My decision: I read online that this product works for eyelashes and eyebrows, so I decided to give it a try before anything else on the market since it's not as expensive. It came up in a top ten list of lash/brow growth products, so I thought, hey, if it doesn't work I'm not out a lot of money, so I'll try it first. If it doesn't work, I can try another one. My experience so far: Brows: I have been using this daily (often twice daily) for slightly under a month now on my eyebrows. I can see a good difference in my eyebrows at this point, and started to see a difference around 2 weeks of use. Again, I use this every single day and a lot of the time I put it on twice a day (morning and night). I rub it into my skin so it doesn't leave any residue so I can use it day and night. (If you don't rub it in, it can peel up a bit and appear white if you happen to touch or rub your brows.) I think rubbing it in also helps to get the nutrients into the skin better and/or more deeply than just applying and letting it dry. I use it a little differently than the instructions: I use the little brush on the end to apply the serum to my brows, then I also use the part of the applicator for the lashes to stroke through my brows to make sure it is thoroughly applied, and then rub it all in until it's dry. I also use a pretty good amount of this as well to make sure I give it the best chance to work - it didn't disappoint! All my eyebrow hairs are longer and therefore my brows look fuller, AND I have new hairs growing in. I think I will see the full effects of this at around the 2 month mark as I can still see improvement now at the 1 month mark, which I think is AMAZING. * Side note: if you have lighter eyebrow hairs, tint them with Refecto Cil tint in light brown (3.1). Make sure you purchase the tube of color in light brown and also buy the Refecto Cil 3% Oxidant Creme (on Amazon Smile so you can give to your favorite charity!) Mix the tint and the oxidant creme according to directions and your brows will show up nicely! Lashes: I don't use it as consistently on my eyelashes, but I see a little bit of extra length to my lashes as well. I will be using it more consistently like I do with my eyebrows and I'm sure it will work even better. * Note: I have slipped a few times applying it to my lashes and gotten it directly in my eye, and there was NO stinging at all (other than my eye not being happy because it was lightly poked). Also, when I apply it to my lashes I don't follow the directions exactly: I use the little brush end, wipe the excess off into the rim of the tube, then apply it directly to the top of my lash-line at the roots where the lashes grow and then use the eyelash brush portion to wipe my lashes. I then close my eyes and rub it very gently into my lash-line to get the nutrients to the root of the lashes. I have not tried putting it on my lashes and then putting mascara over the top of it while still wet (which is what the directions say on the package). Rimmel does have a mascara that is fortified with this lash accelerator, so you may want to try that during the day and put this on at night. I was going to try their lash accelerator mascara, but it's not waterproof and I'm in a hot and humid climate where I need waterproof. (I prefer to use more natural products when I can, so I use Pacifica mascara in Aquarian Gaze in Abyss (black) and it works fabulously! I purchase it at Target which has the best price so far, but feel free to shop around to guarantee best price.) Verdict: Rimmel Lash Accelerator Serum really works for me, and I will continue to use it daily until I max out my eyebrow and eyelash growth. At that point I'll probably use it every other day to maintain the growth I've gotten (which is necessary with ALL growth serums). I use a lot of this daily and after using it for a month I still have almost half the tube left, so it lasts a while. If I have any other experiences with this, I will come back and update it for you. Overall, VERY impressed and not going to bother with any other growth serums for my brows or lashes!