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Amazon is offering major deals on protein powders this month from top-rated brands like Optimum Nutrition and Now Fitness, so it's a great time to stock up if you're trying to bulk up.

Protein powders and protein bars have become increasingly popular in recent years as athletes and exercise enthusiasts look for ways to maximize their workout results. But the price per serving can add up if you're downing one or two servings per day -- especially if you opt for one that actually tastes good and uses high-quality ingredients. 

The best way to keep those costs down is to always be on the lookout for good deals. But nobody has time to constantly hunt down deals. Actually, someone has time for that, and that someone is us. 

We're chasing deals so you can keep chasing gains, and we've rounded up the very best protein powder deals we found below. Many of these protein powders offer even better deals if you're willing to use Amazon's Subscribe & Save feature.

Optimum Nutrition Gold Standard 100% Whey: Save $10


This double rich chocolate Optimum Nutrition whey protein powder is a No. 1 bestseller on Amazon and a personal favorite of the CBS Sports Essentials staff. The aptly named Gold Standard protein powder has earned a 4.7-star average rating after more than 204,000 reviews. 

Its popularity is no mystery. The pure whey powder mixes well. It tastes great and it packs 24 grams of protein into every serving. Each serving also includes over five grams of branched-chain amino acids (BCAAs), the amino acids that support muscle growth and metabolism.

Normally priced at $45 for a 2-pound tub (29 servings), Amazon is offering it for just $35 right now. (If you set up a regular delivery of this protein powder through Amazon Subscribe & Save, you can save an extra 20% on top of that deal.) Other flavors and sizes are also on sale.

$35 at Amazon

Now Sports Pea Protein is 26% off


Consisting of pure pea protein, Now Sports vegan protein powder is a non-GMO vegetable protein isolate that delivers 24 grams of (promised) easily digestible protein. That's good news for those who find protein powders hard to digest. One scoop contains 24 grams of protein.

Get a two-pound tub (27 servings) of pure pea protein powder on Amazon for $24 (reduced from $33).

$24 at Amazon

Save 26% on Dymatize Elite Whey


Earning 4.6 stars after over 10,500 Amazon ratings, Dymatize Elite 100% Whey protein powder is loved for its texture, quality and mixability. A single scoop delivers 25 grams of protein with just 2 grams of sugar and 140 calories.

Right now, you can get a 2-pound tub (25 servings) of the high-quality protein powder for $24, reduced from $33.

$24 at Amazon

Isopure Infusions (save $10)


If you're tired of the thick texture and richer flavors of most protein powders, you need to try this Ispoure protein powder. The refreshingly light drink mix comes in fun flavors like tropical punch, citrus lemonade and mango lime. When added to water, the powder creates a protein beverage closer to a summer cocktail or glass of juice instead of a heavy shake.

As light and refreshing as it tastes, it still packs an impressive 20 grams of protein per serving and no artificial flavors or sweeteners.

Get a 36-serving container of the refreshing twist on protein powder while it's on sale at Amazon for $56 (reduced from $70). You can save an extra 20% on your first order when you sign up for Amazon Subscribe & Save.

$56 at Amazon

Garden of Life Sport Plant-Based Protein: save 45%


Boasting 30 grams of protein per serving, this plant-based formula is a protein powerhouse. But what makes it stand out is everything else you're getting along with the protein, including probiotics, amino acids and antioxidants. Taken all together, this protein powder helps support muscle growth, immune health and gut health at the same time.

Regularly $55 for a 1.85-pound container (19 servings), the chocolate flavor of Garden of Life Sport organic vegan protein powder is on sale at Amazon for $30. That's 45% off.

$30 at Amazon

Save 27% on unflavored Now Sports Whey Protein Isolate 


We like this lab-tested whey powder from Now Sports, a top-seller on Amazon. This certified organic whey powder is produced without the use of synthetic growth hormones (rBGH), antibiotics or pesticides.

This powder does contain BCAAs (branched-chain amino acids), which are attractive to athletes because they are metabolized into skeletal muscle, though studies show BCAAs have a negligible effect on muscle recovery.

Amazon customers gave this unflavored protein powder 4.3 stars. Its ability to dissolve without clumping a highlight. It offers 25 grams of protein per serving.

Regularly $40 for a 1.2-pound container (19 servings), Amazon is offering the versatile unflavored whey protein powder for just $29 right now.

$29 at Amazon

Why protein powder?

A 2018 study from the British Journal of Medicine shows that dietary protein supplementation (up to a maximum of 0.73 grams of protein per pound of body weight per day) significantly increased strength and muscle size in adults, especially those who participate in resistance training.

While most people get enough protein from food, Hillary Ake, a registered dietician who works with professional and college athletes says, "When you exercise the working muscles go into protein breakdown mode, and sometimes even muscle breakdown and muscle damage, depending on the type of exercise. Replenishing protein after a workout can push the body back into muscle protein building mode, to help repair muscle damage and build muscle."

When it comes to protein powder intake, the more active you are, the more protein you need. The average athlete should take between "1.2 - 2.0 grams of protein per kilogram body weight (0.5 - 0.9 grams per pound), while a sedentary adult should take 0.8 grams of protein per kilogram (0.36 grams per pound)" Alex Larson, a registered dietician who works with endurance athletes, said.

While protein powders are generally considered safe, Larson suggests anyone with kidney-related issues consult a doctor before using any protein powders.

Types of protein powder and what to look for when choosing

"First thing to look for in a protein powder is third-party testing," Larson said, "which assures that what's listed on the package is actually what's in the product."  

Next, it's important to know what you're looking for in a protein powder. (The FDA doesn't currently regulate protein powders, which makes getting the right information that much more important.)

There are two kinds of protein powders. Whey protein powders such as Optimum Nutrition's Gold Standard are derived from milk, while vegan options such as Orgain are derived from vegetarian sources such as peas, soy or hemp. Whey proteins are the most common, but vegan options are effective in supplementing protein too (though usually require higher doses).

When shopping for whey proteins, know there are two types: whey protein isolate and whey protein concentrate. Experts generally recommend a whey protein isolate powder, which is strained in a way that yields a higher percentage of protein and a lower percentage of lactose than a protein concentrate.

Athletes and exercise enthusiasts who are looking to replenish their body's supply after long endurance work may opt for a protein powder with added carbohydrates. Ake suggests those looking for a protein powder with an added carbohydrate aim for a "4:1 or 3:1 carb to protein ratio depending on your activity," adding that endurance athletes will require more carbohydrates to replenish their bodies after pro-level workouts.