955 E Main Street, STE E83, Lexington, SC 29073 U.S. toll-free: 1-888-800-5582 International: +1 845-875-6155

Natural Home Cures Since 2004

Freeze-dried botanicals grown on our own farms.

Natural Home Cures products from left to right: Nopal capsules, prickly pear drops, and Nopal powder, with opened capsules and a powder scoop

Shop Now

NATURAL HOME CURES · NOPAL SCIENCE

Cysteine, Cystine
& Nopal

Related building blocks for proteins, hair, nails and the body’s natural cell defenses.

Explore the science
Illustrative portrait of an adult woman with long brown hair and a hand resting on her hair, showing natural fingernails
KERATIN · A STRUCTURAL PROTEINHelping build the protein
in hair and nails.

Cysteine is one of the small building blocks your body uses to make proteins. It helps form keratin, a protein that gives hair and nails much of their strength. Cystine is the linked pair formed when two cysteine units join.(3),(4)

Your body can normally make cysteine using another amino acid called methionine. You also get these related amino acids through foods that contain protein.(2)

Cysteine helps build proteins and make glutathione, a natural compound that helps protect cells. Its linked form, cystine, helps explain the small bridges that give some proteins their structure.(3),(5)

Cysteine & Cystine: What’s the Difference?

Think of cysteine as one building block and cystine as two linked building blocks. Their similar names describe these closely related forms.(3)

What Do Cysteine and Cystine Do?

Alongside their place in proteins, these related forms have two useful roles to understand.

Helping proteins hold their shape

Proteins need the right shape to do their jobs. When two cysteine units join, they can form a small bridge that helps hold parts of a protein together. Scientists call this a disulfide bond.(3)

Keratin in hair and nails is a familiar example. These small connections help support its strong structure.(3),(4)

Helping protect cells

Your body uses cysteine, glutamic acid and glycine to make glutathione. Glutathione is one of the body’s natural antioxidants—substances that help protect cells from damage.(5)

Cysteine is one of the building blocks your cells need to make this protective compound.(5)

Cysteine & Cystine in Everyday Foods

Chicken, eggs, chickpeas, yogurt, seeds, grains and Nopal pads
These related amino acids occur naturally in familiar foods, in different amounts.
  • Roasted chicken
    Meat and poultry
  • A serving of fish
    Fish
  • Eggs
    Eggs
  • Dairy foods
    Milk and dairy products
  • Lentils and chickpeas
    Beans and lentils
  • Nuts and seeds
    Nuts and seeds
  • Whole grains
    Whole grains
  • Leafy green vegetables
    Leafy vegetables
  • Cleaned cactus pads and sliced nopales
    Nopal cactus pads

The amount you get depends on the food and how much you eat. A varied diet supplies these amino acids alongside other building blocks the body needs.(2)

How Much Cystine Is in Nopal?

Illustrative harvest scene with green Nopal cactus pads in a woven basket
Nopal pads are the cactus’s broad, flat stems.

USDA’s food database lists cystine, the linked form of cysteine, in raw nopales, the edible cactus pads.(8)

NATURALLY OCCURRING CYSTINE · RAW NOPALESAbout 8 mgper 100 g of raw edible cactus pads

USDA FoodData Central · “Nopales, raw”

The USDA entry lists 0.008 grams of cystine per 100 grams of raw nopales, equal to 8 milligrams. This gives an idea of the amount in fresh cactus pads.(8)

Cystine has also been reported in studies of Opuntia ficus-indica cactus.(6)

The USDA value is a general food reference.

From Our Farms to Your Bottle

Illustrative Nopal cactus in a mountainous landscape

Our Nopal capsule story begins on our mountain farms in Mexico, where Opuntia streptacantha grows at about 8,200 feet in rich volcanic soil. Sunlight, temperature, and rainfall shape the living cactus.

We stay involved from growing through harvest and preparation of the capsules. This growing environment is part of the story behind each amino acid discussed here.

More Than One Amino Acid

Our capsules and powder bring together the naturally occurring compounds in cactus pads. They are whole botanical products, rather than isolated cysteine or cystine supplements.

Explore the other Nopal articles to learn about its fiber, vitamins, minerals and other plant compounds. Each adds another piece to the story of this familiar cactus.

Natural Home Cures products from left to right: Nopal cactus capsules, prickly pear drops, and Nopal cactus powder

FROM CACTUS TO PRODUCT

Meet Our Nopal Cactus & Prickly Pear Family

Nopal cactus capsules, prickly pear drops, and Nopal cactus powder.

Explore Nopal Cactus →
The research behind this article

Source References

8 sources Show referencesHide references
  1. 01
    Nutrition referencePhysiology, Proteins.

    LaPelusa A, Kaushik R. StatPearls. National Center for Biotechnology Information.

    Full citation
    LaPelusa A, Kaushik R. “Physiology, Proteins.” StatPearls. National Center for Biotechnology Information.
    View source
  2. 02
    Research referenceSulfur Amino Acid Metabolism: Pathways for Production and Removal of Homocysteine and Cysteine.

    Stipanuk MH. Annual Review of Nutrition. 2004;24:539–577.

    Full citation
    Stipanuk MH. “Sulfur Amino Acid Metabolism: Pathways for Production and Removal of Homocysteine and Cysteine.” Annual Review of Nutrition. 2004;24:539–577.
    View source
  3. 03
    Research referenceAlberts B, Johnson A, Lewis J, et al. The Shape and Structure of Proteins. Molecular Biology of the Cell. 4th edition. Garland Science; 2002.
    Full citation
    Alberts B, Johnson A, Lewis J, et al. The Shape and Structure of Proteins. Molecular Biology of the Cell. 4th edition. Garland Science; 2002.
    View source
  4. 04
    Research referenceProteome Analysis of Human Hair Shaft: From Protein Identification to Posttranslational Modification.

    Lee YJ, Rice RH, Lee YM. Molecular & Cellular Proteomics. 2006;5(5):789–800.

    Full citation
    Lee YJ, Rice RH, Lee YM. “Proteome Analysis of Human Hair Shaft: From Protein Identification to Posttranslational Modification.” Molecular & Cellular Proteomics. 2006;5(5):789–800.
    View source
  5. 05
    Research referenceGlutathione Synthesis.

    Lu SC. Biochimica et Biophysica Acta. 2013;1830(5):3143–3153.

    Full citation
    Lu SC. “Glutathione Synthesis.” Biochimica et Biophysica Acta. 2013;1830(5):3143–3153.
    View source
  6. 06
    Research referenceNopal Cactus (Opuntia ficus-indica) as a Source of Bioactive Compounds for Nutrition, Health and Disease.

    El-Mostafa K, El Kharrassi Y, Badreddine A, et al. Molecules. 2014;19(9):14879–14901.

    Full citation
    El-Mostafa K, El Kharrassi Y, Badreddine A, et al. “Nopal Cactus (Opuntia ficus-indica) as a Source of Bioactive Compounds for Nutrition, Health and Disease.” Molecules. 2014;19(9):14879–14901.
    View source
  7. 07
    Research reviewCactus Stems (Opuntia spp.): A Review on Their Chemistry, Technology, and Uses.

    Stintzing FC, Carle R. Molecular Nutrition & Food Research. 2005;49(2):175–194.

    Full citation
    Stintzing FC, Carle R. “Cactus Stems (Opuntia spp.): A Review on Their Chemistry, Technology, and Uses.” Molecular Nutrition & Food Research. 2005;49(2):175–194.
    View source
  8. 08
    USDA food composition referenceNopales, raw.

    U.S. Department of Agriculture. FoodData Central. FDC ID 168571; SR Legacy, NDB 11963.

    Full citation
    U.S. Department of Agriculture. FoodData Central. “Nopales, raw.” FDC ID 168571. Cystine: 0.008 g per 100 g of raw edible food, equivalent to 8 mg.
    View source