What is GHRP-2 peptide?
GHRP-2 (also known as pralmorelin) is a synthetic growth hormone secretagogue which interacts with the ghrelin/growth hormone secretagogue receptor. It was the first growth hormone secretagogue to be introduced commercially, amongst several others. It is a peptide that is now sold as a test peptide to evaluate growth hormone deficiency as well as secondary adrenal failure. GHRP-2 has also been evaluated in stage II clinical trials for the assessment of short stature. Extensive research has also been performed to evaluate its role in the regulation of muscle development, appetite, the immune system, and sleep cycles. GHRP-2 remains orally and sublingually active and hence does not require an intravenous introduction for its physiological efficacy.
AKA: Thymosin Beta 4
Molecular Formula: C45H55N9O6
Molecular Weight: 817.9 g/mol
PubChem: CID 6918245
CAS Number: 158861-67-7
Medical Research Studies
1. Stimulates Appetite
GHRP-2 improves appetite and, thereby, the intake of food. This holds relevance in the backdrop of chronic diseases where appetite stimulation is an important part of overall health care. The ability of the peptide to easily and reliably stimulate the appetite could be beneficial for chronically ill patients and help to improve long-term outcomes.
2. Protect and Enhance Muscle Structure
Research in yaks shows that GHRP-2 peptide can stimulate the growth of muscles in two ways: enhanced protein synthesis and accumulation, as well as reduced protein degradation. The study demonstrated that GHRP-2 helps to overcome natural growth limitation that occurs in yaks because of food deprivation, adverse environmental conditions (such as cold), and disease. The most significant observation has been the role of GHRP-2 in reducing muscle atrophy through repression of atrogin-1 and MuRF1- proteins, which regulate muscle degradation pathways. Therefore, GHRP-2 may be employed for conditions associated with decreased catabolism, commonly observed in chronic illnesses such as autoimmune diseases and cancer.
3. May Protect the Heart
Studies in fetal heart cell culture lines have shown that GHRP-2 and its analogs (GHRP-1 and GHRP-6) can help to protect cardiac cells by minimizing apoptosis or programmed cell death. The peptides thus help to protect cardiac muscles from reduced supply of blood and nutrients, which ensues a cardiac arrest. The use of Hexarelin, a GHRP-2 analog, has shown that these peptides associate with a specific receptor. Identification of new tissue-specific receptors thus may lead to the discovery of novel pathways for newer drugs, as well as improve our knowledge of the human physiology and mechanisms to avoid dysfunction.
4. Improves the Immune System
GHRP-2 peptide has been shown to enhance the functions of the thymus, an organ that helps protect and mature certain cells of the immune system, especially the T lymphocytes. T lymphocytes are crucial for adaptive immunity and our physiological capacity to combat complex infections. However, the efficacy of the thymus diminishes with age, which causes many age-related problems ranging from insufficient tissue repair to poor immunity. This often leads to an inability to ward off infections, guard against cancer, and perform normal tissue functions. In such cases, GHRP-2 has demonstrated the capacity to rejuvenate the thymus, thereby promoting the number and diversity of T-cells, thus boosting the body’s general immunity.
5. May Affect Pain Perception
It was initially thought that GHRP-2 decreases pain associated with osteoarthritis in animal models through the stimulation of growth hormone production and the repair of damaged tissues. However, it has been observed that GHRP-2 causes pain relief before tissue repair, which happens due to its action on opioid receptors.
There are four known opioid receptors. Most opioid pain medications, unfortunately, mediate a universal action on all four receptors. The medicines’ generic mode of action can create challenges as the receptors have differential and diverse functions. Some of the receptors influence pain; some affect sensations such as wakefulness and breathing, while still others impact addiction. GHRP-2, on the other hand, is a selective opioid receptor agonist, binding uniquely to the receptors responsible for pain relief, addiction and, sedation. This observation indicates that selective opioid agonists can help avoid unwanted effects like respiratory distress and addiction.
6. Improves Sleep Quality
GHRP-2 has been observed to influence sleep cycle in several ways. The peptide increases the duration of stages 3 and 4 of the sleep cycles by about 50% as well as improves the duration of REM sleep by approximately 20%. It further diminishes deviation in sleeping patterns from “normal sleep” significantly. Overall, the improvement in sleep leads to betterment in cognitive function, blood pressure, healing, and energy levels. These findings are relevant for adults but specifically for the elderly population where sleep quality gets affected due to age. GHRP-2 can thus be useful in the improvement of sleep quality and help attain all the benefits of a complete night’s sleep in a shorter duration.
Studies have shown the peptide to have minimal to moderate side effects, low oral bioavailability, and excellent subcutaneous bioavailability in murine models. Per kg dosage in mice does not scale up to the requirement for human use.