What is the difference between intramuscular and subcutaneous peptide injections?

Subcutaneous (SC) injections deliver peptides into the fat layer beneath the skin, resulting in slower, more controlled absorption ideal for sustained release. Intramuscular (IM) injections go directly into muscle tissue, providing faster absorption and quicker onset of action. Most peptide therapies use subcutaneous injection because it is easier to self-administer, requires shorter needles, is generally less painful, and provides steady release into circulation.