Amino acids are the organic molecules and are known as the building units of proteins and play a crucial role in biological processes. Amino acid fertilizers are produced from hydrolysis or through enzymatic purification of animal or plant proteins. These fertilizers are rapidly absorbed, transformed and will be used as a source of Carbon and Nitrogen for plants. In addition, these fertilizers save the plant's energy in order to form necessary proteins. They also act as organic chelating agents which lead in increasing the absorption of food elements as well as protecting the plant's surface against metal ions. Amino acids also play a crucial role as bio stimulants in increasing the plant's productivity - especially in biological and non-biological tensions. Although, amino acids are mostly known as nutrients for plants, but they can have other positive effects such as being bio stimulants. For instance, L- Proline amino acid strengthens the plant's cell wall which increases its resistance against environmental tensions. L-Glutamic and L - Glycine are the two important compounds in chlorophyll formation process and are able to increase the absorption of nutrients through chelating them. L-Tryptophan is building unit to the synthesis of the auxin hormone, which is necessary for the growth and development of the roots. L- Methionine is building unit to the synthesis of ethylene hormone, which is necessary for product's puberty. L- Arginine is building unit for the synthesis of the cytokinin, which is necessary for the growth of cells and seeds. Pollination and fruit formation require high level of different types of amino acids. L-Histidine helps the product's puberty. L- Proline increases the fertility of pollen grains. L- Lysine, L- Methionine and L- Leucine increase the quality of fruits.