Rarely for weight loss, often for hypertrophy.
Weight loss must be a lifelong lifestyle. Quick supplements that provide weight loss does not bring long term health and weight loss. For those looking to bulk up then I often recommend a vasodilator (argnine, nitric oxide) and or creatine supplement.
Depends on the client. I don’t recommend any weight loss supplements, but I do recemmend that my strength clients look into creatine, glutamine, and BCAA’s. This of course only comes after a solid nutritional plan. The first priority is not supplementation of a poor diet but instead a solid diet with supplemention to take them to new levels of limit strength by better fueling and recovery nutrition availability.
No, I do not because I am not trained in this field. Of course, people ask me. In that case, I will tell people which supplements I take myself and what my personal rationale is. But I make it very clear that this is not a recommendation for anyone else to follow.
I also point out to people that there can be medication interactions with supplements and that they need to get recommendations from a competent professional.