v3.25.2
Document and Entity Information - shares
 9 Months Ended
Jun. 30, 2025
Aug. 13, 2025
Document and Entity Information [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Jun. 30, 2025  
Entity File Number 001-37410  
Entity Registrant Name ESSA Pharma Inc.  
Entity Incorporation, State or Country Code A1  
Entity Address, Country CA  
Entity Tax Identification Number 98-1250703  
Entity Address, Address Line One Suite 720  
Entity Address, Address Line Two 999 West Broadway  
Entity Address, City or Town Vancouver  
Entity Address State Or Province BC  
Entity Address, Postal Zip Code V5Z 1K5  
City Area Code 778  
Local Phone Number 331-0962  
Title of 12(b) Security Common Shares  
Trading Symbol EPIX  
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 false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   47,308,394
Entity Central Index Key 0001633932  
Current Fiscal Year End Date --09-30  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Amendment Flag false