Our advice

• There are still unanswered questions about hair dyes. Further research is needed to assess the safety of ingredients and their long-term effects. The EU is currently evaluating 42 ingredients; changes to EU regulations may result and our regulations need to keep pace. Questions about patch-test safety also need to be answered.
  
  
• There are no widely accepted alternatives to the chemicals used in hair dyes. Almost all permanent hair dyes - used either at home or at the hairdressers - are likely to contain extreme or strong sensitisers. And many "natural" hair dyes are no different.
  
  
• If you do experience an allergic reaction, see your doctor for treatment. And don't use the product again.
  
  

Tips for safe hair dye use

You may never experience any problems with hair dyes. But there are some safety precautions you should take when using these products:

• Avoid getting the dye on your skin.
• Always use gloves to apply the dye.
• Never leave the dye on longer than the recommended time.

If you're susceptible to eczema or have other allergies, you may have a greater risk of a reaction to hair dyes.

Permanent v semi-permanent

Permanent hair dyes work by penetrating the hair cuticles - the outer layer of your hair. Semi-permanents simply coat the outer layer and usually fade after a few washes. Permanent dyes last much longer - but not "permanently". After a few weeks, you'll obviously get re-growth of your "normal" hair at the roots.

More information

• Environmental Risk Management Authority: www.ermanz.govt.nz
• New Zealand Dermatological Society: www.dermnet.org.nz

Report by Jessica Wilson