Overview
Allantoin is useful only after the formula has a water phase worth trusting. In an after-shave balm or moisturizer, it can support a smoother, quieter skin feel without adding oiliness or scent.
It is also the kind of ingredient that punishes casual formulating. It can be hard to dissolve, can show crystals when handled poorly, and needs preservation because the formula around it contains water. Save it for preserved water-based formulas, not simple oil-and-wax recipes.