Most buyers stock backup lash glue bottles but ignore unopened expiration timelines, using aged expired glue that causes eye swelling and weak lash hold. Sealed unused glue has a fixed shelf life different from opened adhesive. Standard unopened latex-free lash glue shelf life: 12 months sealed at room cool temperature. Waterproof black strong-hold glue lasts 10 months unopened due to more active pigment ingredients. Hypoallergenic sensitive glue expires faster at 8 months sealed, as mild preservatives degrade sooner. Proper long-term storage for unopened glue: place bottles in dark dry drawers away from sunlight, bathroom steam and high temperature (do not leave in car summer heat). Heat accelerates chemical breakdown and shortens sealed shelf life by half. Three signs sealed glue has expired even before printed date: bottle top glue oozes thick yellow liquid, glue separates into watery and thick layers when shaken, strange sour chemical odor when opening seal. Expired glue loses holding power and releases irritant substances; discard immediately without testing on eye skin. After opening any glue bottle, finish use within 3 months maximum.
