Vitamin B12, skin bacteria and acne development
What it found
In people, vitamin B12 supplements changed the activity of skin bacteria and one of ten healthy volunteers developed acne a week later.
Lab tests showed the vitamin made the acne bacterium produce more porphyrins, which can cause inflammation.
What they found
Studies in people
Bacteria differ in acne
The gene activity of skin bacteria separated acne patients from healthy people. In acne patients, the vitamin B12-making pathway in the skin bacterium P. acnes was turned down.
B12 injection changes bacteria
In 10 healthy volunteers, a vitamin B12 injection turned down the vitamin B12-making genes in P. acnes 14 days later. The gene activity looked similar to that seen in acne patients.
One volunteer got acne
One of the 10 healthy volunteers developed acne on the face one week after the vitamin B12 injection. Their skin bacteria gene activity shifted to look like that of acne patients.
Animal and lab studies
Porphyrins in lab cultures
In lab cultures, adding vitamin B12 made P. acnes produce 39% more porphyrins during rapid growth and nearly 19% more later on. Porphyrins are known to cause inflammation in acne.
Cobalt depletion in lab
When cobalt was removed from lab cultures, which blocks vitamin B12 production, porphyrin production increased. This supports the idea that the two pathways compete for the same starting materials.
What the authors conclude
“Our findings suggest a new bacterial pathogenesis pathway in acne and provide one molecular explanation for the long-standing clinical observation that vitamin B12 supplementation leads to acne development in a subset of individuals.”
Also in their conclusions
- They say their findings provide one molecular explanation for the long-standing observation that vitamin B12 supplements lead to acne in some people.
- They propose that high vitamin B12 in the body changes the activity of skin bacteria, causing them to make more porphyrins, which then cause inflammation and acne.
- They call for more research with larger numbers of people to confirm the link between vitamin B12 and acne.
How it was done
The authors wanted to understand how the mix of bacteria living on the skin responds to signals from the body, and whether this plays a role in acne. They focused on vitamin B12 because doctors have long noticed that supplements can trigger acne in some people, but no one knew why.
They compared the gene activity of skin bacteria in 4 acne patients and 5 healthy people, then checked their findings in another 9 acne patients and 15 healthy people. They also gave 10 healthy volunteers a vitamin B12 injection and sampled their nose skin before, 2 days after, and 14 days after. In the lab, they grew the acne bacterium Propionibacterium acnes with and without vitamin B12 and measured porphyrin production.
What it can’t tell you
- Only one person out of ten developed acne, so this study cannot show how often vitamin B12 triggers acne in the general population.
- The study followed people for only 14 days, so it cannot show what happens over longer periods.
- The lab tests used cultured bacteria, which cannot fully copy what happens on human skin.
Who paid
- Funding
- Funded by NIGMS NIH HHS; NIAMS NIH HHS (from the PubMed record).
- Conflicts
- Competing interests : The Regents of the University of California is the owner of a patent application (US application No. 62/078,275, titled “New acne treatment targets”) related to the role of vitamin B12 in acne, which names D.K., B.S., N.C., and H.L. as inventors. The other author declares no competing interests.
- Authors work at
- University of California, USA; Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, USA
The paper
- Title
- Vitamin B12 modulates the transcriptome of the skin microbiota in acne pathogenesis
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Kang D, Shi B, Erfe MC, Craft N, Li H (2015). Vitamin B12 modulates the transcriptome of the skin microbiota in acne pathogenesis. Science translational medicine. doi:10.1126/scitranslmed.aab2009Free full textPubMed 26109103DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error