I have looked into it in the past but we've only ever had a couple of people ask about it.Steve, have you looked into Zynamite (a branded mango leaf extract) https://nektium.com/zynamite/ ?
AZOTH had a standalone product with it but it sold out and hasn't been restocked. some of their other supps have it as one ingredient. LifeExtension has a supp called Brain Fog Relief that has it w/ peppermint essential oil
The issue with offering it as a single ingredient is that the company that supplies it will not let you name the product anything with it in the name; so for example, we couldn't name the product Zynamite or Zynamite XT, and we've found that in cases like that, the products won't sell well because people may not know what the product is. People that are looking for a single ingredient item to try normally are looking for that ingredient by name, so not being able to use the name itself in the product name just doesn't work well. I hope that makes sense.
I have seen that product by Life Extension with Zynamite in it and also see that its on a blow out sale from them right now so that's probably not an indicator that it sells well for them.
From the feedback that I heard on it initially, it ranged from nothing to a good energy hit with some experiencing a comedown from it and too many reports of a headache to make me very comfortable with using it in a formula (just being totally honest). When I tried it myself, I didn't get any energy from it, but I'm pretty stim tolerant so that didn't really surprise me, but I did notice that 2 out of the 3 days I tried it, I did get a headache within 3 hours. I can't say for sure that it was the product bc I have bad allergies and get sinus headaches a lot - but it just worried me, and I'll note that that was before hearing from anyone else about headaches with it so I know it wasn't mental.
If they changed their policies on it and allowed companies to use the ingredient name in the product name, I would do a small run on it to see how it sold; but I doubt they'll change that anytime soon.