Cis male friend keeps asking if I’m taking steroids

I’m not out at work. I work a pretty physically demanding job and present very masculine, though still go by deadname and feminine pronouns at work. I am pretty early on T but my arm muscles are already massive. Granted, I’m 5’1 so any muscle mass is bound to look proportionally large on me.

My friend is not aware of me being on hormones. He keeps asking me if I’m roiding. I just laugh it off but can’t help feeling like I’m lying. 😭

What’s the ethical thing to do here?