Double the concentration and power of Potent Retinol Serum and designed for more mature and imbalanced skins. Be sure to always start with the Potent Retinol Serum (0.5%) and then work your way up to the Retinol Concentrate (1%) if required. Good to Know: Begin with use every second to third evening and slowly build use to every evening or every second evening. If your skin starts to feel itchy, tight or a little sensitive, stop for a couple of nights and then resume application. Use only at night and apply O Mineral Pro SPF 30+ every morning, no excuses! Choosing your Retinol: If you’re new to Retinol, it’s been a while or you can’t remember what percentage of Retinol you’ve used previously start with a 0.5% strength; either Potent Retinol Serum or Retinoic Oil - the Oil is a better choice for dry or sensitive skin. Avoid products containing Salicylic Acid and Retinol during pregnancy and breast feeding.