Peptide injections typically last around 2-4 hours in the body before being broken down and excreted. However, the duration of effects can vary considerably depending on the specific peptide used, the dosage, and the injection protocol. Some of the key factors that influence how long peptide injections last include: Peptide type - Short chain peptides tend to have shorter half-lives than longer peptides. For example, GHRP peptides like GHRP-6 tend to last only 30-60 minutes. In contrast, longer peptides like Ipamorelin can last for several hours. - The amino acid sequence also impacts stability. Some peptide bonds are more resistant to breakdown than others. Dosage - Higher doses saturate receptors more fully and can extend the duration of effects. However, there are limits to how much can be used safely. - Frequent smaller doses spaced throughout the day can help maintain steady peptide levels compared to a single large injection. Injection method - Subcutaneous injections into fat provide slower absorption compared to intramuscular, pushing duration of effects out longer. - Localized injection near target tissues can also help concentrate effects. Individual factors - Age, sex hormone status, BMI and genetics can all influence metabolic rates and thus peptide breakdown. - Fasted vs fed state may also impact absorption rate and kinetics. Those with more fat tissue tend to exhibit longer action. In general, most users find they need to dose peptide injections 2-3 times per day to maintain reasonably steady levels. Some of the more commonly used peptides and their typical duration include: