Vitamin B12 and Acne: The Hidden Link Your Skin Has Known All Along

You take a vitamin to feel better, and a week later your face breaks out. It sounds like a paradox, yet this is exactly what scientists at the University of California, Los Angeles (UCLA) observed when they studied how vitamin B12 affects the bacteria living on our skin. Vitamin B12 is one of the nutrients your skin seems to be quietly "listening" to, and the story is more surprising than most people expect.

In the UCLA experiment, a small group of healthy volunteers with clear skin started taking vitamin B12. Within about a week, one of them developed acne. That single case caught the researchers' attention, and when they examined the skin bacteria more closely, they found that B12 had changed how these microbes behaved. The results were published in the journal Science Translational Medicine (Kang et al., 2015): "Vitamin B12 modulates the transcriptome of the skin microbiota in acne pathogenesis". They gave scientists a possible explanation for something dermatologists had noticed for years: in some people, B12 supplements seem to be followed by breakouts.

What Is Vitamin B12?

Vitamin B12, or cobalamin, belongs to the B-complex vitamins. It differs from other vitamins in its very complex chemical structure, and it contains a metal ion, cobalt. In the body, B12 supports the production of red blood cells (erythrocytes), helps maintain the nervous system, takes part in metabolism and DNA synthesis, and, as newer research suggests, may also influence the appearance of the skin. You can find a detailed overview in the Vitamin B12 Fact Sheet from the U.S. National Institutes of Health (NIH), Office of Dietary Supplements.

How B12 Reaches Your Skin Bacteria

One of the most common bacteria on human skin, Cutibacterium acnes (formerly Propionibacterium acnes), normally makes its own vitamin B12. The UCLA team found that when volunteers took extra B12, the bacteria appeared to "switch off" their own B12 production. Instead, they produced more porphyrins, compounds that can promote inflammation in the skin. The Pharmaceutical Journal summarized the findings in "Vitamin B12 study hints at a molecular mechanism for acne pathogenesis".

The study was small, and the researchers themselves noted that the effect appears only in a subset of people. Most people who take B12 never notice any change in their skin. Still, if you have started a high-dose B12 supplement or a course of injections and your skin suddenly becomes more prone to pimples, it is worth mentioning to your doctor or pharmacist.

Why Your Cells Need B12

The cells in our body are constantly being renewed, and dead cells need to be replaced with healthy new ones. Vitamin B12 is essential for this process because the body needs it to build DNA in new cells. It is especially important for cells that divide quickly, such as those in the bone marrow, the lining of the digestive tract and the skin. It is also important for the nerves and for normal digestion.

The body stores B12 mainly in the liver, and these reserves can last for several years. Because of this, the effects of low intake can appear only after a long time, which is why a balanced diet matters for everyone. Children are a particular concern, because they have not yet built up large reserves.

Signs That You May Be Running Low

According to the NHS guide "Vitamin B12 or folate deficiency anaemia", possible signs of low B12 include:

• tiredness and low energy,


• pale skin,


• a sore, red tongue and mouth ulcers,


• pins and needles,


• lower mood,


• problems with memory and concentration.

Dermatologists also describe skin-related changes that are sometimes linked to low B12. These include darker patches of skin (hyperpigmentation), especially on the hands and feet, changes in hair and nails, and cracks at the corners of the mouth. A good overview is the review "A Review of Vitamin B12 in Dermatology" (American Journal of Clinical Dermatology). If you are wondering whether your mouth is trying to tell you something, read our article Warning Signs of Vitamin B12 Deficiency.

Changes in your skin, including new or more noticeable breakouts, can be one of many signals worth discussing with your doctor. The cause may lie in either direction: a lack of B12, or a sudden high intake from supplements.

Who Is Most at Risk of Low B12?

Absorbing B12 is a complex process. It needs healthy stomach acid and a protein called intrinsic factor. As we age, the stomach often produces less acid, so older adults can absorb less B12 from food, even when they eat enough of it. Absorption can also be reduced by conditions affecting the stomach, pancreas or small intestine, by certain medicines, and by an unbalanced diet. The NIH notes that long-term use of some common medicines, such as metformin and acid-reducing drugs, may be associated with lower B12 levels.

Low B12 affects the whole body. Over time it can contribute to anemia, nerve problems, fatigue, loss of appetite, mood changes and difficulty concentrating.

Where to Find Vitamin B12

The richest sources of vitamin B12 are:

• meat and organ meats, especially liver,


• fish and shellfish, especially clams and mussels,


• dairy products,


• eggs.

Eggs contain B12, but research suggests that the body absorbs it from eggs less efficiently than from meat or dairy. They are a useful addition to the diet, but they should not be your only source.

Vegetarians, and especially vegans, need a reliable source such as fortified foods or supplements, because plant foods contain almost no active B12. Some foods, such as certain seaweeds, contain pseudovitamin B12, a form the human body cannot use. The Vegan Society's guide to vitamin B12 offers practical advice on fortified foods and supplements.

Supplements: How Much Is Enough?

B12 is considered to have a low risk of toxicity, because the body excretes what it does not need. Still, "more" is not always "better." When absorption through intrinsic factor does not work well, only about 1% of a high oral dose can be absorbed through passive diffusion. For this reason, doctors sometimes recommend higher doses or injections for people with absorption problems. These are decisions best made together with a doctor, based on a blood test.

If you notice more breakouts after starting a high-dose supplement, you do not need to panic. Talk to your doctor or pharmacist about whether the dose suits your needs. For general guidance on caring for breakout-prone skin, see the American Academy of Dermatology's acne resource center.

The Bottom Line

Your skin is a mirror of what happens inside your body, and vitamin B12 is one of the nutrients it responds to. Too little can show up as tiredness, a sore tongue or changes in skin tone. Very high doses may, in some people, change the behavior of skin bacteria and be followed by breakouts. The healthiest approach is balance: a varied diet, reliable sources if you avoid animal foods, and a simple blood test if you suspect something is off.

As we get older, our bodies often absorb B12 less efficiently, so pay attention to changes in your energy and your skin. Your body usually tells you what it needs, if you know how to listen.