For normal sweat and perspiration stains, this stuff works great. When funky stuff like aluminum found in many deodorants causes a chemical reaction, it can be more difficult. Based on the coloration you observed, it may be a permanent change, and it may be topical, and a result of the deodorant bonding with the material. If the substance has somehow altered the color of the shirt, then you may not be able to save it. If the antiperspirant did not permanently dye the area, then using this product should get it clean. Please give us a call if you want to discuss this further as there are many tricks and techniques you can try for a stain this tough.