I was always skeptical about eyelash enhancing serums until I recently tried one myself and noticed visible results in just under two weeks. It’s safe to say I am now a true believer. However, if you’re looking to find one of the best eyelash serums for growth on the market, it’s important to keep in mind that while many formulas may, in fact, keep their promise of helping you get longer, fuller lashes, they often aren’t able to perform their magic without serving you a side of some pretty bizarre side effects.

According to my research, these side effects are usually caused by an ingredient called prostaglandin analogs, which are primarily used in prescription eye drops to treat eye conditions like glaucoma. Researchers noticed that patients using this type of eye drop also experienced eyelash growth, eventually leading the FDA to approve it for this unexpected cosmetic purpose.

If you’re not at all particular about the color of your eyes and aren’t prone to irritation or vision problems, by all means, go for the stronger stuff. But, if you’re not exactly on board with this strange side effect, or god forbid, simply like the color of the eyes you currently have, there are plenty of all-natural and completely natural formulas available that still work on boosting volume, hydration, and length — just without all the weirdness. Scroll through below to check out some of my personal favorite formulas.