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    Ingredient guide · Ingredient reference

    Minerals in eggs: keep serving size and units together

    A large egg contributes several minerals, but the amounts are not all expressed in the same units. Selenium is commonly listed in micrograms, while phosphorus and potassium are listed in milligrams.

    Read the evidence ↓

    Supplement Science Insights Editorial Team

    Published September 23, 2026

    Use the preparation attached to each entry

    USDA SR Legacy 2018 gives a large 50 g raw whole egg about 6 mg magnesium and 69 mg potassium. Its separate hard-boiled whole-egg entry gives about 5 mg magnesium and 63 mg potassium per 50 g egg. These come from per-100-g values of 12/138 mg and 10/126 mg, respectively, scaled by one half. They are historical reference entries, not a paired experiment measuring nutrient loss in the same egg or a recommendation to eat eggs raw. [1][2][3][4]

    NIH ODS lists 15 mcg selenium and 86 mg phosphorus for a large hard-boiled egg. Its potassium table lists 69 mg for one large egg. These are food-reference values, not measurements of every individual egg. [1][2][3][4]

    Egg size, preparation and added ingredients affect the portion being compared. A scrambled dish containing milk or other foods is not identical to the single-egg reference. [1][2][3][4]

    A smaller number can use a much smaller unit

    One milligram equals 1,000 micrograms. Comparing 15 mcg selenium with 86 mg phosphorus therefore requires keeping the units visible rather than ranking the bare numbers. [1][2][3]

    These minerals also have different nutritional roles and intake references. Their amounts should not be added into a single meaningful mineral-strength score. [1][2][3]

    Scale the serving without changing the unit

    Imagine two matching large hard-boiled eggs. The reference selenium contribution doubles from 15 to 30 mcg, not 30 mg.

    Key distinctions — Minerals in eggs
    DetailInterpretation
    Selenium15 mcg per listed egg
    Phosphorus86 mg per listed egg
    Potassium69 mg per listed egg
    Minerals in eggs: keep serving size and units together — original article outline diagram
    Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

    Sources for this article

    1. Selenium - Health Professional Fact Sheet
      Source consulted: 2026-09-18. This is a reference resource, not a claim that we conducted the studies or tested a product.
    2. Phosphorus - Health Professional Fact Sheet
      Source consulted: 2026-09-18. This is a reference resource, not a claim that we conducted the studies or tested a product.
    3. Potassium - Health Professional Fact Sheet
      Source consulted: 2026-09-18. This is a reference resource, not a claim that we conducted the studies or tested a product.
    4. USDA FoodData Central: SR Legacy 2018 food composition dataset
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.