Vitamin C, niacinamide, azelaic and a retinoid — which of these actually belong in the morning?

I ran this on myself for three months because I was in the same pile-everything-in place. Split was vitamin C plus sunscreen in the morning, retinoid three nights a week, azelaic on the four nights in between, niacinamide in whichever moisturiser I happened to be using. Total morning time went from about nine minutes to four, and the visible difference showed up in month two, mostly in texture rather than tone. The thing that changed was not the order, it was that nothing was fighting anything else on the same night.

Mild pushback on the standard answer, because the morning vitamin C rule gets repeated with more confidence than it deserves. Modern formulations are far more stable than the ones that rule was written about, and if you are consistently sunscreened, the practical difference between a morning and evening application is small. The version I would actually defend is: put the product you will reliably apply in the slot where you will reliably apply it. A perfectly optimised routine you rush through four days a week loses to a boring one you do daily.

I used all four in one evening for about five weeks and destroyed my barrier so thoroughly that plain water stung. It took three weeks of nothing but a bland cleanser and a ceramide moisturiser to feel normal again, and I threw away most of an unfinished vitamin C serum because I no longer trusted it. The cost was not the products, it was two months of no progress at all while I recovered.

The only one with a strong reason to be nocturnal is the retinoid, and that is partly because a lot of retinoids degrade in light and partly because it plays badly with a morning routine you have to rush. Vitamin C in the morning is the traditional pairing because it sits under sunscreen and the two are complementary rather than because it stops working at night. Niacinamide is agnostic, it will do its job in either slot, so put it wherever it fits your ten minutes. Azelaic is the one I would move to mornings for you specifically, because stacking it on top of a retinoid in the same evening is how most people end up with a flaky face and no idea which product caused it.

Pick two. Run them for three months. Then judge, and only then add a third.