The best Amazon Prime Day deals on protein powder

Amazon Prime Day is almost here (July 11-12), woot, woot! The mega retailer is offering major deals on protein powders like GNC 100% Whey Protein Powder, so it's a great time to stock up.

Protein powders have become increasingly popular in recent years as athletes and exercise enthusiasts look for ways to maximize their workout results. Knowing which protein powder to choose (and if you need one at all) can often mean slogging through endless articles, Google searches, social media posts and word-of-mouth customer reviews. No one has the time for that.

Actually, someone has time for that, and that someone is us. Let us help you find the best protein powders at the best prices so you can spend your time getting those gains this summer.

Optimum Nutrition Gold Standard whey protein powder

This chocolate whey protein powder is a No. 1 bestseller on Amazon. It offers 24 grams of protein and 5.5 grams of naturally occurring branched-chain amino acids (BCAAs) per serving. Find it in other flavors too. Rated 4.7 stars.

ON Gold Standard chocolate whey protein powder (2 lb.), $37 (reduced from $45)

128 at Amazon

Now Sports Nutrition 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 BCAA effect on muscle recovery are negligible.

Amazon customers gave this powder 4.4 stars, its ability to dissolve without clumping a highlight. It offers 25 grams of protein per serving.

Now Sports Nutrition Whey Protein Isolate, (1.8 lb.), $40 (reduced from $55)

$40 at Amazon

GNC Pro Performance 100% Vanilla Whey Protein Powder

Buyers rate GNC's whey protein powder 4.4 stars and say it "actually tastes good" (because so many protein powders don't). This gluten-free protein powder is designed to support lean muscle recovery, offering 24g of protein with just one scoop.

This protein powder is certified Banned Substance Free and contains 9 essential amino acids.

GNC Pro Performance 100% Vanilla Whey Protein Powder, $32 (reduced from $40)

$32 at Amazon

Ka'Chava Vegan Vanilla Meal Replacement Shake

A blend of organic superfoods and plant-based protein, Ka'Chava Meal Replacement Shake earns 4.4 out of 5 stars from certified Amazon reviewers who used this product as a meal substitute or protein shake.

Taste won big here with users calling this powder "addicting."

Ka'Chava Vegan Vanilla Meal Replacement Shake, $109 (reduced from $125)

$109 at Amazon

Dymatize 100% Dunkin' Cappuccino Flavor Whey Isolate Protein Powder

Get the great taste of Dunkin Donuts coffee without veering from your summer goals.

Get 25 mg of protein and 5.5 grams of BCAAs from one scoop (and 95 mg of caffeine per scoop as well). With less than 1 gram of sugar or fat per serving, this powder is the next best (healthier) thing to ordering a treat at Dunkin'.

Dymatize 100% Dunkin' Cappuccino Flavor Whey Isolate Protein Powder, $33 (reduced from $35)

$33 at Amazon

Why protein powder?

A 2018 study from the British Journal of Medicine shows that dietary protein supplementation (up to a maximum 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 carbohydrate. 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.

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