I recently ordered these in the Double Stuffed Cookie flavor based on prior positive reviews on here. I would prefer it to be a bit thicker like a shake but the flavor was good and I might try more flavors.

I noticed on the box that it says "Do not use for weight reduction." For those of you familiar with this product, do you know why this would be? Do you have any problems with losing weight drinking these as an alternative to IP drinks/shakes? They seem to be phase 1 friendly based on the nutritional information in place of an IP packet.

It is phase 1 friendly.
But our plan has us eating more than just the protein. I'm guessing that is what the warning is. Nectar isn't a complete meal replacement. It works fine for our needs.

I use Syntrax Nectar all the time. It's great.
To get a little thickness, get yourself some xanthan gum or guar gum, and using an electric mixer of some sorts (by hand doesn't work well) add about 1/8 to 1/4 of a teaspoon to your Syntrax. Mix very well, and drink immediately. It will be a little thicker. I also sometimes do it with ice and it makes a very fluffy smoothie.

And they are totally fine for our needs.

My mom was told to use them by her dialysis nutritionist who said Syntrax is about the best whey protein there is. That's where I was introduced to them. I love several of the fruity ones, and the vanilla torte makes an awesome iced coffee/latte with instant coffee.

The grapefruit is my new fav

So you use this as a replacement for an IP unrestricted packet, correct?

Correct.

I loved the Caribbean Cooler flavor so much, I got a ton of samples in their other flavors! It is really great.

Thanks so much, everyone! That makes sense that it suits our needs- glad to hear that!

I will have to order some other flavors and try them. Thanks for the guar/xantham gum suggestion too!