Walnut oil (Juglans regia oil) is high in unsaturated fatty acids with a fatty acid profile of palmitic acid (C16:0) at 5% to 11%, stearic acid (C18:0) at 2% to 5%, oleic acid (C18:1) at 16% to 28%, linoleic acid (C18:2) at 48% to 59%, and linolenic acid (C18:3) at 5% to 16%. We know oleic acid is great for softening skin, regenerating skin cells, moisturizing, and behaving as an anti-inflammatory. Linoleic acid helps restore skin's barrier function and reduces transepidermal water loss (TEWL).
Walnut oil has 1.8 to 3.0 mg per gram phytosterols (1.8 grams to 3.0 grams to 1 kg of oil), with most of it composed of sitosterol. It contains between 268.5 ppm to 436 ppm Vitamin E. I couldn't find anything about the polyphenols in the oil, but there are phenolic acids and tannins in the nuts, which might be why walnut oil is a drier feeling oil.
It has a fatty acid profile like hempseed oil and as much linoleic acid as grapeseed oil. This means, unfortunately, it's going to have a short shelf life, something like 3 to 6 months maximum. (I'd consider it at 3 months).
I need to make a comment about the shelf life. I have seen references to walnut oil having a shelf life for a year, but from a chemistry perspective, I can't see this working. It has a ton of linoleic acid but not a lot of Vitamin E, so it'll go rancid pretty easily. This study shows it has a shelf life of less than grapeseed oil, which is 3 to 6 months maximum. ("...the predicted shelf-lives were significantly lower than that of the storage times, especially, walnut oil (very prone to oxidation) gave 15-20 times lower shelf-life than the best-before storage life.") I've seen a variety of shelf lives discussed, including up to a year, but there was the suggestion that the oil be kept in a cool dark place or the fridge to get a year, and we aren't going to be doing that with our lotions, so I feel very comfortable in saying that we should consider it to have a shelf life of 3 months.
It has a nutty taste - not applicable for our bath & body products, but significant when you're making a nice oil and balsamic vinegar dip for your foccacia bread - and a bit of a nutty smell.
Analysis of free and esterified sterols in vegetable oils
Fatty acid and tocopherol contents of walnut oil
Shelf life: Garden of Wisdom
Shelf life: The Soap Queen (3 months)
Nut composition and their health benefits
The picture of the tree in the snow is the picture of the walnut tree in my backyard. Raymond and I were married under that tree, and I just love it!