I've heard good things about chromium and mixed things about cinnamon. Honestly for the price, you won't do any better than recompadrol. I make my own caps from bulk berberine, gymnema, and banaba. It's cheaper but also quite a pain compared to getting 180 doses of recompadrol for 30 bucks and having no work to do and no bright yellow staining powder to have to work with. Na-r-ala gave me horrible stomach pain for literally days, but this is very uncommon. It doesn't seem to have the same kick as recompadrol, but it's very good for you (not cheap, but good things seldom are). Just know that for NA-r-ala, quality is a huge problem so get geranova (Nutraplanet, SAN, etc... just make sure it specifies geranova licensed on the bottle). Agmatine is another compound that people like for GDA properties. Not super strong, but it has so many other benefits, it deserves a mention. Searching 'GDA' will bring up all the info you could ever need. Good luck!