Advil leads to decreased muscle growth

I have long suspected (with no real scientific backing, mind you) that Ibuprofen somehow inhibited muscle growth. My simple, pea-brain somehow connected taking the pain away would also take away the benefits from it. (No, I am not Catholic. Or Jewish).

Well, I saw a blurb in a fitness magazine that aluded to this a while ago, and I decided to hunt down the scientific paper for the source.

Here is the gory abstract from the shortly titled paper "Ibuprofen inhibits skeletal muscle hypertrophy in rats"

PURPOSE: We sought to determine whether cyclooxygenase (COX) activity is necessary for overload-induced growth of adult rat skeletal muscle, and whether nitric oxide synthase (NOS) activity is involved in upregulation of COX messenger RNA (mRNA) expression in skeletal muscle. METHODS: Unilateral surgical removal of the gastrocnemius and soleus was performed on the right hindlimb of 16 female Sprague-Dawley rats (approximately 230 g) to induce chronic overload (OL) of the plantaris for 14 d, with sham surgeries performed on the contralateral leg as a normally loaded (NL) control. Half of the rats were treated with the nonspecific COX inhibitor, ibuprofen (0.2 mg.mL(-1) in drinking water; approximately 20 mg.kg(-1).d(-1)). In a second experiment, the plantaris was unilaterally overloaded for 5 or 14 d in male rats (approximately 350 g; N = 16 rats per time point) and half of the animals were treated with the NOS inhibitor, L-NAME (0.75 mg.mL(-1) in drinking water; approximately 90 mg.kg(-1).d(-1)). RESULTS: Ibuprofen treatment inhibited plantaris hypertrophy by approximately 50% (P < 0.05) following 14 d of OL, as did L-NAME treatment (P < 0.05). COX-1 and COX-2 mRNA did not differ between any groups at 5 d. At 14 d, however, L-NAME caused a 30-fold increase in plantaris COX-1 mRNA expression independent of loading condition. Additionally, OL induced a 20-fold increase in COX-2 mRNA expression compared with NL (P < 0.05) at 14 d, without affecting COX-1 mRNA level. L-NAME treatment significantly inhibited OL-induced expression of COX-2 mRNA. CONCLUSION: COX activity is important for in vivo muscle hypertrophy, and plantaris overload is associated with NOS activity-dependent COX-2 expression.

From Wikipedia, here is a definition of COX:

Cyclooxygenase (COX) is an enzyme (EC 1.14.99.1) that is responsible for formation of important biological mediators called prostanoids (including prostaglandins, prostacyclin and thromboxane). Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain; this is the method of action of well-known drugs such as aspirin and ibuprofen.


Sadly, it took me about 6 reads of the abstract to put it all together (my bio-goggles are pretty damn rusty).

Here's my interpretation:
They wanted to see whether inflammation is needed to create new muscle. Or phrased an even simpler way: The pain / soreness you feel after working out is a necessary step to building muscle -- and specifically, taking ibuprofen (e.g. Advil) stops that. In their study, the muscles were 50% smaller on the rats on advil. That is HUGE.

Good news though: Tylenol doesn't work on the same chemical paths as Advil so it shouldn't be part of this pathway. I would recommend staying away from Advil if you want to build big muscles. It is only one study though. Time will tell if this holds up under other studies.