“Maintaining hydration and electrolytes in your muscle tissues is going to keep your muscles functioning well, rather than cramping up,” says Thornton. She recommends electrolyte tablets especially before, during, and after sweaty workouts.

Caffeine only stimulates the sympathetic nervous system, which is what gets your body up and going. “So it gives your brain the feeling that it has more energy, but your body physiologically can not keep up with that,” Thornton explains, noting that this often leads to overexertion and injuries. The thing that truly gives you the energy to move is food. So, have your pre-workout coffee but combine it with some carbs and protein for the optimal effect.

“I recommend greens powders to my clients who have a hard time getting all of their vegetables in,” says Thornton. They’re essentially broken-down ingredients from fruits and all varieties of vegetables. “Taking it in the morning in your shake or having it in water once a day will give you some good stuff,” she says. “Eat your fruits and vegetables, but toss it into the mix and it won't hurt you.”

When it comes to protein powder, it’s not one size fits all. When you're strength training or trying to build muscle, Thornton recommends a protein powder isolate with added BCAAS to help with building muscle tissue. If you’re looking for something basic that you can customize, grab a simple product (like a dehydrated egg white powder) and add your own extras, like flaxseed oil or nut butter and frozen fruit.

“If you’re vegan, you're going to lack some of the nutrients that you're going to get from meat sources,” says Thornton. Iron is one you’ll definitely want to check and another is vitamin B12 which has a role in your red blood cell production and your nervous system. One good thing with B vitamins, Thornton says, is that they’re water-soluble so you don’t have to worry about overdoing them as you would with certain other vitamins.

Exercise is a stress on the body. “It's a good stress, but you're breaking things down which leads to inflammation and soreness in the body.” If you’re not getting enough omega-3 fatty acids from fish or plant sources like flaxseed oil or walnuts, a supplement may be in order to help keep that inflammation in check. Joint pain is one sign you may need more but you can also talk to your doctor about taking it preventatively.

When you’re exercising, whether it’s weight training or cardio, your body's utilizing iron to supply your muscles' oxygen needs, Thornton says. “Anytime we strike our heels to the ground, we're actually busting blood vessels and that’s also contributing to us losing that iron,” she says. “And women in particular lose even more iron each month during menstruation.” Here’s the thing: If your iron stores are depleted, you’re working at a lower capacity than what your body can actually do. Thornton doesn’t recommend just grabbing a supplement off the shelf, though: See your doctor for a blood test first. Pro tip: Vitamin C helps with iron absorption while milk and dairy products decrease it.