v3.25.1
Cover - shares
 3 Months Ended
Mar. 31, 2025
Jun. 12, 2025
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Mar. 31, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q1  
Entity Information [Line Items]    
Entity Registrant Name Onconetix, Inc.  
Entity Central Index Key 0001782107  
Entity File Number 001-41294  
Entity Tax Identification Number 83-2262816  
Entity Incorporation, State or Country Code DE  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Contact Personnel [Line Items]    
Entity Address, Address Line One 201 E. Fifth Street  
Entity Address, Address Line Two Suite 1900  
Entity Address, City or Town Cincinnati  
Entity Address, State or Province OH  
Entity Address, Postal Zip Code 45202  
Entity Phone Fax Numbers [Line Items]    
City Area Code (513)  
Local Phone Number 620-4101  
Entity Listings [Line Items]    
Title of 12(b) Security Common stock, $0.00001 par value  
Trading Symbol ONCO  
Security Exchange Name NASDAQ  
Entity Common Stock, Shares Outstanding   44,358,422