If I buy NAC as a loose powder in a large bag, as opposed to in tablet form, will it spoil? I've heard it can spoil or degrade into a harmful by-product.
(N-Acetyl-Cysteine) powder can be stored in a closed container at room temperature (away from high heat or humidity) for at least two months, and possibly longer, without spoiling or degrading. Small amounts of NAC may degrade, over longer periods of time, into a by-product called di-NAC — however, this substance is not known to be harmful. (The sulfur in NAC may cause a "rotten egg" odor, but this does not indicate a problem.) If you are concerned about degradation, consider capsules or tablets, as they will be even more stable than powder. You can see ConsumerLab.com's test reports for NAC supplements, and get more information about NAC's effects, side-effects, and dosage in the NAC Supplements Review >>