Peptides are short chains of amino acids that mostly act as signals, for example telling the body to release its own growth hormone or to repair tissue. Anabolic steroids are synthetic forms of testosterone that build muscle strongly but carry serious risks to the heart, liver, fertility and mood. SARMs are unapproved experimental drugs, often sold mislabelled, and linked to liver injury. Peptides generally have milder effects and fewer side effects, but many are still experimental. None of the three should be used without a physician, and all can be banned in tested sport.

Most scholars, including the Islamic Fiqh Academy, hold that non-nutritive injections under the skin or into the muscle do not break the fast, so a prescribed peptide pen can usually continue during Ramadan. The practical change is timing: most patients move their dose to after iftar or before suhoor. Weight-loss peptides need extra care because of dehydration and low blood sugar. Ask your physician to adjust your plan before Ramadan starts, and ask a trusted scholar if you are unsure about the religious ruling.