OPI Fungus Fix contains a number of ingredients that are purported to aid, directly or indirectly in the treatment of toenail fungus
Ethoxydiglycol is added to the formulation as a solvent to make Fungus Fix less viscous and easier to apply to nails. This ingredient is colorless.
Propylene glycol provides increased moisturizing ability and helps to spread the formula evenly by acting as a lubricant.
Undecylenoyl glycine is a natural substance derived from sunflower and oat proteins. This is added to Fungus Fix for two reasons: this is a natural antibacterial which can help control any bacterial infections that may be commensal with the fungus; undecylenoyl glycine also helps to support the natural acidity of the skin, making it more difficult for secondary bacterial infections to begin.
Usnic acid is a byproduct of lichen and is the only active antifungal ingredient in OPI Fungus Fix. Usnic acid does have antifungal properties, so it may have some value in killing off nail fungus. If taken orally, usnic acid can cause liver damage.
Unlike other nail fungus products, Fungus Fix does not appear to contain undyclenic acid, which short circuits the normal development of the nail fungus.