How much do 390cc EHP implants weigh?

Generally speaking, breast implants are just about the weight of water it displaces. The actual density of gel is about 1.02 to 1.07 gm/ml for water, it's 1.00 gm/ml. Fat is roughly 0.9 gm/ml. So, with 2 390cc implants, that's a volume of 780 ml so the weight is 795 to 834 gm (or 28 to 29.5 oz; just shy of two pounds). Of note, the fatty tissue in a breast would weigh nearly 100 grams (three ounces) less.

Hi. In general the cc volume is fairly similar to the total weight of the implants, thus your implants would weigh around 780g (definitely less than 1kg). You are correct that the brand & style of implant is not relevant.  You didn't mention how long post-op you are.  It is not uncommon to have some swelling & fluid gain after surgery, but this should even out after 4-6 weeks.  Continue to eat a healthy diet & everything should settle down.  Kind regards Kim