When multinationals start investing, the promise of nutritional beauty supplements is turning into a reality. Nutrafol, a nutraceutical supplement for healthy hair growth for men and women, has closed its series A financing round. Unilever Ventures, the venture-capital and private-equity arm of the consumer packaged goods conglomerate, joined as lead investor after an initial introduction from investment platform CircleUp. According to Nutrafol, the company’s founders were frustrated by poo...