Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 31, 2021
Entity Information [Line Items]
Entity Shell Company	false
Document Quarterly Report	true
Document Transition Report	false
Entity Registrant Name	MANNATECH, INCORPORATED
Entity Central Index Key	0001056358
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Document Type	10-Q
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		1,921,761
Entity Address, Postal Zip Code	75028
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	75-2508900
Entity Address, Address Line One	1410 Lakeside Parkway, Suite 200,
Entity Address, State or Province	TX
Entity Address, City or Town	Flower Mound,
City Area Code	(972)
Local Phone Number	471-7400
Entity File Number	000-24657
Title of 12(b) Security	Common Stock
Trading Symbol	MTEX
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes