I just received my first shipping of Huel and I directly started with the “Unflavoured & unsweetened” version, because I prefer to have different flavors to mix it with.
I noticed that even after adding a flavor to the mix, the sweetness of the shake is almost non existent.
Does anyone else also experienced that in the beginning and when yes, did you added some sweetener to it, like sugar, etc.?
Are you using the huel flavour samples? If so, I think someone mentioned that the quantities in the samples is how much you’d add to vanilla huel, U/U needs more of the flavour powder. Perhaps try two complementary flavours together?
I personally find it hard to sweeten U/U, though I don’t have many artificial sweeteners on hand because I generally don’t like them.
I like a mix of vanilla and U/U, then I add cinnamon, coffee, flavour extracts etc.
If you want sweet, experiment with low calorie sweeteners- you need quite a lot of sugar to sweeten U/U successfully. Fruit is also a good addition to blend into it but you’d most likely need sweetener and fruit.
If you can’t get it to your liking, I believe huel will allow you to swap unopened bags, so if you have a 2nd bag of U/U you could swap it for vanilla.
There are two differences between vanilla and U/U. One is the presence of the vanilla flavour and the other is the sweetener used which is called sucralose. Sucralose, depending on who you ask is between 300 and 1000 times sweeter than sugar.
The sweetener used in the flavour pouches is stevia which is around 150 times sweeter than sugar. Stevia can also have a bitter aftertaste to it.
The vanilla flavouring in Huel is very mild and does not prevent you from mixing in other flavours, from Huel flavour pouches or fruit etc…
As @Klaire672 mentioned if you are using the flavour sample pouches these are designed to flavour a set amount of Huel which is stated on the pouch. Realistically though Huel chose sucralose for a reason so if you want to make it sweeter you could use the same stuff. Example here.
But you’re probably better off with vanilla 
I load up with frozen berries and if needed, a tsp raw honey because at least that’s got health benefits!