Understanding the Different Perspectives — and Why They Matter
If you’ve ever turned a supplement bottle around and scanned the list of “other ingredients”, you’ll likely have seen terms such as fillers, binders or excipients. For some people, these ingredients raise immediate questions. For others, they’re dismissed as irrelevant or unavoidable.
What’s interesting is that how these ingredients are viewed depends very much on who you ask. Regulators, manufacturers and clinical nutrition practitioners often assess them through very different lenses — and this is where confusion, debate and mistrust can begin.
Our aim here is not to sensationalise or simplify, but to clearly explain what fillers, binders and excipients are, why they are used, and why clinical nutrition often takes a more cautious stance toward them. Ultimately, this is about helping readers make informed, responsible decisions — not about telling anyone what to do.
What Are Excipients?
In the simplest terms, excipients are ingredients added to a supplement that are not the primary nutritional components. They do not appear in the “active” section of a label, but instead under “other ingredients”.
This umbrella term includes substances used to:
- give a tablet or capsule its shape
- ensure powders flow properly during manufacturing
- prevent ingredients from clumping
- hold tablets together
- improve shelf stability
- make a product easier to swallow or handle
In pharmaceutical and food-supplement manufacturing, excipients are considered a normal and often necessary part of producing solid oral products. From this perspective, they are functional tools rather than nutritional contributors.
However, this definition alone doesn’t tell the whole story.
Fillers and Binders: What They Do
Fillers (also called bulking agents or diluents) are added to increase the physical size of a capsule or tablet. Many vitamins and minerals are required in very small quantities, sometimes just a few milligrams. Without a filler, the resulting tablet would be impractically small or inconsistently dosed.
Common fillers include:
- microcrystalline cellulose
- starches or rice flour
- calcium-based compounds
- lactose
Binders, on the other hand, are used to hold powders together when tablets are compressed. Without them, tablets would crumble during manufacturing, packaging or transport.
Common binders include:
- plant-derived cellulose
- starch-based compounds
- certain sugars
From a manufacturing standpoint, both fillers and binders solve real, practical problems. Without them, many supplements simply could not be produced at scale.
The Regulatory View: Safety Through Toxicology
From a regulatory perspective, fillers, binders and excipients used in supplements are assessed primarily for safety, not nutritional value. The key question regulators ask is:
Is this ingredient likely to cause harm at the amounts used?
If an ingredient is shown not to cause acute toxicity, irritation or obvious harm at typical intake levels, it may be approved for use as a food additive or excipient.
This framework is largely based on:
- toxicology studies
- acceptable daily intake thresholds
- short- to medium-term exposure data
Within this system, many excipients are deemed “generally recognised as safe” when used appropriately.
It’s important to understand this clearly: regulatory approval does not mean an ingredient is nutritionally beneficial — only that it is unlikely to cause direct harm at approved levels.
The Manufacturing View: Function and Consistency
Manufacturers tend to view excipients through a practical lens. Their priorities include:
- consistency between batches
- machine efficiency
- stability during storage and transport
- predictable physical behaviour of powders and tablets
From this standpoint, excipients are tools that allow products to be produced reliably and affordably. In large-scale production, even small formulation changes can affect whether a tablet cracks, a capsule fills correctly, or a powder flows evenly.
This explains why excipients are common — not necessarily because they are desirable from a nutritional point of view, but because they make industrial production possible.
The Clinical Nutrition View: A Different Question Entirely
Clinical nutrition often approaches these same ingredients from a very different angle. Rather than asking “Is this ingredient toxic?”, the question becomes:
Does this ingredient interfere with digestion, absorption, gut comfort, or nutritional efficiency?
This shift in perspective is crucial.
Clinical practitioners frequently work with individuals who already struggle with:
- impaired digestion
- reduced stomach acid
- compromised gut lining
- mineral deficiencies despite supplementation
- food sensitivities or intolerances
In these contexts, ingredients that are “safe” from a regulatory standpoint may still be undesirable from a physiological one.
Potential Issues Raised in Clinical Practice
While individual responses vary, clinical nutrition literature and practitioner experience often highlight concerns such as:
1. Digestive Burden
Some fillers, particularly insoluble fibres like microcrystalline cellulose, are not digested or absorbed. While this may be harmless for many people, others report bloating, discomfort or changes in bowel habits when consuming multiple supplements containing these materials daily.
2. Nutrient Absorption Interference
Certain excipients may physically bind minerals or alter how nutrients disperse in the gut. When someone is supplementing specifically to correct a deficiency, even small reductions in absorption efficiency can matter.
3. Cumulative Exposure
One supplement may contain only a small amount of excipients — but many people take several products daily. Over time, the cumulative intake of non-nutritive substances can become significant, even if each individual product remains within regulatory limits.
4. Gut Sensitivity and Reactivity
People with sensitive digestive systems, autoimmune conditions or compromised gut barriers often tolerate simpler formulations better. In these cases, reducing unnecessary ingredients is a common clinical strategy.
Importantly, these concerns are about optimisation, not toxicity.
Why These Concerns Don’t Always Show Up in Studies
One reason this topic is so contentious is that:
- long-term, low-grade digestive interference is difficult to measure
- nutrient absorption varies widely between individuals
- studies often isolate single ingredients rather than real-world combinations
- regulatory research rarely looks at cumulative, multi-product exposure
As a result, the absence of definitive harm in studies does not necessarily mean the absence of subtle physiological effects.
This gap between regulation and clinical observation is where much of the debate lives.
“Clean Labels” and Why They Appeal
The growing interest in supplements with fewer excipients isn’t just a marketing trend. It reflects a broader shift toward:
- digestive efficiency
- ingredient transparency
- minimal intervention
- respect for individual variability
From a clinical nutrition perspective, fewer unnecessary ingredients generally mean fewer variables — and fewer variables often mean better tolerance.
This does not mean that every excipient is harmful, or that every supplement containing them should be avoided. Rather, it supports a guiding principle used widely in nutrition:
When two formulations deliver the same nutrient, the simpler one is often preferable.
Reading Supplement Labels with Context
When reviewing a supplement label, it can be helpful to ask:
- Why is this ingredient here?
- Is it serving a clear function?
- Could the product exist without it?
- How many supplements am I taking that contain similar additives?
Rather than reacting to a single ingredient in isolation, it’s often more useful to look at the overall formulation philosophy.
Transparency, restraint and thoughtful sourcing tend to signal a product designed with nutritional outcomes — not just manufacturability — in mind.
Bringing the Perspectives Together
So where does this leave us?
- Regulation focuses on preventing overt harm
- Manufacturing focuses on consistency and feasibility
- Clinical nutrition focuses on digestion, absorption and long-term efficiency
None of these perspectives are inherently wrong — but they are not interchangeable.
Problems arise when regulatory safety is mistaken for nutritional neutrality, or when manufacturing convenience is assumed to align with physiological optimisation.
A Clear, Responsible Conclusion
From a clinical nutrition perspective, minimising unnecessary fillers, binders and excipients is generally preferable where possible, particularly for individuals concerned with absorption, digestive comfort and long-term nutritional efficiency.
This does not require fear, absolutism or rigid rules — just informed choice.
Understanding why these ingredients are used, and why some practitioners choose to limit them, empowers readers to decide what aligns best with their own health priorities.
Informed consumers don’t need to be told what to think — they simply need clear information and honest context.