The 75% Mitragynine Extract: A Bridge Too Far

In 2025, the industry submitted a New Dietary Ingredient notification for a 75% mitragynine extract: a highly concentrated, standardized product that resembles a pharmaceutical more than a traditional botanical. The FDA reviewed the filing and issued a clear response: the ingredient’s identity was not established, safety data did not match the marketed product, and the submission was fundamentally incomplete.

This is not a minor technicality. The industry argued that because kratom leaf had “traditional use,” a 75% extract should qualify as a supplement. The FDA rejected that logic. Without a valid NDI, any product containing this extract is considered adulterated under federal law, and interstate commerce is prohibited.

Incomplete Data, Evidentiary Gaps

The filing was missing full references, relied on unpublished abstracts, and failed to provide analytical linkage between the studied material and the final 75% extract. The FDA requested additional information, but key gaps remained:

• No reliable method to ensure batch-to-batch consistency
• Toxicological studies performed on different extracts, not the 75% formulation
• No post-market surveillance or adverse event plan
• Unqualified safety claims despite mu-opioid receptor activity

The FDA concluded that the evidence did not demonstrate reasonable certainty of no harm. For a dietary supplement, that is a fatal verdict.

The Industry’s Own Warnings Condemn It

Inside the NDI proposal, the manufacturer listed “conditions of use” that read like a prescription label:

• Use limited to 28 days, not long-term consumption
• Maximum 150 mg mitragynine per day, about 200 mg of extract
• Excludes pregnant or nursing women and people with liver disease or psychiatric conditions
• Warning against combining with CNS depressants, including alcohol, benzodiazepines, and opioids
• Healthcare provider consultation before use

This is not the profile of a safe, unregulated botanical. It is a high-risk substance requiring medical oversight, while the industry continues to push for broad retail availability.

FDA Final Determination: Prohibited and Adulterated

In its formal objection letter, the FDA made clear that the NDI notification does not satisfy the requirements of 21 U.S.C. § 350b. Therefore, any dietary supplement containing this 75% mitragynine extract is adulterated under 21 U.S.C. § 342(f)(1)(B). Introduction into interstate commerce is prohibited.

This is a complete repudiation of the industry’s argument that kratom extracts are safe dietary ingredients. The FDA has drawn a clear line: concentrated mitragynine products cannot be lawfully marketed as supplements.

Download the Evidence: The Failed NDI Files

These are the core documents from this case: the industry submission and the FDA’s formal objection. Download them and share them with legislators and advocates.

These documents show that the industry’s safety claims did not survive FDA review. The FDA found the extract adulterated and its introduction into interstate commerce prohibited.

Full Investigation and Regulatory Timeline

For a deeper dive into the failed NDI, including the FDA’s complete objection and comparisons with other rejected kratom filings, read the full analysis from Mothers Against Herbal Abuse.