The Ordinary Hyaluronic Acid 2% + B5 is a popular facial serum on Amazon for its hydrating and plumping effects. This serum contains a high concentration of hyaluronic acid, a powerful humectant that attracts and retains moisture in the skin. It helps to replenish and restore the skin's hydration levels, improving its overall texture and elasticity. Users appreciate the affordable price and effective results of this serum, as well as the non-greasy formula.