Can vitamin C be used to improve blood circulation?

Blood circulation is a vital system that ensures tissue oxygenation, nutrient delivery and the removal of metabolic waste. It depends on the integrity of the vessels, vascular tone, blood fluidity and the endothelium’s ability to respond to stimuli mechanical or inflammatory. For information, the endothelium is the layer of epithelial cells lining the interior of the heart and blood vessels. When this system is disturbed — by the oxidative stress, chronic inflammation, vascular stiffness or collagen alterations — microcirculation can become less efficient, leading to reduced tissue oxygenation and suboptimal cellular function.

Several scientific findings suggest that vitamin C could support improved blood circulation.

Vitamin C plays an important role in maintaining healthy blood circulation. Its primary mechanism of action is based on its involvement in the synthesis of collagen. Whilst this protein is often linked to preserving skin suppleness, it also contributes to the structure of the basement membrane of blood vessels. By strengthening this support network, ascorbic acid enables capillaries to retain their elasticity, which is essential for functional blood circulation.

Vitamin C also affects endothelial function by modulating the production of nitric oxide (NO), a molecule that ensures vasodilation. It recycles the cofactor BH4, which is essential for the proper function of the enzyme eNOS responsible for NO synthesis. When BH4 is oxidised, eNOS produces superoxide instead of NO, compromising vascular dilation. By restoring active BH4 levels, vitamin C keeps eNOS functional, thus favouring NO production and the relaxation of blood vessels. This mechanism directly helps to improve blood flow in peripheral tissues. Furthermore, vitamin C helps regulate capillary permeability by strengthening the tight junctions between endothelial cells. This stabilising action limits plasma leakage and optimises the efficiency of blood transport.

Another important property of ascorbic acid : its antioxidant activity, which protects cell membranes, preserves vascular integrity and maintains the fluidity of blood flow.

In addition to mechanistic studies, there is clinical evidence for the effects of vitamin C on blood circulation. Notably, one study was conducted in nine hypertensive men with pronounced insulin resistance. The researchers aimed to assess whether an intra-arterial infusion of vitamin C could improve vasodilation and, consequently, influence glucose uptake by forearm muscle tissues. Each participant received a local infusion of acetylcholine, an endothelium-dependent vasodilator, followed by a co-infusion of vitamin C (12 mg/min) into the brachial artery of one arm. Blood flow was measured in both arms, with the non-infused arm serving as a control. The muscle tissue response to insulin, with and without vitamin C, was also tested.

The results demonstrate that acetylcholine caused a clear increase in blood flow in the perfused forearm, rising from around 2.6 to 10.6 mL·min⁻¹·dL⁻¹. When the researchers added vitamin C, this increase became even more pronounced, reaching 13.4 mL·min⁻¹·dL⁻¹. This indicates that vitamin C helps blood vessels to dilate more effectively, by counteracting the effects of oxidative stress that impair endothelial function.

Researchers also examined what happened under hyperinsulinaemia. In this context, insulin alone failed to increase blood flow, demonstrating that the vessels were resistant to its action (vascular insulin resistance). By contrast, when vitamin C was added, insulin regained its ability to induce vasodilation in the treated forearm. This suggests that vitamin C may help to restore the signalling normally triggered by insulin. However, this restoration of vasodilation was not accompanied by any improvement in glucose uptake by the muscle tissues. In other words, even though vitamin C corrects endothelial dysfunction, it does not alter metabolic insulin resistance, indicating that the vascular and metabolic mechanisms are distinct.

In the same vein, other studies have examined the impact of vitamin C on microcirculation, particularly in situations where oxidative stress markedly impairs endothelial function. One investigation specifically assessed the effect of a single oral dose of vitamin C (2 g) on blood circulation in 13 young male smokers compared with 12 non-smokers—two populations with similar metabolic profiles but very different levels of oxidative stress. Indeed, smokers provide a relevant model of endothelial dysfunction induced by free radicals, notably characterised by a reduction in blood flow.

The researchers therefore measured coronary flow velocity in the anterior interventricular artery. Values were recorded before vitamin C intake, then two hours and four hours after ingestion, alongside measurements of plasma ascorbate concentrations. The results show a significant reduction in flow velocity among smokers (3.8 cm/s compared with 4.3 cm/s in non-smokers). After vitamin C intake, plasma ascorbate concentrations increase rapidly in both groups, and, in smokers, allow blood flow to reach levels similar to those of non-smokers.

The authors conclude that orally administered vitamin C is capable of restoring coronary microcirculation in smokers, probably by reducing oxidative stress that impairs nitric oxide-mediated vasodilatory signalling.

Thus, the available data indicate that vitamin C can contribute to improving blood circulation, particularly in contexts where oxidative stress impairs endothelial function. The findings suggest a corrective effect rather than an amplifying one: vitamin C appears especially beneficial when the microcirculation is compromised. However, while several studies demonstrate a benefit following oral supplementation, no data are currently available regarding the efficacy of topically applied vitamin C in improving blood circulation, a gap that calls for the conduct of clinical studies on the subject.

Note : If the studies presented demonstrate that oral vitamin C intake can be beneficial for improving blood circulation, we advise against beginning supplementation without first consulting your doctor.

• FERRANNINI E. & al. Effect of vitamin C on forearm blood flow and glucose metabolism in essential hypertension. Arteriosclerosis, Thrombosis, and Vascular Biology (2000).

• KOMURO I. & al. Acute effect of oral vitamin C on coronary circulation in young healthy smokers. American Heart Journal (2004).

• HARRISSON F. E. & al. Role of vitamin C in the function of the vascular endothelium. Antioxidants and Redox Signaling (2013).

• TELANG P. S. Vitamin C in dermatology. Indian Dermatology Online Journal (2013).