The brand, created by venture capitalist Jon Flint, markets itself as using breakthrough science to solve hair problems.
Hollywood A-Lister Aniston became an investor in Living Proof in 2012 and began promoting it as its brand spokeswoman a year later. The actor became a style icon in the late 90s through her portrayal of Rachel Greene in the globally popular sitcom Friends, with her distinctive haircut becoming known as "The Rachel".
Living Proof claims to bring advanced bio-medical technology to the beauty industry by calling upon a team of scientists and hair stylists that enable people to get visibly healthier hair and fight frizz.
The brand uses patented tech from the world-renowned Massachusetts Institute of Technology. It was founded by Flint and Amir Nashat of Polaris, with scientific help from MIT biochemist Robert Langer.
The acquisition is expected to close in the first quarter of next year and Unilever did not disclose the terms of the deal.
Living Proof will be part of Unilever’s ‘prestige’ portfolio, which includes brands such as Dermalogica and Kate Somerville.
Alan Jope, president of personal care at Unilever, said, "We are delighted to be adding Living Proof to our portfolio of Prestige brands. The Prestige Hair retail market is very attractive and offers significant potential for growth.
"Through compelling product result demonstrations and influencer driven marketing, Living Proof is already a successful business in this space and we look forward to further developing and growing this wonderful brand."