What are the benefits of Vitamin K for the skin?

In a 2019 study, Behnam GHORBANZADEH and his team sought to investigate the effects of a topical application of Vitamin K on the healing of skin wounds in humans. For this purpose, 63 patients, for whom electrocautery (destruction of unwanted tissues) was indicated, were recruited for a trial. After electrocautery, some patients received a 1% Vitamin K cream, while others (controls) received a commercially available healing cream. The condition of the wound was evaluated two weeks later.

The results demonstrated that the application of Vitamin K improved wound healing from the fourth day, with statistical significance from the seventh day (from 6mm to 0mm in width over 14 days) compared to the control group (from 6mm to 2mm in 14 days). Furthermore, the average healing time was 12.4 days and 10.6 days in the control and Vitamin K groups, respectively. Therefore, the use of topical Vitamin K could potentially accelerate the healing process.

Topical Vitamin K is suggested to promote wound healing due to its ability to increase the formation of fibroblasts, collagen, blood vessels, and the content of hydroxyproline, an amino acid involved in collagen synthesis. Furthermore, it has been reported that blood coagulation can coordinate wound healing. Given that Vitamin K has a known effect on blood coagulation, this could contribute to its mode of action.

Furthermore, reactive oxygen species (ROS) play a central role in the pathogenesis of skin wounds. Overproduction of ROS during oxidative stress leads to delayed wound healing. Therefore, Vitamin K could potentially improve wound healing, possibly through the elimination of ROS, taking into account its antioxidant capacity.

However, further studies aimed at elucidating the exact mechanism of action of Vitamin K in wound healing will be necessary to confirm this.

Michio KOMAI and his colleagues aimed to identify an anti-inflammatory role of vitamin K by observing its effect on gene expression in the rat liver. They induced a vitamin K deficiency in rats through diet, then observed the genes affected by the deficiency. They found that the expression of a family of genes involved in the acute inflammatory response was higher in vitamin K deficient rats than in rats supplemented with vitamin K. The genes coding for α-1 acid glycoprotein (AGP), a marker of the inflammatory response, had a relative expression of 5 in the deficient group compared to 0.5 in the control group.

They then orally supplemented other rats with vitamin K to observe its effect on inflammation induced by the lipopolysaccharide (LPS), which promotes the release of pro-inflammatory cytokines. The RNA level of the liver macrophage migration inhibitory factor, an inflammation marker, significantly decreased in the supplemented animals. These results suggest that orally ingested vitamin K could suppress the inflammatory response triggered by LPS.

Vitamin K1 is also believed to suppress theincrease in the expression of IL-6, a pro-inflammatory cytokine involved in chronic inflammatory skin diseases. The reduction of inflammation by vitamin K could therefore be mediated by the regulation of the expression of inflammatory cytokines. Additionally, LPS stimulates the production of IL-6 via the NF-kB pathway. Factors can modulate this pathway, such as the cAMP-dependent protein kinase (PKA), which inhibits the activation of NF-kB in human cells. Studies have shown that one of the analogues of vitamin K2, MK-4, could activate PKA. Therefore, the anti-inflammatory effect of orally administered vitamin K could be expressed through a inhibition of the NF-kB pathway.

Human studies could clarify these results.

Leslie BAUMANN and her team sought to study the effects of topical Vitamin K on bruising following laser treatment for telangiectasias. 22 patients were divided into two groups: those in the first group applied a Vitamin K cream (5%) to one half of their face and a placebo to the other half twice daily for two weeks prior to the laser treatment, and those in the second group followed the same procedure for two weeks post-laser.

Bruises were assessed using a visual score. In the first group, there was no significant difference between the scores of the vitamin K cream (4.577) and the placebo (4.778). In the second group, there was a significant difference between the scores of the vitamin K cream (3.858) and the placebo (4.364).

In another study, Mohammad Ali SHATALEBI and Fatemeh AHMADRAJI evaluated the effectiveness in vivo of an anti-wrinkle and anti-dark circle eye patch composed of 3% caffeine and 1% vitamin K. An in vivo trial was conducted to visually study its effectiveness on 11 healthy women. They found that after four weeks, the skin around the eye of all subjects experienced a reduction in the pigmentation of dark circles compared to the use of a placebo. This result could suggest an effectiveness of vitamin K against dark circles.

It is therefore understood that the topical application of vitamin K could improve bruises and other blood circulation alterations. No clear mechanism of action has been identified. However, its effect on blood coagulation can be assumed as potentially responsible, for instance through the strengthening of vascular walls. These results represent a significant hope in the context of treating dark circles or conditions prone to micro-circulation blood defects such as rosacea.

Today, the vitamin K1 in its pure form is prohibited in cosmetics in Europe due to the risk of skin allergies it poses. Instead, brands utilise the vitamin K oxide (oxidised form), which is more stable and less irritating.

A study has demonstrated that the efficacy of Vitamin K1 oxide is similar to its pure form in treating post-operative redness. However, regarding the claimed antioxidant and anti-inflammatory effects of Vitamin K1, further evidence is required.