Vitamin C: What are the benefits for hair?

When vitamin C is applied to the scalp, it can have benefits similar to a topical application. However, one of the most widely accepted theories, initially proposed by HARMAN in 1956 and supported by experimental data, suggests that oxidative stress plays a major role in the hair ageing process. As a result, ascorbic acid is a powerful antioxidant that could help protect the scalp and hair from oxidative damage caused by free radicals.

Indeed, it has been demonstrated that these reactive species, produced internally during normal metabolism and externally through exposure to various environmental stressors (cigarette smoke, UV rays, etc.), can affect the condition of hair fibres that emerge from the scalp, leading, for example, to premature greying of the hair by prematurely inducing apoptosis in the melanocyte stem cells.

However, by neutralising and eliminating these harmful free radicals, the vitamin C could potentially limit these damaging reactions from occurring by possibly protecting the melanocytes and hair follicles from oxidative stress. It would then help to protect the hair from premature greying and maintain their shine. However, no research results explicitly mention the effect of applying vitamin C to the scalp to date.

Several laboratory reports have demonstrated that vitamin C can influence hair growth. One study found that the addition of 0.25 mM L-ascorbic acid 2-phosphate (magnesium salt), a stable derivative of vitamin C, to the culture medium resulted in increased proliferation of human dermal papilla cells. These cells, located at the base of hair follicles, are essential for hair formation and the regulation of the growth cycle. It has also been shown that L-ascorbic acid 2-phosphate promotes the elongation of hair shafts in human scalp hair follicles in culture.

In vivo data from mice has also shown that L-ascorbic acid 2-phosphate promotes hair growth, by inducing an earlier conversion from the telogen (resting) phase to the anagen (growth) phase compared to the control group. It has been suggested that L-ascorbic acid 2-phosphate would induce the expression of growth factors, including IGF-1 by dermal papilla cells, which in turn increase the proliferation and differentiation of follicular keratinocytes to stimulate the growth of human hair follicles in vitro via the PI3K signalling pathway.

Although these research findings have not yet been subjected to clinical studies, they suggest that vitamin C could potentially influence hair growth.