The FDA recently approved one of these, elamipretide, for the treatment of a rare genetic mitochondrial disorder
Same peptide sequence

its relevance to retatrutide specifically is not yet established A history of pancreatitis or significant gastrointestinal disease Gallbladder disease , including a history of gallstones or cholecystitis Diabetes mellitus , particularly if managed with insulin or sulphonylureas, due to hypoglycaemia risk Cardiovascular disease , including arrhythmias or recent cardiac events Renal or hepatic impairment , which may affect tolerability and increase the risk of dehydration-related complications Pregnancy or breastfeeding no safety data exist for retatrutide in these groups Use of oral medicines where absorption may be affected by delayed gastric emptying , such as levothyroxine or combined oral contraceptives Seek urgent medical attention if you experience severe or persistent nausea or vomiting, persistent abdominal pain (which may indicate pancreatitis or gallbladder disease), signs of an allergic reaction (rash, swelling, difficulty breathing), chest pain, palpitations, or signs of dehydration

FDA material governs the United States rather than the United Kingdom, but it provides a useful illustration of the unresolved safety and quality questions surrounding the compound
document standing BP measurements CIDP / Immune-Mediated Neuropathies IVIG: first-line