Does Arachidonic Acid Increase Muscle?

Does Arachidonic Acid Increase Muscle?

A kind of omega-6 polyunsaturated fatty acid, arachidonic acid is naturally found in many foods. A good balance of polyunsaturated fatty acids is essential for wellness, and ARA is known to support brain function, vision, immunity, and general cellular and metabolic health.  This essential fatty acid can primarily be found in red meats, organ meats such as liver and kidney, and egg yolks. It is sometimes also found as a supplement in vegan and vegetarian food. As with anything, there are some assumptions regarding the negative effects of a diet high in n-6 fatty acids. Previously, arachidonic acid has not enjoyed a good press in the bodybuilding world. The metabolites – the products of metabolism, which increase fuel, signaling, and structural effects on enzymes – were previously assumed to agitate inflammation. Thankfully, studies have been conducted to fully explore the pros and cons of supplementation with the acid, and have found it very safe for healthy people to use.  


Specializing in the field of hormonal medicine and nutrition, William Llewellyn has spent the last 10 years researching into the effects of arachidonic acid, and has come up with some interesting findings. About seven years ago, Llewellyn sponsored a study in arachidonic acid, where young strength athletes were given doses of the acid. The anaerobic capacity of the athletes increased greatly, with several other performance variables approaching significance (strength, average power, endurance). James Markworth, a New Zealand PhD researcher, would later go on to do work that reaffirmed Llewellyn’s original theory about arachidonic acid. Testing on mice, Markworth applied ARA, in varying concentrations, to C2C12 muscle cells across three days. The experiments were then repeated using compounds to inhibit the COX-2 enzyme. COX enzyme converts arachidonic acid into prostaglandin F2-alpha, which in other studies has been shown to support protein synthesis. In addition, an experiment with a non-metabolizing version of arachidonic acid was carried out.


According to the results, the higher dosages of arachidonic acid rendered a wider myotube (muscle fibre) diameter, and a remarkably higher amount of protein by the third day. The experiment without COX enzyme blocked the anabolic effects of arachidonic acid. In addition, the experiment with the non-metabolisable version rendered no results.  


The supplementation of arachidonic acid did increase the size and thickness of muscle fibres. Arachidonic acid requires the COX-2 enzyme to function beneficially.  

Our Take

While at present more research is required to fully understand the effects and benefits of arachidonic acid, the key findings have already offered up some very promising data. There’s no doubt that the essential fatty acid does indeed play an important role in muscle building by assisting the process. Aside from the effects highlighted in this study, the use of arachidonic acid supplements such as X-Factor by Molecular Nutrition are becoming very popular among bodybuilders. By increasing levels of prostaglandins in the body, arachidonic acid will increase inflammation in the muscles, which is a central part of the repair and growth process. By making muscles more responsive to the damage imposed in the gym, arachidonic acid supplements effectively allow your body to break plateaus in muscle development. As far as the negative effects of this EFA go, as with anything moderation is the key. The most commonly reported side effect of arachidonic acid is increased post workout muscle soreness, which is often regarded as an indicator the supplement is working to intensify the repair response. The experiments showed that muscle fibre growth is encouraged by the acid, and Llewellyn’s initial findings certainly hold water. When increasing muscle function and size, it’s important to take the right supplements and eat the right foods. 


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Roberts MD, Iosia M, et al. Effects of arachidonic acid supplementation on training adaptations in resistance-trained males. J Int Soc Sports Nutr. 2007 Nov 28;4:21.

Markworth JF, Cameron-Smith D. Arachidonic acid supplementation enhances in vitro skeletal muscle cell growth via a COX-2-dependent pathway Am J Physiol Cell Physiol. 2013 Jan 1;304(1):C56-67. doi: 10.1152/ajpcell.00038.2012. Epub 2012 Oct 17.

Horsley V, Pavlath GK. Prostaglandin F2(alpha) stimulates growth of skeletal muscle cells via an NFATC2-dependent pathway. J Cell Biol. 2003 Apr 14;161(1):111-8.