From the Amazon TOS for venders: (FYI...deleting this doesn't make it less true)

Examples of prohibited listings
• Products that are subject to a recall or safety alert.
• Dietary supplements, such as weight loss products, that contain undeclared or prohibited active pharmaceutical ingredients, or are marketed as unapproved new drugs, such as: ◦ Growth hormones or products that claim to support or promote hormone production.
◦ Homeopathic drugs that are prescription, mislabeled or unapproved new drugs.
◦ Patches marketed as dietary supplements.
◦ Sexual enhancement products.
◦ Steroids.

• Supplements claiming that they can be used to cure, mitigate, treat, or prevent disease in humans.
• Supplement listings that include disease names in their keywords.
• The following cannabidiol (CBD) and Hemp products: ◦ Rich Hemp Oil containing concentrated CBD. Hemp seed oil and hemp oil supplements are permitted.
◦ All non-ingestible and ingestible products that contain cannabidiol/cannabinoid (CBD)
◦ Hemp products containing Resin or THC (tetrahydrocannabinol)
◦ Hemp (or any cannabis Sativa L. strain) seeds capable of germination.