I ordered both the Sildenafil and the Cialis generic, Tadalafil, both liquids from LRS labs. Yes, they both work. Since there were no instructions, I tried one drop sublingual, waited one hour observed no effects positive or negative. Next day, one full dropper-ful (probably 30 drops) sublingual, and after 20-30 minutes positive effects similar - in my experience - to 20mg pharmaceutical grade Sildenafil. Taking one full dropper-ful of both, I had a memorable performance at my local house with a frequent provider who was equally impressed.
Overall, these research liquids seem legit, but not any better than pill form. If you already allow a Sildenafil or Viagra dissolve under your tongue you already know this is a faster way to deliver the drug with more immediate results. So then the comparison involves safety and economy, wherein the liquid LRS labs products offer no advantage.
Of the three online services I tried, Roman is in every way superior.