2000 Nissan Sentra - Stop leak, or no?

2000 Nissan 1.8L. Coolant disappearing slowly with no puddles. Will “stop leak” type products work on a presumably bad head gasket, or just delay the inevitable? Thank you

Sometimes it is a short delay, sometimes a long one.

If you intend to replace the head gasket, ever, I would not use stop leak. If you just want to get a few more miles on this old car before you get rid of it, go right ahead.