Sheep milk tops the protein charts among commonly available animal milks, delivering roughly 5.5 to 6 grams of protein per 100 milliliters compared to about 3.3 grams in regular cow milk. But the answer shifts depending on whether you mean raw animal milks, processed dairy products, or plant-based alternatives. Ultra-filtered cow milk, for instance, can pack 13 grams of protein into a single cup by mechanically concentrating the milk’s natural proteins. And once you factor in protein quality, not just quantity, the rankings get more interesting still.
Dairy Milks Ranked by Protein
Among the animal milks most people can actually buy, here is how they stack up per 100 milliliters, from highest to lowest protein content:
- Sheep milk: roughly 5.5–6 g protein per 100 mL
- Buffalo milk: roughly 4.0–4.5 g
- Cow milk (whole): roughly 3.2–3.5 g
- Goat milk: roughly 3.1–3.5 g
- Camel milk: roughly 3.4 g
- Donkey milk: roughly 1.1 g
Sheep milk consistently leads in multiple analyses. A comparative study of milk from several species found that sheep milk had the highest total protein content, as well as the highest total solids and density, outperforming cow and goat milk in all protein measures.1PubMed Central. Characterization and Comparative Evaluation of Milk Protein Variants from Pakistani Dairy Breeds A separate analysis of milk from the Mount Ida region confirmed that protein and fat contents were higher in every sheep breed tested than in any cow or goat sample.2Small Ruminant Research. General composition and protein surface hydrophobicity of goat, sheep and cow milk in the region of Mount Ida
Buffalo milk comes in second, rich enough in protein and fat to be the preferred base for mozzarella di bufala and many South Asian dairy products.3PubMed Central. Buffalo milk: nutritional composition, bioactive properties, and advances in processing technologies-a comprehensive review Its casein profile is somewhat different from cow milk, with specific casein fractions that influence how the milk behaves during cheesemaking.4Journal of Dairy Science. Protein composition affects variation in coagulation properties of buffalo milk
Cow and goat milks are close to each other in total protein, usually landing in a similar range. Goat milk differs from cow milk less in quantity and more in protein structure. Goat milk contains substantially less alpha-s1 casein, the protein fraction most associated with dairy allergies, which is one reason some people who react to cow milk tolerate goat milk better.5PubMed Central. Comparative Analysis of the Protein Composition of Goat Milk from French Alpine, Nubian, and Creole Breeds and Holstein Friesian Cow Milk: Implications for Early Infant Nutrition
Camel milk is a bit of an outlier. It delivers protein comparable to cow milk, around 3.4 grams per 100 mL, but its whey proteins are structured differently. Camel milk lacks beta-lactoglobulin, the dominant whey protein in cow, goat, and donkey milks and a common trigger for milk protein allergies.6Mljekarstvo. Comparison of composition and whey protein fractions of human, camel, donkey, goat and cow milk Human milk also lacks beta-lactoglobulin, which is one reason camel milk has attracted research interest for infant nutrition in regions where cow milk alternatives are limited.
Donkey milk sits at the bottom of the dairy list, with only about 1.1 grams of protein per 100 mL. Its overall composition, low protein and low fat, closely resembles human breast milk, making it a poor choice if you’re looking for a high-protein dairy option but an interesting reference point for infant feeding research.6Mljekarstvo. Comparison of composition and whey protein fractions of human, camel, donkey, goat and cow milk
Where Plant-Based Milks Stand
If you are comparing plant milks to dairy, the gap is wide for most options. Soy milk is the clear standout among plant alternatives, typically delivering around 7 to 8 grams of protein per cup, which puts it roughly on par with cow milk in total grams. Every other common plant milk falls well short.
Pea protein milk, sold under brands like Ripple, matches or sometimes exceeds soy milk in total protein per serving. The protein is added as an isolate, so the amount varies by brand, but many pea milks advertise 8 grams per cup. Pea protein on its own is lower in the amino acid methionine than dairy, but blending it with casein (in roughly a 40/60 pea-to-casein split) significantly improved the availability of essential amino acids including methionine and leucine in a study of older adults.7PubMed. Postprandial amino acid response after the ingestion of pea protein, milk protein, casein and a casein-pea blend, in healthy older adults
Almond, rice, coconut, oat, and hemp milks all hover between 0 and 4 grams of protein per cup in most commercial versions. A big part of the reason is that the plant ingredient often makes up a surprisingly small fraction of the final product. One analysis found that the main plant material ranged from just 3 percent in certain almond milks to 40 percent in one coconut brand, with the rest being water, emulsifiers, and added vitamins.8npj Science of Food. How animal milk and plant-based alternatives diverge in terms of fatty acid, amino acid, and mineral composition When your “almond milk” is 97 percent not-almonds, it is unsurprising that the protein content is negligible.
Here is a rough ranking of plant milks by protein per cup, though exact figures vary by brand and formulation:
- Pea protein milk: 8 g (added protein isolate)
- Soy milk: 7–8 g
- Oat milk: 2–4 g
- Hemp milk: 2–3 g
- Almond milk: 1 g
- Rice milk: 0.5–1 g
- Coconut milk (beverage): 0–1 g
Ultra-Filtered Milk Changes the Game
If sheer grams of protein per glass are what you want, ultra-filtered cow milk is the practical winner on grocery store shelves. Brands like Fairlife run regular cow milk through fine membranes that concentrate the protein and filter out much of the lactose and sugar. The result is typically 13 grams of protein per cup, nearly double the protein of regular cow milk, with roughly half the sugar. The filtration process uses membranes with pore sizes small enough to retain protein while letting smaller molecules (lactose, some minerals) pass through.9PubMed Central. Ultrafiltration of Whole Milk: Impact of Homogenization and Ultrafiltration Temperature on Processing Efficiency and Component Retention
Milk protein concentrates produced by similar ultrafiltration and diafiltration techniques can reach protein levels above 80 percent on a dry-weight basis.10Journal of Dairy Science. Preparation of milk protein concentrates by ultrafiltration and continuous diafiltration: Effect of process design on overall efficiency You are not drinking those concentrates as a glass of milk, but they form the backbone of many protein-fortified dairy beverages and protein powders. The practical ceiling for liquid milk protein concentrates is around 15 percent protein before solubility problems start to surface.
Why Protein Quality Matters as Much as Quantity
Ranking milks by total grams of protein only tells part of the story. Your body does not use all protein equally. What matters is whether the protein contains the right amino acids in digestible form. The standard scoring system for this is DIAAS, which measures how well a protein delivers each essential amino acid after digestion.
Dairy proteins score exceptionally well. Cow milk protein scores above 100 across all essential amino acids for adults, with values ranging from 117 for tryptophan up to 198 for histidine.11Frontiers in Nutrition. A review on nutritional quality of animal and plant-based milk alternatives: a focus on protein A score above 100 means the protein delivers more than enough of that amino acid to meet requirements. Casein and whey, the two major dairy protein fractions, are both classified as high or excellent quality, with casein scoring above 100 and whey scoring at or above 75 on the standard scale.12PubMed Central. Comprehensive overview of the quality of plant- And animal-sourced proteins based on the digestible indispensable amino acid score
Among plant milks, soy is the only one whose protein consistently scores above 100 for adults and older children, with all its essential amino acid scores clearing the bar.13Frontiers in Nutrition. Comparison of nutritional composition between plant-based drinks and cow’s milk Every other plant milk tested falls short on at least one amino acid. Oat milk’s weakest link is lysine, scoring 73. Almond milk scored just 39, making it the lowest-quality protein source among common plant beverages. Hemp, rice, and coconut milks were inadequate in multiple amino acids.13Frontiers in Nutrition. Comparison of nutritional composition between plant-based drinks and cow’s milk
For young children, the gap widens further. Even soy protein fails to fully meet the amino acid requirements for children aged six months to three years, with a score of about 92, falling short on the sulfur-containing amino acids methionine and cysteine. The digestible amounts of methionine and lysine in dairy proteins are roughly double and 1.3 times higher, respectively, than in soy proteins.14Journal of Dairy Science. The Digestible Amino Acid Composition of Several Milk Proteins: Application of a New Bioassay This is why European nutrition guidelines require soy infant formulas to contain more protein per calorie than cow-milk-based formulas to compensate for the lower digestibility and bioavailability.15PubMed. Soy protein infant formulae and follow-on formulae: a commentary by the ESPGHAN Committee on Nutrition
How Heat Processing Affects What You Actually Absorb
The protein listed on a nutrition label is measured by chemical methods that detect total nitrogen, then multiply by a conversion factor to estimate protein content. These methods cannot distinguish between intact, digestible protein and protein that has been denatured or chemically modified during processing.11Frontiers in Nutrition. A review on nutritional quality of animal and plant-based milk alternatives: a focus on protein That means two milks with the same number on the label can deliver meaningfully different amounts of usable protein to your muscles and tissues.
Standard pasteurization, the quick heat treatment that most fresh milk undergoes, does not significantly change how your body handles the protein. But ultra-high-temperature (UHT) treatment, the process used for shelf-stable milk sold in cartons at room temperature, is a different story. In a controlled human study, people who drank UHT milk lost about 26 percent of the ingested protein nitrogen to deamination (essentially, waste), compared to about 18.5 percent losses with pasteurized or microfiltered milk.16The Journal of Nutrition. Ultra High Temperature Treatment, but Not Pasteurization, Affects the Postprandial Kinetics of Milk Proteins in Humans The UHT process causes denaturation and aggregation of milk proteins, altering their structure and potentially changing how efficiently your gut breaks them down.17PubMed Central. Influence of Ultra-Heat Treatment on Properties of Milk Proteins
This does not mean shelf-stable milk is nutritionally worthless. You still absorb most of the protein. But if you are specifically choosing milk for its protein and comparing labels side by side, fresh pasteurized milk delivers more of that protein to your bloodstream in usable form than the same amount of UHT milk.
Milk Protein and Muscle Building
For people drinking milk specifically to support muscle recovery after exercise, the type of protein matters beyond just the total grams. Dairy milk contains both whey (about 20 percent of total protein) and casein (about 80 percent), which digest at very different speeds.18PubMed Central. Adjustment of Whey:Casein Ratio from 20:80 to 60:40 in Milk Formulation Affects Food Intake and Brainstem and Hypothalamic Neuronal Activation and Gene Expression in Laboratory Mice Whey hits your bloodstream fast, peaking muscle protein synthesis about 60 minutes after drinking. Casein is slower, peaking around 120 minutes. Whole milk protein, with its natural mix of both, peaks at about 90 minutes and produced the highest overall muscle protein synthesis response in a comparison of all three.19PubMed Central. Effects of Whey, Caseinate, or Milk Protein Ingestion on Muscle Protein Synthesis after Exercise
When researchers compared skim milk head-to-head with a soy beverage matched for total protein and calories after resistance exercise, the milk group showed a higher rate of muscle protein synthesis (0.10 percent per hour versus 0.07 percent per hour for soy).20The American Journal of Clinical Nutrition. Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage That is a meaningful difference if you are training regularly and relying on milk as a protein source. However, in older adults, a soy-dairy protein blend produced muscle protein synthesis responses that were not statistically different from whey protein isolate alone, suggesting that blended approaches can work well.21PubMed Central. Soy-Dairy Protein Blend or Whey Protein Isolate Ingestion Induces Similar Postexercise Muscle Mechanistic Target of Rapamycin Complex 1 Signaling and Protein Synthesis Responses in Older Men
The Protein Measurement Problem
There is a wrinkle in all of this that most consumers never think about. The standard methods for measuring protein in milk, whether on a nutrition label or in a lab, work by measuring total nitrogen and then converting it to a protein estimate. The issue is that milk contains nitrogen-containing compounds that are not protein at all. These non-protein nitrogen compounds are normally a minor fraction, but the measurement method cannot tell the difference. This vulnerability was exploited in the 2008 melamine scandal, when melamine (a nitrogen-rich industrial chemical) was added to milk powder in China to make it appear to contain more protein than it did.11Frontiers in Nutrition. A review on nutritional quality of animal and plant-based milk alternatives: a focus on protein
For consumers buying milk at a reputable grocery store in a well-regulated market, this is not something to lose sleep over. Regulatory testing has tightened considerably since that scandal, and screening for non-protein nitrogen is now part of quality control for milk powders and protein ingredients.11Frontiers in Nutrition. A review on nutritional quality of animal and plant-based milk alternatives: a focus on protein But it is worth knowing that the protein number on a label is an estimate, not a direct measurement of how much usable protein is inside.
Extreme Milks From the Animal Kingdom
If you broaden the question beyond what you can buy at a store, the protein rankings look wildly different. Marine mammals produce some of the most protein-dense milk on the planet. Antarctic fur seal milk, for example, averages about 11 percent protein and can spike to nearly 15 percent when a mother resumes feeding after a foraging trip at sea.22PubMed Central. Characterisation of proteins in the milk of fur seals That is roughly three to four times the protein concentration of cow milk. Hooded seal milk is even more extreme, with protein content exceeding 10 percent alongside a fat content over 60 percent, making it more of a protein-and-fat slurry than anything resembling the milk in your fridge.
These milks evolved for a specific purpose: delivering massive calories and building blocks to pups that need to grow fast in freezing environments, often while the mother is absent for days at a time on foraging trips. The protein concentration in fur seal milk did not change much over the course of lactation overall, though the balance between casein and whey shifted as the pup aged.22PubMed Central. Characterisation of proteins in the milk of fur seals None of these milks are commercially available, of course, but they put into perspective just how much variation evolution has produced in what is fundamentally the same biological fluid.