Natural eyelash loss: Our eyelashes fall out naturally. Since eyelash extensions stick to natural lashes, it's normal for extensions to fall out as natural lashes replace themselves. Eyelash extensions that are not well attached to the natural eyelash won't last. The eyelash extensions will be lifted.
In addition, if an incorrect extension (too long or too thick) is selected, the proper application is more difficult and, in some cases, impossible. If the extensions are not placed the right way, they will inevitably fall out. That's why you don't need to use mascara when applying eyelash extensions. In fact, mascara has been shown to have the ability to break down the glue that holds eyelashes together, especially if you use a waterproof mascara.
So, if you continued to use mascara while you had eyelash extensions, this could be the culprit. Eyelash extensions don't damage eyelashes when applied correctly. To avoid damaging natural lashes, eyelash extensions should be carefully selected (length and thickness) and correctly applied to one natural eyelash at a time. There is no need to let natural lashes break up between eyelash extension sessions when applied correctly.
However, if you lose most of your eyelash extensions in a week or less, something is definitely wrong, whether it's with your aftercare technique, the quality of the eyelashes or the glue used, or with the skills of the eyelash technician you've turned to. When mascara is applied to eyelash extensions, the ingredients can compromise the adhesive and weaken the bond, causing the extensions to detach from the eyelashes and peel off. If, unfortunately, an eyelash technician fixed your eyelash extensions and didn't apply them correctly and you made one of the three mistakes above (extensions that are too heavy, sticky, or shaped like a nail head), your natural lashes could be damaged. If an eyelash is torn off, it will eventually grow back; however, a few months may pass, especially if there has been a break in the growth cycle and the eyelash needs to return to the resting telogen phase.
When eyelash extensions are applied correctly, they must absolutely respect the natural growth cycle of natural lashes. Eyelash extensions won't cause natural lashes to fall out faster than normal: natural lashes simply follow their growth cycle. If the growth cycle of your natural lashes is carefully respected, eyelash extensions won't damage your natural lashes. Taking these two variables into account will allow you to select an eyelash extension that balances with natural lashes.
I've been working in the industry for the past decade and, during that time, I've seen a good number of people who say that eyelash extensions don't work because they start to fall out right away.