This site states this specific wording directly: Gelagen is sold with a 60-day money-back guarantee from your purchase date.
Worth marking your actual purchase date specifically when tracking your guarantee window, since this site names purchase date directly rather than shipping date or delivery date as the starting point.
Since this site separately requests at least 30 days of use before requesting a refund, worth reading both figures together — the 60-day window starts at purchase, while the brand's own suggested minimum-use period eats into roughly half of it.