From a compliance lens, dosage guidance can also blur into advising/claiming outcomes. Better to keep it informational and general.

So what can I ask without getting shut down?

Ask about: what 'variability' means, risk factors (who should avoid), how to evaluate sourcing/testing, how to read labels/COAs, and what to do if someone feels severely unwell (seek help).

Also you can just learn without doing anything. Curiosity doesn't require action.