Tolerability of hair cleansing conditioners: a double-blind randomized, controlled trial designed to evaluate consumer complaints to the U.S. Food and Drug Administration

Abstract

Importance: Consumers have reported skin rash/irritation and hair loss/breakage with Wen by Chaz Dean Sweet Almond Mint Cleansing Conditioner (WCDSAMCC), however epidemiologic, toxicologic and clinical hair loss studies have not provided an explanation. Contact dermatitis has been hypothesized.

Objective: To assess the tolerability of six products: WCDSAMCC, three other hair cleansing conditioners, and two controls [salicylic acid shampoo (SAS) and baby shampoo (BS)].

Design: Double-blind, randomized, controlled trial.

Setting: Single-site study.

Population: General population volunteers.

Intervention: Standard semi-open patch tests (SOPTs) and duration-escalation repeat open application tests (ROATs) over 5 weeks.

Main Outcome Measures: Primary outcome measure was “stopping point” [ROAT total component score ≥6 (maximum 10) or global ≥4 (maximum 5)]. Secondary outcomes included “any reaction” (ROAT component score ≥1) and SOPT ≥ doubtful.

Results: Two hundred of 298 volunteers were enrolled. There were no significant differences in the tolerability of WCDSAMCC and any of the other three hair cleansing conditioners as assessed by SOPT or ROAT. WCDSAMCC was significantly better tolerated than SAS (“stopping point”, or “any reaction”, p values<0.0001) as well as BS (p = 0.01). The frequency of doubtful SOPT reactions was lowest for WCD (2.2%) and highest for SAS (7.1%, p = 0.04).

Conclusions: As assessed by both ROAT and SOPTs, WCDSAMCC was similar in tolerability to three other hair cleansing conditioners and significantly better tolerated than both controls (SAS and BS).

Summary: This double-blind, randomized, controlled study found that WCDSAMCC was similar in tolerability to three other HCCs and was significantly better tolerated than both SAS and BS. This study provides critical clinical evidence on the comparative lack of cutaneous effects with use of WCDSAMCC.

Trial Registration: NCT03483025 ClinicalTrials.gov.

Keywords:

• Allergic contact dermatitis
• irritant contact dermatitis
• patch test
• shampoo
• hair cleanser

Acknowledgements

The authors appreciate the support of Maureen Busch, RN (study coordinator) and Min Xi, PhD (HealthPartners statistician) as well as the many individuals who volunteered as participants in this study.

Authors’ Contributions

EW designed the study, served as principal investigator, and wrote the manuscript. JS, RK, YL, AN, AZ and SH helped with conducting the study. AM provided advice on study design.

Data integrity

Erin Warshaw had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Disclosure statement

Erin Warshaw, MD MS and Andrew Monnot PhD have served as a consultants for Wen by Chaz Dean. The other authors declare no conflict of interest.

Additional information

Funding

This study was supported by a grant from Wen by Chaz Dean. Role of the sponsor: The sponsor requested a clinical trial to be designed to address the skin symptoms described in FDA complaints. The study was designed by Erin Warshaw, MD MS and the study protocol was approved by the sponsor. The following was completed entirely dependent of the sponsor: conduct of the study; collection, management, analysis, interpretation of the data; preparation of manuscript. A study report with main findings was provided to the sponsor but the sponsor did not review this or any other manuscript prior to submission for publication nor did they provide advice on where to submit the manuscript. The sponsor did not provide (or require) final approval of the manuscript.