HEAVENLY product. I use in the pm on face and neck. It use to have retinol in it but the new formulation does not. Thus, I can get this on my neck without my neck having a reaction. My face is very tolerant (built up over time by using high quality ZO products) but the neck skin is fragile and has a stronger reaction making growth factor a beautiful product to add to my neck. This feels so amazing on my skin that I look forward to putting it on. I feel this is a product for anyone, any age, any ...