Stability testing is non-negotiable for any CPG product with a shelf-life claim. The "Best By" date on your label has to be substantiated by stability data. The FDA can ask. Retailers will ask. Your insurance carrier will ask after a claim.
Standard ICH Q1A(R2) protocol uses two conditions in parallel:
- Accelerated stability: 40°C ± 2°C / 75% RH ± 5%. Mimics shelf aging at an accelerated rate. Pull points at 0, 1, 2, 3, and 6 months. Useful for predicting shelf life and identifying failure modes early.
- Long-term (real-time) stability: 25°C ± 2°C / 60% RH ± 5% (or 30°C ± 2°C / 65% RH ± 5% for "Zone IV" tropical conditions). Pull points at 0, 3, 6, 9, 12, 18, 24, and 36 months. The actual shelf-life evidence.
What gets measured at each pull point depends on the product class:
- Supplements: Active ingredient potency, moisture content, microbial counts, visual appearance, dissolution (for tablets/capsules).
- Cosmetics: pH, viscosity, color, odor, microbial counts, preservative challenge.
- Food and beverage: Sensory (taste, smell, texture), moisture, water activity, microbial counts, oxidation markers (peroxide value for oils).
Cost ranges: a 6-point accelerated stability protocol with full chemistry and microbiology costs $4,000-15,000 per SKU at a third-party lab. Long-term stability extends across years and accumulates similar per-pull-point costs.