to come from direct action on the pituitary and is separate from its growth‑hormone‑boosting action.
Martínez. Rebeca R; Hernández. Liz L; Gil. Lázaro L; Carpio. Yamila Y; Morales. Anton...
In animal experiments, the peptide GHRP‑6, which normally makes the body release growth hormone, was found to boost the amount of antibodies produced after a vaccine was given. This effect was seen in mice, tilapia and catfish when the peptide was mixed with the vaccine, but the study only shows results in these animals and does not include any human testing.