What is it?
Glyceryl monothioglycolate is a component in “acid” permanent waving formulations.

How can I avoid it?
Glyceryl monothioglycolate can be avoided by not using permanent hair-waving solutions that contain this chemical. These solutions are found only in salons in the United States and are usually referred to as acid or hot permanents. These permanents can be identified because the packages usually contain three bottles or containers. There is no cross-reactivity with ammonium thioglycolate, the active ingredient in alkaline permanents, which can be recognized because these preparations contain only two bottles or containers. Salon product labeling, which is voluntarily being introduced in the United States, should help hairdressers and clients to avoid glyceryl monothioglycolate. Hair that has been permed with glyceryl monothioglycolate may have persistence of allergen for at least 3 months after permanent, and this can cause long-lasting dermatitis in clients or beauticians. Glyceryl monothioglycolate easily penetrates through many rubber and vinyl gloves, which makes it difficult to impossible for beauticians to continue permanent hair-waving with this allergen.

  • Essential ingredient in acid permanent hair-waving solution
  • Depilatories
  • Hair straighteners
  • Permanent hair dyes
Other names for glyceryl monothioglycolate:
  • Acetic acid, mercapto-, mono ester with 1,2,3 propanetriol
  • Acid permanent waves
  • Hot permanent waves
  • Mercaptoacetic acid, mono ester with 1,2,3 propanetriol
  • Glycerol monomercapto acetate
  • GTG
  • GMTG
Potential cross-reacting/co-reacting substances:
  • Other thioglycolates


How safe is it?

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