Virtually anyone who lifts weights on a regular basis has heard of Insulin-like growth factor-1 (IGF-1) and its importance for muscle growth. What a lot of bodybuilders and other athletes don’t realize is that their muscles produce a specific form of IGF in response to heavy resistance training. This highly specific form of IGF is intimately involved in the recovery process and the mechanisms that underline increases in muscle size.1

Also, the research on this topic clearly shows that a focus on maximum overload during training results in a significant increase in the production of muscle IGF-1.2 This is probably a major reason why Max-OT provides such rapid gains in strength and lean muscle mass. However, new research has shown us how a bodybuilder can boost IGF-1 production within their muscles by 30%! Even before they’ve stepped into the gym!

This new information is exciting stuff for anyone that lifts weights to improve their physique. This research clearly demonstrates that a very simple strategy can be used to boost the expression of IGF-1 mRNA within muscle by 30% to ensure a much greater anabolic response to training.

When a group of healthy participants loaded their muscles with creatine monohydrate for 5 days, it resulted in a dramatic (significant) increase in the expression of IGF (I and II) in muscle compared to a placebo treated group.3 Amazingly, this 30-40% increase in IGF transcription was achieved before any exercise was performed!

Loading muscles with creatine monohydrate immediately increased IGF by 30%!

However, when the participants undertook an intense workout, the group that loaded their muscles with creatine monohydrate experienced a much greater anabolic response to exercise. Analysis of muscle samples taken from the participants revealed that loading with creatine resulted in a higher activation (phosphorylation) of at least one key anabolic activator after the workout.3 This signaling molecule (called 4E-BP1), is considered to be one of the all-important initiators of protein synthesis in muscle. The data showed that loading muscles with creatine really whacked this sucker. Therefore, a much higher rate of muscle protein synthesis can be achieved after training.

As a scientist, this research is fascinating to me. It provides some explanation for the incredible growth effect that I’ve observed in my research on bodybuilders supplementing with Micronized Creatine during Max-OT training. 4,5 In the clinical trials I’ve completed, supplementation with Micronized Creatine increased the size of the type-2 muscle fibers by up to 25% after 10 weeks of training. 4,5

To give you an idea of how significant this is, the placebo groups in these studies (not treated with Micronized Creatine) showed an increase in fiber size of 5-7%. That’s a very respectable increase in muscle growth. However, it pales in comparison to the whopping 25% increase observed in bodybuilders using Micronized Creatine. Also remember that a 25% increase in muscle fiber size equates to a substantial gain in lean muscle mass; anywhere from 5-14 pounds.4,5

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As I mentioned, this new research has shed some light on the enormous muscle-building potential of Micronized Creatine. It looks as though loading with this product will actually trigger an increase in IGF production within the muscle itself. However, the benefit doesn’t stop there. These results suggest that training with creatine-loaded muscles will also ensure a more powerful anabolic response from each workout.

Supplementation with Micronized Creatine during intense training can result in a 15-25% increase in muscle fiber size. This equates to a substantial gain in lean muscle mass; anywhere from 5-14 pounds. No supplement I’m aware of is shown in well-controlled studies to provide this effect.

Micronized Creatine 530 GramsThe bottom line is that when you hit the gym with muscles loaded with creatine monohydrate it will stimulate some dramatic growth responses at the muscle-gene level. More importantly, this translates into rapid gains in muscle mass. Creating and maintaining a high concentration of creatine within muscle appears to accelerate gains in lean mass and strength during training. That’s why I designed a supplement strategy designed specifically to ensure ultra-high muscle creatine concentrations during training.

This strategy is called Creatine Cycling. The feedback from the athletes I have worked with overwhelmingly agree that it’s definitely the most effective way to use creatine. It’s particularly useful for smashing through plateaus in strength and body weight.

There is one final thing I’d like to point out. The increased muscle IGF production and powerful anabolic-response observed in this research was achieved with creatine monohydrate. These benefits have not been documented with liquid creatine, creatine ethyl-ester or any other form of creatine. In fact, despite the marketing spin on the new creatine products, I still haven’t found a single study that documents any beneficial effect from using them, and there’s definitely no studies that suggest these forms of creatine may be better than pure Micronized Creatine. That’s something to consider next time you purchase your creatine supplement.


1. Goldspink G. J Physiol 20:232-8, 2005.
2. Hameed M. et al. Exerci. Sport Sci Rev. 30:1;15-19, 2002.
3. Deldicque L, et al. Med Sci Sports Exerc 37; 731-6, 2005.
4. Cribb PJ, et al. FASEB J , 17: A1153, 2003.
5. Cribb PJ, et al. Med Sci Sports Exerc 37; A2188, 2005.

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Boost IGF-1 Levels by 30%! New Research Shows You How!

by Paul Cribb Ph.D. CSCS. time to read: 4 min