The protective role of vitamins

The normal hair growth cycle involves three distinct stages: the anagen or growth phase, the catagen or regression phase, and the telogen or resting phase. Excessive hair thinning and shedding can occur when the hair follicles shrink – a process known as miniaturisation. Hair follicles can be affected by internal stressors, such as psycho-emotional stress and metabolic imbalances, but are also affected by external stressors such as hair dye1 and air pollution, which can lead to an accumulation of reactive oxygen species (ROS). 

Although ROS accumulation has a functional role to play in the normal homeostasis of the hair follicle, there is evidence to suggest an association between imbalances in ROS accumulation and impaired hair growth^2,3.

Can vitamins support hair follicle health under oxidative stress?

Oxidative stress in hair follicles may also be the consequence of a lack of micronutrients due to vitamin deficiency. Several studies point to vitamins having a beneficial effect on hair follicle health: dexpanthenol, a precursor of vitamin B5 has been shown to promote cell growth in cultured hair follicles ⁴, while vitamin B3 has been shown to protect cultured human dermal papilla cells against oxidative stress in vitro⁵ and to increase hair fullness in patients suffering female pattern hair loss⁶. 

Additionally, vitamin C, a potent antioxidant, has been associated with proliferation of hair follicle keratinocytes, and promotes elongation of hair shaft⁷, while decreased levels of vitamin E, which is known to help protect immune cells against oxidative damage, have been reported in several studies on alopecia areata⁸. 

In view of evidence supporting the role individual vitamins may play in maintaining healthy, functional hair follicles, dsm-firmenich decided to investigate whether a proprietary vitamin complex could potentially limit the extent of hair loss by offering protection against oxidative stress conditions and having a beneficial impact on hair follicle biology. 

The initial findings with a proprietary
vitamin complex  

The all-in-one vitamin complex “BeauPlex VH” that was investigated was initially promoted for skin care applications and contains vitamins B3, B5, B6, C and E, most of which have antioxidant properties. 

In response to the growing interest in using skin care ingredients in hair and scalp care products – a trend which has become known as “haircare skinification” – dsm-firmenich had previously explored this complex’s potential for this purpose through studies which showed that it could prolong the anagen phase of hair follicles ex vivo and promote the proliferation of hair follicle keratinocytes ex vivo. 

An initial in vivo study, which will be described below, had also found that, in healthy volunteers, the complex can help increase hair density and hair thickness. This randomised, placebo-controlled, double-blind study involved 60 volunteers aged between 18 and 65 (with a mean age of 45). Over a five-month period, 30 of the volunteers applied a leave-on formulation containing 1.5% of the vitamin complex daily, and 30 of the volunteers applied a placebo leave-on formulation daily. As the graph and images in Figure 1 show, after five months, daily treatment with the vitamin complex resulted in a 7% increase in hair density whereas no changes in hair density were observed in the placebo group.

An improvement in hair thickness was also observed in volunteers who had applied the leave-on vitamin complex daily for five months. Indeed, in these subjects, an increase in hair diameter was recorded while hair thinning was observed in subjects who had applied the placebo leave-on formulation (Figure 2).

While this in vivo study showed that treatment with the vitamin complex could indeed lead to a visible improvement in hair density and thickness, it did not explore its performance under oxidative stress conditions. However, in situ analysis of the morphology of human hair follicle samples – using light microscopy and hematoxylin/eosin-stained follicle cryosections – has shown us that oxidative stress induced by exposure to 2mM hydrogen peroxide resulted in noticeable signs of dystrophy in hair follicle samples, and that treatment with 0.1% of the vitamin complex appeared to have a preventive effect. The images in Figure 3 visualise this analysis.

On the basis of these findings, dsm-firmenich has therefore conducted further ex vivo studies to confirm and understand more about the impact that oxidative stress induced by hydrogen peroxide (H2O2) has on the hair follicle and hair growth, and to explore whether the vitamin complex has a protective effect against this impact.

New studies reveal new potential 
to protect against ROS

For the new ex vivo study, human hair follicle samples were subjected to oxidative stress induced by hydrogen peroxide at concentrations of 1mM and treated with 0.1% of the vitamin complex. A lower concentration of H2O2 was chosen for this study due to the severe damage to cultured hair follicle tissues observed previously when using a concentration of 2mM. Various parameters were evaluated, but the ones that were focused on here are hair follicle elongation/hair shaft production, early catagen development and hair follicle dystrophy, and pNrf2 expression in the germinative hair matrix. Samples treated with the vitamin complex were compared to a vehicle group.

The key findings

1. Hair shaft 
production 

The graph in Figure 4 presents data on hair shaft production in a vehicle hair follicle sample, samples exposed to 1mM H2O2 and samples treated with both 1mM H2O2 and 0.1% of the vitamin complex. As can be seen, H2O2 strongly inhibits hair shaft production but this inhibition is reduced in the presence of the vitamin complex.

2. Premature catagen development and hair follicle dystrophy

Macroscopic hair cycle staging was determined according to several established parameters⁹. This evaluation found that compared to a vehicle group, early catagen development and hair follicle dystrophy were induced in samples exposed to 1mM H2O2 but treatment with 0.1% of the vitamin sample protected against these effects. The graph in Figure 5 shows the data from this analysis.

3. pNrf2 expression in the 
germinative hair matrix

Nrf2 is a “master regulator” of genes controlling cellular redox homeostasis. Its activated form, pNrf2 (phosphorylated Nrf2), has been reported to play a role in protecting the hair follicle from excessive ROS production and preventing catagen development3. For the study dsm-firmenich evaluated pNrf2 expression in the germinative hair matrix and found that treatment with 0.1% of the vitamin complex appeared to counter the effects of H2O2 treatment and to prevent the reduction of pNrf2 levels in this part of the hair follicle. The data from this evaluation is shown in the graph in Figure 6.