“We really want to look at that interpretation and ensure that it is the best interpretation,” Welch said during a virtual fireside chat with CRN’s Andrea Wong at Convergence 2026 in Carlsbad, California.
Welch said the agency is examining whether its longstanding interpretation of the dietary substance category remains appropriate under the current dietary supplement framework and the statutory language.
The work could lead to a standalone draft guidance addressing how the definition applies to different ingredient types and production methods.
“What I’m hoping for is a distinct draft guidance discussing this topic,” Welch said. “What is the best interpretation of dietary substance? How does this apply to certain ingredient types?”
She said the agency is still working through the questions, including how the definition applies to specific types of ingredients such as microorganisms. The aim is to develop a clearer interpretation that can be shared with industry for feedback.
Industry-led effort on pre-DSHEA ingredients
Welch also addressed the long-running question of how to establish an authoritative list of ingredients marketed before the Dietary Supplement Health and Education Act of 1994 (DSHEA).
She welcomed efforts by trade associations to develop their own list, saying FDA could be a major user of the resource.
“I was very excited when the trade associations started talking about building their own list,” Welch said. “I think FDA would be one of the biggest users on this list.”
Welch said FDA has not developed its own list because the agency is not best positioned to establish which ingredients were marketed before DSHEA, particularly given the marketing information needed to document their presence in the marketplace at that time.
“So that’s why we have not acted on it for the last nine years, because we are not best positioned to do this,” she said.
Such a list could help the agency assess whether an ingredient is a pre-DSHEA dietary ingredient or a new dietary ingredient (NDI), a distinction that is important in determining the applicable regulatory requirements.
“Figuring out whether an ingredient is pre-DSHEA versus NDI is really important to almost every one of our assessments of ingredients,” Welch said.
However, Welch cautioned that the list should not be treated as exhaustive: an ingredient’s absence from it would not automatically mean that it qualifies as an NDI.
GRAS pathway for supplement ingredients
Welch also discussed the use of the generally recognized as safe (GRAS) pathway for ingredients intended for dietary supplements.
She said her concern arises when manufacturers actively choose a pathway to avoid FDA review.
“I would prefer that new ingredients, where the intended use is to be in dietary supplements, come into the Dietary Supplement Program, get reviewed by the Dietary Supplement Reviewers against the dietary supplement safety standard,” Welch said.
Her comments highlight the agency’s interest in how companies determine the appropriate regulatory pathway for novel ingredients intended for use in supplements, something that remains a point of debate as companies navigate the boundaries between the GRAS and NDI pathways.
