Wet n Wild's Megalash Clinical Lash Serum claims: "In just 4 weeks, get longer, thicker, fuller-looking lashes!" Lashes have a growth cycle: individual lashes grow to a maximum length (pretty much dictated by one's genetics, as it turns out), the lashes fall out, new lashes begin in their place, and the cycle starts over. This cycle lasts 30-45 days...in other words, four to six weeks. I've been using Wet n Wild's Megalash Clinical Lash Serum on my upper lashes nightly for one week. Since I've never tracked my lash growth cycle before, I figure that if I track my lashes' appearance over seven weeks while using this product as directed, I might get an idea if these claims are just tied to the natural lash cycle, or if there's really something to this product. (Remember: Latisse, the best-known eyelash growth product, works in mysterious ways. Literally. They don't know how or why it works. So any other lash growth serums may be just so much marketing-and-a-prayer; but at least with this I didn't have to get a prescription, and I spent less than $5.)