Incidentally, the healthy reference range is 191-663 pg/ml and correlates closely with oral cobalamin intake, which is why the vitamin B12 blood level alone is not an adequate parameter to diagnose a deficiency (Herrmann and Obeid, 2014)
While naturopathic doctors wouldnt prescribe B12 for most people without a lab-confirmed deficiency, studies show that B12 injections may improve endurance in athletes
2024 Xintong Ji, Chenxia Li, Xiaozheng Zhu, Wenlei Yu, Yanyu Cai, Xinyi Zhu, Linjie Lu, Qiwei Qian, Yu Hu, Xuan Zhu, Huanhuan Wang
The Importance of Vitamin B12 The Vital Role of B12 in the Body Vitamin B12 is a powerhouse nutrient that plays a pivotal role in maintaining the health and proper functioning of the body