Omega-3 fatty acids have been shown to reduce inflammation and have an impact on glutathione levels
Giustarini, D., Milzani, A., Dalle-Donne, I., & Rossi, R
But in this space, the more common pattern is stacking to compensate for weak evidence, not stacking because combination efficacy is proven
GSH acts as an inhibitor of extended inflammation directing components of innate immunity like polymorphonuclear neutrophils specifically to the site of infection/damage allowing a proper response to infection
Glutathione and vitamin C are not two separate ingredients arbitrarily mixed in a drip bag
Cysteine is often the "rate-limiting" factor in glutathione production