Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In


Amino Acids

How Amino Acids Can Help You Build Strength

Delay fatigue, increase strength, improve energy and stay focused with these “essential” supplements.


Amino acids form all the proteins for life and are the building blocks of all muscle; that’s why protein supplementation is so effective for increasing muscularity. Beyond providing the materials for muscle building, many amino acids play several other important cellular and molecular signaling roles in the body, increasing exercise performance and muscular gains. Through capitalizing on these direct cellular and molecular effects, supplement R&D teams have created several safe and effective muscle-building amino acid supplements.

Amino acids are classified as essential, nonessential and conditionally essential. Essential amino acids are those which cannot be produced by the body and must be taken in the diet with food or supplementation. Nonessential aminos can be produced by the body and conditionally essential aminos are produced by the body but become depleted under certain conditions (e.g., during exercise). From an athletic standpoint, there are several essential, nonessential and conditionally essential amino acids that have been proven as effective ergogenic aids. In this article, we have distilled the science behind six key amino acid “must haves” for athletes.


Facts: Three essential amino acids: leucine, isoleucine and valine

Supplemental Benefits: Increased strength, focus, energy, muscle building, decreased catabolism

Mechanisms of Action: BCAAs make up a large proportion of the total amino acid content in skeletal muscle and are readily broken down (catabolized) to produce energy during exercise. Taking BCAAs before and after training ensures that the blood has an abundance of essential aminos necessary to fuel your workout and support recovery, which increases fatigue resistance, protects the body from catabolism and decreases recovery time. The BCAA leucine also boosts the release of the anabolic hormone insulin. You want insulin levels to be rapidly elevated after your workouts because this hormone carries nutrients such as glucose and amino acids into muscle cells — promoting greater protein synthesis and muscular gains.

Dosing and Timing: The BCAA product you choose should have at least twice as much leucine as the other two aminos. Take 5 to 10 grams of BCAAs, three times daily. Take one dose 30 minutes preworkout, another immediately postworkout and one more at any other time of the day.



Facts: A nonessential amino acid

Supplemental Benefits: Mass builder, energy booster, strength booster, pump enhancer

Mechanisms of Action: In the body, this amino acid is produced by the conversion or combination of other amino acids. Citrulline increases the rate of phosphocreatine and adenosine triphosphate production, which provide the energy that fuels muscle contractions during exercise. In addition to boosting ATP, supplemental citrulline is converted to arginine in your body. Arginine is the precursor to nitric oxide, the gas molecule that optimizes blood flow, nutrient delivery and waste removal in working muscles. Notably, citrulline supplements increase blood levels of arginine and NO more effectively than arginine supplements.

Dosing and Timing: Take 3 to 6 grams 30 to 60 minutes before training.


Facts: A conditionally essential amino acid, produced in the body by the enzyme glutamine synthetase from glutamate and ammonia

Supplemental Benefits: Promotes immune system support, muscle building, recovery

Mechanisms of Action: Glutamine is one of the most abundant amino acids in skeletal muscle and is the most prevalent amino acid in the circulation. It is considered a conditionally essential amino acid in athletes, as the body’s supply may not meet demand under conditions of intense training and dieting. Taking glutamine before training has been shown to boost training volume and intensity. Loading muscle glutamine levels immediately after training is also important because it is a primary regulator of protein synthesis, which enhances recovery. Glutamine also helps muscle cells load with glycogen, which is critical for muscle size (glycogen pulls water into muscle cells) and energy storage to fuel subsequent workouts.

Dosing and Timing: Take 5 grams 30 to 60 minutes prior to training and immediately postworkout.



Facts: A nonessential amino acid derivative synthesized in the liver and kidneys from lysine and methionine

Supplemental Benefits: Promotes fat burning, fatigue resistance, anabolism, enhanced recovery

Mechanisms of Action: L-carnitine is essential for fat metabolism since it is responsible for transporting fatty acids to the mitochondria to be oxidized and used as fuel by the body. In the world of L-carnitine supplements, the most notable and highly bioavailable forms are acetyl L-carnitine (ALCAR) and L-carnitine tatrate (Carnipure). Scientists developed these forms of L-carnitine to be readily digested, thus boosting the L-carnitine bioavailability and absorption in skeletal muscle and making them more effective than other forms. Carnitine provides antioxidant support, which keeps blood nitric oxide levels elevated, which optimizes blood flow and decreases fatigue in working muscles. Combined with weight training, L-carnitine tartrate boosts anabolism by augmenting testosterone’s effects in skeletal muscle, resulting in enhanced recovery and greater gains. When combined with dieting and cardio, carnitine supplements have been shown to increase fat burning and weight loss without promoting catabolism (muscle breakdown).

Dosing and Timing: Take 1 to 3 grams of ALCAR or L-carnitine tartrate, two or three times per day. Make sure to take one dose immediately after training.


Facts: A nonessential amino acid synthesized in the body from phenylalanine

Supplemental Benefits: Improved mood, focus, energy

Mechanisms of Action: Tyrosine is a naturally occurring amino acid that functions as a precursor to the production of many neurotransmitters (e.g., norepinephrine, epinephrine and dopamine). These neurotransmitters are closely involved in fat burning and weight loss, and they play major roles in the brain, controlling motivation, mood, focus, movement and anxiety. Exercise and stress from caloric restriction (while dieting) can severely impact the turnover of these neurotransmitters, making transmitter levels decline. Studies suggest this decline is because the rate of neurotransmitter production is limited by tyrosine. Therefore, taking a tyrosine supplement can combat the adverse effects of severe stress: Measures of mental and physical performance, reaction time, mood and fatigue have all been shown to improve greatly.

Dosing and Timing: Take 500 to 1,500 milligrams two times daily, one dose upon waking and the other 30 minutes prior to training.


Facts: A nonessential amino acid that reacts with histidine to form carnosine in the body

Supplemental Benefits: Increased exercise intensity and volume, strength gains

Mechanisms of Action: In skeletal muscle, beta-alanine reacts with histidine to produce carnosine. Beta-alanine is the rate-limiting substrate in the formation of carnosine; thus, when it is supplemented adequately, it elevates muscle carnosine levels. Research shows that just four weeks of beta-alanine supplementation can increase muscle carnosine levels by more than 60 percent. Elevated muscle carnosine increases exercise performance through its ability to reduce skeletal muscle acidity during prolonged high-intensity exercise. Since fatigue during heavy exercise is exacerbated by the accumulation of acidic metabolic byproducts, it follows that increased intramuscular carnosine levels would be beneficial to bodybuilders and strength athletes.

Dosing and Timing: Take 1.6 to 3 grams of beta-alanine 30 minutes before and right after training. On rest days, take 1.6 to 3 grams with breakfast and 1.6 to 3 grams later in the day.