One thing it doesn’t say is how and when to take the supplements. Morning, evening, before or after meals.
bitt’s doctor said to take prescriptions in the morning on an empty stomach. You can try taking the supplements the same way, or search online
WebMD has a page for Sulfate or powder. The instructions whether to take on an empty stomach or not depend on the illness for which it is taken to avoid upsetting the stomach.
“How to use Hydroxychloroquine SULFATE
Take this medication by mouth, usually with food to prevent stomach upset, exactly as directed by your doctor. The dosage and length of treatment are based on your medical condition and response to treatment. In children, dosage is also based on weight.”
WebMD also has information about other illneses/medications that drive decision making (some reduce HCQ effectiveness so should be timed accordingly). I highly recommend you read a few pages like theirs:
https://www.webmd.com/drugs/2/drug-5482/hydroxychloroquine-oral/details