Betamethasone vs Dexamethasone: what is the difference?

How they differ

Betamethasone and dexamethasone have the same formula, C22H29FO5, the same weight of 392.5, and the same atoms connected in the same order. They differ in one methyl group that points up from the ring in one and down in the other, which makes them stereoisomers rather than one molecule. Both are long-acting corticosteroids with a fluorine atom that makes them many times stronger than the body's own cortisol. Dexamethasone became famous in 2020 as the first treatment shown to reduce deaths from severe COVID-19, and betamethasone is widely used in skin creams such as Betnovate. Both are prescription medicines, sold as Decadron and as Celestone.

Side by side

Structural similarity 1.00 of 1, computed as a Morgan fingerprint Tanimoto coefficient. It measures shape, not effect.

Common questions

What is the difference between Betamethasone and Dexamethasone?

Betamethasone and dexamethasone have the same formula, C22H29FO5, the same weight of 392.5, and the same atoms connected in the same order. They differ in one methyl group that points up from the ring in one and down in the other, which makes them stereoisomers rather than one molecule. Both are long-acting corticosteroids with a fluorine atom that makes them many times stronger than the body's own cortisol.

Do Betamethasone and Dexamethasone have the same formula?

Yes. Both are C22H29FO5 at 392.5 g/mol. They are isomers: the same atoms arranged differently, which is why they behave differently despite weighing the same.