I think the tips and techniques here will better help you retain the hair that you do grow. Furthermore, I also think that vitamins, healthful eating, exercising, certain topical growth aides etc will help your hair grow quicker (ie. 1/2 inch per month instead of 1/4 inch per month) but I do not think we can change our anagen phase.
If your anagen phase is just two years than your anagen phase is just two years.
That, in my opinion, is the genetic part. I think whatever the length of your anagen phase, the tips and techniques here can help you take advantage of it and get the most growth out of your particular growth cycle.
While sitting here typing the above, I'm not even 100% sure that the anagen phase is absolute either. For example, Saw Palmetto helps prevent shedding. So couldn't one argue that, in essence, SP helps extend the anagen phase??? IDK
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