Amino acid supplements have soared in popularity in recent years. Social-media influencers peddle them with promises that they’ll build muscle, enhance athletic performance, promote weight loss, boost metabolism, and improve mental focus. But they’re not right for everyone. Here’s what to know about the trendy supplements.
What are amino acids?
Amino acids are the building blocks of protein, and there are a total of 20. Nine essential amino acids—histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine—are available only through foods or supplements. “You can’t store amino acids in your body, so if you have a diet that’s unhealthy, you’re not going to get all the amino acids your body needs,” says Joan Salge Blake, a clinical professor of nutrition at Boston University and host of the nutrition and health podcast Spot On!
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There are also 11 non-essential amino acids—alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine—that can be produced by your body. While each amino acid plays a specific role in the body, as a group, they’re involved in nearly every biological process, including building and maintaining muscle, helping with wound healing, regulating hormones and immune function, and producing energy.
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Because they do so many different things, “you need a good circulating pool of these floating around in your body,” says Wendy Bazilian, a nutrition and wellness expert based in San Diego and host of the 1,000 Waking Minutes podcast. “You want them in your system so they’re available when you need them.”
Who might benefit from a supplement?
If you consume a healthy, balanced diet and don’t do a lot of intense exercise, you may get enough amino acids from food. But other people may benefit from taking supplements. These include older adults who want to preserve muscle mass and function and prevent sarcopenia, an age-related condition characterized by a loss of muscle mass and strength, says Leslie Bonci, a sports dietitian and owner of Active Eating Advice in Pittsburgh. Research has found that taking an amino acid supplement enriched with leucine for eight weeks led to increased muscle mass, strength, and function in older adults with sarcopenia.
Athletes and other people who are very physically active may also benefit from taking amino acid supplements to promote muscle maintenance and recovery after exercise. This category includes what Lindsay Malone, a registered dietitian at the Case Western Reserve University School of Medicine, calls “invisible athletes”: people with physically demanding jobs like delivery drivers, construction workers, utility workers, and camera operators. “Taking essential amino acids regularly helps your body replace old or damaged muscles so your muscles keep working well,” she says.
Research has found that taking supplements of branched-chain amino acids [BCAAs]—namely leucine, isoleucine, and valine—can ease muscle damage and soreness after resistance training in athletes. BCAAs have also been shown to reduce people’s ratings of their perceived exertion (how hard it feels like they’re exercising), which can help people exercise longer and harder.
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People who are consuming limited calories (because they’re trying to lose weight, for example) or who are following a vegan or vegetarian diet also may benefit from taking amino acid supplements, Bonci says. They may not be consuming enough protein, which means taking a supplement with essential amino acids could protect their muscles.
Regardless of dietary habits or age, there’s also some evidence that amino acid supplements could help people who are recovering from surgery or an injury, Bazilian says. In these instances, she explains, “you need more of the building blocks [of protein] to help you recover.” Research has found that people who took amino acid supplements after surgery for bone fractures had fewer medical complications during recovery, including surgical-site infections, than those who didn’t take these supplements.
The best way to take them
If you’re interested in taking an amino acid supplement, it’s always a good idea to talk to your doctor about it first to make sure it’s safe for you. “If you have diabetes or liver disease, you shouldn’t be taking them,” Salge Blake says.
If you decide to move forward, Bazilian recommends looking for a formula that contains all the essential amino acids or at least the BCAAs. Choose products that have undergone third-party testing and certification by an organization such as NSF, Informed Choice, or BSCG, Bonci adds. “That means it’s been tested in a facility to make sure it doesn’t contain impurities,” and that it contains the ingredients and potency it claims to.
Amino acid supplements come in lots of different forms, including powders, capsules, liquids, and gummies. Before choosing one, think about which form is likely to agree with yourdigestive system, Bazilian says, and “skip those with artificial sweeteners or other unnecessary ingredients.” Take it with food—ideally, something with protein, carbs, and fat—to reduce the risk of gastrointestinal distress.
Be sure to maintain the right perspective about how these supplements might fit into your life. “It’s important for people to understand that these are not a replacement for protein,” says Bonci. “They can offer a false sense of security if you think you can eat like crap as long as you’re taking an amino acid supplement.” Amino acid supplements are meant to complement a healthy diet—not replace one.