10,000 IU 10ml is 1000 units/ml. So .25ml is 250 units. I fill a .5ml insulin syringe and that is 500 HCG units. For 250 HCG IUs the syringe reads 25, which works out very well.
The diluent supplied is 10ml, so use it all.
I use half of the loaded .5ml syringe one day for 250IU then use the rest for the next time. For a 1ml syringe you can get four injections from that. Keep the loaded syringe in the refrigerator with the vial. You can warm the syringe a bit in your hand before injection if that makes it more comfortable, then chill again if not empty.
Clean the injection site and if reusing the syringe, clean the needle and end of syringe, inject and clean the needle again (cleaning before and after), recap and refrigerate if not empty. Clean the needle first and allow to flash off (to avoid stinging) with cap removed while selecting and cleaning the injection site. If injecting IM in the leg, find a spot without visible veins and mark by pressing with thumb nail, the clean with alcohol and the marked location is then obvious. Package insert says IM injection, but docs and others recommend subcutaneous for comfort and claim similar effectiveness. For its intended usage for female fertility treatment, the injected amounts are large and IM is probably indicated for that. IM on the leg can bleed or bruise if you go through a surface vein, and you should aspirate before injecting. If injecting in the belly fat, I don't think that bleeders or bruising will ever happen.
Men should take small doses as large doses can cause the testes to down regulate the LH receptors that the HCG also acts on, then you are doing harm at worst and waisting your money at best. Research shows that 250IUs EOD restores the testes to their normal internal testosterone levels. So that should be considered a maximum to restore or maintain normal activity when TRT is shutting down the LH and the testes.