The absorption of B12 requires a substance called intrinsic factor that is produced in the stomach. Malabsorption of B12 can occur in disorders of the stomach. People with HIV disease appear to be prone to B12 malabsorption due to the various types of infections and disorders that may occur in the small intestine. I'm curious about whether or not you had a baseline B12 level or CBC done. Vitamin B12 injections are usually given on a monthly basis.
Weekly injection seems a bit excessive.
There is data to suggest that some people with HIV have low vitamin B12 levels, but I am unaware of information regarding long term use of B12 in HIV patients. If the weight loss, fatigue and muscle aches recur, you and your medical provider should revisit some other potential cause of your symptoms. I hope things continue to improve for you. Experts appearing on this page are independent and are solely responsible for editing and fact-checking their material. Neither The Body nor any sponsor is the publisher or speaker of posted visitors' questions or the experts' material.