A herbicide formulation in the form of a microemulsion, with enhanced agricultural efficiency, that allows lower use of the active substance and has a lower environmental impact, with the active substance being present in its acid form and no need for chemical modification thereof to dissolve it in the water of the application solution, and which exhibits effectiveness synergies in tank mixtures with other active substances. The active substance comprises glyphosate, Imazapir, Imazapic, Picloram, and mixtures of active substances comprising glyphosate and 2,4-dichlorophenoxyacetic acid, glyphosate and Dicamba, and Picloram and 2,4-dichlorophenoxyacetic acid, said active substances being dissolved in a specially designed co-adjuvant generated using a specific combination of surfactants and solvents. Tank mixtures of the products formulated using the specially designed co-adjuvant and the active substances Imazapir and Imazapic, or Picloram and 2,4-D, are also included in the scope of the invention.
