I would like to know how to use retinol serum.

I received a retinol serum as a gift, but I only use it in the evenings.

For some reason, I think retinol shouldn't be exposed to sunlight, but I'm not entirely sure.

It wasn't stated on the product that it should only be applied in the evening, and I'm not sure if what I know is correct.

I would also like to know at which stage I should use the serum.

And what are the effects of retinol serum?

I’d like to know if it’s good for skin whitening or wrinkle care, and if it’s good for me to use retinol products since I’m in my 50s.

I want to know the proper way to use it.