Consumer demand has fundamentally changed what supplement manufacturers are allowed to put on a label. But knowing why you need to switch to clean label excipients is easier than knowing how. This guide covers both — starting with the definition, and walking through the practical formulation steps that determine whether your transition goes smoothly or sends you back to the bench.
What “Clean Label” Actually Means
The term is widely used but inconsistently defined. According to the Clean Label Alliance — an industry group formed specifically to support manufacturers navigating this transition — clean label comes down to three questions:
- Can the consumer pronounce the name of the ingredient or excipient?
- Does the consumer know where the ingredient comes from?
- Does the consumer feel better knowing what they’re consuming?
As Steve Peirce, President of RIBUS and Clean Label Alliance member, puts it: the goal is to enable companies to remove chemistry lab-sounding words and replace them with clean label alternatives — like “rice extract” instead of “magnesium stearate” — while maintaining the same functionality and quality.
Clean label is also an umbrella concept. It encompasses certifications (Gluten-Free, Non-GMO Project Verified, Organic, Vegan), applicable statements (Halal, vegetarian), and consumer-facing terms like “natural” and “free-from.” Sustainability and supply chain transparency increasingly fall under this umbrella too — consumers want to know not just what’s in the product, but where it came from and how it was made.
Why Excipients Are the Hardest Part of Going Clean Label
For most supplement brands pursuing clean label status, the active ingredient is already organic or natural — it’s the excipients that create the problem. Magnesium stearate, silicon dioxide, calcium silicate, titanium dioxide — these synthetic processing aids have been the industry default for decades. They’re reliable, inexpensive, and well-understood by equipment. But they label as chemicals, and today’s consumers notice.
The challenge is that excipients aren’t decorative. They’re functional. Swap them out carelessly and you may find your capsule filler jamming, your tablets crumbling, or your powder bridging in the hopper. Achieving the proper balance between API, excipients, and equipment is the core challenge of the clean label transition — and it requires knowing your powder properties before you start and after you switch.
Start With a 1:1 Swap — Then Test
The right starting point for any clean label excipient transition is a 1:1 substitution: replace your current synthetic excipient with a natural alternative at the same inclusion rate. This gives you a baseline comparison. From there, three key powder tests will tell you what adjustments are needed.
1. Flowability: Angle of Repose
Flow is the first thing that changes when you switch excipients. The angle of repose test measures how well a powder flows — you pour it into a pile and measure the angle of the slope. Lower angles mean better flow; higher angles indicate the powder will struggle on a machine.
| Flow Property | Angle of Repose |
|---|---|
| Excellent | 25–30° |
| Good | 31–35° |
| Fair — aid not needed | 36–40° |
| Passable — may hang up | 41–45° |
| Poor — must agitate/vibrate | 46–55° |
| Very poor | 56–65° |
| Extremely poor | >66° |
An increase in angle of repose between your old and new formula predicts increased weight variance in the finished solid dose form. If your natural excipient formula shows significantly worse flow, you have three options: adjust inclusion rate, change blending sequence, or look at equipment modifications (vibration assist, powder scrapers).
2. Compressibility: Carr’s Index
Powder compaction affects both capsule filling (forming a cohesive slug) and tablet pressing. Carr’s Index gives you a quick read on compressibility using two simple density measurements:
Carr’s Index = (Tapped Density − Bulk Density) / Tapped Density
| Carr’s Index | Flow / Compaction Character |
|---|---|
| <15 | Free flowing |
| 15–25 | Good |
| 25–35 | Acceptable / poor |
| >35 | Extremely poor / no flow |
Significant differences between your synthetic and natural formula Carr’s Index values mean you’ll need to adjust tamping force on capsule fillers or compression pressure on tablet presses. This is normal — natural excipients often have different bulk densities from their synthetic counterparts, but equipment adjustments are straightforward once you know the magnitude of the difference.
3. Particle Size Distribution: Sieve Analysis
Changing ingredients changes particle size — and particle size distribution predicts compaction behavior. Pull the Certificate of Analysis for both your old and new excipients and compare the particle size specifications. Then run a sieve shaker test on your formulated blends to confirm distribution.
A well-distributed formula for solid dose typically looks like:
- Oversize (20 mesh / 850μm): 0%
- Intermediates (40–120 mesh / 425–125μm): 70–80%
- Fines (200 mesh / 75μm): 10–20%
Most formulas won’t hit this ideal, but if your current formula is running successfully, your goal is to match its particle size distribution as closely as possible with the clean label version.
Equipment Adjustments for Natural Excipients
Natural excipients are not nature-identical — they don’t behave exactly like their synthetic counterparts on equipment that was designed around synthetic powder standards. Solid dose equipment manufacturers have responded to this by developing tools specifically to support cleaner formulations: powder scrapers, powder bowl cones, adjustable tamping pin holders (inside pins independently from outside pins), and specially designed ladder bowls all improve weight consistency when working with powders that don’t flow as freely as conventional synthetics.
The key is to develop a good relationship with both your excipient supplier and your equipment manufacturer. RIBUS, for example, provides formulation support directly and can advise on starting parameters for each product based on existing customer data. Most natural excipient transitions don’t require new equipment — just configuration changes and tuning.
The Clean Label Excipient Toolkit from RIBUS
RIBUS has offered rice-based clean label ingredients to the food industry for years, and now makes the same functionality available to supplement manufacturers. The full lineup covers every major excipient function:
- Nu-MAG™ (Rice Extract Blend) — lubricant, replaces magnesium stearate
- Nu-FLOW™ (Rice Hulls / Rice Fiber) — flow agent / anti-caking, replaces silicon dioxide
- Nu-BIND™ (Gum Fiber Blend) — binder, replaces synthetic polymers
- Nu-SORP™ Oil (Fiber Blend) — oil adsorption, replaces silicon dioxide / calcium silicate
- Nu-SORP™ Water (Fiber Fruit Blend) — moisture adsorption
- Nu-FILL™ (Rice Syrup Blend) — filler / bulking agent, replaces MCC
All are certified organic and non-GMO. Getting Started Guides with specific use levels, blending instructions, and formulation tips are available for each product at ribus.com/resources.
The Bottom Line
Clean label excipient transitions are achievable for virtually any supplement formula. The manufacturers who struggle are the ones who make a blind swap without testing powder properties first. The ones who succeed take the time to understand their current formula’s flow, compaction, and particle size characteristics — then systematically tune the natural alternative to match. API, equipment, and excipients all have unique functionality. Getting the balance right between all three is what makes a clean label product not just compliant, but production-ready.
Getting Started: Download Getting Started Guides for all RIBUS supplement excipients at ribus.com/resources, or contact the RIBUS team for a free formulation consultation.
