Most Important Ingredients that should be in your routine!

What is the most important product that should be in your skin care routine? I work in the product room at a Dermatology and Laser Center. I work very closely with the Dermatologist developing a ultimate skin care routine for EVERY skin concern. Working with prescriptions, physician dispensed products, highly active products and mineral makeups. The most important ingredient is a retinoid which comes in many strengths and forms such as tretionoins, retrinals, tazarotene etc (some prescriptions some not)... we have all forms at Renew (where I work) each skin type can start at different strengths. Most commonly people can start at the obagi tretionion .025% which is a prescription and eventually move up in strength with time and proper use.
This product originated as a acne treatment roughly 25 years ago and they found it was helping with fine lines, texture, skin thickness and collagen production. It is now the gold standard in dermatology for anti-aging. The dermatologist I work for, highly recommends each patient to be on this product and is the first product that is pulled (aside from spf). There are four important ingredients that should be implemented into your skin care routine: Sunscreen, Tretionin, Antioxidants, Growth Factors.
Examples:
Suncreen: Elta Tinted 41 Spf (tinted) or UV shield spf 45 (no tint) , Revision Intellishade spf 45 (tinted), Colorscience Sunforgettable Stick Spf 50 (all mineral, great for reapplication tinted or non tinted)
***Retinoid:.05% or .1%  ( non percription, sensitive hesitant or rosacea skin) Obagi Tretinoin .025% .05% /1% (prescription, start at tretinoin .025% and move up in strength with consultation with clinical esthetician or dermatologist)
Antioxidant: Obagi Vitamin C 20% (non prescription my favorite, LOVE) or the obagi c-clarifying serum with hydroquinoin 4% for people who have pigment concerns and want the benefits of an antioxidants (prescription)
Growth Factors: TNS Essential serum (non prescription has growth factors and antioxidants) TNS recovery complex ( non prescription my Favorite!)

My Routine:

My skin concerns: Acne prone, acne scars, prevention and GLOW:)
My Routine, there is importance in the order of application
AM: Clarisonic, PCA Blemish bar, TNS recovery complex, Obagi Vitamin C 20%, Elta 41, JaneIredale makeup (will blog my makeup routine later:)
PM: Clarsonic, PCA BPO 5% cleanser, TNS Recovery Complex, Epiduo (acne prescription), Avene cicilfate (amazing thick moisturizer that wont break you out but will make you wake up glowing )Tretionin .1%