This serum is for experienced users only. You can use it if you've previously used the Retinol 3 serum (old formula) or finished at least one bottle of the Environ Tri-Retinoid Complex Retinol Serum. It's a stronger step up! Absorbing quickly, this lightweight retinol serum is formulated with a tri-retinoid complex that consists of retinyl propionate and retinol in a stable colloidal serum concentrate with the addition of the retinoid effect boosters Revinage® and NovoRetin™. A step up from Environ Tri-Retinoid Complex Retinol Serum, this rejuvenating, skin health-boosting serum should be used only when your skin has become acclimatised to retinol serums. Enhancing skin health and resilience, as well as rejuvenating your complexion, this retinol serum smooths fine lines and wrinkles, blurs blemishes, and balances uneven skin tones, leaving your skin fresh, bright, and youthful.