I recently posted a similar respose to Timuk who was concerned over his shed so thought i would embellish a little further to help make people aware of the dreaded seasonal shed:
Shedding is something that guys (and girls) need to be well aware of so that when its your time and it occurs (often seasonally) that you do not panic and start organising your next HT in a desperate attempt to regain your lack of "density".
Shedding unfortunately is part and parcel of the HT "process". Seasonal shedding occurs to us all along with med shedding (if on meds) - I personally experienced a shed recently which left my hair looking very thin and even though i knew it was only a shed it still made me anxious and very self conscious - it does every time - BUT i know through experience it is because of the periodic "shedding process" and that given time it will slowly but surely come back in. Yes a waiting game ...yet again!
When it does occur just park it and ride it out and try your very best like in the early days of your HT to not scrutinise it by watching it, applying products, washing in, conditioning it, washing it again ;-) Important point also when you shed and then it returns..remember for the next time in order to limit the anxiety levels associated with it.
What you must be aware of is that HT 's when they shed do expose the fact that they perform the "art of illusion" as are not dense, not like a "normal" head of hair - but can give the illusion of density with skilled placement performed appropriately with accurate direction and correct use of characteristics. HT's appear thicker than they actually are ..until a dreaded shed.
HT hair is no where near as dense as a "normal" head of hair - therefore when you shed say 25% of it if not more in a "shed cycle" it makes the HT area appear thin in comparison to pre shed. This is when the panic and anxiety sets in - trust me i have experienced many sheds and it unnerves me still most times.
Best advice I can give is just ride it out and be patient (again) and it will all come back in over time - often 3/4 months. Maybe get on MSM if not already just to help things along and also bulk up the regime with a hair vitamin, omega 3 - DO NOT start applying Minoxodil or Nizoral shampoo (if not a regular applier) to boost growth - Big NO NO - It will only shed more ,potentially. The best thing you can do it try forget about it as it will then come back in much quicker if you do - rather than watching / waiting for it.