| Document And Entity Information | Mar. 28, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 28, 2023 |
| Entity Registrant Name | Biomea Fusion, Inc. |
| Entity Central Index Key | 0001840439 |
| Entity Emerging Growth Company | true |
| Securities Act File Number | 001-40335 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 82-2520134 |
| Entity Address, Address Line One | 900 Middlefield Road, 4th Floor |
| Entity Address, City or Town | Redwood City |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94063 |
| City Area Code | 650 |
| Local Phone Number | 980-9099 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Ex Transition Period | false |
| Title of 12(b) Security | Common Stock, $0.0001 par value |
| Trading Symbol | BMEA |
| Security Exchange Name | NASDAQ |
