In fact, serrapeptase is an unusually broad-spectrum supplement. . .Its fans consider it to be effective in helping to break down everything from uterine fibroids to coronary artery plaque, but for those of us with respiratory sequelae of COVID, the really good news is that serrapeptase has been considered a go-to remedy, even among many doctors, in Europe and Japan, for rhinosinusitis and lower respiratory (bronchial and pulmonary) congestion disorders. The literature on serrapeptase is huge. Initially discovered in 1960s by Japanese researchers, and now grown in laboratories via fermentation of organic products that yield or come with bacteria that secrete the enzyme (serrapeptase). Serrapeptase is also popular among people dealing with musculoskeletal pain (e.g. arthritis) and even some inflammatory/autoimmune illnesses. I would guess that if your fatigue derives from one of serrapeptaseś known applications, indeed this enzyme might be useful. If you survey the serrapeptase products now widely available, literature accompanying these may summarize the various actions and applications of serrapeptase. And before I started on it, I read several helpful peer-reviewed articles reporting on findings relating to these actions and applications. A KEY point here is that this enzyme, like other proteolytic enzymes, must absolutely be taken on an empty stomach (defined as at least 2 hours after any food and also at least 30 minutes prior to taking any food). Last night, I found a dosing recommendation for 3 daily doses, and this came with a product with a relatively quite high concentration-per-capsule of the enzyme. . .I am gradually moving my strength upward (that is usually the recommendation), and I will now increase dosing frequency (dividing total daily dose accordingly). As with all nonpharmaceutical remedies, itś still important to explore any risks involved and to learn about how much of the supplement can easily be tolerated . . . but when our doctors and researchers are at a loss, it is, in my view, entirely defensible for us to try products that are generally considered safe at particular doses, while ruling out interactions with drugs we may still need/take and also paying attention to how we are responding. And patience is important. Very few nutraceuticals quell symptoms immediately. Most require sustained use and following instructions for proper use along the way. The payoff, though, is that some nutraceuticals work deeply enough actually to modify the course of our illness over time.