HCG will spike your test levels, and some of this test will convert to estrogen. Estrogen can/does increase fluid retention. This can be controlled using a small dose of AI, such as adex. How much you need will depend on how sensitive you are to estrogen and what your dose is of HCG and any aromatizing steroids you may be on. Be aware, that HCG can cause enough of a spike in estrogen to cause more intense side effects like gyno. The AI will be a good idea, for that reason alone. Start low around .25mg EOD or .5mg a couple times a wk and see what happens. If you need to, you can move up to .5mg EOD. Just be careful not to take the dose too high, and wipe your estrogen out.