Nails grow continuously, not just at night. While you might notice a difference in nail length after a night's sleep, this is simply because you haven't been looking at them for a while. The rate of nail growth is consistent, around a tenth of a millimeter per day. While factors like age, health, and diet can influence this rate, nails do not grow faster at night.
Many people believe that applying oil or other treatments overnight helps nails grow faster, but this is not true. These treatments primarily work by moisturizing and strengthening the nail, which can improve its appearance but won't actually speed up growth.
In summary, nails grow constantly, not just at night. You might notice them seeming longer after sleep because you haven't observed them for a while.
