Does Domino's pizza use L-Cysteine?

December 24, 2025 •

3 min read

According to Domino's official ingredient statement for its Thin Crust pizza, the dough does contain L-Cysteine Monohydrochloride, an amino acid used as a dough conditioner. This ingredient serves a specific purpose in commercial food production to create a more pliable and consistent dough.

Quick Summary

Domino's Thin Crust pizza includes L-Cysteine to relax the gluten in the dough, improving its texture and machinability. The L-Cysteine used is synthetically or microbially derived, not from animal sources, and is considered safe for consumption.

Key Points

Official Statement: Domino's officially lists L-Cysteine Monohydrochloride as an ingredient in its Thin Crust pizza dough.
Dough Conditioner: The amino acid functions as a reducing agent to relax and soften pizza dough, making it more pliable for high-speed commercial production.
Variable Sourcing: While historically derived from animal products like hair or feathers, modern L-cysteine is often produced via microbial fermentation, as claimed by Domino's in some regions.
Dietary Implications: The specific source is crucial for individuals following vegan, vegetarian, or Halal diets. Domino's UK claims a synthetic source, but consumers should check local information.
Safety: L-cysteine is regulated and considered safe for consumption by food safety authorities like the FDA.

What is L-Cysteine and Why is it in Pizza Dough?

L-Cysteine is a semi-essential amino acid that is commonly used as a dough conditioner in commercial baking. Its primary function is to act as a reducing agent, which breaks down the disulfide bonds within the gluten network in wheat flour. By doing so, it effectively softens the dough, making it more extensible and elastic. This relaxation of the dough is crucial for high-speed automated production lines, as it prevents the dough from snapping back after being stretched and rolled. The use of L-cysteine leads to a more uniform and consistent product with improved texture and shorter mixing times.

Domino's Use of L-Cysteine: Official Ingredients and Sourcing

Domino's explicitly lists L-Cysteine Monohydrochloride as an ingredient in the dough for its Thin Crust pizzas in some regions, such as the United States. For other menu items, like their Hand-Tossed Crust, the company has stated that the L-cysteine comes from a microbial fermentation source. The specific source is a point of interest for many consumers due to the historical use of animal and human byproducts in L-cysteine production. However, modern technology provides alternative methods, including synthetic and microbial fermentation, which are considered vegetarian and vegan-friendly. Domino's UK, for example, states that its L-cysteine is chemically synthesised and suitable for vegetarians. For consumers with specific dietary requirements, it is important to confirm the ingredient source with the local franchise, as practices can vary by region.

How Different L-Cysteine Sources Compare

To better understand the differences, here is a comparison of the various commercial L-cysteine sources.


Feature	Animal-Derived	Microbial Fermentation	Synthetic
Source Material	Animal byproducts (e.g., feathers, hog hair) or human hair	Plant-based substrates (e.g., corn, sugar) cultured with microorganisms	Chemically synthesized from inorganic materials
Dietary Suitability	Not suitable for vegans, often not suitable for Halal or Kosher diets	Suitable for vegan, vegetarian, Kosher, and Halal diets	Suitable for vegan, vegetarian, Kosher, and Halal diets
Process	Acid hydrolysis and electrolysis	Fermentation using genetically engineered bacteria	Chemical synthesis
Ethical Concerns	Significant ethical concerns, particularly regarding human-derived sources	Minimal ethical concerns for vegans and vegetarians	Generally no ethical concerns related to sourcing materials

The Role of L-Cysteine and Its Alternatives

The use of L-cysteine is part of a larger trend in modern commercial baking to improve product consistency and manufacturing efficiency. This is particularly relevant for high-speed production. While effective, it has led to the development and use of alternatives for consumers who wish to avoid it.

List of Dough Conditioners

Enzymes: Some bakeries use specific enzymes, such as proteases, to break down gluten and relax dough.
Inactivated Yeast: Deactivated yeast is a natural source of glutathione, which has a similar relaxing effect on dough to L-cysteine.
Ascorbic Acid (Vitamin C): In certain continuous mix applications, ascorbic acid can function as a reducing agent in the absence of oxygen.
Vegetable Protein: Brands like BreadPartners offer alternative dough relaxers, such as 'Extenza,' derived from vegetable protein and designed to mimic the effects of L-cysteine.

Safety and Dietary Considerations

From a food safety perspective, L-cysteine is regulated and considered safe for consumption by regulatory bodies like the U.S. Food and Drug Administration (FDA). However, the source of L-cysteine is a significant factor for individuals adhering to certain dietary or religious practices. The historical use of animal byproducts and human hair has prompted concerns, but modern production has shifted towards synthetic and microbial methods.

For those following a vegan diet, L-cysteine from synthetic or microbial sources is acceptable, but animal-derived sources are not. For those with Halal or Kosher dietary restrictions, the source is critical. L-cysteine derived from microbial fermentation is generally considered Halal and Kosher, whereas animal-derived forms are often forbidden. Consumers with these concerns are advised to check local allergen and ingredient statements or contact the company directly for confirmation.

While Domino's has made efforts to use non-animal sources for L-cysteine in some products and regions, it is a complex ingredient that requires scrutiny for those with specific dietary needs or ethical concerns. Customers can make informed choices by consulting ingredient information and understanding the different production methods of L-cysteine.

Find out more about the origins and production methods of L-cysteine on The Vegetarian Resource Group website.

Frequently Asked Questions

The L-Cysteine used in Domino's products depends on the specific crust and region. While Domino's UK states its L-Cysteine is chemically synthesised and vegetarian, the US version may differ. Historically, L-cysteine could be animal-derived, but modern, vegan-friendly microbial fermentation is common.

Domino's Thin Crust pizza officially lists L-Cysteine Monohydrochloride as an ingredient. Other crusts, like the Hand-Tossed, may use a different source or method, so checking the official ingredients list for your region is recommended.

L-Cysteine acts as a dough conditioner, relaxing the gluten network in the dough. This makes the dough softer, more extensible, and easier to handle during high-speed, automated commercial production.

No. While L-Cysteine can historically be derived from human hair, Domino's has stated that the L-Cysteine used in some of its products comes from microbial fermentation. Consumers concerned about sourcing should check their local Domino's ingredient information.

L-Cysteine from fermentation or synthetic sources is considered Halal. Therefore, if Domino's sources its L-Cysteine from these methods, the dough is acceptable. However, since Domino's does not market all its products as Halal, customers should verify with the company if this is a concern.

Alternatives to L-Cysteine include using inactivated yeast, which releases glutathione to relax dough, or enzymes like proteases. Ascorbic acid (Vitamin C) is another common flour treatment agent, but it functions differently.

Yes, L-Cysteine is regulated by food safety authorities like the FDA and is generally regarded as safe for consumption in the amounts used in food products.