I've never tried one, mostly because so far my stems have been strong. I have read that silica also helps with trich development, but have not chased that one. If I did, I would just go with the Raw product mentioned by
@Lil Dab. It is a lot cheaper than some of the alternatives, and it seems to work. I would never pay the exhorbitant price of the fancier liquid products - no doubt they are good, but I very much doubt that the extra bud or potency would cover the cost. Just my opinion of course, and every asshole has one eh?