Most users have reported that they notice changes within the first 2-3 days of usage. Others have reported much slower progress and no noticeable changes for several weeks of usage.
If no changes are seen within the first week of usage, perhaps a different approach may need to be considered.
Tip From Michael
My own belief is that if a formulation does not produce any noticeable changes within the first week of usage, it’s unlike to work. This is what I’ve typically told people that have asked this question. However, there have been users that indicated seeing changes after more then a month. As a result, it’s difficult to really give a definitive answer.