Once opened, matte liquid foundation typically begins to deteriorate after about 6 to 12 months, depending on the packaging type and formula ingredients.
Packaging differences: Pump-style bottles offer better protection against air exposure, allowing for a shelf life of around 12 months after opening; wide-mouth jars expose the product to air more frequently, so it is recommended to use them up within 6 months.
Special formulas: Matte foundations containing natural ingredients or low levels of preservatives may show signs of spoilage as early as 3 to 6 months after opening.
Signs of spoilage: If you notice separation of oil and water, an unpleasant odor, clumping, or a dull, cloudy appearance, the product has spoiled. Discontinue use immediately to avoid skin irritation, redness, or breakouts.
