Belle21 eyelash serum promotes the natural growth of eyelashes. It results in longer and thicker lashes and improves flexibility and strength. With daily use, you'll see the first results after just 14 days. application: Belle21 eyelash serum is applied once a day to the skin on the upper lash line using the supplied applicator after cleansing in the evening. The usual care products can then be applied after a short exposure time. For ideal results, use once a day.