Supplemented zinc makes it into your blood stream.

One of the biggest myths is that supplements gives you expensive urine/fecal matter. This is one of the reasons I wrote the book. Anyway research published today shows that supplemented zinc makes it into your blood stream, well at least if you are a "healthy" adult male. A placebo double blind trial looked at zinc blood levels between a placebo, 10mg and 20 mg of zinc sulfate a day. The zinc blood levels rose within 5 days to be massively statistically different to the placebo (P < 0.0001).

Interestingly enough the blood levels between 10 and 20 mg dose were not significantly different. This means that say if you were eating lots of oysters and you were getting your 10 mg of zinc through your food that supplementation wouldn't effect it. However as this study shows healthy men on Western diet aren't getting enough zinc. So you need to supplement! and when you do supplement the zinc makes it into the blood.

Now I would assume that if you are getting zinc into your blood stream that your body uses it.....

Reference: K. Ryan Wessells, Joshua M. Jorgensen, Sonja Y. Hess, Leslie R. Woodhouse, Janet M. Peerson and Kenneth H. Brown  Plasma Zinc Concentration Responds Rapidly to the Initiation and Discontinuation of Short-Term Zinc Supplementation in Healthy Men J. Nutr. (October 13, 2010). doi:10.3945/jn.110.122812