Cortisol is released in response to stress to generate fuel for the body to react with. The more stress you create via weight training/cardio, the more cortisol gets released. So there are a lot of factors that play into that. For one, it depends on how much of a stress you create on your body. For example, on days that you train legs, because of the great amount of energy it requires to move those heavy weights while squatting/leg pressing, more cortisol is released compared to when you train biceps. Also, it depends on if you do a heavy cardio session after training, which is yet again another stressor and will likely add to the release of cortisol. It also depends on how many grams of simple sugars you're taking in with your post-workout meal. 20g of simple sugars won't lower cortisol levels nearly as much as 60g of simple sugars.
So, given those factors it is really hard to say. I believe that a solid post workout meal of 50g whey protein and 60g of simple sugars will be enough to blunt the effects of cortisol. Follow that meal up 1.5-2 hours later with another high protein meal (solid food this time) and complex carbs and you should be solid. However, it may not necessarily lower it/reduce to total count of cortisol. So while food consumption will help to blunt the effects of cortisol, Retain2 will be able to actually reduce its presence.
If your workouts are extremely exhausting to you, I would take Retain2 both before and after working out, along with a solid post workout meal. If you're in a post cycle therapy, I would definitely take one cap pre and one cap post workout.