Rethinking the inactive ingredient: clean label pressure forces a new look at excipient science

Excipients have long served as the functional backbone of supplement formulation. As clean-label expectations extend from food to dietary supplements, formulators and contract manufacturers are re-evaluating ingredient choices that were previously driven by cost and convenience.

This creates a technical challenge: replacing well-characterised synthetic excipients with nature-derived alternatives that can deliver comparable performance at scale without compromising compressibility, flowability, disintegration or long-term shelf stability. Alicia Peirce Kasch, Vice President at RIBUS, explores the topic.

The regulatory landscape driving reformulation

Clean-label standards in supplement manufacturing remain less defined than those for food. In the EU and UK, products are governed by Directive 2002/46/EC and related additive regulations, with some ambiguity remaining about the classification of processing aids.

In the United States, excipients are governed by 21 CFR Part 111 GMP requirements. But, with no formal positive list, interpretation falls to brands and certifiers.

Retailers and certification bodies have begun restricting certain synthetic excipients, including magnesium stearate and titanium dioxide. Organisations such as NSF International and the Soil Association apply additional standards. As a result, formulators must address excipient selection early, with supporting documentation aligned to target markets.