SCALP CARE
hygrometry) treated with the patchouli leaf active at 0.5%. The content of the NMFs was quantified using the LC/MS system. The patchouli leaf active stimulated
the expression of all the selected markers: keratohyalin, filaggrin +56% and caspase-14 +49% (Ordinary ANOVA followed by Dunnett’s post hoc test p<0.001), and NMFs +35% (Mann-Whitney test: * p<0.05).
Regulation of keratinocytes migration and exfoliation root causes White dry flakes are associated to dry scalp and anarchic migration of keratinocytes, leading to the accumulation of big visible skin scales. Normalisation of keratinocytes migration is thus mandatory to limit the formation of dry flakes.
Keratinocyte migration On a scratch test (a mechanical lesion on a culture of keratinocytes), we assessed cell migration in vitro by tracking the ability of the cells to close the lesion after eight hours. The patchouli leaf active showed an impressive -100% (Student’s t-test p<0.001) inhibition of keratinocyte migration.
Stratum corneum thickening The patchouli leaf active was applied at 0.5% in a Carbopol carrier gel to a scalp explant that had been kept in culture for 10 days to trigger the thickening of the stratum corneum. The product induced a -35% (Mann-Whitney test: p<0.001) reduction in the thickness of the stratum corneum compared to the placebo.
Safety and efficacy Next, we conducted several independent double-blind versus placebo clinical studies to compare the efficacy of the patchouli leaf active as used in rinse-off (shampoo) and leave-on (lotion) hair-care products. For the rinse-off application, two independent double-blind versus placebo clinical studies were performed on 80 volunteers in total, with two groups of 20 volunteers for each. Men and women presenting with dry scalps, itching, irritation,
-35%* Placebo stratum coreum at D10 Thickness of the
measure alpha diversity (as related to sebum quantity1
111
) and specific Cutibacterium abundance
through metagenomics analysis with 16S rRNA gene sequencing methodology. Additional data from previous studies
compared the evolution of these three parameters between dry and oily scalps to calibrate how the patchouli leaf active impacts scalp sebum and microbiota. The results show that the patchouli leaf
active normalises the level of sebum on the scalp and rebalances alpha diversity for a healthier microbiota. Finally, to assess the leave-on application,
two groups of 15 volunteers with dry scalp, itching, irritation, scalp discomfort and dry white flakes applied a lotion containing 0.5% the patchouli leaf active twice a day for 28 days. In the double-blind versus placebo clinical study, the patchouli leaf active significantly reduced the presence of white flakes versus placebo by -31%. The volunteers also expressed significant
Patchoul'Up™ 0.5%
Figure 3: The patchouli leaf active Slow down exfoliation root causes (Mann-Whitney test: *p<0.001)
scalp discomfort and dry white flakes applied a shampoo every two days for 28 days containing the patchouli leaf active at 0.5% or not (placebo). Observations measured the quantity of sebum on the scalp (using Sebufix®), dry white flakes were scored by an expert and illustrative photos were taken of the scalp. After 28 days, the active group (versus
placebo) showed a visible improvement in the quality of the scalp on 100% of volunteers: ■ +34% increase in sebum production versus placebo (Mann-Whitney test: p<0.1) ■ -13% reduction of white flakes versus placebo (Mann-Whitney test: p<0.05) Low sebum levels are inversely associated with an increase in alpha diversity, which impacts the overall microbiome balance of the skin. We collected scalp samples of the microflora to
AFTER 28 DAYS
10 0
Patchoul'Up™ diversity
Cutibacterium abundance
Sebum Alpha
Low level
Low High
+34%
-15% +22%
Δdry/oily: +719% Decrease
Δdry/oily: +54% Figure 4: Normalisation of scalp sebum and microbiota (in vivo)
www.personalcaremagazine.com
Δdry/oily: -24% High
High level
-10 -20 -30
-21% *
-31% **
10%
results compared to placebo on the improvement of itching, with 87% reporting a reduction of the frequency and intensity of the itching and 93% revealing they no longer had dry flakes on their clothes.
Wellbeing and self-confidence As importantly, our experts decoded the volunteers’ moods and emotional responses after the leave-in clinical study by asking: ‘Thinking about your scalp, how do you feel about it now?’ We used prosody analysis methodology – pitch (i.e. tone) and tonality (i.e. vocal intensity) measurement, correlated into emotional valence – and two unique non-verbal neuroscience methods (Emotion Decoding System® and Mood Portraits®) to assess the responses. The patchouli leaf active triggers 9.5 times
more positive emotions than the placebo, while it triggers 3.5 times less negative emotions than the placebo.
Footnote 1. Alpha diversity is directly related to sebum content on scalp, similarly to the skin (Mukherjee et al., 2016. Shibagaki et al., 2017)
PC
Patchoul'Up™ 0.5% Figure 5: Reduction of white flakes (in vivo) April 2023 PERSONAL CARE
Placebo
Wilcoxon test: D28 vs D0 Mann-Whitney test: Patchoul'Up™ vs Placebo * p<0.05, **p<0.01
ΔDODx scoring white flakes normalisation / D0 (%)
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