Simple answer: Most health food stores and Asian grocers.
Phytessence Wakame is found in seaweed products, many of which
will be available from your local Asian supermarket. Since it is
also a 'health food' it can be found at most health food stores
too.
Wakame (seaweed) usually comes dried, in sheets. You can eat it
dry, wrap it around some salmon and bake it (my personal
favourite), soak it in water and chop it into a salad, or even
munch on it dry if you like. Wakame can also be bought as 'Nori
Sprinkles' (I like the brand Clearwater for these, though there are
many these days) which you can shake over a salad, a curry, or even
a soup. They pack a serious nutrient punch as they inflate up to 15
times when soaked in water!
Most people are probably reading this article because they read
about Phytessence Wakame's amazing skincare benefits. My advice is
to cast a critical eye over all the websites selling expensive
lotions and potions via the internet containing Wakame. You can
take your chances with pricey potions, but I'd recommend keeping it
simple (like the japanese!) and eating the cheap and effective
Wakame available in your local store. I live in the UK, so for
those who do too you can buy directly from the Japan Centre for
really reasonably priced wakame in many forms. They deliver
anywhere in the UK...link below.
http://www.japancentre.com/?cmd=itm&id=1661
Just one note: For those who haven't eaten it before the flavor
can be kind of odd. you might not like the taste at first! If you
want to ease yourself into it you can buy Miso soup sachets that
contain wakame. Having it in the miso soup broth makes the flavor
WAY less noticeable.
Good luck!