Hello Robbase916 in Nampa, ID, Thank you for your question regarding 55 years old, 5'9, and 180 lbs and how you can improve your sagging butt? You have several options, including a BBL or butt lift. During a BBL, fat is harvested from one area and transferred to the buttocks. The transferred fat lifts the buttock. The transferred fat can be targeted to individualized creases and indentations on your butt. The transferred fat should work well in your butt, unless trauma caused the indentations. If you do not have enough fat to transfer, consider Alloclae or cadaver fat. Some call Alloclae "Zombie" fat. Another way to lift and smoothe the indentations in your buttocks is with a posterior buttock lift. During a posterior butt lift, an incision is made across the top of the buttock, and the buttock is lifted. Excess upper buttock skin and fat are removed. Most plastic surgeons offer free virtual or in-office physical consultations. Therefore, explore what other plastic surgeons have to say. Good luck. I hope that I have answered your question regarding 55 years old, 5'9, and 180 lbs and how you can fix your sagging butt. If you have any more questions regarding BBL surgery, liposuction, or posterior buttock lift, contact an experienced plastic surgeon. Since BBL, lipo, or buttock lift surgeries are big procedures, please seek an experienced, board-certified plastic surgeon who has significant experience with BBL surgeries. Do your research. If you cannot find an experienced BBL, lipo, or buttock lift plastic surgeon in your neighborhood, consider traveling out of state if you must. Sincerely, Dr. Katzen (Plastic Surgeon, President of the American Society of Bariatric Surgeons, certified by the American Board of Plastic Surgery, Fellow of the International Society of Aesthetic Plastic Surgery, American College of Surgery, and International College of Surgery and member of the American Society of Plastic Surgery, American Academy of Cosmetic Surgery, RealSelf Hall of Fame, and RealSelf Doctor Advisory Board for Medical Review and Consumer Panel.)