General alternatives:
* Humiliating
* Insulting
* Disparaging
* Contemptuous
* Scornful
* Belittling
* Degradation
* Abasing
* Diminishing
More specific alternatives:
* If it's about social status: Lowering, degrading, debasing
* If it's about personal worth: Despicable, worthless, contemptible
* If it's about language: Insulting, abusive, offensive, derogatory
Example:
* Instead of saying "His remarks were demeaning," you could say:
* "His remarks were humiliating."
* "His words were disparaging and offensive."
* "He belittled her achievements."
The best word will depend on the specific situation and the desired level of formality.