I've been using L'Oreal Double Extend Lash Boosting Serum for about a month. I have always had problems with my eyelashes falling out easily and I decided to try this lash boosting serum to see if it would help any. So far in my experience it has made my eyelashes stronger. They fall out a lot less than they used to and they're even a little bit longer. I haven't experienced any new lash growth (although I've seen many reviews where women say this serum did make them grow more lashes). I think if you're looking for something that will make you grow new lashes then you might be better off getting a prescription for Latisse. But if you are just looking for something that will help your lashes become stronger and a little bit longer, then I absolutely recommend this lash serum.
The only negative thing I can think of is that you have to keep using it on a regular basis or you lose the effect and your eyelashes go back to the way they were before. (But I think this is probably the case with all lash serums). But since this serum only costs about $12 and lasts for a long time, I don't think having to use it regularly would be a problem for anyone.