Dietary Supplement vs Drug: A Three-Gate Screen for Buyers

An ingredient can be barred from supplements for something that happened before anyone sold it as one. The US Food and Drug Administration (FDA) places a product on one side of the line or the other using two facts: what the ingredient was before it reached the supplement market, and what the product is represented to do.

An ingredient that was approved as a drug, or publicly investigated as one, before it was sold as a supplement can be barred from supplements entirely. A label that promises to treat a disease turns a supplement into an unapproved drug.

We supply Supplement active pharmaceutical ingredients (APIs), meaning the active ingredients and raw materials for supplements, and drug-category APIs from Haridwar, India. This page sets out the screen to run on any raw-material list before you ask anyone for a quote: three gates, a worked table, and the documents that prove each answer.

• A product is a dietary supplement when it contains a dietary ingredient and is not represented as treating, preventing or curing a specific disease. FDA does not approve supplements before sale.
• The ingredient's history can disqualify it. An article approved as a new drug, or publicly investigated as one first, is excluded from the supplement definition unless it was sold as a supplement or food earlier.
• A supplier's "Supplement" category is a description, not a ruling. Run three gates (ingredient history, claim, paperwork) on every line and re-check, because FDA positions on N-acetyl-L-cysteine (NAC) and nicotinamide mononucleotide (NMN) have moved.
• COA, lot and CAS matching proves identity, not legal category.

A dietary supplement is a product for ingestion that contains a dietary ingredient such as a vitamin, mineral, herb, amino acid or probiotic. A product becomes a drug when it is represented, explicitly or implicitly, for the treatment, prevention or cure of a specific disease (FDA, Questions and Answers on Dietary Supplements, updated August 27, 2026). Medications undergo FDA review before sale (USADA). Our Supplement APIs list shows the supplement side of what we supply.

COA is a certificate of analysis. SDS/MSDS is a (material) safety data sheet. CAS number is the CAS Registry Number, the unique identifier for a chemical substance.

Because the category comes from the ingredient's history and the product's claim, and a catalog line records neither. Two tests decide it, and both sit outside the supplier's paperwork.

Test 1: ingredient history. The statute excludes from the supplement definition an article approved as a new drug or licensed as a biologic, and an article authorized for investigation as a new drug when substantial clinical investigations have been instituted and made public (21 U.S.C. §321(ff)(3)). FDA adds the exception: an article sold as a supplement or food before that point stays eligible. FDA's ingredient directory (updated May 1, 2026) names sildenafil, tadalafil and sibutramine among excluded drugs.

Test 2: claim. Under the drug definition in 21 U.S.C. §321(g)(1), intended use is what counts. A supplement may describe an effect on normal structure or function if the claim is substantiated and the label states: "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease." The company must also notify FDA of the structure/function claim within 30 days of first marketing it (21 U.S.C. §343(r)(6)). In our reading, "supports healthy joint function" is a structure/function claim and "treats arthritis" is a drug claim.

Skipping the tests is costly. A 2018 study in JAMA Network Open reviewed FDA warnings from 2007 to 2016 and found 776 products sold as supplements (746 distinct, from 146 companies) that contained unapproved pharmaceutical ingredients:

• 353 (45.5%) were sexual enhancement products, 317 (40.9%) weight loss and 92 (11.9%) muscle building.
• 157 (20.2%) contained more than one drug.
• Of 28 products warned about more than once, 19 (67.9%) carried a new drug on the later warning.

The study covers products FDA flagged, not the whole market, and ends in 2016. Our inference is that a clean-looking label cannot be trusted alone and the lot has to be tied to documents. USADA makes the related point that supplements are regulated after they reach the market (USADA, Medications vs. Supplements).

Run three gates on every line, in order, and stop at the first fail. Each gate has a test you can run; gate 1 ends in stop, hold or pass. This screen is our recommendation, built from the FDA rules above.

Worked examples show how gate 1 behaves. They illustrate the rules.

The NAC row shows that FDA can change its enforcement stance without changing the exclusion, and the NMN row shows that it can reverse an exclusion. Peptides raise the same gate; our page on BPC-157's legal status works through one.

A new dietary ingredient raises a separate question, a premarket notification. That is covered in NDI Notification: Does Your Ingredient Need One, and When?.

Gate 3 needs three documents per lot: a COA, a specification and an SDS/MSDS. They prove the material in the drum is the material you screened. They do not prove the legal category. That depends on gates 1 and 2.

Run these pass/fail tests on arrival:

• Lot match. The lot number on the container equals the lot on the COA. Fail on any difference.
• Identity match. The CAS number on the COA equals the CAS number you screened at gate 1. Fail on any difference, even where the name looks the same.
• Written end use. You hold a written statement of the product's intended use and claim, so gate 2 is documented. Fail if you cannot produce it.

Supplement manufacturing is governed by current good manufacturing practice, which FDA requires of facilities that make or hold supplements. For what a supplier's COA can and cannot prove, read 21 CFR Part 111: What a Supplier's COA Can and Can't Prove. For the wider supplier check, use Qualify Nutraceutical Raw Material Supplier: US Checklist.

Because our offer lines up with the screen: identifiers you can check, documents you can match, and both categories under one supplier. Each reason below rests on a fact about us.

1. One supplier on both sides of the line. We supply Supplement APIs and steroid, peptide, hormone and general pharmaceutical APIs. If your product turns out to be a drug, you do not have to start a new supplier search for the drug-category API.
2. A list with CAS numbers. Our Supplement APIs list has 191 numbered entries, some of which repeat a name, each with a CAS number, so the identity match in gate 3 runs on identifiers, not product names.
3. Documents for matching. Available documentation may include a COA, specifications and SDS/MSDS where applicable, which is what gate 3 needs.
4. Evaluation before commitment. We support sample and evaluation quantities for qualified B2B buyers, confirmed product by product, with bulk supply after you approve the evaluation.
5. Support for US importers. We provide documentation and supply support for US importers and have supported customers in the USA.

We determine regulatory status and permitted end use product by product, according to the molecule, manufacturer documentation, intended application and destination rules. We do not present research-only, veterinary-only or export-only materials as approved human pharmaceutical APIs. Before commercial supply, the buyer confirms local registration, import authorization and permitted end use.

To start, send the product name or CAS number, quantity, destination, grade or purity, documents needed, payment terms and Incoterms (the International Commercial Terms that fix who arranges and pays for shipping) to sunil@aarisepharma.com, on WhatsApp at +91 9899783330, or by phone at +91 9461840333. You can also use our contact form. Prices are quoted from the current rate once we have the API name and CAS number.

The drug route applies when the product is meant to treat disease or when the ingredient fails gate 1.

• Your claim is a disease claim. If the product is to be represented as treating, preventing or curing a disease, FDA treats it as a drug.
• The molecule is a steroid, peptide or hormone. Status depends on the specific molecule and the destination market. We supply peptide APIs as bulk raw powder for B2B requirements, not finished vials. For how supplier types differ, see API Manufacturer vs Distributor vs CDMO.
• Gate 1 says stop. An excluded drug cannot be sold as a supplement, so the product cannot go on the supplement route. Whether an excluded drug can be supplied as a pharmaceutical API depends on the molecule, its approval status and the destination market.