My weights has reached the static equilibrium from more than 1 year between 77-79 KG. I wanted to make it 74 Kg, but no success so far.
Is it somehow related to testosterone? Would it be safe to take testosterone supplements or it has consequences?
Your weight will not be 74kg from 77-79 KG maybe because you don't exert much effort to reach it? You don't have that kind of determination to achieve it. I know you will tell me that you do everything to lose weight but I think it's not enough because you're still struggling.
I understand, it's not easy to lose weight that much because it requires you to be serious and focus on your goals. You need to change your lifestyle starting from the way you eat, sleep and exercise. Being healthy starts really in the kitchen, you should avoid alcoholic drinks, pizza, burgers and eating in fast food chain. Start eating healthy foods or make your own healthy recipes and have fun. If you are planning to go to the gym I suggest you get a gym instructor, in that way he/she can monitor on your improvements. You need also to drink more water every day before you start eating and every before and after your workout. Have a good sleep and everything will be fine. I know you can do it. AJA!!
Testosterone might have some indirect influence in this, but the bottom line is that your change in weight is decided by your caloric intake versus how many calories you burn.
That's really all you should focus on. If you want to lose extra weight, you either need to increase your physical activity (how many calories you burn) or reduce how much you eat (how many calories you intake) or both.
A little routine cardio exercise (running) will help you achieve this easily.
Hope this helps!