Product stability testing: How to avoid costly formula failures

Product stability testing: How to avoid costly formula failures

Developing a new product is an exciting yet complex journey that balances innovation, effectiveness and safety. While product stability might not be the most thrilling aspect of development, it’s critical in ensuring quality and consumer trust—especially for trailblazer brands creating something that’s never been done before.

If you’re developing a product from scratch (rather than using a standard white-label formula), you’re well on your way to setting your brand apart. But the greater the reward, the greater the risk.

To help you navigate the myriad of variables, here’s what you need to know about stability risks so your cosmetic or food product reaches the consumer exactly as intended.

Major stability risks in cosmetic product development

An unstable product can lead to texture changes, microbial contamination or reduced effectiveness. Below are the four primary ways a product can become unstable:

Physical instability

Physicochemical changes in a formulation can make a product ineffective or unappealing. Common forms of physical instability include:

• Phase separation: Oil and water components splitting in emulsions

• Precipitation or crystallisation: Uneven texture or sedimentation

• Viscosity changes: Formulations becoming too thick or too thin

• Sensory degradation: Color shifts, fragrance loss, or texture inconsistencies

Chemical instability

Chemical instability can degrade active ingredients, making the product ineffective. This may cause:

• Oxidation: Exposure to air and light leading to rancidity or discoloration

• Chemical reactions: Temperature-induced changes that produce gas or alter pH levels

• Oxidation: Exposure to air and light leading to rancidity or discoloration

• Chemical reactions: Temperature-induced changes that produce gas or alter pH levels

• pH shifts: Destabilisation of emulsion and active compounds

• Hydrolysis: Water-sensitive ingredients degrading over time

Microbial contamination

Microbial growth in products can pose serious risks. Inadequate preservation or storage conditions can cause bacterial and fungal contamination, which can lead to:

• Skin irritation or infection

• Unpleasant odour, gas or breakdown of the formula

• Further instability that can reduce preservative effectiveness, compromising product safety

Packaging incompatibility

Packaging plays a crucial role in product stability. Common issues include:

• Leaching: Packaging material migrating into the product, changing its composition

• Permeability: Air and moisture infi ltration leading to degradation or clumping in powder products

• Reactivity: Chemical interactions between packaging and formula causing instability

Product stability testing: Your best defence

Choosing the right combination of ingredients and the right packaging is essential. What’s the best way to ensure this? Well-designed stability testing that helps predict and mitigate potential risks before your product is launched.

Accelerated stability testing

The industry standard for predicting product longevity—accelerated stability testing exposes products to elevated temperatures and humidity levels over a set period to simulate real-time aging and potential degradation.

If a product remains stable under these conditions, its shelf-life confi dence increases. Periodic evaluations during testing assess key stability markers like:

• Colour and odour shifts

• Texture and viscosity changes

• Microbial growth

• pH and active ingredient retention

Food stability testing

For food products, stability testing evaluates how a product’s quality, safety and sensory attributes change over time under different storage conditions. Key factors that are assessed include:

• Temperature: Different temperatures in storage conditions can accelerate or slow down microbial growth and physical changes. Testing at ambient, refrigerated, frozen and other conditions can help predict long-term stability.

• Humidity: High humidity can cause caking in food powders. While low humidity can cause drying and textual variations in liquid products.

• Light exposure: UV and visible lights can affect vitamins or antioxidants in food components, leading to discolouration and degradation.

• Oxygen exposure: Exposure can cause rancidity in oil-based foods and nutrient degradation.

• Chemical reactions: Enzyme-catalysed and acid-base reactions are the most common causes of discolouration and gas production in food products.

• pH levels: Bacteria can’t survive in acidic environments. So the more acidic, the longer the product will last.

• Preservative effectiveness and challenge testing: Ensuring the preservative performs within the complexity of ingredients optimises shelf life..

• Physical characteristics: Hardening, softening, crystallisation and phase separation are common problems associated with textual changes, which may affect the appeal of food products over time.

• Packaging materials: Quality packaging extends shelf life, while poor packaging risks chemical migration, affecting safety and flavour.

BiomeCentric: Your partner in product quality

At BiomeCentric, we help brands safeguard their product integrity. Our team of scientists can advise on and perform suitable tests, including:

• Preservative Efficacy Testing

• Packaging Compatibility Testing

• Accelerated Stability Testing

• Period After Opening Testing

• Challenge Testing

Whether you’re developing a cosmetic, food or therapeutic* product, we highly recommend supporting your products with external validation and real-time testing. A pilot batch is always recommended as lab samples may not fully represent fi nished product stability.

By partnering with BiomeCentric for your new product development, you retain full control over your intellectual property while ensuring consistent quality and consumer satisfaction.

Let’s ensure your products have the highest quality and stability for your customers and their microbiome.

*Therapeutic and listed medicinal products require a dedicated stability program, BiomeCentric recommends consulting with an external independent stability expert to ensure compliance with regulatory requires and product integrity.