Arachidonic Acid (AA or ARA) is a polyunsaturated omega-6 fatty acid occurring in dietary animal sources—meat, eggs, dairy or is formed by biosynthesis from linoleic acid . It is worth mentioning that the overall conversion of linoleic acid to arachidonic acid is extremely low, certainly below 0.5% . Arachidonic acid plays an essential role in growth and repair of skeletal muscle tissue . This makes arachidonic acid an important dietary component in muscle anabolic process. Nutritional supplements are often marketed to resistance-trained athletes as nutritional ergogenic aids purported to promote gains in strength, muscle mass, and/or performance during training, and arachidonic acid is one of them.
Arachidonic Acid Supplementation for Bodybuilding
Andersson, A. et al.  have shown that increased activity depletes omega-6 fatty acid levels from skeletal muscles. So it may be wise to supplement your diet with arachidonic acid as an athlete. Arachidonic acid is not essential fatty acid, however, it does become essential if there is a deficiency in linoleic acid.
Interactions with Exercise
Since arachidonic acid has been purported to promote muscle hypertrophy, Roberts MD et. al.  supplemented 31 resistance-trained males in a randomized and double-blind manner either with arachidonic acid (1 gram per day, n = 15) or a placebo (1 gram of corn oil per day, n = 16). They were training 4 day per week for 50 days. Relative peak power (7.1%) and average power (3.6%) were increased in the arachidonic acid group (0.3 ± 1.2 W·kg-1) compared to placebo (0.2 ± 0.7 W·kg-1) after 50 days of supplementation (Fig 1). However, arachidonic acid didn’t influence muscle mass or weight lifting measures of power (bench press and leg press). This study provides a weak preliminary evidence that arachidonic acid supplements might enhance a response to resistance training. Furthermore, study was funded by Molecular Nutrition (arachidonic acid manufacturer and patent holder).
Fig 1. – Delta changes in Wingate peak power normalized to body mass over the 50 d supplement intervention. All values are expressed as means ± SD.
In study by Ormes et al.  thirty recreationally trained males participated in an 8-week, 3-day per week, resistance-training program. Subjects receiving arachidonic acid exhibited significantly greater lean body mas gains and skeletal muscle thickness compared to placebo group. Total strength and power were also greater than in placebo group.
There is some promise in currently available evidence for ergogenic effect of arachidonic acid, however more research needs to be performed.
Interactions with Testosterone and Cortisol
Free and total testosterone both remained unchanged after 50 days of supplementation with arachidonic acid . There was also no evident difference in cortisol concentrations .
Arachidonic Acid and Inflammation
Inflammation is the immune system’s response to infection and injury. Acute inflammation can also be a result of eccentric and concentric muscle training . Inflammation is also is also present in a number of disorders, including arthritis, allergies, asthma, obesity, atherosclerosis and others. It may sound counter intuitive but it is theorized that the acute localized inflammatory response may have anabolic effect .
Arachidonic acid is oxygenated and further transformed into a variety of products which mediate or modulate inflammatory reactions . Arachidonic acid stimulates the production of pro-inflammatory prostaglandins and leucotrienes through in the COX (cyclooxgenase), LOX (lipoxygenase) and cytochrome P450 enzyme conversion process . However, studies are mixed. It is argued that higher dietary intake of omega-6 polyunsaturated fatty acids may lead to a competition between omega-6 and omega-3 metabolism resulting in a reduced production of anti-inflammatory molecules from omega-3 polyunsaturated fatty acids . In human subjects, higher intakes of omega-6 fatty acids do not appear to be associated with elevated levels of inflammatory markers . However, arachidonic acid consumption is known to exacerbate symptoms of joint pains or active inflammatory disease, presumably because it is being more readily converted to inflammatory compounds. Therefore, consumption of high doses of arachidonic acid is not advised for individuals with a history of inflammatory disease.
Arachidonic Acid and Protein Synthesis
Arachidonic acid, through its conversion to eicosanoids known as prostaglandin F2alpha (PGF2a) and prostaglandin E2 (PGE2), plays a role in the repair and growth of skeletal muscle tissue (through protein synthesis) [11-13, 16]. In vitro arachidonic acid supplementation stimulates prostaglandin release and skeletal muscle cell hypertrophy via a COX-2-dependent pathway . Pro-inflammatory prostaglandin F2alpha has been shown to induce skeletal myotube hypertrophy via stimulation of PI3K/ERK/mTOR signaling .
Usage of COX-2-specific inhibitors (which blunt arachidonic acid to prostaglandin biosynthesis) such as ibuprofen and acetaminophen may also provide some evidence for the involvement of arachidonic acid and PGF2a  as well as PGE2  in muscle protein synthesis. Study by Dr. Trappe et al.  reported that twenty-four hour post-exercise intramuscular protein synthesis rates as well as intramuscular PGF2a levels increased by 76% and 77% respectively in the placebo group whereas protein synthesis and intramuscular PGF2a levels remained unaltered in the two groups receiving ibuprofen or acetaminophen.
Therefore, inhibiting COX2 enzyme is thought to reduce the anabolic effects of exercise.
Arachidonic Acid Dosage
Proper dose of arachidonic acid to induce muscle growth has not been established, however in clinical studies doses around 1 to 1.5 grams per day are used. Supplements containing arachidonic acid usually provide only 250 mg per serving.
Arachidonic Acid Side Effects and Safety Risks
Arachidonic acid supplementation appears to have no significant toxicity or safety risks in healthy adults. Several clinical studies reported no significant side effects for dosages ranging from 1,000–1,500 mg for up to 50 days of supplementation [5-7]. No adverse effect of omega-6 polyunsaturated fatty acid (including arachidonic acid) intake on blood pressure, inflammatory markers or haemostatic parameters has been observed, even with intake up to 15 % of total energy .
(Other common names: Arachidonate, Sodium Arachidonate, Vitamin F, Arachidonsaeure, Arachidonicacid, Immunocytophyte, Eicosatetraenoic acid)
- “Dorland’s Medical Dictionary – ‘A'”. Archived from the original on 11 January 2007.
- Trappe, TA; Fluckey, JD; White, F; Lambert, CP; Evans, WJ (2001). “Skeletal muscle PGF(2)(alpha) and PGE(2) in response to eccentric resistance exercise: influence of ibuprofen acetaminophen.”. The Journal of Clinical Endocrinology and Metabolism 86 (10): 5067–70.
- Roberts MD, Iosia M, Kerksick CM. et al. Effects of AA supplementation on training adaptations in resistance-trained males. J Int Soc Sports Nutr. 2007;4:21. doi: 10.1186/1550-2783-4-21.
- Wilborn, C., et al. “Changes in whole blood and clinical safety markers over 50 days of concomitant arachidonic acid supplementation and resistance training.” Journal of the International Society of Sports Nutrition 3.1 (2006): S25.
- Kelley, Darshan S., et al. “Arachidonic acid supplementation enhances synthesis of eicosanoids without suppressing immune functions in young healthy men.” Lipids 33.2 (1998): 125-130.
- Nelson, G. J., et al. “The effect of dietary arachnidonic acid on plasma lipoprotein distributions, apoproteins, blood lipid levels, and tissue fatty acid composition in humans.” Lipids 32.4 (1997): 427-433.
- Czernichow, Sébastien, Daniel Thomas, and Eric Bruckert. “omega-6 Fatty acids and cardiovascular health: a review of the evidence for dietary intake recommendations.” British Journal of Nutrition 104.6 (2010): 788.
- Hussein, Nahed, et al. “Long-chain conversion of [13C] linoleic acid and α-linolenic acid in response to marked changes in their dietary intake in men.” Journal of lipid research 46.2 (2005): 269-280.
- Samuelsson, B. “ARA metabolism: role in inflammation.” Zeitschrift fur Rheumatologie 50 (1990): 3-6.
- Markworth, James F., and David Cameron-Smith. “Arahidonic acid supplementation enhances in vitro skeletal muscle cell growth via a COX-2-dependent pathway.” American Journal of Physiology-Cell Physiology 304.1 (2013): C56-C67.
- Trappe, Todd A., et al. “Effect of ibuprofen and acetaminophen on postexercise muscle protein synthesis.” American Journal of Physiology-Endocrinology And Metabolism 282.3 (2002): E551-E556.
- Trappe, T. A., et al. “Skeletal Muscle PGF2αand PGE2 in Response to Eccentric Resistance Exercise: Influence of Ibuprofen and Acetaminophen.” Journal of Clinical Endocrinology & Metabolism 86.10 (2001): 5067-5070.
- Ormes, Jacob, et al. “Effects of Arachidonic Acid Supplementation on Skeletal Muscle Mass, Strength, and Power.” Journal of Strength & Conditioning Research. Abstract
- Brash, Alan R. “AA as a bioactive molecule.” The Journal of clinical investigation 107.11 (2001): 1339-1345.
- Markworth, James F., and David Cameron-Smith. “Prostaglandin F2α stimulates PI3K/ERK/mTOR signaling and skeletal myotube hypertrophy.” American Journal of Physiology-Cell Physiology 300.3 (2011): C671-C682.
- Wilmore, Jack H., David L. Costill, and Gilbert W. Gleim. “Physiology of sport and exercise.” Medicine & Science in Sports & Exercise 27.5 (1995): 792.
- Marimuthu, Kanagaraj, Andrew J. Murton, and Paul L. Greenhaff. “Mechanisms regulating muscle mass during disuse atrophy and rehabilitation in humans.” Journal of Applied Physiology 110.2 (2011): 555-560.