The study was undertaken by females aged 20 to 60 who expressed concern about their hair condition.

A total of 40 participants were included, with an average age of 45 in the experimental group and 42.2 years in the control group.

Following a four-week wash-out period, participants used either the test shampoo or a placebo for 12 weeks. The shampoo under investigation was prepared by incorporating 0.03% of the Plantago asiatica L. extract.

Hair measurements using phototrichograms and hair count tests were conducted at baseline and at weeks 4, 8, and 12.

The researchers, from Korea, reported: “The test group demonstrated progressive improvements in hair strand thickness (0.009 mm, 0.017 mm, and 0.020 mm at weeks 4, 8, and 12, respectively) and hair density (0.9 hairs/cm2 at weeks 4 and 8, 1.1 hairs/cm2 at week 12).

“Additionally, a significant reduction in hair shedding was observed compared to the placebo group.”

The researchers’ previous studies had found that Plantago asiatica L. positively influenced several biological mechanisms related to hair growth. Notably, it enhanced the production of growth factors such as VEGF (vascular endothelial growth factor), KGF (keratinocyte growth factor), and FGF (fibroblast growth factor), which are known to play critical roles in follicular development, cellular proliferation, and angiogenesis.

They added: “Moreover, it facilitated the phosphorylation of CREB (cAMP response element-binding protein) and increased intracellular accumulation of β-catenin—a key component of the Wnt signaling pathway involved in follicular activation and regeneration. As a result, dermal papilla cell proliferation was significantly enhanced, suggesting a strong mechanistic basis for the observed hair-promoting effects.

“Additionally, the observed induction of angiogenesis may support hair follicles through enhanced vascularization, allowing for improved nutrient and oxygen delivery during the regeneration process.”

However, it is important to note that these mechanistic insights were derived from in vitro experiments, and the current clinical study did not include biomarker analysis or molecular assessments using scalp tissue from participants.

That said, these clinical results align with and reinforce the findings of their earlier in vitro studies, demonstrating that Plantago asiatica L. not only promotes dermal papilla activity and angiogenesis but translates these molecular effects into measurable outcomes in human participants.

“The fact that such results were observed through the use of a rinse-off shampoo formulation highlights the potential for Plantago asiatica L. to exert its effects through relatively brief yet consistent topical exposure. This suggests a promising application for this natural extract in everyday hair care products without the need for complex delivery systems or leave-on treatments,” they added.

“Taken together, the findings from both the mechanistic and clinical perspectives suggest that Plantago asiatica L. holds considerable potential as a functional ingredient in hair growth-promoting formulations. Its ability to improve key indicators of hair health, such as thickness, density, and shedding, positions it as a compelling candidate for use in non-invasive, cosmetic interventions for individuals experiencing early signs of hair loss or seeking to maintain healthy scalp conditions.”

The researchers added that further long-term studies may help determine the duration of these effects and optimise dosage or formulation strategies for enhanced efficacy.

“As such, while the clinical findings are promising, the direct confirmation of these pathways in vivo remains to be elucidated. Future studies incorporating biomarker evaluation in clinical samples or employing ex vivo human scalp models would be valuable to validate the activation of these biological pathways and strengthen the mechanistic understanding of the effects of Plantago asiatica L. in a real-world context,” they added.

Source: Cosmetics

https://doi.org/10.3390/cosmetics12020084

‘Effects of Shampoo Containing Plantago asiatica L. on Hair Thickness, Density, and Shedding: A Double-Blind, Randomized, Placebo-Controlled Clinical Study’

Authors: Jiyeon Lee, et al