For years, bodybuilders wanted to know if their OTC pain killers like Asprin or Tylenol or prescriptions like vicodin had any effect on their muscle building efforts. Bodybuilders often take pain killers to get through an injury, aching joints, or to recover from muscle soreness. Unfortunately, certain groups of these pain killers may actually be hurting your muscle building efforts. You may have been sabatoging your muscle gains all these years and not even realized it.

NSAIDs Painkillers’ Effect on Muscle Growth

Most of the common over the counter paink killers we use are called NSAIDS (Non-steroid anti inflammatory drugs), which include Asprin, ibuprofen (Motrin), Naproxen (Aleve), and various others. Some prescription painkillers are also NSAIDs too. Acetaminophen (brand name tylenol), often used over the counter is the only commonly used over the counter pain killer not a NSAID.

It turns out according to studies in the last year that NSAIDs and Acetaminophen, both can dramatically drop your rate of protein synthesis. When protein synthesis drops you can’t build muscle effectively. In order to build muscle, you need a higher protein synthesis rate than breakdown rate, so there is a net gain in the muscles.

The first study came out in 2001 J Clin Endocrinol Metab. 2001 Oct;86(10):5067-70.. 24 men after 10 to 14 resistance workout sets took either Ibuprofen, Acetaminophen, or a control placebo group. This study only measured prostaglandins, but researches concluded that it’s impact could effect muscle building. The impact of the study didn’t hit the bodybuilding community at the time because it didn’t quite have the link yet.

A year later the researchers performed another study measuring this time protein synthesis and published it in Am J Physiol Endocrinol Metab. 2002 Mar;282(3):E551-6.. They had the same 3 groups, acetaminophen, ibuprofen, and placebo, do resistance excercises. The results were stunning, the control group had 75% higher protein synthesis, compared to the ibuprofen and acetaminophen group. Interesting enough, the study showed that it had no impact on overall protein synthesis, only at the site of the worked muscle. This implies to me that these pain killer drugs interact to block some action that promotes the inflammatory response in muscle building locally.

Since then, studies have also shown the impact of Asprin Biol Chem. 2007 Apr;282(14):10164-71. Epub 2007 Feb 6. on protein synthesis. Therefore it appears the whole class of NSAIDs and Tylenol definitely effect protein syntehsis. One study Med Sci Sports Exerc. 2006 May;38(5):840-6. went further than measuring protein synthesis. They actually compared muscle growth between rats who took ibuprofen and those who did not, with both groups overloading the muscle. Results showed a 50% drop in muscle growth!

Opiate based pain killers’ effects on Muscle building

Opiates are a stronger groups of pain killers that work via a very different mechanism than the over the counter pain killers. There is no studies that I can find that yet show its impact on muscle growth. However, Loperamide is an opiate pain killer found in the over the counter drug Imodium. Loperamide is used as an anti-diarrhetic drug. Imodium is over the counter because it doesn’t have a effect on the brain on recommended dosages in Imodium. Interesting enough, it has strong anti cortisol properties according to research. Whether or not this effect on blocking cortisol is seen in other opiate pain killers, I do not know, as I can’t find research on cortisol effects and other opiates. There also is no studies on protein synthesis and taking opiates, so even if it does lower cortisol, we don’t know if opiates can effect muscle building by possibly reducing protein synthesis and cancel a possible benefit from reducing cortisol.