In a mixing bowl, combine brown sugar, onion powder, garlic powder, salt, pepper, and optional red pepper flakes, stirring until well blended. Set aside.

Rub the seasoning mixture over the entire surface of the pork loin roast.

Place the seasoned pork roast in your slow cooker. Pour in the chicken broth and Worcestershire sauce around the roast.

Set the slow cooker to low temperature and cook for 6-8 hours, checking after 6 hours for tenderness.

In a saucepan, combine balsamic vinegar, honey, minced garlic, and brown sugar to make the glaze. Heat until it boils, then reduce to simmer for about 10 minutes.

Once cooked, remove the roast from the slow cooker and let it cool for about 10 minutes. Brush with the balsamic glaze.

Slice the pork roast and serve on a platter with any remaining glaze.