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Hair dyes and cancer: Should you be worried?

After reading the Left Brain’s post on the link between hair dye and cancer, I felt pretty good about coloring my hair. But then I saw this article from Cosmetics Design that says a new study shows hair dyes CAN cause cancer.

New data on hair dye?

According to Cosmetics Design:

A small but consistent risk of bladder cancer was reported in male hairdressers and barbers.

While the panel was agreed that regular occupational exposure to hair dye increased cancer risk they found data on personal use inconclusive.

The evidence was adjudged to be insufficient to make a definitive conclusion on the carcinogenicity of hair dye when exposure is limited to personal use.

Clarification or confusion?

I was anxious to find out if this study contradicted the Left’s earlier assessment, so I downloaded the full report. (You can find the hair dye report here.)

Now I’m no medical researcher, but I’m even more confused after reading this. Basically it says the panel evaluated 17 different chemicals and rated them by the following criteria:

  • Exposure data (where/how used)
  • Human carcinogenicity data (any proof it causes cancer in humans)
  • Animal carcinogenicity data (any proof it causes cancer in animals)
  • Other relevant data

The study evaluates whether or not there is sufficient data to indicate the chemical poses a risk of human or animal carcinogenicity. It also provides an overall assessment that states whether the chemical can be classified as not carcinogenic, possibly carcinogenic, or probably carcinogenic.

What does this all mean?

Of the 17 chemical reviewed:

  • 10 were not classifiable as to their carcinogenicity
  • 6 where possibly carcinogenic
  • 1 was probably carcinogenic.

The one chemical that had any clear indication of human carcinogenicity was 4, 4′-Methylenebis (2-chlorobenzenamine) or MOCA for short. But based on the report, MOCA is not used in hair dyes (and in a quick web search, I couldn’t find any evidence of hair dyes that used MOCA either.)

Of the six chemicals that were rated as “possibly carcinogenic” none are listed as being used in hair dyes. (One of them HC Blue 1, was banned from hair dye use in the 1980s. The rest are used in textiles, leather, or wool and one was used in manufacture of pesticides and similar compounds.) So to summarize:

  • The report says there’s no evidence of cancer risk for consumers who color their hair.
  • The report says there is a risk for professional hairdressers and barbers.
  • But looking at the details in the report, I only see risks associated with chemicals that are not used in hair dyes anymore.

The Beauty Brains bottom line

I’m not trying to come across as a defender of dangerous chemicals, but based on this report it doesn’t seem to me that they’ve shown any link real between the dyes used in hair dyes and cancer. If anyone else has another take on this report (are there any medical research technicians reading this?) please leave a comment for the rest of the Beauty Brains community.

–Mid Brain