A nationwide outbreak of alopecia associated with the use of a hair-relaxing formulation

Arch Dermatol. 2000 Sep;136(9):1104-8. doi: 10.1001/archderm.136.9.1104.


Objective: To study the long-term outcome of adverse effects reported by persons who used a commercial hair-straightening product known as the Rio Hair Naturalizer System (World Rio Corporation).

Design: Survey of individuals who contacted the Food and Drug Administration in 1994 and 1995 to report adverse effects linked to using the product.

Setting: Persons residing in the United States.

Patients: A total of 464 (59% of 790 eligible) patients who returned a completed questionnaire.

Main outcome measures: Adverse effects associated with using the Rio Hair Naturalizer System products (neutral or color enhancer).

Results: Ninety percent of respondents were African American women between the ages of 15 and 55 years. The most common complaints associated with the use of the products were hair breakage and/or hair loss, reported by 95% of respondents. Three quarters of those experiencing hair loss reported losing 40% or more of their original hair. The median time between the loss of original hair and the growth of new hair was 8 months; however, 40 (9%) respondents reported having no new growth at the time of completing the survey, some 2 years after using the product. When mixed according to package instructions, the mean pH of a sample of 20 neutral product kits tested was 1.39 (range, 1.1-3.15). For the 21 color-enhancer products tested, the mean pH was 2.82 (range, 2. 29-3.08).

Conclusions: A nationwide outbreak of alopecia and scalp injuries involving tens of thousands of women (and some men) occurred following the marketing of a chemical hair-relaxing product. Most of those affected reported substantial hair loss, with a majority indicating growth of new hair that was abnormal in both quantity and quality.

MeSH terms

  • Adolescent
  • Adult
  • Alopecia / chemically induced*
  • Black People
  • Disease Outbreaks*
  • Female
  • Hair Preparations / adverse effects*
  • Humans
  • Male
  • Middle Aged
  • Product Surveillance, Postmarketing
  • United States


  • Hair Preparations