What is Protein Powder and Is It Worth It? A Comprehensive Guide

A registered dietitian weighs in on whether it's worth the investment

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If the fitness and health industry had a mascot, protein powder would be it. The supplement is popular among active people, both athletes and casual exercisers alike. Protein powder is also touted as a must-have supplement for myriad goals, including weight loss, weight gain, and muscle maintenance.

However, if you're new to the complex world of supplements, you might wonder if protein powder is something you actually need. To help you out, we asked registered dietitians for the 411 on this supplement. Ahead, experts explain the potential benefits and risks of protein powder, plus how to figure out if you need protein powder at all.

Protein is an essential macronutrient, meaning the body needs it in large amounts. (The other macronutrients are carbohydrates and fats, ICYDK.) According to the National Library of Medicine, protein is made of building blocks called amino acids, and there are 20 that humans use. Eleven of those amino acids are non-essential, meaning the body can make them on its own, says registered dietitian Linzy Ziegelbaum, M.S., R.D., C.D.N. The remaining nine—known as essential amino acids—aren't produced by the body, so we need to get them via food.

According to Ziegelbaum, amino acids are involved in many functions in the body. Examples include immune function, metabolism, muscle building and repair, and hormone regulation. Amino acids also give structural support to body tissues, provide energy, and maintain digestive function. In other words, amino acids are pretty darn important.

Animal products such as meat, dairy, and eggs contain all nine essential amino acids, so they're known as "complete" sources of protein, says Victoria Whittington, R.D.N., a registered dietitian at Atlas Optimization. Meanwhile, certain plant foods—think grains, legumes, nuts, and seeds—contain some, but not all, essential amino acids, earning them the title "incomplete" proteins. (There are several exceptions, like soy and quinoa, which are complete proteins.)

It's totally possible to get all the amino acids you need by combining different plant-based proteins, says Whittington. This is helpful if you follow a vegan or vegetarian diet, or if you're simply trying to nosh on more plants.

Protein powder is a powdered form of protein sourced from animals or plants. It's a nutritional supplement, so it's not meant to be a main source of protein. Instead, it's meant to be added to your existing diet to bolster your protein intake. Because protein powder can include anywhere between 10 to 30 grams of protein per scoop, it can be especially useful if you eat little to no animal products, says Whittington.

There also are different types of protein powder that vary by source. The most common animal-based proteins are whey and casein, which are both derived from milk, says Whittington. "Whey protein is a byproduct of the cheese-making process. [To make it,] enzymes are added to separate the curd from the liquid whey, [which] is then pasteurized." This isolates the whey, which is dried into a powder. Casein is made from the curd of milk, which goes through a separation process that isolates the protein. Both whey and casein are complete sources of protein (meaning they contain all 9 essential amino acids).

Plant-based protein powder is often derived from soy, brown rice, pea, or hemp—but it can also come from foods like watermelon seeds, chia seeds, and pumpkin seeds. In general, the powder is made by extracting protein from the plant source, which is then processed and milled.

According to Whittington, most plant-based powders contain a blend of plant proteins to provide all the essential amino acids you need. Many versions contain soy, as it's one of the few plant-based complete proteins—but you can certainly find soy-free versions on the market, too.

Because protein powder can be sourced from a variety of animal or plant foods, the exact benefits of a specific protein powder can vary greatly. Still, when it comes to protein powder in general, the supplement has been shown to have myriad health benefits.

Protein increases feelings of fullness because it takes longer to digest, says Whittington. It also reduces ghrelin—a hormone that promotes hunger—and increases peptide YY (a hormone that promotes satiety), she adds.

When you add protein powder to a meal or snack, research shows it can keep you satisfied for a longer time. This could help reduce hunger in between meals, which can be a lifesaver on busy days. Additionally, if losing or maintaining weight is on your health to-do list, the increased feeling of fullness can help decrease overall caloric intake throughout the day, says Whittington.

If protein powder had a claim to fame, building muscle would be it. More specifically, it helps recover and grow muscle after exercise, resulting in increased muscle mass. Here's how it works.

During physical activity, muscle tissue breaks down, says Ziegelbaum. But, specific exercises (think weighted biceps curls or barbell squats) cause muscles to grow. In fact, research shows resistance training in particular stimulates the synthesis of muscle protein (aka muscle growth). Supplementing with protein enhances this growth effect, as the amino acids trigger the production of muscle tissue. Amino acids found in protein powder also serve as structural components of the actual muscle, helping repair the tissue. (BTW: To maximize these effects, Ziegelbaum suggests consuming protein or protein powder 30 minutes to one hour after physical activity.)

Another benefit of protein powder is muscle maintenance. This is undoubtedly important for athletes, but non-athletes can also benefit from this perk. Unfortunately, muscle mass naturally decreases with age. A 2019 study shows this can increase the risk of falls and reduced mobility—so much so that muscle strength has a strong correlation with the chances of disability in older folks. However, consuming more protein can help slow down muscle loss, especially when paired with strength training twice a week.

That's where protein powder comes in. According to a 2019 scientific review, the combo of strength training and protein supplements can help improve muscle strength and mobility in older adults. Another 2022 review found similar results, noting that protein supplements can decrease the risk of sarcopenia, or age-related muscle loss. Meanwhile, a 2021 study found that six months of whey, soy, or whey-soy protein supplementation helped maintain lean muscle and physical function in older adults.

When it comes to adding protein powder to your eating plan, there tend to be few risks. "Most healthy individuals can consume protein powder without any side effects or risks," says Whittington. However, as with many supplements, it's possible to overdo it. Taking too much can cause gas and bloating, particularly if you have a dairy sensitivity and consume whey or casein.

Also, if you have an allergy to an ingredient in a protein powder (like soy or milk, for example), you can develop an allergic reaction. The signs of a food allergy are different for each person, but common ones include stomach cramps, wheezing, coughing, trouble swallowing, and dizziness.

In general, healthy folks can consume protein powder without worrying about kidney damage, says Whittington. But if you have pre-existing kidney disease, a high intake of protein may cause complications, so you may need to limit protein (from powder or otherwise), she adds. To be safe, if you have a kidney condition or another chronic disease, speak with a healthcare provider before taking protein powder—or any new supplement, for that matter.

Protein powder is super user-friendly, as it's easy to add to things you already eat and drink. It's typically blended into smoothies or with liquid, such as dairy or plant-based milk, to make protein shakes. You can also sprinkle it into coffee, yogurt, oatmeal, chia pudding, or cereal. Unflavored iterations work well in savory preparations—such as chili or soup—while flavored versions are particularly tasty in pancakes, waffles, and baked goods.

Here's the tricky part: There's no overall recommended daily intake of protein powder. That's because protein needs are different for each person, says Ziegelbaum. The amount is calculated based on many factors, including age, weight, activity level, and health goals. Plus, protein powder is meant to supplement an existing diet, so your ideal daily intake depends on how much protein you're already eating.

That said, the recommended daily allowance for protein is 0.8 grams per kilogram of body weight, which is the minimum amount you need to meet basic nutrition needs and prevent protein deficiency. You can calculate your daily protein requirement (in grams) by multiplying your weight (in pounds) by 0.36.

But again, that's the amount needed for basic health. If you're an athlete looking to build muscle, you'll likely need closer to 1.1 or 1.2 grams per kilogram of body weight. The best way to figure out your exact protein requirement is to chat with a registered dietitian. They can determine the amount of protein you need based on your personal factors and lifestyle, including how much protein powder you should take per day, if at all. As Ziegelbaum explains, you might not need protein powder if you're meeting your protein requirements through food. Perhaps it's a great option for you on-the-go or an easy way to add variety.

From increased satiety to enhanced muscle growth, protein powder has an impressive list of health benefits. It also doesn't hurt that the supplement can be sourced from both animals and plants, making it easy to add to different diets. Plus, protein powder is generally well-tolerated, though taking too much can cause gastrointestinal issues like bloating and gas.

Despite its benefits, protein powder is not something everyone needs, says Ziegelbaum. Depending on your current diet, you might already be getting enough protein for your personal needs and lifestyle. Alternatively, if you're having trouble meeting your protein needs via food, a protein powder could help you meet the mark, says Ziegelbaum. A registered dietitian is the best person to determine if you need protein powder, and if so, how much to take each day.