No, and this is the most important thing on the page. The reassurance often given about nut oils applies specifically to highly refined oils, where processing strips out the protein that causes allergic reactions. Pistachio oil is sold as a cold pressed, unrefined finishing oil precisely because it keeps the flavour compounds, and protein comes with them. Anyone with a pistachio or tree nut allergy should treat it as they would the nut. Because pistachio sits in the same family as cashew and mango, cashew allergic readers should be equally cautious.

Because of what pressing separates. Oxalates, minerals such as nickel, and much of the salicylate load in a nut are associated with the protein and fibre fraction, and that fraction stays behind in the press cake when the oil is extracted. What comes out is largely triglyceride. That is why the oil sits well below the whole nut on several trigger columns. It is a genuinely useful route to the flavour of a nut for someone managing oxalate or nickel, but only if allergy is not the reason they are avoiding it.

You can, but there is little point. It has a low smoke point, so it degrades at frying and searing temperatures, and its delicate roasted nut aroma, which is the reason to buy an expensive oil in the first place, does not survive heat. Treat it as a finishing oil: over roasted carrots, on a piece of white fish after cooking, in a dressing, or over vanilla ice cream. If you need a nut flavoured oil that tolerates some warmth, a refined nut oil is the better tool and is also the lower allergen risk.