Is water or silicone-based better and what is the best option from a vaginal health standpoint? The short answer is that silicone-based lubricants are better. 

Water-based lubricants require preservatives to prevent bacterial growth, which means it can interfere with the "good" (Lactobacillus) vaginal bacteria  and thus set off  the pH-balance and potentially lead to infections or discomfort. A silicone-based formula does not require preservatives—which means it won't interfere with the "good" (Lactobacillus) vaginal bacteria and won't disrupt its delicate pH balance. From a vaginal health perspective, we recommend silicon based lubricants.