Have been without thyroid (99%) for 54 years, on levothyroxin for 53 years and added pa 35 years ago, which am now on b12 injections bi-weekly and I folic acid tablet daily. Am able to regulate body temperature with a little extra levo, but becomes more difficult toward the end of b12 period. Being in the sun on a clear day is tough, body heats up faster and to much sun leaves skin blotchy. Still have a tough time regulating hemoglobin, is always a little low. Folic seems to help also between shots. Have seen pictures of how the pa is affecting lining of stomach wall. Closely monitored.