The Serum

The Serum by Christian Dior is listed here as a skincare product. Active ingredients can be effective and irritating at the same time, which is why the usual advice is to introduce one at a time. Patch test on the inner arm or along the jaw first, especially if you are already using retinoids, acids or vitamin C. Whether it is discounted this week says more about the shop's stock than about the product. Check the period-after-opening symbol on the pack; once opened, a formula is on a shorter clock than the printed expiry. Add delivery to the cheapest price and you will see whether it is genuinely the best deal.