What are supplements is good for body builders? Like l-arginine is safe? What other suppl. Can I use? Both benefits for my body and sex life?

Yes. L-arginine is safe. It's benefit remains debatable. It is reported to benefit the Nitric Oxide cycle. However it appears the more expensive l-citrulline may be a better, yet more expensive choice. Large doses of l-arginine have been used for those trying to boost natural hgh production. The research however shows that high dose bedtime dosing is required, causes diarrhea.