Interlukin-15.

***BajanBastard*** · 02-23-2005, 02:07 PM

Ok I have seen some people ask about this cytokine in some posts on the board. It's not widely available and quite expensive but I decided to do a short, basic profile on IL-15 and its potential use in bodybuilding.

Interlukin-15 (IL-15) is an anabolic cytokine that is produced in skeletal muscle tissue and has a highly active roll in muscle growth.(1) Evidence suggests it has both anti-catabolic and anti- adipocyte(fat cell) activity.(2 3) Studies show that Interlukin-15 overexpression caused a 2-5 fold increase in the muscle contractile protein myosin(2)and significantly reduces muscle wasting(4) this will surely result in a net anabolic effect. Since the proteins that are responsible for muscle contractions are increased an improvement of muscle strength or power may be seen from IL-15 administration.

Fat loss.

Studies also show it to be a potent fat loss agent(3)IL-15 acts directly on the fat cells (adipocytes) to control fat accretion by enhancing fat breakdown or suppressing fat formation(3) and may be an important factor in mobilizing fat and shuttling it to other cells in the body(3) The fat loss effect of IL-15 also seems to be dose-dependent(3).

Interlukin-15 and insulin -like growth factor-I.

IL-15 seems to be far superior to insulin-like growth factor-I (IGF-1) when it comes to improving body composition. IL-15 induces muscle growth via mechanisms that IGF-1 does not(2), while IGF-1 promoted protein build-up only, IL-15 stimulated protein buildup and inhibited protein breakdown.(2) This also suggests that IL-15 promotes anabolism in a different manner than IGF-1(2). One other study showed that IL-15 was as effective as IGF-1 but at a tenth of the dosage(5).

IL-15, IGF-1 combo.

Interesting thing about anabolic steroids is stacking compounds that induce muscle growth via different pathways independent of each other, trenbolone and stanozolol are good examples. IL-15 and IGF-1 are no exception with the combo increasing the muscle protein myosin chain accumulation close to five-fold(5).

As good as IL-15 sounds on paper in regard to muscle growth it also has a vital role to play in the immune system(2). So the drugs side effects in humans using it for muscle mass and fat burning are unknown.

References:
1) J Appl Physiol. 2004 Dec;97(6):2214-9.
2) Exp Cell Res. 2002 Oct 15;280(1):55-63.
3) Am J Physiol Regul Integr Comp Physiol. 2004 Sep;287(3):R608-11.
4) FEBS Lett. 2004 Jul 2;569(1-3):201-6.
5) Endocrinology. 1995 Aug;136(8):3669-72.