Cow’s milk delivers about 8 grams of protein per cup regardless of fat level, making it one of the highest-protein milks available. But if you want even more, ultra-filtered cow’s milk pushes that number to around 13 grams per cup, and sheep’s milk naturally contains more protein than any other common mammal milk. Among plant-based options, soy and pea milk come closest to dairy, while most other alternatives fall well short.
Cow’s Milk: The Baseline
Whole, 2%, 1%, and skim cow’s milk all land in a tight range of 8 to 8.3 grams of protein per 8-ounce cup. The fat content changes the calorie count dramatically but barely moves the protein needle. That’s because protein lives in the watery portion of milk, not the fat.
Where the fat level does matter is calorie efficiency. A 16-ounce glass of skim milk provides 16.5 grams of protein for just 167 calories, while the same amount of whole milk gives you 15.4 grams for 298 calories. If your goal is to maximize protein while keeping calories low, skim milk is nearly twice as efficient.
Ultra-Filtered Milk: The Highest-Protein Option
Ultra-filtered milk is regular cow’s milk pushed through a fine membrane that separates out water and lactose while concentrating the protein. The result is roughly 50% more protein per cup than standard milk, landing around 13 grams in an 8-ounce serving. Brands like Fairlife and Joyya are the most widely available examples.
Because lactose gets removed or broken down during processing, ultra-filtered milk is also lower in sugar and typically marketed as lactose-free. The taste is slightly creamier than regular milk. If raw protein per serving is your primary concern, this is the grocery store winner.
Sheep and Goat Milk
Among mammal milks, sheep’s milk contains significantly more protein than both cow and goat milk. Research comparing all three consistently finds that sheep milk is higher in protein, fat, calcium, and phosphorus. A cup of sheep’s milk typically provides 14 to 15 grams of protein, nearly double what cow’s milk offers.
Goat milk falls closer to cow’s milk, usually around 8 to 9 grams per cup. It has a tangier flavor and slightly different fat structure that some people find easier to digest, but it won’t give you a meaningful protein boost over regular cow’s milk. Sheep’s milk is harder to find in most U.S. grocery stores and tends to cost significantly more, which limits its practicality for everyday use.
Plant Milks Ranked by Protein
Plant-based milks vary wildly in protein content. Here’s how the main options compare per cup (unsweetened, unflavored varieties):
- Pea milk (Ripple): 8 grams, matching dairy
- Soy milk (Silk Organic): 7 grams, close to dairy
- Oat milk: 2 to 4 grams, depending on brand
- Hemp milk: 3 grams
- Almond milk: 1 to 2 grams
- Rice milk: less than 1 gram
- Coconut milk: less than 1 gram
Pea and soy milk are the only plant options that come within striking distance of cow’s milk. Almond, rice, and coconut milk are essentially protein-free in practical terms. If you’re choosing a plant milk for its protein, soy and pea are the only two worth considering.
Protein Quality Matters, Not Just Quantity
Grams per cup tells you how much protein you’re getting, but not how well your body can use it. Protein quality depends on two things: whether the protein contains all nine essential amino acids, and how efficiently your digestive system absorbs them.
Dairy protein scores at the top of the scale. Using DIAAS, the current gold standard for measuring protein quality, all dairy proteins tested qualify as “excellent” or “high” quality sources. Soy protein scores as a “good” source, one tier below dairy. The gap comes down to amino acid balance: soy and pea protein are slightly lower in sulfur-containing amino acids that your body needs for building muscle and other tissues.
This means that 8 grams of protein from cow’s milk delivers more usable amino acids than 8 grams from pea milk, even though the number on the label looks identical. For most people eating a varied diet, this difference is minor. But if milk is a major protein source for you, or if you’re feeding young children, dairy and soy are the strongest choices.
Quick Comparison: Protein Per Cup
- Ultra-filtered cow’s milk: ~13 g
- Sheep’s milk: ~14–15 g
- Cow’s milk (any fat level): 8 g
- Goat’s milk: 8–9 g
- Pea milk: 8 g
- Soy milk: 7 g
- Hemp milk: 3 g
- Almond milk: 1–2 g
For most people, ultra-filtered cow’s milk offers the best combination of high protein, wide availability, and reasonable cost. If you’re avoiding dairy entirely, pea milk is the closest match in both quantity and completeness of protein. And if you can find it, sheep’s milk is the quiet champion of the dairy case.