I use Delsym exclussivly - both because its flavor aint too bad, and because I have perfected when I peake nad how fast I trip. On average - for sum1 who is empty stomach - it will hit at around 1hour to 1:30hours - at latest, the real effects are there by 2 hours. It will last up to or a lil over 12 hours on a good day - it rapidly declines after 12hours to settle. - it has the best come up wave, and come down - no crash!
The only problem IS that it is unlike most DXM because of its release - when I do a Gram of Deslym, its good and hard- but if i did a gram of robotussin DM - I will be swimming with dolphins and flying with wings - robo is faster and harder then the Deslym - so dont dose the same on diffrent syrups, just because they both have the same ingrediant. Always be a good psychonaut and research them.