Make sure to take a recovery drink within 1/2 hour of completing your workout. I would also suggest durning high training peaks, take some Organic Echinacea Plus Tea by Traditional Medicinals (2 X Day for 7 Days), In addition to rest and recovery.
Glutamine. There are some studies showing it has a positive effect on immune response, but I also think there’s some evidence to the contrary. We do know with good certainty that glutamine levels drop after extended exercise. There is less clarity about whether post-exercise supplementation helps.
In any event, I usually take some (I find protein powder that has high glutamine content and use it for my recovery drink).
Google it and decide for yourself whether it’s worth doing.