Objective Evaluation of the Placebo Effect in Cosmetic Treatments. A Randomized Controlled Study

• Published in: International journal of cosmetic science Vol. 29; no. 1; p. 64
• Main Authors: Distante, F., Pagani, V., Bonfigli, A., Rigano, L., Fluhr, J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2007
• ISSN: 0142-5463; 1468-2494
• DOI: 10.1111/j.1467-2494.2007.00355_3.x

A product's packaging and claimed efficacy may stimulate pleasant emotions during the use of cosmetics, thus enhancing their perceived benefits. The aim of this study was to evaluate if smart packaging and strongly claimed efficacy attributes can influence the objectively measured efficacy, allowing a true placebo effect to be associated with a given cosmetic treatment. A marketed anti‐aging gluconolactone‐based formulation was selected for the study and packaged both in a fancy sophisticated jar and in an unbranded plain container. Thirty‐six female volunteers (age range: 30‐‐55 years) with facial photoageing were selected for the study and randomly assigned to the fancy or plain packaged product. Pre‐agreed messages aimed at extolling the product's cosmetic effects accompanied delivery of the fancy‐packaged product to panellists. The given product was applied to the face twice a day for 8 weeks. Instrumental measurements of the skin colour (a* and L* parameter), skin capacitance, skin tensile properties (R0, R2, R6), skin thickness and skin microrelief parameters (Ra and Rz) were taken at baseline and after 4 and 8 weeks of use. Clinical and subjective evaluations were also carried out at each control visit. Moreover, the amount of cream consumed during usage was calculated by weighing the given jars at each visit. Statistical analysis of the data obtained showed a significant improvement in all instrumental parameters for both groups (‘fancy’ and ‘plain’ packaging), although no significant differences were detected between the two groups at any time. The improvement was higher in the ‘plain’ group for most instrumental parameters except for micro‐relief parameters where the outcome was better in the ‘fancy’ group. Promotion of facial muscle relaxation deriving from the application of the fancy‐packaged cream could be a possible explanation for this finding. Also the product's efficacy and sensory properties were perceived with a higher positive impact in the fancy group. The better performance of the plain packaging group could be related to daily application of the ‘proper’ amount of cream. In fact, this group consumed a larger amount of cream than the ‘fancy’ group. These results show that a true placebo effect cannot be induced by packaging characteristics, although they can slightly influence the degree of the expected skin benefits in different ways. Moreover, proper daily dosage of the product appears to be a key factor in improving the biophysical skin properties related to anti‐ageing and restoring effects. Paper presented at the IFSCC Conference 2005, Florence, Italy.