That would be 40/20 mg of tamoxifen (not tamoxifen citrate). If you have the research tamoxifen citrate, than 40 mg of tamoxifen citrate would be closer to 30 mg of tamoxifen. If you want 40 mg of tamoxifen, you have to take more than 40 mg of tamoxifen citrate. I'd say you are better of starting with 60 mg of tamoxifen citrate if you are using the research stuff. The prescription pills are based on the amount of tamoxifen (active ingredient), so this wouldn't be a concern.