Standard mayonnaise does not contain lactose. Traditional mayo is made from oil, egg yolks, and an acid like vinegar or lemon juice. None of these ingredients come from milk, so lactose is not part of the recipe.
Why Mayo Seems Like It Might Be Dairy
The confusion is understandable. Mayonnaise is white, creamy, and sold in the refrigerated section of some stores, right alongside dairy products. Eggs, its key ingredient, sit in the dairy aisle at most grocery stores. But eggs are not a dairy product. They contain no milk sugar (lactose) and no milk proteins. Eggs are safe on both lactose-free and dairy-free diets.
In the U.S., the FDA defines mayonnaise specifically: it must be an emulsion of vegetable oil (at least 65% by weight), egg yolk, and vinegar or lemon juice. The only optional add-ins allowed under this standard are salt, sweeteners, spices, flavor preservatives, and crystallization inhibitors. Milk and cream are not on that list. If a jar is labeled “mayonnaise,” it follows this formula, and dairy plays no part in it.
When Mayo Could Contain Lactose
There are a few exceptions worth checking for.
- Eggless mayonnaise: Some eggless recipes substitute condensed milk for eggs. Condensed milk is a concentrated dairy product and contains significant lactose. If a jar says “eggless” or “egg-free,” flip it over and read the ingredients.
- Low-fat or fat-free versions: These products replace some of the oil with modified food starch and other emulsifiers to mimic the texture of full-fat mayo. While most still skip dairy, the ingredient lists are longer and less predictable. A quick label check is worth it.
- Mayo-based sauces and dressings: Ranch, aioli spreads, and other creamy condiments often start with a mayonnaise base but add buttermilk, sour cream, or cheese. These contain lactose. The base mayo is fine, but the finished product may not be.
Regular, full-fat mayonnaise from major brands like Hellmann’s, Duke’s, or Kraft is consistently dairy-free. Store-brand versions typically follow the same formula. When in doubt, the ingredient panel will list any milk-derived ingredient clearly, since milk is one of the major allergens that U.S. food labeling laws require manufacturers to disclose.
Vegan Mayo Is Also Lactose-Free
If you want to avoid eggs entirely, plant-based mayonnaise removes both dairy and eggs from the equation. Most vegan mayo is built on soy milk, a neutral oil like sunflower or canola, and salt. The soy milk serves as the emulsifier that egg yolk normally provides, creating a similar thick, creamy texture. Brands like Just Mayo, Vegenaise, and Sir Kensington’s Fabanaise all skip animal products completely, making them inherently lactose-free.
Reading Labels for Hidden Dairy
If you’re lactose intolerant and buying a condiment that looks like mayo, the fastest way to check is to scan the allergen statement at the bottom of the ingredient list. U.S. manufacturers must declare “Contains: Milk” if any dairy-derived ingredient is present. Words like whey, casein, milk solids, or lactose in the ingredient list are also giveaways. For standard mayonnaise, you won’t find any of these. For flavored spreads, dressings, or specialty products that sit near the mayo on the shelf, it’s worth the three seconds to look.