Revitalize your skin with Paula's Choice Azelaic Acid Booster. Perfect for all skin types. Infused with licorice and salicylic acid. Price is already reduced 50%. Please no offers — price is firm. This product does not have a printed expiration date. Based on the batch code, it was manufactured approximately 4 years ago. Azelaic acid is widely regarded as a stable active ingredient with an unopened shelf life commonly cited in the 3–5 year range when properly stored. Product has been kept sealed in a cool, dry environment.