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Optimum Nutrition Glutamine Powder 1000g Supplement Review

Optimum Nutrition Glutamine Powder often costs 70% less than the equivalent supplement in capsule form, which is one of the reasons it has hundreds of highly rated reviews on Amazon. But is the method of delivery (powder vs. capsules) the only reason for the difference in price?

There are hundreds of L-Glutamine supplements now available, making it difficult and time consuming to search for the best purity in the most convenient delivery form at the best price.

That’s why we’ve provided an in-depth guide to Optimum Nutrition Glutamine powder, to help you decide if you really need amino acids to support your strength, endurance, and fitness goals.

We also added comparisons between two other top-rated L-glutamine powders; NOW Foods Glutamine and AMRAP L-Glutamine. Health benefits and experiences of other customers who have already bought and used this supplement are included.

Optimum Nutrition Glutamine Ingredients

Optimum Nutrition Glutamine Ingredients

As an unflavored powder, Optimum Nutrition Glutamine can easily be stacked with protein powders and post-workout recovery drinks.

But with 5 grams of pure L-glutamine being the only ingredient, what sets O.N. apart from other supplement companies?

One big benefit is they’re one of the largest supplement companies in the world, which means they’re in a better position to produce larger tubs (up to 1 kg). This helps to cut the cost by over 50% compared to if you kept buying the 150 gram tubs, down to $0.20 per serving at time of review.

Although this was less than MusclePharm and MuscleTech, there are still companies that are slightly more affordable. Nutricost for example priced their L-glutamine at $0.13 per serving for their largest 1 kg tub.

Powdered glutamine or capsules?

Apart from price, Optimum Nutrition are also more flexible in their delivery systems. This means they offer glutamine in tubs of powder, as well as in capsule form. The only downside with the capsules is they tend to be much more expensive, and have a coating made from gelatin. This makes them unsuitable for vegetarians and vegans.

Before making a final buying decision, you might want to check out our BCAA buying guide. Some of the best BCAA supplements often include L-glutamine, and if you’re also getting a dose from your protein powder, you may not need to buy a separate glutamine supplement to get your 5 grams per day.

Optimum Nutrition Glutamine Powder 1000 g Supplement

O.N. Glutamine Powder – Product Summary

  • Pure Free Form L-Glutamine Amino Acid Powder
  • 5,000 mg pure L-Glutamine
  • Mixes easily with a spoon
  • Supports muscle recovery efforts
  • Optimum Nutrition’s Glutamine Powder is produced and packaged in ON’s own state-of-the-art manufacturing facility.
  • Suitable for vegetarians.
  • The in-house manufacturing operation has been registered under the NSF International, The Public Health and Safety Company, Good Manufacturing Practices (GMP) Program.

Health benefits of O.N. Glutamine

For a comprehensive list of glutamine health benefits, we recommend taking a look at our Glutamine Buying Guide.

When is the best time to take it?

Recommended use

Mix one rounded teaspoon of glutamine powder with 8 oz. water or your favorite beverage.

O.N. Glutamine vs. NOW Foods Glutamine

Optimum Nutrition Glutamine
NOW Foods Glutamine

Glutamine: 5 g
Glutamine: 5 g

Serving size: 5 g
Serving size: 5 g

Container size: 1000 g
Container size: 454 g

Cost per serving: $0.20
Cost per serving: $0.19

O.N. Glutamine vs. AMRAP L-Glutamine

Optimum Nutrition Glutamine
AMRAP L-Glutamine

Glutamine: 5 g
Glutamine: 5 g

Serving size: 5 g
Serving size: 5 g

Container size: 1000 g
Container size: 200 g

Cost per serving: $0.20
Cost per serving: $0.83

What sizes are available?

With a serving size of 5 g and a product weight of 1000 g, each tub provides you with approximately 200 servings. Smaller tubs are also available, weighing 150g, 300g, and 600g.

At the time of writing this review, the best value for money comes from the 1000g tub. This was priced at $0.20 per serving, compared to $0.23 for the 600g, $0.38 for the 300g, and $0.43 for the 150g. We always recommend calculating the average cost per serving before making a final buying decision.

If your training schedule includes 3 workouts per week, this is enough to last you:

  • 28 weeks: 1 serving before each workout
  • 14 weeks: 1 serving before and after each workout

Save money with Amazon

If you’re looking to save money on your monthly supplement order, you might want to consider the Amazon Subscribe & Save program.

Subscribe & Save allows you to unlock savings of up to 15% on a wide range of sports nutrition products, including Optimum Nutrition Glutamine Powder.

You can save 5% with a subscription to 1 product, or save the full 15% by subscribing to 5 products, provided they’re all delivered to the same address. The delivery schedule can be set from monthly, up to once every 6 months.

Although 5 products might sound a lot, if you already supplement with a protein powder, multivitamin, creatine, BCAA, and glutamine, the savings can soon add up. But it’s best to order before you run out of your current supplements, because Amazon set the day of the month each order is sent (same day each month e.g. 14th.).

Who are Optimum Nutrition?

With over 30 years in the sports nutrition industry, Optimum Nutrition currently produces some of the bestselling sports nutrition products in the world. These have been designed to improve your strength and recovery, health and wellness, and help increase your protein intake, such as their Gold Standard 100% Whey.

To find out more about their protein powders, bars, ready to drinks, BCAAs, glutamine, pre-workout supplements, creatine, multivitamins, and weight loss products, we recommend our Optimum Nutrition buying guide. This includes a summary of the health benefits you can expect from each product, which sizes and flavors are available, and dosages for the top ingredients.

We’ve also added in-depth reviews and comparisons with other top rated nutrition companies, to guarantee you only buy the best supplement for your fitness goals.

Glutamine Supplement Buying Guide
Optimum Nutrition Glutamine Powder often costs 70% less than the equivalent supplement in capsule form, which is one of the reasons it has hundreds of highly rated reviews on Amazon. But is the method of delivery (powder vs. capsules) the only reason for the difference in price? There are hundreds of L-Glutamine supplements now available, making it difficult and time consuming to search for the best purity in the most convenient delivery form at the best price. That's why we've provided an in-depth guide to Optimum Nutrition Glutamine powder, to help you decide if you really need amino acids to…

Review Overview

Overall Review Rating

5 / 5

We featured Optimum Nutrition already in our creatine guide, where they led the field in terms of value for money and purity, as one of the few brands to use Creapure®. Now we’ve featured them at the top of our glutamine guide as well.

Something we noticed during our review was how much the price per serving dropped once you started buying the larger tubs. But even at 1 kg, if you’re taking 10 g per day, this is enough for just over 3 months - much more realistic than buying a 25 kg sack from Bulk Supplements.

At around $0.20 for 5 grams, it’s one of the cheapest glutamine supplements on the market, and is also available in capsule for for added convenience.

Overall, you’ll struggle to find a more trusted and established supplement brand than Optimum Nutrition, which is one of the companies owned by Glanbia. As part of quality control, ON requires a Certificate of Analysis for each ingredient, together with NSF and cGMP certifications.

O.N. Glutamine is a high quality, affordable supplement, that’s perfect for mixing with your favorite protein shake. Although some O.N. protein powders contain glutamine (Pro Complex and Serious Mass to name two), the dose is usually limited to 500 mg, so there’s no danger of wasting your money by combining the two products.