Usma oil in this product comes from the seeds of Isatis tinctoria, also known as woad. In Central Asian beauty tradition, usma has been used for centuries as a cosmetic plant for brows and lashes. The source describes it as a conditioning ingredient: it contains omega fatty acids that help reduce dryness, plus tocopherols and phytosterols that help keep the hair surface supple and smooth. The practical result, according to the description, is that hairs look less brittle and reflect light better — which makes them appear glossier and more defined.
It is not the only conditioning ingredient here. The formula also includes vitamin A as retinyl acetate, which is commonly added to products for dry, fragile-looking hair to maintain a nourished appearance, and panthenol (a form of vitamin B5), a classic conditioning agent that binds moisture and improves the feel of the hair shaft. Eleuthero root extract contributes plant compounds that condition the skin around the brow line and lash base, so the whole area is cared for, not just the hair itself.
You do not need to understand every ingredient to use the product well, but knowing what is in it helps you judge whether it matches your routine. If you prefer oils without added vitamin A, or if you have reacted to panthenol or plant extracts in the past, check the full ingredient list before purchasing. As with any cosmetic, the value is in the overall formula and how consistently you use it, not in a single ingredient.