Lipase supplements on the market claim to help you lose weight, on the grounds that lipases are digestive enzymes that break down fat. While this is certainly a true statement, it's not correct to assume that consuming supplemental lipase will help break down and get rid of stored fat.
Enzymes are frequently misunderstood. While they're essential to cellular function and human health, you don't need to obtain them from food and can't benefit from enzyme supplements, with very few exceptions. Enzymes are proteins that help speed up and regulate the reactions that take place in your cells. They're very reaction-specific; each can do only one thing. Further, your cells have to make them for themselves; there's no evidence that cells can take up enzymes that you consume.
Lipases are fat-digesting enzymes. When you eat fat, for instance, it passes into your small intestine where it reacts with pancreatic lipases, enzymes released into the small intestine by the pancreas. These break the fat down into smaller particles that you can then absorb and burn for energy, or store. Your cells use lipases as well, both to break down your stored fat and to break down and recycle other lipids, such as membrane components.
There are several problems with the idea that taking lipase will help you lose weight. First, digestive enzyme deficiencies are quite rare; if you're overweight, it's not because you're lipase-deficient. Second, lipase that you swallow won't make it into the cells; it will stay in your intestine. If it retains any function at all on its trip through your digestive tract, all it would do is break down the fat you eat, leading to increased uptake of fat calories from your food. There's no way to get lipase into your cells by swallowing it.
Frankly, however, it's not likely that supplemental lipase would cause you to absorb more fat from the food you eat. This is because lipase is not an acid-tolerant enzyme. When you swallow lipase and expose it to the acidic interior of the stomach, the acid destroys the lipase enzyme. You'd digest it like any other protein. For this reason, lipase supplements have no effect, either for good or for ill, except to cost you money.