Long, strong and healthy hair is on everyone’s bucket list but for those whose mane needs a strong helping hand, Agent Nateur's high potency, overnight topical strengthening hair serum is the answer.. Backed by advanced hair science and clinical studies, four scientifically proven active ingredients, an array of shine-inducing compounds and more, holi locks stimulates and encourages healthier looking hair. When applied topically for at least 12 weeks, our overnight strengthening serum helps your hair to appear denser, thicker and fuller, all without the use of harsh silicones.. Available to buy online