Will I lose my beard gains after stopping Minoxidil?

Minoxidil is effective as long as it is in use. Once you quit using it, the beard that you gained during minoxidil use won't grow any longer.

This is a good question. The most important factor in beard growth is time. If you are under 30, it is possible you have not yet achieved your full potential for growth. Beard growth does not reach the full potential until 30. You are correct that beard growth is not negatively affected by DHT. It is unlikely that there are many minoxidil dependent hairs after stopping- most men do not notice loss after stopping but its not impossible. I always encourage users of minoxidil for beard growth to consult a physician for guidance.

Hair that is grown by the drug minoxidil is usually dependent upon minoxidil and may be lost upon stopping the drug+