Vitamin B12: what are its benefits for the skin?

Used both to formulate cosmetics and dermatological creams, the principal benefit of vitamin B12 when applied topically lies in its ability to soothe the skin. Studies in vitro have indeed shown that this active ingredient can reduce the production of pro-inflammatory cytokines. As a reminder, cytokines are proteins involved in intercellular communication, but also in the emergence of skin irritations (redness, itching, etc.). They are notably produced by T lymphocytes, cells of the immune system.

It is also assumed that vitamin B12 exerts an inhibitory effect on the synthesis of nitric oxide (NO), a molecule involved in the pathogenesis of eczema and of psoriasis. This compound is produced by the action of the enzyme nitric oxide synthase (NOS), whose overactivity is implicated in both aforementioned dermatoses. Indeed, an excess of nitric oxide in skin cells stimulates keratinocyte differentiation and promotes the dilation of blood vessels, leading to redness and oedema. These anti-inflammatory properties of vitamin B12, first observed in vitro, were subsequently demonstrated in clinical trials. A few are presented below.

The soothing properties of vitamin B12 render it a valuable asset for compromised or irritated skin.

Besides its anti-inflammatory effects, vitamin B12 has antioxidant activity that allows it to counter the damage caused by the free radicals. Generated following prolonged exposure to UV rays, pollution or tobacco smoke, these reactive molecules contribute to alterations in the structure of proteins and lipid membranes and damage DNA, compromising skin integrity and potentially causing pigmentation spots, while accelerating the onset of wrinkles and skin sagging.

Studies in vitro have shown that vitamin B12, owing to its chemical structure rich in double bonds, can stabilise free radicals by donating an electron. Moreover, this active ingredient works by activating certain molecules that play a key role in maintaining the cellular redox potential, such as glutathione. These various effects enable vitamin B12 to protect the skin from oxidative stress and help to prevent skin ageing.

Meanwhile, some studies in vitro have shown that vitamin B12 could be of interest in the skin regeneration process. It appears that this vitamin can stimulate the proliferation of fibroblasts, the cells that synthesise collagen and elastin. These structural proteins are essential for the skin, particularly in wound healing, when a wound closes.

In addition, still according to these studies in vitro, vitamin B12 appears to be strongly involved in angiogenesis and could therefore contribute to the formation of granulation tissue, a transient, vessel- and cell-rich tissue whose production corresponds to one of the important phases of wound healing. In view of these preliminary findings, we can cautiously assume that vitamin B12 may play a regenerative role in the skin.

A study specifically evaluated an innovative dressing composed of a polycaprolactone/gelatine nanofibrous matrix enriched with vitamin B12. The researchers first confirmed that adding vitamin B12 did not alter the material’s physical properties (mechanical strength, water uptake, permeability, hydrophobicity). In a rat skin wound model, this dressing showed a marked improvement in healing. Histological analysis also revealed a greater epithelial thickness with the enriched formulation, indicating better healing.

In view of these promising results, it would be worthwhile for researchers to examine the vitamin’s wound-healing properties in future clinical trials.

The vitamin B12 is sometimes regarded as a potential hydrating agent. Some hypotheses suggest that it could enhance the skin’s water-retention capacity by limiting specific inflammatory processes that impair the skin barrier. This indirect effect on hydration also underscores its potential value in eczema, where the skin barrier is compromised and transepidermal water loss is often elevated.

In this regard, a study evaluated the efficacy of a topical gel containing 0.07% adenosylcobalamin, one of the active forms of vitamin B12, in 22 children aged 2 to 12 years with atopic dermatitis. Over eight weeks, participants applied the gel twice daily to the affected areas. The results demonstrate a continuous and significant improvement: the SCORAD score decreased from 21.95 at baseline to 13.92 (a 36.58% reduction) at four weeks, and to 6.56 at eight weeks (a 70.11% reduction). Skin hydration almost tripled, whilst transepidermal water loss decreased markedly.

Nevertheless, these results must be interpreted with caution. The study did not include a control group using the same moisturising base without vitamin B12, which does not allow the formal isolation of the effect of vitamin B12 itself.

Vitamin B12 plays a role in skin pigmentation. Several studies demonstrate that vitamin B12 deficiency is often accompanied by hyperpigmentation, due to excessive stimulation of the melanogenesis. A recent study recreated a B12-deficient state in vitro by exposing melanocytes to a specific B12 antagonist. These cells then exhibited a marked increase in melanin production and tyrosinase activity, approximately 130%. This overactivation was accompanied by a significant oxidative stress, which disrupts melanocyte homeostasis.

Treating a vitamin B12 deficiency can help alleviate hyperpigmentation when it is the underlying cause.

A clinical case illustrates this well: a 49-year-old man presented with marked hyperpigmentation of the skin and mucous membranes due to malabsorption following a gastrectomy. Laboratory tests revealed a severe vitamin B12 deficiency, and histological examinations showed an accumulation of melanin in the basal layer, as well as a large number of melanosomes in melanocytes and keratinocytes, confirming an overproduction of the pigment. After one month of daily vitamin B12 supplementation (0.5 mg per day by injection), blood levels returned to normal and the hyperpigmentation gradually regressed.

This close relationship between vitamin B12 levels and the regulation of melanogenesis occasionally suggests that topical application of vitamin B12 could likewise exert a depigmenting effect.

The idea is based on a straightforward premise: if a deficiency increases melanin synthesis, then a local supply could, in theory, help restore balance to melanocyte activity. However, this remains purely hypothetical at present. To date, no studies have demonstrated that a topical application of vitamin B12 can lighten the skin or reduce hyperpigmentation. The available data concern only systemic supplementation in cases of confirmed deficiency. It would nonetheless be valuable for clinical research to explore this possibility.

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