What It Is: If you don’t know where to start, a multivitamin is always a good choice, Brannan says. She recommends starting with a trip to your doctor’s office for a blood test to see if you have any vitamin deficiencies, especially if you’ve been feeling sluggish.

What It Does: A multivitamin, particularly one with extra iron, provides support for your immune system, muscles, bones, and metabolism so you can keep on truckin’.

What To Know: Brannan recommends taking a multivitamin with water and a meal.

What It Is: Beetroot is a beet-based supplement that’s been shown to enhance performance for runners, according to Tobelem.

What It Does: Beetroot juice or powder contains a compound called nitric oxide that boosts blood flow to the muscles, strengthens muscle contractions, and improves oxygen uptake, Tobelem explains. “This allows runners to reach a higher VO2 max and increase the time until they reach exhaustion,” she tells Bustle. “With increased blood flow and improved oxygen uptake, runners will feel less fatigued after their workouts and be able to train for longer durations.”

What To Know: Tobelem recommends taking 310 to 560 mg of beetroot two to three hours before running — but always read your labels and check in with your doctor before adding a new supplement to your diet.

As a side note, she says some people might experience gastrointestinal upset when taking beetroot. “The best thing to do when starting a new dietary supplement is to start slowly and see how your body responds before increasing the dosage.”

What It Is: Creatine and beta-alanine are amino acids that support energy.

What It Does: Joel Totoro, RD, the director of sports science at wellness brand Thorne, says these two supplements work in conjunction to enable muscles to function optimally whilst you run. “Creatine serves as a fuel source for the muscle, while beta-alanine supports endurance by buffering the lactic acid formed when muscles are used,” he tells Bustle.

What To Know: Totoro recommends taking 3 to 5 grams of creatine and 3.2 grams of beta-alanine daily. If you’re training for a big race, he suggests taking 6.4 grams of beta-alanine for the 28 days leading up for more of a boost.

What It Is: Electrolytes are essential minerals that include sodium and potassium. They’re naturally found within your body and play a key role in keeping you hydrated.

What It Does: “We all know hydration is important for runners, but it's more than just replacing lost fluid,” Totoro says. “Equally important is replacing the electrolytes — sodium and potassium — and minerals — magnesium and calcium — lost in sweat.”

What To Know: Electrolyte dosing recommendations vary based on your local climate, altitude, and personal sweat rate, Totoro says. But a good rule of thumb is to drink enough to replace all the sweat you lost.

What It Is: Caffeine is a nervous system stimulant found in coffees, teas, energy drinks, sodas, and energy shots, says Stacy T. Sims, MSC, Ph.D., an exercise physiologist and nutrition scientist.

What It Does: “Aside from the stimulating effects on the brain, caffeine also raises blood pressure, heart rate, and stomach acid production, and it helps break down fat stores and releases them into the bloodstream for easy access during exercise,” Sims tells Bustle. “Research on women hasn’t shown the benefits of caffeine for short high-intensity sprints, but is most effective for longer, sustained exercise.”

What To Know: Always check with your doctor before adding any new supplements to your diet, including caffeine. That said, the recommended dose is 2 to 3 mg of caffeine per kilogram of body weight. “Higher doses of caffeine do not appear to produce any additional performance benefit,” Sims says. “Athletes should make sure they practice with caffeine during training prior to using it as an ergogenic aid on competition day.”

What It Is: Magnesium is a mineral and electrolyte required in over 350 processes in the body, including energy production, muscle relaxation and recovery, bone development, normal blood pressure support, and fatigue reduction, says Brittany Michels, a registered dietician nutritionist with The Vitamin Shoppe.

How It Helps: If you’re struggling with recovery, try taking magnesium. “In addition to the benefits above, some research shows that magnesium may reduce the accumulation of lactic acid during hard exercise sessions,” Michels tells Bustle. “We lose magnesium via sweat, so runners — especially those with high sweat rates — are prone to magnesium depletion.”

Get low on magnesium and you might experience muscle cramps and fatigue, which Michels says are symptoms you definitely want to avoid when training or racing.

What To Know: It’s recommended to take one tablet daily with a meal. Michels says you can also aim to eat more magnesium-rich foods, like leafy greens, nuts, beans, and seeds. She suggests getting 300 to 600 mg a day.

What It Is: Vitamin D is a fat-soluble vitamin that helps you absorb calcium, magnesium, and phosphate.

What It Does: “I recommend runners include vitamin D [in their diet] as this helps to promote healthy bones and reduces inflammation,” says Shena Jaramillo MS, RD, a registered dietitian. So it’ll not only help you recover, but will ensure you stay strong for your fave sport — especially one that’s so high-impact.

What To Know: Take two Vitafusion gummies per day for a serving of 50mcg of vitamin D.