Almond milk and soy milk are two different products made from completely different ingredients. Almond milk is made by blending almonds with water and straining out the solids. Soy milk is made the same way but from soybeans. They look similar on the shelf, but they differ significantly in protein content, calorie count, and how they perform in cooking.
How They Differ Nutritionally
The biggest gap between these two milks is protein. A cup of unsweetened soy milk delivers about 7 to 9 grams of protein, roughly the same as a glass of dairy milk. Unsweetened almond milk contains just 1 gram or less per cup. If you’re using plant milk as a meaningful protein source, soy milk is the clear winner.
Both contain about 2 to 4 grams of fat per cup, and in both cases those fats are predominantly the heart-healthy monounsaturated and polyunsaturated types. Almond milk has no saturated fat, similar to skim cow’s milk. Unsweetened almond milk is typically lower in calories overall, usually coming in around 30 to 40 calories per cup, while unsweetened soy milk runs closer to 70 to 90 calories.
Most commercial brands of both milks are fortified with calcium, vitamin A, and vitamin D to approximate what you’d get from dairy milk. However, fortification levels vary widely between brands, so checking the nutrition label matters. One thing worth knowing: soy naturally contains phytate, a compound that can reduce how much calcium your body actually absorbs from the drink.
Almonds are naturally rich in vitamin E, but almond milk contains very few almonds per serving, so the actual vitamin E you get from a glass is modest.
The Soy and Hormones Question
Soy contains isoflavones, a type of plant compound that’s structurally similar to human estrogen but much weaker. This has fueled persistent concerns about hormonal effects, but the research paints a more nuanced picture.
Isoflavones can bind to estrogen receptors and produce either a weak estrogen-like effect or an anti-estrogen effect, depending on your body’s existing hormone levels. In premenopausal women with higher circulating estrogen, soy tends to act as an anti-estrogen. In postmenopausal women with lower estrogen levels, it can act more like a mild estrogen. A meta-analysis of 18 randomized controlled trials found that soy supplements slightly raised thyroid-stimulating hormone levels but had no effect on actual thyroid hormone production.
On cancer risk, reviews of randomized controlled trials looking at isoflavone intakes ranging from 36 to 235 mg per day found no changes in breast cancer risk factors. Studies observing people who eat soy foods over time show either a protective or neutral effect. For prostate cancer, research has similarly found no significant effects from soy consumption. In short, drinking soy milk in normal dietary amounts does not appear to pose a hormonal risk for most people.
Blood Sugar and Weight Management
If you’re watching your blood sugar, both milks perform similarly when unsweetened. Glycemic index values for commercial almond milks range from about 49 to 64, and soy milks range from about 48 to 62. Neither causes a dramatic blood sugar spike compared to sweetened beverages, but the exact number depends heavily on the brand and whether it contains added sugars. Sweetened versions of either milk will behave quite differently, so always check the label.
For low-calorie diets, unsweetened almond milk has an edge simply because it’s lower in calories. For satiety, soy milk’s higher protein content keeps you feeling fuller longer.
Cooking and Coffee
Soy milk’s higher protein content gives it a structural advantage in the kitchen. Protein is what allows milk to froth, thicken sauces, and hold up under heat. Soy milk froths more reliably in espresso drinks and works better in baking recipes that depend on structure, like muffins or pancakes. Almond milk is thinner and can separate or curdle when added to hot coffee, especially acidic blends, though “barista” formulations with added stabilizers reduce this problem.
Almond milk adds a subtle nutty sweetness that works well in smoothies, cereal, and lighter recipes. Soy milk has a more neutral, slightly beany flavor that blends into savory dishes without competing.
Allergies and Who Should Avoid Each
Soy is one of the eight major food allergens. Tree nuts, the category almonds belong to, are another. Both allergies are common enough that these milks are clearly labeled. If you have a soy allergy, almond milk is a safe alternative (assuming no tree nut allergy), and vice versa. Some newer almond and nut milks now include added pea protein to boost their protein content, which is worth checking if you have additional food sensitivities.
Environmental Footprint
Almond milk consistently requires more water to produce than soy milk. Some studies have measured almond milk’s water use at over 6,000 liters per liter of finished product, far exceeding soy milk and most other plant-based alternatives. This is largely because almonds themselves are a water-intensive crop, predominantly grown in drought-prone regions like California. Soy milk’s water footprint is substantially lower, making it the more sustainable choice if water use is a concern for you.
Which One to Choose
Your best pick depends on what you’re optimizing for. If you want a protein-rich dairy substitute that performs well in cooking and coffee, soy milk is the stronger option. It’s the closest nutritional match to cow’s milk among all plant-based alternatives. If you want something light, low-calorie, and mildly flavored for cereal or smoothies, and you’re getting your protein elsewhere, almond milk works well. Neither is unhealthy, but they solve different problems.