Prednisone is about five times more potent than cortisone, meaning 5 mg of prednisone delivers roughly the same anti-inflammatory effect as 25 mg of cortisone. That potency gap is the single biggest practical difference between these two drugs, and it shapes almost everything else: how they’re dosed, how long they last in your body, and which conditions they’re used for. Both are synthetic corticosteroids that mimic cortisol, the stress hormone your adrenal glands produce naturally, but they’re far from interchangeable.
How Potency Compares
On a standardized scale where hydrocortisone (the pharmaceutical form of your body’s own cortisol) rates a 1.0 for anti-inflammatory potency, cortisone scores 0.8 and prednisone scores 4.0. That makes prednisone five times stronger milligram for milligram. In practical terms, a doctor prescribing prednisone can use much smaller tablets to achieve the same level of inflammation control, which also means fewer total milligrams passing through your system each day.
This potency difference is why prednisone dominates modern prescribing for inflammatory and autoimmune conditions. Cortisone, being weaker and shorter-acting, is now used far less often as an oral medication and is more commonly encountered as a cortisone injection into a joint or soft tissue.
Both Are Prodrugs That Need Your Liver
Neither prednisone nor cortisone is active on its own. Both are prodrugs, meaning your liver has to convert them into their active forms before they can do anything. Cortisone gets converted to cortisol (hydrocortisone), and prednisone gets converted to prednisolone. The conversion happens through the same enzymatic pathway: a reaction that reduces a specific chemical group on the steroid molecule.
This matters if you have liver disease. When liver function is impaired, the conversion of prednisone to prednisolone can be incomplete, which reduces how much active drug actually reaches your tissues. In those situations, a doctor may prescribe prednisolone directly instead of prednisone, bypassing the need for liver conversion altogether. The same logic applies to cortisone and cortisol, though this comes up less often in practice since cortisone is rarely prescribed orally anymore.
Duration of Action
Cortisone is classified as short-acting. Its active form, cortisol, has a half-life of about 1.8 hours, which means it clears quickly and typically requires two or three doses spread across the day to maintain steady levels. Prednisone’s active form, prednisolone, has a longer half-life of up to 3.2 hours. That roughly doubles the time it stays active in your bloodstream, and in many cases allows for once-daily dosing.
For someone managing a chronic condition, that difference in dosing frequency can be significant. Taking one pill in the morning is simpler and easier to stick with than splitting doses throughout the day. It also more closely mimics the body’s natural cortisol rhythm, which peaks in the early morning and tapers off by evening.
What Each One Is Used For
Prednisone is the workhorse of oral corticosteroid therapy. Its higher potency and longer action make it the go-to choice for a wide range of conditions where the goal is to suppress inflammation or calm an overactive immune system. Common uses include asthma flares, COPD exacerbations, rheumatoid arthritis, lupus, inflammatory bowel disease, severe allergic reactions, and certain blood cancers like leukemia and lymphoma. It’s also used after organ transplants to prevent rejection.
Cortisone occupies a narrower role today. Oral cortisone acetate is sometimes used for adrenal insufficiency and congenital adrenal hyperplasia, conditions where the body doesn’t produce enough cortisol on its own and the goal is simply to replace what’s missing at physiologic (normal body-level) doses rather than suppress inflammation at high doses. More commonly, though, you’ll encounter cortisone as a joint injection for localized pain and swelling in conditions like osteoarthritis, tendinitis, or bursitis.
How They’re Taken
Prednisone comes in a wide range of oral formulations: standard tablets (from 1 mg up to 50 mg), delayed-release tablets, liquid solutions, syrups, and pre-packaged taper packs designed for short courses where the dose steps down over several days. This flexibility makes it easy to fine-tune dosing for everything from a brief flare to long-term maintenance therapy.
Cortisone is available as oral tablets but is more limited in its range of strengths and formulations. Its most familiar form for many people is the injectable suspension used for cortisone shots, where the drug is delivered directly into a joint, bursa, or tendon sheath to reduce local inflammation without flooding the entire body with steroids.
Side Effects
The side effects of all oral corticosteroids overlap heavily because they work through the same pathways. Changes in body fat distribution affect 61 to 69 percent of people on longer courses, and insomnia affects roughly half. Other common effects include increased appetite, weight gain, elevated blood sugar, mood changes, fluid retention, and thinning skin. With use beyond five years, the risk of cataracts rises substantially.
Because prednisone is more potent, it’s typically used at lower absolute doses than cortisone to achieve the same effect, but that doesn’t necessarily mean fewer side effects. Side effects from corticosteroids are driven primarily by the total glucocorticoid activity your body experiences over time, not the raw milligram count. At equivalent anti-inflammatory doses, prednisone and cortisone carry similar risks. One meaningful difference: cortisone has slightly more mineralocorticoid activity, which means it’s more likely to cause salt and water retention compared to prednisone at equivalent doses. This can show up as puffiness, mild swelling, or a bump in blood pressure.
Breastfeeding and Pregnancy
Prednisolone (the active form of prednisone) passes into breast milk at very low levels. No adverse effects have been reported in breastfed infants whose mothers were taking corticosteroids, including mothers on long-term prednisone at doses of 5 to 10 mg daily. The older recommendation to wait four hours after a dose before nursing is no longer considered necessary given how little drug actually reaches the milk. Medium to large doses of any corticosteroid can temporarily reduce milk supply, but this effect is reversible.
Less safety data exists specifically for cortisone during pregnancy and breastfeeding, largely because it’s prescribed less frequently as an oral medication. In general, prednisone and prednisolone are the preferred corticosteroids during pregnancy when one is needed, partly because the placenta breaks down prednisolone before it reaches the fetus more efficiently than it handles some other steroids like dexamethasone.