I don't think there is any scientific data showing that hcg will do anything positive for your hot flashes; those are most likely due to being pushed into "instant menopause" from your hysterectomy. I had a hysterectomy, also, many years ago and went through the same thing. There are other supplements you could try that might be more beneficial than hcg. You might talk to your doctor about taking black cohosh. I took that for a while and it did help some with the hot flashes, though it didn't do anything for the night sweats.
On a norm, hormones hurt anyone who has lupus. However, I too have Lupus but had a complete hysterectomy, therefore, the hormone I hope; will help with the horrible hot flashes that I have daily. I'll let U know!
I'm going to guess that you are right. There's a very strict diet that goes along with hcg diet, which I don't believe is good under any circumstances, but with your lupus the diet could have serious effects.
My daughter has lupus - I'd rather see her a bit over weight.