[3]: 271 Both corticotropin and tetracosactide have been used for diagnostic purposes to determine adrenocortical insufficiency, particularly in Addison's disease, via the ACTH stimulation test.

[10] In the US corticotropin is used to treat epileptic spasms in infants, acute exacerbations of multiple sclerosis in adults; acute episodes of psoriatic arthritis and rheumatoid arthritis and ankylosing spondylitis; in acute exacerbations or as maintenance therapy for collagen disorders like systemic lupus erythematosus and systemic dermatomyositis; for skin conditions like severe erythema multiforme and Stevens–Johnson syndrome; for serum sickness; for severe acute and chronic allergic and inflammatory processes involving the eye such as keratitis, iritis and iridocyclitis, diffuse posterior uveitis, choroiditis, optic neuritis, chorioretinitis, and anterior segment inflammation; sarcoidosis in the lungs; and to treat edema in certain nephrotic syndromes.

[10] In the US the only contraindication for tetracosactide for diagnostic use is hypersensitivity to ACTH[7] but in the UK, regulators placed contraindications for hypersensitivity to ACTH and additionally, for people with allergic disorders including asthma, acute psychosis, infectious diseases, peptic ulcer, refractory heart failure, Cushing's syndrome, treatment of primary adrenocortical insufficiency and adrenocongenital syndrome.

If the adrenal glands are healthy, a single injection of tetracosactide results in a rise in blood cortisol concentrations in 30 minutes.

[3]: 271 The synthetic form consists of the first 24 (of a total of 39) amino acids of ACTH and retains full function of the parent peptide.

[36][37] The Federal Trade Commission and attorneys general from five states sued Mallinckrodt for anti-competitive behavior with regard to the acquisition of Synacthen Depot and the monopolistic pricing of Acthar, and in January 2017 the company settled, agreeing to pay $100 million and to license Synacthen Depot to a competitor.

[33] According to Kaiser Health News, Mallinckrodt responded by increasing its Congressional lobbying to $610,000, and its contributions to Congress members to $44,000, in the first quarter of 2017.

[38] In Canada, Synacthen Depot's pricing increased by 2000% in 2015, causing some provincial single payer authorities to delist the drug from funded medications.