I’m an arrow, but I never fly, Tho lift me up, and posts climb high. I’m worth no coin, yet you’ll agree, Nobody wants the minus from me.

I am a poison, but can be bought at the store. I can help a conversation, or make you speak no more. Many have been lost to me, and locked behind doors. When I am done with you, you might end up on all fours.

You break this when first time meeting someone

I help to power your brain and every stride, but too much of me, and pants grow wide. You burn me fast on treadmills and in gyms, then count me up with meals to look slim.

I never read what you write, yet I swear I know what you meant. I fix your mistakes into different ones, and apologize with a duck. What am I?