IGF-1 – or insulin-like growth factor 1 to give it its full name – is an intriguing anabolic hormone that has proven itself to be an excellent addition to the PED cycling regimes of bodybuilders and athletes alike. In this guide we take a closer look at IGF-1s action, what results you can expect from its use and what potential side effects to watch out for.
Naturally produced by the liver, IGF-1 is a hormone similar in structure to that of insulin, hence its name. During childhood it is one of the primary hormones responsible for growth and remains a powerful precursor to cell growth in adults – something bodybuilders and athletes have naturally taken an interest in!
IGF-1 in action
When it comes to its effect on the body, IGF-1 shares many of the same traits as human growth hormone (HGH). This is to be expected; HGH is in fact a precursor to IGF-1, signalling for its release when the HGH binds to its receptors. It’s the IGF-1 that stimulates muscle growth and promotes protein anabolism.
IGF-1 is highly anabolic and will promote both muscle hypertrophy (growth) and hyperplasia (formation of new muscle cells). While the level of muscle growth from IGF-1 use is likely to be less than that of most anabolic androgenic steroids, the hyperplastic effects of IGF-1 is highly desirable and cannot be achieved from steroids which merely hypertrophies the existing muscle tissue.
In addition and of particular interest to athletes, IGF-1 has a positive effect on connective tissue and cartilage repair making it a superb compound to run during rehab and heavy training phases within the year.
Unlike HGH, IGF-1 doesn’t appear to directly cause heightened fat mobilisation. This is interesting because many users of the hormone do note its apparent ability to reduce or maintain body fat levels during periods of high calorie consumption, yet this is likely down to the insulin-like effect of IGF-1 which promotes a state of lower blood sugar. This is important to note and is covered later when we discuss side effects.
The difference between IGF-1 LR3 and IGF-1 DES
When most people talk of IGF-1 they are in fact usually talking about the popular IGF-1 LR3 variation.
Having a very short half-life (< 10 minutes) and being acutely unstable, IGF-1 in its base form is not commonly used by bodybuilders or athletes. The two popular variations, IGF-1 LR3 and IGF-1 DES, are both modifications of the base protein and possess superior qualities for use; less sensitive, more potent and a longer half-life.
IGF-1 LR3 – while IGF-1 in its base form has a half-life of less than ten minutes, IGF-1 LR3 has a half-life of a day. With such an extended half-life the hormone has a far greater timeframe to circulate around the body, bind to receptors and exert its effects.
With IGF-1 LR3 it is neither necessary nor effective to perform site specific injections as the hormone will have ample opportunity to propagate from the injection site given its half-life.