Annual report [Section 13 and 15(d), not S-K Item 405]

Cover

v3.26.1
Cover - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2025
May 26, 2026
Jun. 30, 2025
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Dec. 31, 2025    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2025    
Current Fiscal Year End Date --12-31    
Entity File Number 001-39555    
Entity Registrant Name GREENWICH LIFESCIENCES, INC.    
Entity Central Index Key 0001799788    
Entity Tax Identification Number 20-5473709    
Entity Incorporation, State or Country Code DE    
Entity Address, Address Line One 3992 Bluebonnet Dr.    
Entity Address, Address Line Two Building 14    
Entity Address, City or Town Stafford    
Entity Address, State or Province TX    
Entity Address, Postal Zip Code 77477    
City Area Code (832)    
Local Phone Number 819-3232    
Title of 12(b) Security Common Stock, $0.001 par value    
Trading Symbol GLSI    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 56
Entity Common Stock, Shares Outstanding   14,678,208  
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] true    
Document Financial Statement Restatement Recovery Analysis [Flag] false    
Entity Listing, Par Value Per Share $ 0.001    
Auditor Firm ID 206    
Auditor Opinion [Text Block] We have audited the accompanying balance sheets of Greenwich LifeSciences, Inc. (the “Company”) as of December 31, 2025 and 2024, and the related statements of operations, stockholders’ equity, and cash flows for the years then ended, and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for the years then ended, in conformity with accounting principles generally accepted in the United States of America.    
Auditor Name MaloneBailey, LLP    
Auditor Location Houston, Texas