Eyelash Extensions are synthetic fibers which come in various lengths, thickness and curves to create a natural look. Lash extensions are attached one at a time using a specially formulated waterproof adhesive. Applying the initial full set of lashes takes about two hours. When professionally applied, lash extensions will feel like your natural eyelashes. Lash extensions typically last 4-6 weeks. Factors such as your lifestyle and the general care of your lashes will affect how long your extensions last. Since lash extensions are attached to a single eyelash it will shed with your natural growth cycle; therefore it is recommended to come in at least every two to three weeks for refills. Refills usually take up to an hour.