Bests & Worsts Reviews from Amazon

Update (5/17/17): This product (which I've been using for a few years) now contains rice flour as a filler in addition the alleged 100% L-lysine (per the product description: "ZERO ADDED INGREDIENTS: Our product contains ZERO added ingredients and NO fillers"). My cat has a severe grain allergy so I can no longer use this product to treat him. The manufacturer very graciously and quickly refunded my most recent purchase when I asked him about this new filler ingredient listed on label. I have enjoyed purchasing this product from him over the years, and I would happily continue to so if he'd return to the original formula. However, this product should not continue to advertised as being 100% pure with no fillers, as this no longer accurate. I'm very glad I happened to look at the label before I gave the reformulated product to my cat, as he would've become extremely sick. I therefore feel morally obligated to drop my rating from 5 stars down to 1 star because this product is now being falsely advertised as being 100% pure with no fillers/additives, when this is no longer true. Buyer beware. ----- I've got 2 cats who have the feline herpesvirus, which causes all of the following symptoms: ocular drainage (runny eyes) and conjunctivitis (secondary eye infections), excessive sneezing/upper respiratory infections (which can easily progress into lower respiratory infections), and severe lethargy (acting really tired all the time, with no interest in playing). Fortunately, L-lysine supplementation brings all that mess to a screeching halt, and allows my cats to be happy, healthy, and completely symptom-free. I mix up batches of approximately 6 servings of food at a time (they eat freeze-dried raw food due to one cat having very severe food allergies, so the food has to be pre-mixed with water prior to feeding). I empty the contents of 9 capsules of Superior Labs L-lysine into each batch of 6 servings of food, and this amount fully controls all symptoms. Not sure how the math works out for that, but at 8 capsules per 6-serving batch, we were still experiencing symptoms.Every cat is different, so if you're trying to figure out dosing, start with the smallest amount, and keep increasing the dosage til all of the symptoms stop (I've noticed that, for my cats at least, some symptoms will often stop before others let up, so keep gradually increasing dosage til all your cat's symptoms are gone). I had been using Bulk Supplements brand L-lysine powder, and the cats were getting approx. 1/2 teaspoon per cat 2-3x per day. But this wasn't working, and no matter how much I increased the dosage, the cats were still very lethargic. Prior to the Bulk Supplements, I was using the contents of L-lysine capsules from Whole Foods (which I was opening and sprinkling into food), and prior to that, I was spending a small fortune adding Viralys L-lysine powder to their food at each meal. I attempted to switch back from the Bulk Supplements to the Whole Foods brand, but the Whole Foods brand had been back-ordered and has been missing from store shelves for several months now, so I was looking for a replacement for it (L-lysine supplement in a capsules that had little or no additional ingredients), and that's how I ended up trying Superior Labs L-lysine supplements. In case you were wondering, regardless all three of the varieties of the pure L-lysine powder (meant for human consumption) I've tried so far have no flavor, and my cats (even my picky princess palette cat) are not able to taste it at all whatsoever. Aside from the cost savings, this is another huge advantage using supplements has over using something like Viralys, which is flavored, since often the Viralys flavoring would clash with the flavor of their food. Long story short, I would very highly recommend the Superior Labs L-lysine for treatment of cats with feline herpesvirus. It has even fewer fillers than the Whole Foods brand, so I wil likely stick with Superior Labs even after Whole Foods returns their brand to their shelves. If you're buying these for human consumption, another benefit to this product is that the capsules are about half the size of other brands, presumably due to lack of fillers, so the capsules would likely be very easy to swallow. ***********UPDATE*********** So now I am on bottle # 3 of the Superior Labs L-lysine. Both cats' symptoms are completely gone. Lesson learned: not all "pure" supplements are created equal (and as I have now learned the hard way, some brands' supplements are "more equal" than others, and my experience has been that Superior Labs brand is much more potent than all the other brands I've tried). If you are looking for reviews based on human usage, I technically can't help you with that specifically. But I can tell you this: cats do not exhibit any placebo effects like humans tend to do, so they end up being a decently accurate, reliable, unbiased measure of potency. This is because the feline herpesvirus symptoms are not subtle. The symptoms are either present, or they're gone - no fuzzy grey area or "maybes." The Superior Labs brand makes all the symptoms go away (when other brands have not been able to do so). Simple enough, right?