Deployment-related asthma happens when someone gets asthma, or their asthma gets worse, because of breathing harmful air during military deployment. Research shows some service members may have lower levels of nitric oxide, a natural chemical that helps keep airways open. This might be why their asthma gets worse after deployment. L-citrulline can help the body make more nitric oxide, and we think that raising the L-citrulline levels in the blood may improve nitric oxide production and make asthma symptoms better. If you want to join this study, you will first have a visit to see if you qualify. If you qualify, you will be put into one of two groups at random, like flipping a coin. One group will take 15 grams of L-citrulline every day for 7 weeks, then take no study medicine for about 6 weeks, and then take a placebo for 7 weeks. A placebo is a pill that looks like the study drug but has no real medicine in it. The second group will get the placebo for the first 7 weeks, then take 15 grams of L-citrulline every day for 7 weeks. You will have up to 6 in-person visits and 2 phone visits. During these visits, you will fill out health and asthma surveys, have a physical exam, and take lung function and breath tests. We will also take blood samples and do nasal brushings. If you are female, you will take a urine pregnancy test. The study lasts about 22 weeks. You can earn up to $545 if you complete all the visits.

Who can Participate

You may be able to join this study if you are a military service member between 18 to 70 years old, have asthma related to deployment after 9/11, and have not smoked in the past 3 months.

Study ID

More information available at ClinicalTrials.gov: NCT05259904