I'm impressed with the action of this Vitamic C serum to bright my eye area as well as to reduce my fine lines. I can't apply it in the morning as my skin is very thin and photosensitive despite of my high SPF. Against the general rule, I've started applying it at night insisting around my eye area with the help of my jade roller which also stimulates my blood circulation. I've read I can skip the SPF until the morning, so I let the serum completely absorb and I wake up noticing a gradual difference in my skin brightness and smoothness above all.
However, a little lesson of chemistry might come in handy here: it's crucial not to combine vitamin C with retinol, which is typically used at night, as layering them together can be counterproductive and may irritate your skin. Vitamin C, being acidic, penetrates the skin more effectively at a lower pH. Retinol, on the other hand, performs best at a higher pH.
To maximize their benefits when used in the same routine, apply Vitamin C first, then wait at least 30-40 minutes before applying retinol, allowing your skin's pH to adjust and prevent irritation.