Already a top-seller in the United States, the First Aid Beauty Ultra Repair Firming Collagen Cream (£38) arrives in the UK this month. Aimed at plumping and hydrating the skin, the cream also contains collagen, peptides, and niacinamide. "Topically applied collagen doesn't really build collagen, it keeps your skin soft and supple, but it doesn't build collagen," First Aid Beauty founder Lilli Gordon told POPSUGAR via Zoom. "So the two workhorse ingredients in this cream are really peptides and niacinamide. And together what they do, they help you hold onto the collagen you have, and to rebuild the collagen you've lost."