I am not familiar with gluten allergies and sensitivities, but since there are people looking to find out if gluten is in a hair dye product, it must be fairly serious. People are asking if Garnier Olia is a gluten-free product.
The answer is yes. Olia doesn't contain gluten.
Just to be sure, I asked Garnier's customer service. Garnier (a part of L'Oreal) was very clear in saying there isn't gluten and that if ever there is an ingredient question, be sure to check the product label. If the product is very small, ingredients may be found on the in-store display. To ensure there is consistency and make life easier for customers, Garnier uses FDA-recognized industry standard ingredient names.
So there you have it. Olia is gluten-free.