Sort of! There isn't consistent evidence that -any- antitussive is more effective than placebo. A majority of studies show a statistically significant result fo

Sort of! There isn't consistent evidence that -any- antitussive is more effective than placebo. A majority of studies show a statistically significant result for DXM, but not all, and they aren't fully replicable which definitely calls it into question. But that's true of every purported cough suppressant, and there's understandable reasons for that; coughing is a voluntary response to irritation, so there's definitely a lot going to determine whether you cough or not on beyond a purely autonomous system response. Plus there's not really much clarity in how to measure improvement (reduction in frequency may not actually be a reduction in irritation; reduction in severity is hard to measure. Etc). So, really, for a given incident, try it, see if it helps. If it does, great, if it doesn't, stop taking it.