A process for isolating low molecular weight ("LMW") peptides from tissue in situ comprising the steps: a) homogenizing the tissue; b) mixing the homogenized tissue with an organic solvent to form a fully-wetted slurry; c) standing or agitating the slurry to denature the proteins in situ within the tissue; d) removing the organic solvent from the tissue; e) mixing the organic solvent-treated tissue of step d) with a sufficient volume of water or an aqueous solution to extract the peptides; f) separating a liquid extract from the tissue residue of step e) to obtain an aqueous solution containing the low molecular weight peptide fraction removed from the tissue.