Okay, hear me out. Honey contains trace amounts of hydrogen peroxide, but in a much gentler form. Mixed with cinnamon, it can subtly lighten hair over time.
Mix a few tablespoons of honey with a teaspoon of cinnamon and enough conditioner to make a paste. Slather it on your hair, put on a shower cap, and leave it for an hour (or overnight if you’re brave).
This isn’t a miracle worker, but it will warm up your color and leave your hair feeling silky. And if it doesn’t lighten much, at least you’ll smell like a holiday dessert. Win-win, right?