Comparison
Pistachio Milk vs Soy Milk: Protein, Taste & Nutrition
Soy is the protein heavyweight of plant milks. Pistachio is the best of the nut milks on the same measure, and that is a different contest.
Quick answer
Soy milk has roughly twice the protein. Across the cartons we read, unsweetened soy declares 6.0 to 8.0 g a cup against 3 to 4 g for unsweetened pistachio milk. The figure worth knowing is that every almond, cashew, walnut and macadamia carton in the same set declares about 1 g, so pistachio is the highest-protein nut milk and still under half of soy. Soy also carries six to ten times the calcium, which is fortification rather than the bean. Choose soy for protein, pistachio for flavor and lower carbs, and note they are separate allergens.
The short answer: soy milk has far more protein and is the plant milk closest to cow's milk; pistachio milk is nuttier, lower in carbs and lower in calories. Soy is the nutritional workhorse; pistachio is the flavor pick. Your choice usually comes down to whether you want protein or taste, and which allergen you can have.
Protein: soy wins, and pistachio comes second
This is the headline difference, and the size of it is worth being precise about. Across the cartons we read, the four unsweetened soy panels declare 6.0 to 8.0 g of protein a cup. The two pistachio panels declare 3 to 4 g. So soy carries roughly twice what pistachio does.
The more interesting half is where pistachio sits against the rest of the nut shelf. Every unsweetened almond, cashew, walnut and macadamia carton in the same set declares about 1 g. So pistachio is the highest-protein nut milk we measured, at three to four times its neighbors, and still under half of soy. Both facts are true at once, and brand copy tends to quote only the first.
Soy is also the only common plant milk whose protein is complete, with all nine essential amino acids, which is why UF/IFAS Extension calls unsweetened soy "the closest plant-based milk that is comparable to cow's milk in terms of protein." If you are drinking plant milk to hit a protein target, soy is the answer. More on the pistachio side in pistachio milk protein.
Nutrition side by side
| Per 1 cup (237 to 240 ml), unsweetened | Pistachio milk | Soy milk |
|---|---|---|
| Cartons read | 2 | 4 |
| Calories | 80 to 100 | 79.2 to 91.2 |
| Protein | 3 to 4 g | 6.0 to 8.0 g |
| Fat | 8 g | 2.5 to 4.5 g |
| Saturated fat | 1 g | 0.5 to 1.5 g |
| Carbohydrate | 4 g | 3.0 to 6.0 g |
| Total sugars | 1 g | 0 to 2.0 g |
| Added sugars | 0 g | 0 g |
| Calcium | 45 mg | 286 to 451 mg |
| Allergen | Tree nut (pistachio) | Soy |
| Protein type | Incomplete | Complete |
Per-serving Nutrition Facts values for real US cartons: soy from USDA FoodData Central, read 9 November 2026; pistachio from our own panel study, since FoodData Central holds no usable pistachio record. Method, limits and the CSV are in best plant milk.
The calcium row is the one most people will not expect. The pistachio carton publishing a full panel declares 45 mg a cup against 286 to 451 mg for the soy cartons, a six to tenfold gap. That is fortification rather than the bean: soy milk is routinely fortified with calcium carbonate and the plainer nut cartons often are not.
A correction to what this page used to say. Earlier versions put pistachio milk at "roughly 2 g" of protein. Our own panel study does not support that: the published US panels run 2 to 4 g, and the two unsweetened cartons sit at the top of that range. The 2 g figure came from one brand's sweetened Original Blend. The range above is what the panels actually say.
Taste and use
Pistachio milk is distinctly nutty with a pale green color and a creamier body than most plant milks. See what it tastes like. Soy is more neutral, with a mild beany note some people detect in the unsweetened version. Both steam reasonably for coffee, and soy actually foams quite well thanks to its protein, while pistachio makes a softer foam unless it's a barista formula (see pistachio coffee). For flavor and color, pistachio leads; for an all-purpose, protein-rich milk, soy is hard to beat.
Allergens: the deciding factor for many
These two milks suit opposite groups. Pistachio milk is a tree-nut product, off-limits for anyone with a nut allergy but fine for those avoiding soy. Soy milk is the reverse: soy-free diets rule it out, but it's safe for people with nut allergies. If allergies are in the picture, that often settles the choice before nutrition does.
Which should you choose?
Choose soy for the most protein, a complete amino-acid profile and a neutral all-rounder. Choose pistachio for nutty flavor, a pale green color, lower carbs and fewer calories, provided tree nuts are fine for you. Also compare pistachio milk vs almond, vs oat and the full comparisons hub.