From simple blood tests B12 levels can be evaluated, often even with a diet high in protein we see low levels. If you are wondering what your nutrient status is, come and have us evaluate you.
Dr. Michael Kane
This common vitamin deficiency can mimic normal aging
A vitamin measured in millionths of a gram may hold surprising secrets about energy, aging, and why some people feel exhausted.
Date:
June 25, 2026
Source:
The Conversation
Summary:
Vitamin B12 is needed in microscopic amounts, but a shortage can have major effects on health and energy. The vitamin was first linked to a lifesaving liver treatment for pernicious anemia nearly 100 years ago. Today, researchers are finding that B12 may also help keep cellular powerhouses called mitochondria functioning properly. This could explain why some people experience fatigue and brain fog even before traditional signs of deficiency show up.
Two micrograms is an almost unimaginably small amount. It weighs less than a tiny fragment of a grain of table salt. Yet adults need only around this amount of vitamin B12 each day, depending on the guideline used, to support red blood cells, nerves and DNA production.
In 2026, it is 100 years since George Minot and William Murphy reported that a liver-rich diet could treat pernicious anemia, then a frequently fatal disease. Their work transformed medicine and eventually led scientists to identify vitamin B12 as the substance in liver that treated the disease.
Two micrograms is an almost unimaginably small amount. It weighs less than a tiny fragment of a grain of table salt. Yet adults need only around this amount of vitamin B12 each day, depending on the guideline used, to support red blood cells, nerves and DNA production.
In 2026, it is 100 years since George Minot and William Murphy reported that a liver-rich diet could treat pernicious anemia, then a frequently fatal disease. Their work transformed medicine and eventually led scientists to identify vitamin B12 as the substance in liver that treated the disease.
People at higher risk, including vegans, vegetarians, older adults and those taking medicines that affect stomach acid or diabetes treatment, may need testing or supplementation advice from a health professional.
Doctors have traditionally linked tiredness in B12 deficiency to anemia. Without enough vitamin B12, the bone marrow cannot produce healthy red blood cells. Instead, it releases unusually large and immature cells that carry oxygen less effectively around the body.
But anemia may not be the only reason people with low B12 feel exhausted.
Low energy
In humans, vitamin B12 is directly needed by only two enzymes, the proteins that help chemical reactions happen in the body. One helps the body make DNA, which cells need when they divide. The other helps mitochondria process certain fats and protein building blocks. Mitochondria are the tiny structures inside cells that help turn food into usable energy.
This mitochondrial role has attracted growing interest from researchers studying ageing, muscle function and vitamin B12 status. A 2026 study explored what happens when cells do not have enough B12. Researchers found that low B12 could interfere with the DNA inside mitochondria and reduce energy production in laboratory models of skeletal muscle (muscle cells studied outside the human body).
A related study in aged female mice found that B12 supplementation improved several signs of mitochondrial health in muscle, including the number and structure of mitochondria. Together, this work points to one possible reason why some people with low B12 report fatigue before obvious anemia is detected.
These findings do not mean vitamin B12 supplements can reverse ageing or act as an energy booster for people whose B12 levels are already normal.
Scientists have suspected a link between B12 and mitochondrial function for many years, because one of the two B12-dependent enzymes works inside mitochondria. Earlier research has also suggested that low B12 status may be linked with poorer muscle function in older adults, although much of this work is observational and cannot prove cause and effect.
So if you’re feeling persistently tired, is it worth paying for vitamin B12 injections at a wellness clinic or medispa? For most people, no. B12 injections are an established treatment for diagnosed deficiency, particularly when absorption is impaired, and the NHS uses hydroxocobalamin injections for vitamin B12 deficiency anemia.
But there is little evidence that B12 shots boost energy, weight loss or performance in people whose B12 levels are already normal. The more useful first step is to find out what is causing the tiredness.
The story of vitamin B12 is unusual because the body needs so little of it, yet the consequences of deficiency can be profound. Long before scientists understood its chemistry, doctors recognized that something in liver could restore strength, appetite and vitality to desperately ill patients.
A century later, researchers are still finding that this tiny cobalt-containing molecule does more than prevent anemia. It may also help explain how cells maintain energy and function as the body ages.
Story Source:
Materials provided by The Conversation. Original written by Martin Warren, Chief Scientific Officer and Group Leader, Synthetic Biology and Biosynthetic Pathways, Quadram Institute. Note: Content may be edited for style and length.
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