The present invention provides compositions and methods and for increasing the bioavailability of therapeutic agents in a subject. The compositions include at least one alkyl glycoside and at least one therapeutic agent, wherein the alkylglycoside has an alkyl chain length from about 10 to about 16 carbon atoms. In various aspects, the invention provides compositions and methods for oral delivery of glucagon-like peptide-1 analogs, such as exenatide, albiglutide, taspoglutide, liraglutide and lixisenatide.