Protein and Fitness

NOW® L-Carnitine Pure Powder features this non-essential amino acid that helps to maintain overall good health by facilitating the transfer of fatty acid groups into the mitochondrial membrane for cellular energy production. It naturally occurs in red meat and other animal source foods, but we recommend supplementation to obtain optimal levels of this excellent amino acid. 

Get targeted support for healthy aging with NOW L-Carnosine. L-carnosine is naturally found in muscle and nerve tissue but levels decrease with age. Supplementing with L-carnosine can boost levels in the body to support muscle vitality and cell integrity. A free-radical scavenger, it promotes membrane stability as well. Each serving delivers 500 mg L-carnosine to promote healthy aging.

Classified as a dipeptide, L-carnosine is a combination of two amino acids, in this case alanine and histidine. It naturally occurs in high concentrations in skeletal muscle tissue and, therefore, may support muscle vitality. L-Carnosine is also an antioxidant that stabilizes cellular membranes, protecting them from damage by free radicals. Because L-carnosine is only found in vertebrates, it is especially important for persons who do not consume beef, pork or chicken.

L-Carnosine is a dipeptide that occurs naturally in muscle, brain and other tissues. It may reduce glycation, a process whose end products are highly reactive molecules which have been associated with aging. Source Naturals L-Carnosine delivers 500 mg per single-tablet serving. No yeast, dairy, egg, gluten, corn, soy or wheat.

Swanson Ultra L-Carnosine features L-carnosine, an organic compound composed of the amino acids histidine and beta-alanine. It's highly concentrated in important tissues like those of the brain, the heart, and the muscles. Carnosine supplements function as a broad-spectrum antioxidant and support the healthy functioning of enzyme systems.

You know watermelon is a tasty summertime treat, but did you know it’s also one of nature’s best sources of citrulline? Unfortunately you’d have to eat several pounds of watermelon every day to reap the benefits. Just what is citrulline though? It's bursting onto the fitness scene in a big way, helping people of all ages break through the boundaries of personal health and fitness. L-citrulline is active in both the Krebs cycle and the Urea cycle of metabolism, which means it promotes energy production to fuel activity while simultaneously helping to rid the body of metabolic waste products, helping to promote muscle recovery after exercise¹. The addition of malate, a form of malic acid, further bolsters the bioavailability of L-citrulline.

L-citrulline is an amino acid precursor to—and more efficiently absorbed by the body than—arginine which in turn produces nitric oxide. Nitric oxide works to deliver oxygen and other nutrients throughout the body to feed muscles and tissues. This is especially beneficial during high-intensity exercise, and may also help maintain blood pressure already within the normal range², support men’s sexual health², and encourage active aging by promoting cardiometabolic health in older adults³.

Sources

1. Farney, T, et al., Journal of Strength and Conditioning Research 33(9):p 2464-2470, September 2019. | Read more.
2. Neri, L. Examine.com, accessed 10 June 2025
3. Allerton TD, et al. Nutrients. 2018 Jul 19;10(7):921. Read more.

Move over creatine! Swanson® L-Citrulline Malate Complex is the energizing combination that kicks in beyond the Krebs cycle. It's bursting onto the nutrition scene in a big way, helping people young and old break through the boundaries of physical health, energy and performance. L-Citrulline Malate is active in both the Krebs cycle and the urea cycle of metabolism, which means it promotes energy production while simultaneously helping to rid the body of fatigue-causing metabolic waste products.

L-Citrulline is a unique amino acid first isolated from watermelon and produced in the body from the amino acids ornithine and arginine. It's a key player in the urea cycle, which is the process responsible for eliminating the metabolic by-products of protein metabolism. These by-products, primarily ammonia and lactic acid, contribute to muscle fatigue. By helping to efficiently remove them, L-citrulline helps fend off fatigue for greater comfort and endurance. L-citrulline also acts as a precursor to nitric oxide, a compound that helps relax blood vessels to promote healthy circulation and ensure a steady supply of oxygen and nutrients throughout the body.

Malic acid is an organic compound made by all living organisms. It performs a vital function in cellular energy production as an intermediary in the Krebs cycle (also known as the citric-acid cycle), the metabolic pathway that produces ATP (adenosine triphosphate), the primary energy source for every cell in the body.

The dual-action effects on energy production and waste elimination make our L-Citrulline Malate Complex the perfect nutritional boost for physical comfort and endurance.

NOW Foods' L-Citrulline Powder not only supports detoxification pathways, but also supports nitric oxide production and a healthy cardiovascular system. Citrulline is a non-essential amino acid that is an important intermediate in the urea cycle, functioning along with Arginine and Ornithine to rid the body of ammonia, a byproduct of protein metabolism. Because Citrulline is a precursor of Arginine, it provides a readily available source material for Arginine production, which in turn, can be used for the production of Nitric Oxide (NO). NO plays a fundamental role in vascular function and blood flow.

NOW Foods' L-Glutamine features 500 mg per capsule. Glutamine has recently been the focus of much scientific interest. A growing body of evidence suggests that during certain stressful times, the body may require more glutamine than it can produce. Under these circumstances glutamine may be considered a "conditionally essential" amino acid. Glutamine is involved in maintaining a positive nitrogen balance (an anabolic state) and also aids rapidly growing cells (immune system lymphocytes and intestinal cell enterocytes). In addition, glutamine is a regulator of acid-base balance and a nitrogen transporter. 

Glutamine has recently been the focus of much scientific interest. A growing body of evidence suggests that during certain stressful times, the body may require more glutamine than it can produce. Under these circumstances, glutamine may be considered a "conditionally essential" amino acid. Glutamine is involved in maintaining a positive nitrogen balance (an anabolic state) and also aids rapidly growing cells (immune system lymphocytes and intestinal cell enterocytes). In addition, glutamine is a regulator of acid-base balance and a nitrogen transporter.

Pure Encapsulation's l-Glutamine powder provides a key amino acid in a convenient form. L-Glutamine is the most abundant amino acid in the body. In times of metabolic stress, glutamine is utilized by the body for tissue repair, gastrointestinal tract support and natural defense system function. Glutamine plays a large role in maintaining healthy intestinal integrity by enhancing the intestines protective mucosal lining. In addition, glutamine is important in the preservation of muscle mass.

Fortify your muscles and your mind every day with the pure amino acid nutrition of Swanson L- Glutamine! A favorite among fitness buffs, glutamine is the most abundant amino acid in skeletal muscle tissues, where it works to promote strength and endurance—but that's not all it does. Glutamine's unique molecular structure allows it to pass through the blood/ brain barrier to nourish vital brain tissues. Once in the brain, glutamine is converted into glutamic acid, the base material for key neurotransmitters needed for healthy mental and nervous system function.

Glutamine also provides fuel for immune cells through its activity in the gut where it may help maintain intestinal barrier function to promote GI tract integrity. Since a solid 70% of your immune system stems from your gut, keeping your digestive system happy is a win for your immune function as well. Swanson L-Glutamine Powder mixes easily into juice or water and delivers a potent 5 g per scoop.

L-leucine is an essential amino acid and it must be acquired through diet or supplementation. Food sources for L-leucine are meat, almonds, cashews eggs, fish, chicken, lentils and liver. It helps increase energy, enhance endurance and aid in muscle recovery. Swanson L-Leucine delivers a potent 500 mg per serving from vegan-sourced AjiPure pharmaceutical grade L-leucine.

Swanson Lecithin, Kelp, B-6 & Cider Vinegar is the stimulant free approach to healthy weight management! Each ingredient in this formula has unique properties that along with a sensible diet and exercise program can help you control your weight. Together, they provide superior weight loss support.

Along with a sensible diet and exercise, Swanson LipoSan ULTRA Chitosan is an effective addition to your weight loss regimen. The fat-absorbing chitosan binds up to five times more fat than competing brands, but that's not all. While conventional chitosan products can take up to two hours to work, our chitosan goes to work immediately, so you can take it when you eat!