Hi,
Welcome to ehealthforum,
Sagging breast can occur due to various reasons like obesity, aging, lack of estrogen, menopause, pregnancy & breastfeeding etc. To reduce breast sagging without aid of medical treatment is difficult, and the claims made are not proven. You can try with push-up bras for proper support, use of massage with creams and serum, exercising pectoral muscles, etc. The effective treatment is surgical correction. If these measures fail to give you desired results, consider visiting your doctor/cosmetologist for breast lift surgery.
Take care.