As one of the most potent antioxidants for the skin, vitamin C is a crucial component of skincare routines due to its ability to create a more radiant and even complexion, and to protect against photoaging. But does it have as many benefits for the scalp and hair as it does for the skin? The effectiveness of vitamin C on hair health is garnering increasing attention. Let's explore this in this article.
Vitamin C: What are the benefits for hair?
Summary
Published on July 4, 2024, by Stéphanie, PhD, Doctorate in Life and Health Sciences — 5 min of reading
Themes:
Benefit No.1: Vitamin C to slow down premature hair whitening?
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.
Benefit No. 2: Vitamin C could enhance hair growth.
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.
Benefit No. 3: Vitamin C to prevent hair loss.
Androgenetic alopecia is the most common cause of hair loss, induced by hormones (androgens). Research reveals that the dihydrotestosterone (DHT), produced from testosterone by the enzyme 5-α reductase, contributes to the miniaturisation and shrinkage of the hair follicle. It has been shown that this hormone induces the expression of DKK-1 mRNA in the cells of the dermal papilla. However, a high level of DKK-1 has been observed in the scalp of bald individuals, thus inducing hair loss. Nevertheless, in 2010, a study revealed that the addition of L-ascorbic 2-phosphate (0.25 and 1 mM) to the culture medium caused a downregulation of DKK-1 levels in response to DHT in the cells of the dermal papilla, which means it may help prevent androgen-induced baldness.
Although promising, these initial data (in vitro) need to be replicated on actual patients.
Sources
KIM J. C. & al. The hair growth promoting effect of ascorbic acid 2-phosphate, a long-acting Vitamin C derivative. Journal of Dermatological Science (2006).
SUNG Y. K. & others. L-Ascorbic acid 2-phosphate stimulates the extension of hair shafts by inducing the secretion of insulin-like growth factor-1 from dermal papilla cells via the phosphatidylinositol 3-kinase pathway. British Journal of Dermatology (2009).
SUNG Y. K. & others. L-ascorbic acid 2-phosphate suppresses the dihydrotestosterone-induced dickkopf-1 expression in human balding dermal papilla cells. Experimental Dermatology (2010).
