"many dietary supplement brand owners are looking to manufacture "pharmaceutical grade" supplements. The phrase, which has served as the fuel for a considerable amount of industry chatter, is built upon the notion that there are standards for manufacturing dietary supplements that are comparable to pharmaceutical manufacturing standards"
https://www.nutrasciencelabs.com/blog/what-is-pharmaceutical-grade-manufacturing
"Supplements that are made in a way to ensure an extremely high standard of purity and maximum absorption are certified pharmaceutical grade. No product is ever 100% pure, however pharmaceutical grade products must exceed 99% purity and not contain any fillers, binders, dyes, or other inactive ingredients that serve as a vehicle for active substances. Less than 3% of supplements meet pharmaceutical grade standards."
https://thefeed.com/blogs/news/what-does-pharmaceutical-grade-mean
"A pharmaceutical-grade compound (PGC) is defined as “any active or inactive drug, biologic or reagent, for which a chemical purity standard has been established by a recognized national or regional pharmacopeia (e.g., the United States Pharmacopeia (USP).”
In plain English, this basically comes down to the purity of the product you are putting into your body."
https://www.higherhealthspineandsport.com/blog/what-is-pharmaceutical-grade
"Pharmaceutical-grade substance: means any active or inactive drug, biologic, reagent, etc., manufactured under Good Manufacturing Practices (GMP) which is approved, conditionally approved, or indexed by the Food and Drug Administration (FDA) or for which a chemical purity standard has been written or established by a recognized compendia (e.g., United States Pharmacopeia-National Formulary (USP/NF) or British Pharmacopeia (BP))."
https://www.bu.edu/researchsupport/compliance/animal-care/working-with-animals/procedures/use-of-pharmaceutical-grade-chemicals-and-other-substances-iacuc/