How long should it take Stridex or Proactiv, etc. to start working?

All acne treatments including Stridex and Proactiv will start working in around 3-4 weeks.
Even if you do everything right it will take your skin at least 6-8 weeks to really improve.
To get the maximal benefit from these and all other acne products you need to commit to the treatment for at least 3 months and continue to use the products in a preventive manner. 
If you do not see significant improvement in 2-3 months you may have a more severe case of acne that requires a Dermatologist's advice and prescription medicine.

To find the right acne treatments for your unique skin, take the free skin assessment by clicking here.