Yeah, it's closed permanently. Apparently there is also there is another shop called York Sport Nutrition.

They have two branches:
York Sports Nutrition (Shop 1) : Tel : 4371434 23 Al – Jazeera St. –
Fariq Bin Mahmoud York Sports Nutrition (Shop 2) : Tel : 4874347 Bin Omran Main Road

Their webpage is http://www.yorksnutrition.com

I haven't been there myself but I'll try to go tomorrow.