Cover - shares	3 Months Ended
	Mar. 31, 2025	May 07, 2025
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2025
Document Transition Report	false
Entity File Number	001-40551
Entity Registrant Name	Acumen Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-4108129
Entity Address, Address Line One	1210-1220 Washington Street
Entity Address, Address Line Two	Suite 210
Entity Address, City or Town	Newton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02465
City Area Code	617
Local Phone Number	344-4190
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	ABOS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,573,425
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001576885
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q1