Egg white vs yolk protein: do you need to cook them?
A large egg provides about 6.4 g of protein: 3.6 g in the white and 2.8 g in the yolk (USDA). The white is the part that most needs cooking: it contains avidin and proteins that digest poorly raw. Whole egg is about 91% digested when cooked and about 51% when raw (small study).
USDA values per 100 g, grams calculated by us. Cholesterol: 1,085 mg per 100 g of yolk (USDA, record 172184), or 184 mg for 17 g. Digestion measurements are for the whole egg, not the white and yolk separately.
How much protein is in the white and in the yolk?
The white provides 3.6 g and the yolk 2.8 g, which is 57% and 43% of the 6.4 g in a large egg. The white provides more because it weighs twice as much (34 g vs 17 g). Per 100 g, the yolk is richer: 16.2 g vs 10.7 g. Grams per part are our calculation from USDA values per 100 g.
What does egg white contain?
Mostly water and protein, with no measurable fat. A 34 g white contains 29.3 g of water, 3.6 g of protein, 0.8 g of carbohydrates, 0.2 g of minerals and 0 mg of cholesterol, for 19 kcal. Its main proteins are ovalbumin (54%), ovotransferrin (12%), ovomucoid (11%), ovomucin (1.5 to 3.5%) and lysozyme (3.4%). Avidin makes up only 0.05%, about 2 mg, but it is the one that binds biotin.
What does egg yolk contain?
Water, fat and protein. A 17 g yolk contains 8.9 g of water, 4.9 g of fat, 2.8 g of protein, 0.2 g of carbohydrates, 0.3 g of minerals and 184 mg of cholesterol, for 57 kcal. Its proteins are called lipovitellins, livetins, phosvitin and yolk LDL. Their shares are still to be checked: our figures of 22% for LDL and 11% for phosvitin come from different sources, and the rest (67%) is our subtraction.
Do you need to cook egg white?
Yes, this is the part where cooking changes the most, for three reasons. Ovalbumin, the main protein, sets at around 80 °C and then breaks down more easily. Ovomucoid slows trypsin, an enzyme that digests protein; it holds up better to heat (to be checked). Raw avidin binds biotin, a vitamin: it breaks apart above 70 °C and largely from 85 °C.
Do you need to cook egg yolk?
For biotin, no: the yolk has no avidin and provides biotin itself. For the digestion of its proteins, nobody knows: we found no recent measurement of yolk alone in humans. The real reason to cook it is safety: the FDA advises cooking eggs until both white and yolk are firm, because of Salmonella. The yolk sets at around 65 to 70 °C.
What do studies say about raw and cooked eggs?
They all look at the whole egg, never at the white and yolk separately. The boxes on this page therefore apply these percentages to the whole egg only; "cooked from 80 °C" is our own marker.
Evenepoel, 1998: 5 people, 25 g of protein. 90.9% digested with cooked egg, 51.3% with raw egg.
Evenepoel, 1999: 10 volunteers. 5.73% not absorbed with cooked egg, 35.10% with raw egg.
Fuchs, 2022: 45 men, 5 eggs. Muscle builds as much protein after raw eggs as after cooked eggs (0.067 and 0.065% per hour), but the peak of essential amino acids in the blood is 20% higher with cooked eggs.
Page updated on October 30, 2026. Composition: USDA, large Grade A eggs. Cholesterol: USDA, older reference table (SR Legacy), because the recent table does not list it.
Frequently asked questions
How much cholesterol is in an egg yolk?
About 184 mg for a 17 g yolk (our calculation from 1,085 mg per 100 g, USDA). The white has none.
Does the yolk have more protein than the white?
Per 100 g, yes: 16.2 g vs 10.7 g. In one egg, no: 2.8 g vs 3.6 g, because the white weighs twice as much.
Can eating raw egg whites cause a biotin deficiency?
Yes, but it takes a lot of them, for weeks or years. A large cooked egg provides 13 to 25 µg of biotin, against an adequate intake of 30 µg a day (Linus Pauling Institute).
White alone or whole egg: which is better for muscle?
A study of 10 men, at 18 g of protein, measured a stronger muscle response with whole eggs than with whites alone (van Vliet, 2017). It is a small study.
Is a runny yolk dangerous?
The risk comes from Salmonella. The FDA advises cooking until both white and yolk are firm, and using pasteurized eggs for lightly cooked dishes, especially for people at risk: pregnancy, young children, older or frail people.
See also
The stomach, live The route of fats Creatine
Sources
- USDA FoodData Central. Eggs, Grade A, Large, egg white (record 747997) and egg yolk (record 748236), Foundation Foods. white, yolk
- USDA FoodData Central. Egg, yolk, raw, fresh (record 172184) and Egg, white, raw, fresh (record 172183), SR Legacy. yolk, white
- Evenepoel P, et al. Digestibility of cooked and raw egg protein in humans as assessed by stable isotope techniques. J Nutr. 1998. PubMed 9772141
- Evenepoel P, et al. Amount and fate of egg protein escaping assimilation in the small intestine of humans. Am J Physiol. 1999;277:G935.
- Fuchs CJ, et al. Raw eggs to support postexercise recovery in healthy young men. J Nutr. 2022. PMC9644172
- van Vliet S, et al. Consumption of whole eggs promotes greater stimulation of postexercise muscle protein synthesis than consumption of isonitrogenous amounts of egg whites. Am J Clin Nutr. 2017. PubMed 28978542
- Egg white proteins: PMC9407204 and Wikipedia, Egg white
- Egg yolk proteins: PMC11675581 and WPSA, 2006
- Protein setting temperatures: LibreTexts, Food Chemistry. Avidin: Wikipedia, Avidin
- Linus Pauling Institute, Oregon State University. Biotin. lpi.oregonstate.edu
- FDA. What you need to know about egg safety. fda.gov
True or false?
The white has more protein per 100 g than the yolk.
False. The yolk has 16.2 g per 100 g, the white 10.7 g. The white provides more per egg only because it weighs twice as much (USDA).
All the cholesterol in an egg is in the yolk.
True. A 17 g yolk has about 184 mg, the white 0 mg (USDA).
Whole egg digests better cooked than raw.
True. About 91% of the protein is digested when cooked, vs 51% raw, in a small study of 5 people (Evenepoel, 1998).
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Metabolive. "Egg white vs yolk protein: do you need to cook them?" Updated October 30, 2026. https://metabolive.com/en/everyday/egg-protein.