Narrowing down which supplements you need to take is a daunting enough task as it is — and then you find yourself staring down a shelf full of different kinds of very specific daily multivitamins. One of the most common dividing lines: sex. And because male and female bodies are different in some ways, it sort of makes sense — but do you actually need a vitamin that's tailored to your sex? To find the answer, a smart place to start is the National Institutes of Health's (NIH) recommendations for the amounts of vitamins and other elements that we should be getting. Although those amounts are mostly the same, there are a few places where the recommendations differ between people who are biologically male and female (the NIH, by the way, uses the terms "male" and "female," but most manufacturers label vitamins as "men's" and "women's"). For instance, it's recommended that premenopausal women take more than twice as much iron as men because menstruation ups your need for iron. So, although each supplement company's formula is a bit different, most manufacture their vitamins to help you meet those requirements. That means that, with some very minor exceptions, no: It really doesn't matter that much which ones you buy because you're getting almost entirely the same stuff from men's and women's vitamins. If you identify as a woman and you accidentally pick up a bottle of men's multivitamins, you're not going to throw your body out of whack. But because those minor differences can add up over time, you probably don't want to buy them regularly. For example, taking too much iron can leave potentially dangerous deposits in your organs. And, if you rely on vitamin supplements to treat or prevent a specific vitamin deficiency, make sure you're getting supplements that actually contain the amount of that vitamin you need. (Your doctor is probably the best place to go for that information.) Of course, all of this talk about sex and gender brings up an important question, which is what vitamin should you be taking if you're trans? If you're taking hormones it's best to consult your doctor during your regular checkups to make sure the vitamins you're taking won't interfere. But otherwise, it really doesn't make a big difference. And whether you're trans or cis, if you're feeling confused by all of this, there are also a ton of multivitamin options out there that aren't gendered — so you might decide to just go that route. Then again, that brings us to a larger question: Do you really need multivitamins at all? It may surprise you, but an increasing number of experts will tell you those supplements are actually unnecessary — especially for the young and generally healthy among us. Again, if you are treating a specific deficiency, that's a different story and your doctor will either prescribe supplements or make sure you get the right ones from the drug store. So if you're concerned that you may have a deficiency, check in with your doc. However, the vast majority of us in the developed world don't need extra help — we get what we need from our food and environment. Consuming more than you need, however, may come with some dangers: There are situations in which vitamins can interfere with your other medications (e.g. blood thinners), and it's even possible to overdose on vitamins in some rare cases. So definitely don't think of these as a harmless "just in case" type of thing. Whatever ones you decide on, your doctor needs to know you're taking 'em.