Redditors are going wild for these K-beauty hair supplements, which work sort of like fillers (only, you know, no shots). When hair is dry or damaged, the strands weaken and become more porous. This solution is packed with proteins and collagen that users claim add strength and volume directly to those vulnerable areas. Mix with 10ml of water until it becomes a thick and creamy paste, the apply it to hair like a mask. Leave it on for 20-30 minutes, then rinse with warm water. But the craziest thing of all? It only costs one dollar.