AmiN.O. Energy Review: An Evidence-Based Analysis

This review is medically reviewed or fact checked to ensure factually accurate information.

With strict editorial sourcing guidelines, we only link to reputable media sites, academic research institutions and, when research is available, medically peer-reviewed studies. Note that an extensive list with all used Sources is available at the end of the review.

The information in our reviews is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

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Whether you need an afternoon pick-me-up or something to keep you energized during your morning workout or commute, Optimum Nutrition’s AmiN.O. Energy is specially designed to keep you focused and alert throughout the day. 

Advertised as one of the best pre-workout supplements, AmiN.O. Energy contains natural stimulants like green tea and caffeine for a quick energy boost without harmful chemicals.

Our AmiN.O. Energy review below will analyze the most critical elements of this pre-workout formula, starting with the manufacturer and finishing with the claimed benefits, cost per serving, potential side effects, and what real buyers think of the product.


Optimum Nutrition AmiN.O. Energy is a pre-workout energy supplement intended to supply the muscles with the amino acids they need to grow while providing reasonable amounts of green tea and caffeine for antioxidant support and extra energy.

The formula contains a simple blend of free-form amino acids and caffeine-based stimulants and, according to Optimum Nutrition, the formula is perfect for any time of the day. It may improve energy and focus in the morning, help you stay productive in the afternoon, and improve your energy and focus during workouts.

However, due to the high amount of caffeine available in this pre-workout supplement, we recommend caution, especially if you are sensitive to caffeine.

About Optimum Nutrition

Optimum Nutrition is one of the biggest sports supplement manufacturers. The company is part of the Glanbia Global Nutrition Group and has been setting the Gold Standard in sports nutrition for more than 30 years.

With five state-of-the-art manufacturing facilities located in the United Kingdom and the United States, Optimum Nutrition is the only sports nutrition company to produce items in every supplement category, including protein powders, multivitamins, nutritional bars, energy products, ready-to-drink beverages and shakes, and other health and wellness products that support a healthy lifestyle.

Popular Optimum Nutrition supplements include:

  • AmiN.O. Energy Advanced
  • Gold Standard 100% Whey
  • Serious MASS
  • Pre-Workout
  • Gold Standard 100% Plant
  • Platinum Hydro Whey
  • Opti-Men
  • ZMA Capsules
  • Immunity + Probiotic Gummies

How to contact Optimum Nutrition:

  • Address: 3500 Lacey Road, Suite 1200 Downers Grove, IL 60515 
  • Website:
  • Phone: 1-800-705-5226 Monday – Friday: 8.30 am -5.00 pm CST
  • Email:

What’s inside

Optimum Nutrition AmiN.O. Energy contains the following active ingredients:

  • Amino Blend [Micronized L-Glutamine, Micronized Taurine, Micronized L-Leucine, Micronized L-Arginine, Micronized L-Citrulline, Beta-Alanine (as CarnoSyn), Micronized L-Isoleucine, Micronized L-Threonine, Micronized L-Tyrosine, Micronized L-Valine, Micronized L-Histidine, Hydrochloride, Micronized L-Lysine, Micronized L-Phenylalanine, Micronized L-Methionine] 5 g
  • Energy Blend [Caffeine (from Green Tea), Green Tea extract (Camellia sinensis)(leaf)(standardized for EGCG), Green Coffee extract] 160 mg
  • Electrolyte Blend (Magnesium Oxide, Sodium Chloride, Potassium Chloride) 440 mg

Other inactive ingredients include citric acid, natural & artificial flavor, malic acid, silicon dioxide calcium silicate, tartaric acid, sucralose, Caffeine (from tea leaf and/or coffee bean), gum blend (cellulose gum, carrageenan, xanthan gum), lecithin, inulin, Yellow #5 and Yellow #6, and Red #40.

Is AmiN.O. Energy right for you?

The formula contains micronized amino acids, caffeine, green tea, and a mineral blend. While the company claims its supplement may effectively improve focus and attention, its primary purpose is to serve as a pre-workout product. However, the 160 mg of various coffee extracts may still give you a boost of energy and help with focus and attention.

All amino acids available in the Amino Acid Blend are found in protein sources – though not all sources contain all proteins. The main benefit of adding amino acids to the diet is to support muscle growth, recovery, and health. 


Optimum Nutrition AmiN.O. Energy’s most apparent benefit is the inclusion of BCAAs – L-Isoleucine, L-Leucine, and L-Valine. 

L-Leucine is conducive to stimulating protein synthesis in the body so that your muscles have what they need to repair themselves more efficiently.

Citrulline is also a good addition in that it, combined with L-Arginine, boosts nitric oxide production throughout the body resulting in improved pumps and vascularity.

Furthermore, the inclusion of caffeine means that you will benefit from enhanced energy output.


Caffeine is, probably, the most popular and widely used natural stimulant. It is commonly found in coffee, tea, and cacao plants. 

Caffeine works by stimulating the central nervous system and the brain, preventing the onset of tiredness, and helping you stay focused. It blocks adenosine’s effects, a neurotransmitter that relaxes the brain and makes you feel tired.

Usually, adenosine levels increase throughout the day, making you increasingly exhausted and making you want to go to sleep.

Caffeine connects adenosine receptors in the brain without activating them, which helps you stay awake and focused. This blocks the effects of adenosine, lessening the tiredness.

A comprehensive review on caffeine consumption concluded that after participants ingested between 37.5 and 450 mg of caffeine, they had better reaction time, short-term recall, and alertness.

Also, another study associated consuming 2–3 cups of caffeinated coffee (providing about 200–300 mg caffeine) daily with a 45% lower risk of suicide.

Another study reported a 13% lower risk of anxiety and depression in caffeine consumers.

However, when it comes to mood, more caffeine isn’t necessarily better.

A study observed that the second cup of coffee offered no additional benefits unless drunk at least eight hours after the first cup.

Several other clinical studies concluded that drinking more than 3 cups of tea per day may or between 3–5 cups of coffee per day may reduce the risk of brain diseases such as Parkinson’s and Alzheimer’s by 28–60%.

It’s important to note that coffee and tea contain other bioactive compounds (besides caffeine) that may also be beneficial.

Cost per serving

Optimum Nutrition AmiN.O. Energy is available in many different packages (190 g, 270 g, 585 g), forms (powder and drink), and flavors. The price varies based on these factors and the store you are buying from.

For instance, large retailers like Amazon, may offer significant discounts, free shipping, and other promotions and advantages if you choose to purchase from their stores.

  • AmiN.O. Energy 190 g (20 servings) costs $29.99
  • AmiN.O. Energy 270 g (30 servings) costs $21.97
  • AmiN.O. Energy 585 g (65 servings) costs $36.97
  • AmiN.O. Energy Drink (12 count) costs $24.99

Optimum Nutrition AmiN.O. Energy can be purchased from the official Optimum Nutrition store, many online retailers, and local supermarkets. 

Some of the best buying options are available on Amazon, BodyBuilding, Walmart, Supplement Superstore, GNC, VitaminShoppe, A1 Supplements, and Costco.


Optimum Nutrition AmiN.O. Energy is available in a wide range of different flavors:

  • Concord Grape
  • Blueberry Mojito
  • Iced Chai Tea Latte
  • Fruit Fusion
  • Lemon Lime
  • Iced Mocha Cappuccino
  • Strawberry Lime
  • Orange Cooler
  • Pineapple
  • Watermelon
  • Green Apple
  • Blue Raspberry
  • White Peach Tea
  • Raspberry Black Tea
  • Half & Half Lemonade Iced Tea
  • Cotton Candy
  • Peach Lemonade
  • Tangerine Wave (+ Electrolytes)
  • Sweet Mint Tea
  • Wildberry
  • Blueberry Lemonade
  • Iced Caramel Macchiato
  • Juicy Strawberry Burst
  • Pineapple Twist (+ Electrolytes)

AmiN.O. Energy review – Pros and cons


  • It may be an excellent choice for beginner athletes and individuals looking for an affordable pre-workout supplement
  • Ideal amino acid blend for energy production and muscle growth
  • Available in different flavors
  • Supports recovery before, during, and after exercise
  • Made in GMP Certified Optimum Nutrition owned & operated facilities
  • It features a unique blend of proven amino acids
  • For both men and women


  • It contains large amounts of caffeine
  • Some claims are not substantiated by scientific evidence
  • More of a “jack of all trades, master of none” type of supplement – great overall formula but not the best for professionals who prefer specifically targeted workout supplements

AmiN.O. Energy reviews

OneBrainReviews Avatar

One of my absolute favorite supplements when I am doing any activity. Whether I am at work for my night shift and take a scoop or two with my water to keep me alert and awake, or when I am about to lift weights and run. It’s beneficial to prevent my muscles from being super sore if I don’t take anything at all after a workout. I love this also because it’s affordable for any person. I honestly prefer this over a pre-workout. […] Read full review

OneBrainReviews Avatar

I bought this to replace my afternoon coffee or spark. I wanted something with a little less Caffeine and fewer calories, and this met those needs. It doesn’t give you the jitters but does give you a boost of energy. […] Read full review

OneBrainReviews Avatar

First off, I love this product. I love it so much that I choke down the grape flavor. It is an excellent BCAA, a great pre-workout, and makes me sweat like no other (some people like that kind of thing.) BUT the grape flavor is so so so bad! […] Read full review

Safety and side effects

AmiN.O. Energy contains caffeine, which is a potent stimulant that may produce adverse effects in some individuals. Consuming over 400 mg of caffeine a day can lead to:

  • Fast or uneven heartbeat
  • Disrupted sleep
  • Headaches
  • High blood pressure
  • Anxiety
  • Nervousness
  • Dependency
  • Dizziness
  • Irritability
  • Dehydration
  • Stomach upset
  • Heartburn
  • Nausea
  • Diarrhea

Caffeine may also interact with estrogens, valproate, diuretics, and some other prescriptions.

Several herbs and supplements can interact with caffeine to varying degrees. Some examples include:

  • Red clover
  • Calcium
  • Ephedra
  • Echinacea
  • Kudzu
  • Magnesium

Recommended serving size

As a dietary supplement, mix two (2) scoops of AmiN.O. Energy in 10-12 oz of cold water. 

For pre-workout energy – Take 1 to 3 servings 20-30 minutes before training.

For post-workout recovery – Take 1 or 2 servings immediately after exercising.

For an amino acid boost – Take 1 to 3 servings in the morning and/or between meals.

Do not exceed 5 servings per day.

As always, we strongly recommend reading and understanding the label before taking any dietary supplements or medications.

How it compares

Before we conclude our AmiN.O. Energy review, let’s take a quick look over several other pre-workout supplements that may represent good alternatives for those not convinced by this formulation’s benefits.

N.O.-XPLODE made by BSN – This is one of the highest-rated pre-workout supplements available. The formula contains a good amount of Creatine and Beta-Alanine, making it a good choice before and during intense workout sessions. 

Furthermore, N.O.-XPLODE is produced by BSN (Bio-Engineered Supplements and Nutrition, Inc.), a company with a long tradition in developing and delivering quality workout supplements. 

Just as AmiN.O. Energy, N.O.-XPLODE is available in a variety of packages, strengths, and flavors.

Gold Standard Pre-Workout made by Optimum Nutrition – With a more complex formula including several B-Vitamins, minerals, Creatine (3 g), Beta-Alanine (1.5 g), L-Citruline malate (1.5 g), and caffeine (175 mg), Gold Standard Pre-Workout is a more potent pre-workout supplement designed to offer enough energy during extended training sessions.

Gold Standard Pre-Workout is available in several packages and flavors. The price varies from $25.00 to 35.00 per bottle.

AminoLean made by RSP Nutrition – This is another excellent all-in-one pre-workout and weight management supplement. The formula includes an Amino Acid Blend (5 g), an Weight Management Blend (1.5g), an Energy and Focus Blend (130 g), and reasonable amounts of Vitamin C, Chloride, and Sodium.

Each serving of AminoLean contains 125 mg of caffeine from a natural source (green tea extract), making it an alternative for those looking for a pre-workout supplement with less caffeine. 

AminoLean also has the added benefit of the Weight Management Blend, which may be appealing to people looking to combine a pre-workout product with a weight loss supplement.

Our final take

If you are looking for a pre-workout and energy booster, you can’t go wrong with Optimum Nutrition AmiN.O. Energy. Combining BCAA with L-Glutamine, Citrulline, and L-Arginine, this supplement can offer a well-rounded variety of amino acids that may provide you with a remarkable boost of energy, strength, and overall endurance while training.

Overall, Optimum Nutrition is one of the best supplement brands on the market these days, and they’ve done an excellent job with AmiN.O. Energy.

Frequently Asked Questions

Optimum Nutrition AmiN.O. Energy is one of the best pre-workout supplements available today. Combining BCAA with L-Glutamine, Citrulline, and L-Arginine gives you a well-rounded variety of amino acids that may provide you a remarkable boost of energy, strength, and overall endurance while training.

AmiN.O. Energy works best when taken before workouts or other physically intensive activities. For post-workout recovery, take 1 or 2 servings immediately after exercising.

AmiN.O. Energy is a pre-workout supplement, but it can also be taken by those looking for a quick energy boost, making it a solid alternative to coffee. One serving contains only 30 calories, so it is also suitable for weight loss. One AminN.O. Energy serving contains about 160 mg of naturally occurring caffeine (green tea and green coffee beans extracts). The green beans are higher in some antioxidants versus roasted coffee beans.

AmiN.O. Energy side effects may include shakes, jitters, fast or uneven heartbeat, disrupted sleep, headaches, high blood pressure, anxiety, nervousness, dependency, dizziness, irritability, dehydration, stomach upset, heartburn, nausea, diarrhea, and muscle tremors.

AmiN.O. Energy doesn’t contain sugar. Furthermore, there are only 5 calories per serving and 1 gram of carbs.

You can take Optimum Nutrition AmiN.O. Energy daily as long as you don’t exceed 5 servings per day. Please keep in mind that this pre-workout supplement contains caffeine, which may cause unwanted adverse effects in users sensitive to caffeine.

Optimum Nutrition AmiN.O. Energy is available in many different packages, forms, and flavors. The price varies based on these factors and the store you are buying from, ranging from $21.97 (30 servings bottle) to $36.97 (65 servings bottle).

This pre-workout amino acid-based supplement doesn’t contain any potentially dangerous, toxic, or banned ingredients. It has, however, caffeine obtained from coffee and tea extracts. Caffeine is habit-forming and may cause side effects in some individuals, especially those with a sensitivity to caffeine.

Optimum Nutrition AmiN.O. Energy is intended for individuals looking for a solid pre-workout supplement. According to the manufacturer, AmiN.O. Energy’s unique formula is great for supporting your energy levels and focus in the gym, keeping you energized and focused in the morning, or even helping to stay focused and productive in the afternoon.

You can contact the Optimum Nutrition customer service department by visiting their website and emailing them at or calling 1-800-705-5226.


At OneBrainReviews, we only use primary references for our articles, including peer-reviewed medical journals or well-respected academic institutions.

  • Prominent Sports Nutrition Brand Optimum Nutrition Celebrates Thirty Years – Published on July 13, 2016. Retrieved on May 31, 2021. [Source]
  • T. V. Dunwiddie and S. A. Masino – The role and regulation of adenosine in the central nervous system. Published in 2001. Retrieved on May 31, 2021. [Source]
  • Sergi Ferré – An update on the mechanisms of the psychostimulant effects of Caffeine. Published on December 18, 2007. Retrieved on May 31, 2021. [Source]
  • Melanie A. Heckman, Jorge Weil, and Elvira Gonzalez De Mejia – Caffeine (1, 3, 7‐trimethylxanthine) in Foods: A Comprehensive Review on Consumption, Functionality, Safety, and Regulatory Matters. Published on April 5, 2010. Retrieved on May 31, 2021. [Source]
  • Michel Lucas, Eilis J. O’Reilly, An Pan, Fariba Mirzaei, Walter C. Willett, Olivia I. Okereke, and Alberto Ascherio – Coffee, Caffeine, and risk of completed suicide: Results from three prospective cohorts of American adults. Published on July 2, 2013. Retrieved on May 31, 2021. [Source]
  • Giuseppe Grosso, Agnieszka Micek, Sabrina Castellano, Andrzej Pajak, and Fabio Galvano – Coffee, tea, Caffeine, and risk of depression: A systematic review and dose-response meta‐analysis of observational studies. Published on October 31, 2015. Retrieved on May 31, 2021. [Source]
  • Susan V. Heatherley, Robert C. Hayward, Helen E. Seers, and Peter J. Rogers – Cognitive and psychomotor performance, mood, and pressor effects of Caffeine after 4, 6, and 8 h caffeine abstinence. Published on February 5, 2005. Retrieved on May 31, 2021. [Source]
  • A. J. Carman, P. A. Dacks, R. F. Lane, D. W. Shineman, and H. M. Fillit – Current evidence for the use of coffee and Caffeine to prevent age-related cognitive decline and Alzheimer’s disease. Published on February 16, 2014. Retrieved on May 31, 2021. [Source]
  • Vanessa Flaten, Cyril Laurent, Joana E. Coelho, Ursula Sandau, Vânia L. Batalha, Sylvie Burnouf, Malika Hamdane, Sandrine Humez, Detlev Boison, Luísa V. Lopes, Luc Buée, and David Blum – From epidemiology to pathophysiology: what about Caffeine in Alzheimer’s disease? Published on May 21, 2015. Retrieved on May 31, 2021. [Source]
  • Hui Qi and Shixue Li – Dose-response meta-analysis on coffee, tea, and caffeine consumption with risk of Parkinson’s disease. Published in April 2014. Retrieved on May 31, 2021. [Source]
  • Gang Hu, Siamak Bidel, Pekka Jousilahti, Riitta Antikainen, and Jaakko Tuomilehto – Coffee and tea consumption and the risk of Parkinson’s disease. Published on August 21, 2007. Retrieved on May 31, 2021. [Source]
  • Chad J. Reissig, Eric C. Strain, and Roland R. Griffiths – Caffeinated energy drinks–a growing problem. Published on January 1, 2009. Retrieved on May 31, 2021. [Source]
  • Niels P. Riksen, Gerard A. Rongen, and Paul Smits – Acute and long-term cardiovascular effects of coffee: implications for coronary heart disease. Published in February 2009. Retrieved on May 31, 2021. [Source]
  • Christopher Drake, Timothy Roehrs, John Shambroom, and Thomas Roth – Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Published on November 15, 2013. Retrieved on May 31, 2021. [Source]

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