* Since 1947 * (Free Form) * Suitable for Vegetarians * Kosher Parve * Essential Amino Acid * Dietary Supplement L-Threonine is an essential amino acid. Long chains of molecularly bonded individual amino acids from protein. The body must first break these molecular (peptide) bonds for amino acid absorption to take place. Solgar"s free form amino acids are already in their simplest form (no peptide bonds) and can be readily absorbed into the bloodstream.