L-Lysine

“Lysine is the amino acid most likely to limit protein synthesis in equine diets, making it an important nutrient for topline, growth and muscle maintenance.” — Dr. Priska Darani, PhD Equine Nutritionist, Director of Research Lysine Supports: Muscle Development Athletic Performance Bone Health and Growth Hoof Strength and Growth Joints and Connective Tissue Coat Quality and Skin Health Post-Exercise Care Energy Metabolism Topline Muscles Immune Function Mad Barn’s L-Lysine powder is a pure amino acid supplement for horses, providing a 99% pure crystalline source of lysine to support protein synthesis, muscle development, growth, collagen formation, hoof quality, coat condition, exercise recovery and immune function. Lysine is an essential amino acid, meaning it must be supplied by the horse’s diet. It is also considered the first limiting amino acid in many equine rations. This means lysine is the amino acid most likely to restrict protein synthesis when it is not supplied in the right amount relative to the horse’s needs. After dietary protein is digested, it is broken down into single amino acids or peptides that are absorbed from the small intestine and delivered throughout the body. These amino acids are then assembled together inside cells in a specific sequence to form new proteins. If dietary lysine is insufficient relative to the horse’s needs, it limits the rate of protein synthesis. Lysine is often limiting in equine diets because many common feeds including grass hay, pasture and cereal grains have relatively low lysine content. A horse can meet its overall protein requirement and still be deficient in lysine. Lysine is especially important for horses with higher protein turnover, including horses in work, growing horses, broodmares, lactating mares, senior horses and horses on hay-based or forage-first diets. These horses rely on a steady supply of essential amino acids to build and maintain muscle, collagen, keratin, enzymes, immune proteins and other functional tissues. According to the NRC (2007), the minimum lysine requirement for a 500 kg (1,100 lb) horse at maintenance is at least 18 grams per day. Requirements increase during growth, work, pregnancy and lactation because the horse is building, repairing or maintaining more protein-based tissue. Roles of Lysine in the Body Protein Synthesis & Amino Acid Balance Lysine is required to assemble proteins throughout the body, including muscle proteins, collagen, keratin, enzymes, transport proteins and immune proteins. Protein synthesis depends on all essential amino acids being available at the same time and in the right proportions. As the first limiting amino acid, lysine helps determine how effectively the horse can use the other amino acids supplied by forage, grain and supplements. Muscle Development & Topline Muscle tissue is constantly being broken down and rebuilt through normal protein turnover. Lysine supplies amino acid building blocks for contractile and structural muscle proteins involved in posture, movement, strength and topline development. Horses in regular work have higher demands for muscle remodeling, making lysine important for maintaining lean tissue and supporting normal recovery after exercise. Growth & Bone Matrix Formation Growing horses are actively depositing new protein into muscle, skin, hair, connective tissue and the organic matrix of bone. Bone is not only mineral; it also contains a collagen-rich protein scaffold that supports normal bone structure during growth and development. Lysine helps supply the amino acids needed for new tissue formation during active growth stages. Collagen & Connective Tissue Collagen is a major structural protein in tendons, ligaments, cartilage, skin, bone matrix and other connective tissues. Lysine is incorporated into collagen proteins and contributes to collagen maturation and cross-linking. This makes lysine relevant for tissues exposed to repeated loading, stretching and remodeling during turnout, training, growth and competition. Hoof, Skin & Coat Quality Hoof horn, skin and hair are protein-rich tissues that require a consistent supply of amino acids. Lysine supports the protein synthesis needed to build and maintain keratin-containing tissues. Balanced amino acid nutrition helps maintain normal hoof quality, skin integrity and a healthy hair coat. Immune Function & Tissue Maintenance Antibodies, enzymes, acute-phase proteins and many immune signaling molecules are made from amino acids. Lysine supports the protein synthesis required for normal immune defenses, tissue repair and cellular maintenance. This is especially relevant during growth, training, breeding, lactation and other periods of increased nutrient demand. Energy Metabolism Lysine is a precursor for carnitine, a vitamin-like compound involved in fatty acid metabolism. Carnitine helps transport long-chain fatty acids into mitochondria, where they can be used to produce energy through beta-oxidation. This connects lysine nutrition to normal metabolic pathways that support working muscle and day-to-day body function. Breeding & Lactation Support Broodmares need adequate lysine to support reproductive function, fetal growth and the higher protein demands of pregnancy. During lactation, the mammary gland uses circulating amino acids to synthesize milk proteins that support foal growth and development. Lysine helps supply one of the essential amino acids required for mare maintenance, milk production and normal growth of the foal. Which Horses Benefit Most from L-Lysine? L-Lysine is beneficial for horses with higher demands for protein synthesis or horses whose diets may provide less lysine relative to total protein intake. Performance horses Training increases muscle protein turnover and connective tissue remodeling. Horses in heavier work have higher lysine needs to support muscle protein synthesis, topline maintenance, exercise recovery and adaptation to training. Growing horses Foals, weanlings and yearlings are rapidly building muscle, bone matrix, connective tissue, skin and hair. Lysine is required for new tissue formation and is a key amino acid for normal growth and development. Broodmares and lactating mares Pregnancy and lactation increase the demand for essential amino acids. Lysine supports maternal tissue maintenance, fetal growth and the synthesis of milk proteins used to nourish the foal. Senior horses Older horses benefit from high-quality protein nutrition to support lean tissue, topline, immune proteins, skin, coat and normal tissue maintenance. Lysine helps ensure dietary protein provides the amino acid balance needed for these functions. Horses on forage-only diets Forage is the main protein source in many equine diets, but hay and pasture can vary widely in lysine content. Supplemental lysine helps balance the amino acid profile of forage-only rations so dietary protein can be used more efficiently. Horses on underfortified grain rations When horses do not receive the full recommended amount of a fortified feed, their essential amino acid intake is largely determined by forage quality. L-Lysine supplies the amino acid most likely to limit protein synthesis in these rations. Mad Barn’s bulk L-Lysine contains pure crystalline lysine with no added fillers, flavors or carriers. It is a concentrated top-dress powder that can be added to the daily ration for horses needing targeted support for protein synthesis, muscle development, growth, connective tissue, hoof quality and overall amino acid balance. References National Research Council. Nutrient Requirements of Horses. 6th rev. ed. National Academies Press. 2007. Tome, Daniel et al. Impact of low protein and lysine-deficient diets on bone metabolism (P08-072-19). Curr Dev Nutr. 2019.