Ok so I just started working out using the 5x5 method. But I think I am doing it wrong.

I just started 2 weeks ago and I am onto 40lb dumbel curls I can do 5x5 so I thought ok ad 5 pounds. But I can't do 45lbs clean my form is so bad. I would understand if I could only do 5set of 1 or 2 45s and then try for 5x3-4 next session. But I can't do 1 good one so what do I do. Today I just did 5x5 40lbs and then did a few 45lb ones but they were terrible form.

To describe my BADform when I did hammer curls I had to use my back to get it the rest of the way up, to do regular curls I used momentum to get them up.

The 5x5 is a great method. I dont know your program but its mainly used with compound movements (bench press, squats ect.) Im not sure what your asking but ill try and help.

If you can do 40lb dumbell curls then you should be able to do 80lb barbell curls. Try doing 5x5 90lb barbell curls then if you can next time attempt 45lb dumbell curls. Really all your doing is getting your body familar with weight but on a easier lift. Also try doing compound movements that assist with your biceps like reverse grip bent over rows and chinups.

If your having form problems with hammer curls try doing seated incline hammer curls. Being seated will not allow you to use your back and cheating is pretty hard to do.

Good luck with the training !