Get property (none object) laravel

I have a recommends table which has user_id and product_id column and I'm trying to display mostly viewed products but I get an error Trying to get property of non-object from the view, if I dd($viewed) it shows all the products correctly but the problem is it can't display products and throws an error, any idea on how to solve this?

Controller

$viewed = Recommends::with('product')
     ->where('user_id', Auth::user()->id)
     ->select('product_id')
     ->inRandomOrder()
     ->groupBy('product_id')
     ->orderby('product_id', 'DESC')
     ->take(8)
     ->get();

Blade file

 @foreach($viewed as $view)

   <h1>USD: </h1>
   <h2>USD: </h2>
  @endforeach

via Chebli Mohamed