There are 20 amino acids known that make up the building blocks for mammalian body protein. Approximately one-half of the amino acids are considered essential (this means the body is unable to make those nutrients so the nutrients must be ingested). However, the micro-organisms in the hind gut of a horse can manufacture a small portion of the essential amino acids.

Methionine is an essential amino acid that can be converted to cystine by the body. Cystine is important because it furnishes the sulfur crosslinks that are necessary for healthy collagen and thus strong hoof infrastructure (hoof, skin, hair, ligaments, tendons and cartilage). Most hoof supplements containing methionine are the DL-methionine form. L-methionine is the biologically active form amounting to approximately 50% of the total DL-methionine. A supplement containing 6,000 milligrams of DL-methionine would contain 3,000 milligrams of the biologically active L form. There is no data on the equine requirements of methionine however; the average requirements for other species converted to the metabolic size of a horse amounts to approximately 3,000 milligrams of L-methionine per day.

Because methionine is readily converted to cystine by the liver in mammals it is necessary to supplement only methionine to fulfill the methionine/cystine requirement.

Dr. Frank Gravlee graduated from Auburn University School of Medicine and practiced veterinary medicine for several years before attending graduate school at MIT . During a three-year residency in nutritional pathology he received a masters degree in nutritional biochemistry and intermediary metabolism. In 1973, he founded Life Data Labs to determine equine nutritional deficiencies through laboratory testing, and developed individualized feeding programs to correct the deficiencies he discovered. After ten years of research, he launched Farrier’s Formula.