Packaging and Formula Stability: How to Protect Products Sensitive to Light, Oxygen and Moisture

A lot happens between the lab and everyday use. Products are stored, transported, exposed to temperature fluctuations and, once opened, repeatedly come into contact with their surroundings. Throughout this journey, packaging plays a crucial role, particularly when dealing with formulations sensitive to light, oxygen or moisture.

In these cases, choosing the right packaging goes beyond aesthetics, materials or trends. The starting point is understanding what the formulation needs protection from.

A Great Formula Deserves the Right Packaging

Not all cosmetic products respond to external factors in the same way. A serum, an oil, a facial cream or a formulation containing specific active ingredients may have very different stability and preservation requirements. These differences directly influence packaging selection.

For some products, showcasing the formulation is part of their appeal. For others, limiting exposure to external factors is far more important.

The same applies to dispensing systems. A jar, dropper, pump or airless system offers more than a different user experience: each one changes how the formulation interacts with its environment.

That's why, before selecting the packaging, it's worth asking one simple question:

What do we need to protect the product from?

When a Formula Is Light-Sensitive, Transparency Becomes More Than an Aesthetic Choice

Transparent packaging is widely used in cosmetics. It allows consumers to see the product, highlights the formulation's colour and creates a clean, appealing visual identity. But it isn't always the most suitable option.

When a formulation is sensitive to light, transparency needs to be considered from a different perspective. Coloured glass, opaque materials, protective coatings or other packaging solutions may be required to reduce light exposure.

This is where a common challenge in packaging development arises: what works visually doesn't always meet the product's technical requirements.

That doesn't mean compromising on design. It means developing the design around the formulation's needs. And often, that's where some of the most interesting packaging projects begin.

Oxygen Exposure Doesn't Start and End with the First Opening

Oxygen presents a similar challenge. We sometimes focus on product preservation during storage, overlooking the fact that a significant part of a cosmetic product's life takes place after opening.

Take a face cream in a jar. Every time the consumer uses it, the packaging is opened and the formulation is exposed to the surrounding air. Over several months, this can happen dozens of times.

A pump dispenser changes that interaction. An airless system can go a step further by reducing the amount of air entering the container during use.

Does that mean every sensitive formulation should be packaged in an airless system? Not necessarily.

Airless packaging is a solution, not an automatic choice. Viscosity, dosage requirements, application method, component compatibility and the desired consumer experience all need to be considered.

The best packaging isn't necessarily the most technically sophisticated. It's the one that best meets the product's needs.

Moisture Matters Too, Even When It's Less Obvious

Light is visible. Air exposure is easy to understand. Moisture, however, often receives less attention, even though it can be equally relevant.

Certain formulations require protection against moisture transfer between the product and its surroundings. In some cases, the priority is preventing moisture from entering the packaging. In others, it's minimising water loss or the evaporation of volatile ingredients.

This is where the barrier properties of packaging materials become important, along with the performance of the complete packaging system.

Choosing the right material is essential, but it doesn't guarantee that every other component will perform as expected.

It's Not Just the Bottle That Protects the Formula. It's the Entire System.

This is one of the most important considerations when discussing product preservation.

We often focus on whether a particular material provides sufficient protection for a formulation. But the finished pack consists of much more than a bottle or container.

There are neck finishes, closures, pumps, valves, seals, connection points and dispensing mechanisms. Every component needs to work together.

At Rafesa, this is why we approach packaging as a complete system.

Product preservation doesn't depend solely on choosing glass, PET or PP.

It depends on how all the elements interact:

Formula + container + closure + dispensing system + real-life use.

If one element doesn't perform as intended, the overall performance of the packaging can be affected.

And Then There's the Consumer

Another factor that's easy to overlook during product development is how the packaging will actually be used.

Cosmetic products don't spend their entire lives in a laboratory. They end up in bathrooms, handbags, bedrooms and travel bags. They may be opened several times a day and exposed to changing temperatures and humidity levels.

The way consumers interact with packaging matters.

How often will the container be opened? Will the user come into direct contact with the formulation? How long will the product be used after opening? Does the dispensing system minimise exposure to external factors, or increase it?

Considering these everyday situations helps brands select packaging that is designed not only to pass validation tests, but also to perform where it matters most: in the hands of the consumer.

Testing Has the Final Say

Understanding material properties, knowing how a dispensing system works and drawing on previous experience all help make better packaging decisions.

But none of these can replace compatibility testing.

When a formulation has specific preservation requirements, the complete packaging system needs to be validated under representative conditions.

This means monitoring how the product evolves over time, including its appearance, colour, odour, viscosity and weight, as well as the functionality of the dispensing system and the performance of the packaging itself.

Two components may appear compatible in theory, but that doesn't necessarily mean they will perform throughout the product's intended shelf life.

Protecting the Formula Starts Before Choosing the Packaging

When developing a new product, it's tempting to begin by exploring capacities, shapes, colours and finishes.

But when working with a sensitive formulation, the process should start somewhere else.

First, understand the product. Then, identify what it needs protection from. Only then should the search begin for the packaging system that best meets those requirements.

At Rafesa, we approach every project with this broader perspective because packaging goes far beyond design.

When properly selected, it protects the formulation, enhances the user experience and helps ensure that the product envisioned by the brand is the same product consumers experience.