Or, well, you can, but it's probably not the best idea. You'll want to take into account your skin type — many sensitive types are too delicate for the full-strength stuff and can do more harm than good with dryness and irritation if they dive into it too fast — and you'll also want to be extra cautious about only purchasing from brands you trust, not just the cheapest formula or the one that promises to be the most potent. (You'll also want to not be pregnant. There is no reported evidence of topical retinoids causing any harm to an unborn child, but some studies have shown that high doses of vitamin A can be harmful, and oral retinoids like Accutane are known to cause birth defects .)