Whether you are introducing Retinaldehyde to your routine for the first time or are an experienced user, we have you covered! If you are new to Retinaldehyde we recommend starting with our 0.05% and gradually building up to our more potent formulas. Once your skin can tolerate 0.05%, meaning you are able to use it regularly without irritation, it may be time to move up to our more advanced formulas. (We recommend patch testing before going to the next strength to makes sure your skin is ready.) Last chance to use the code: YELLOW20 to save 20% at Naturium.com!