Hyperthyroidism. Without any check up?

You can have a multivitamin without any check up but i strongly oppose taking any thyroid medication without undergoing a blood check up for it, you may require other blood investigations as well to find the underlying cause for the loss of weight and muscle. These following steps may help you with gaining weight and muscle: - Eat healthy, avoid junk food, Increase your calorie intake, eat more calories than your body burns in order to gain weight. Aim for 300-500 calories per day above your maintenance level - Eat increased amount of protein as protein will help in muscle gain - In order to gain weight, eat at least 3 meals per day and make sure to eat plenty of fat, carbs and protein in each meal. - Eat food like nuts, dried fruit, high-fat dairy, Fats and Oils, grains, meat, tubers, dark chocolate, avocados, peanut butter, coconut milk, granola, trail mixes. - Drink plenty of fluids(3 liters per day) - Exercise regularly, you can join the gym to gain muscle as well I would advise you to do the whole body check up to rule out any underlying cause for the loss of weight