An older neighbor asked for Lysine, Monolaurin & Liposomal Vitamin C to prevent #COVID19. A friend sent them these recs accompanied by lots of false "science" (eg. "Lysine good, arginine bad")

So, PSA: while some vitamins help your immune system, many can hurt you!

See below:

Examples:
(1) too much vitamin c (over 2000mg) can cause diarrhea, cramping & nausesa. [source, NIH
https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/ ]

(2) The tolerable limit for zinc is 40mg. overdose = vomiting, etc. [source, NIH https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/]

(3) Echinaecea, present in so many teas & supplements can be harmful for anyone with an autoimmune disease, causing flares. [source JAMA https://www.hopkinsmedicine.org/gim/_pdf/consult/herbal_meds.pdf] -- this paper discusses lots of other herbs too!

(4) Lastly, arginine is not bad for you. It is an amino acid that helps build protein & is involved in wound healing, helping your kidneys remove waste, and regulate blood pressure. (but you probably don't need this as a supplement) [source, Mayo Clinic https://www.mayoclinic.org/drugs-supplements-l-arginine/art-20364681]

The best way to get vitamins like A, C & D while ensuring you don't overdo it is through whole foods . But if you do take a supplement, look for US Pharmacopeia (USP) or NSF International (NSF) logos to be sure it's safe.
[ https://www.hopkinsmedicine.org/cam/Internet%20Resources/useful_links.html]

Know what you're taking!