I really don’t use supplements nor do I recommend them to my clients. As Ariadne said, it’s out of the scope of practice for Trainers. Besides, there are too many horror stories out there about people suffering terrible side effects from using supplements – it’s simply not worth it. Most supplements aren’t supported by any credible research anyway. I’ve been relying on good old sensible nutrition & it’s been working just fine for my clients and me for years.
But to answer your question, the only supplements I ever used were protein powders (bodybuilding days in the ’80’s!), & a multi-vitamin – that’s really about it. But my question to you is – Why did you answer your own question on this thread?