Endura mass and Serious mass are products made of certain nutrients which are helpful for gaining weight.
But these products are only dietary supplements & should not compromise on routine healthy food such as:
Consume more of natural diet like fresh fruits, green vegetables, milk, eggs, wheat, etc.
Avoid oily and junk food.
Stay away from smoking
Also avoid taking steroids
or other medications that claim to increase weight or build muscles...they may be harmful.
Best is to stay active, exercise regularly, avoid stress
, get good sleep, think positive and stay happy.
Wish you a healthy life.