High-Quality Whey

Excellent source of pure whey

GNC Genitix HD Iso-Define has muscle gaining and fat burning qualities and is meant to be taken along with a diet and exercise regimen; those looking for a quick solution to weight loss without the work should look elsewhere. It’s a high-quality source of pure whey.

  • Flavor
  • Mixability
  • Ingredient Quality
  • Value
  • Price

GenetixHD Iso-Define is a new product offered by GNC that promises to set the standard in gaining and maintaining the chiseled physique everyone wants.

Sounds too easy, I decided to see if this product really gives the promised results.


GNC GenitixHD Iso-Define is 100% whey protein isolate mixed with a hyper defining matrix.

Whey Protein Isolate

Whey Protein Isolate is an extremely filtered cheese by-product. It is so filtered it is considered lactose free, and it contains 90-94% protein.

Studies done on elderly subjects show whey protein is beneficial in gaining and keeping skeletal muscle mass. [1]

In other studies, whey protein was shown promote muscle gain during training. However, researchers agree more research is needed to prove a link. [2]

Hyper Defining Matrix

Clarinol CLA

Clarinol is a brand name for CLA, which purportedly reduces body fat and builds lean muscle mass when combined with diet and exercise.

CLA’s effectiveness as an anti-obesity ingredient is still debated. In a test done on several overweight rats, results showed no decreases in body fat. [3]

However, in several other animal studies, CLA reduced body fat and increased lean muscle mass. [4]

Medium Chain Triglycerides (MCTs)

Preliminary evidence suggests MCTs are a good substitute for those who have trouble digesting fat. It is believed MCTs enhance fat burning.

However, most studies have not found MCTs to be beneficial as a weight loss aid but instead show it improves the ratio of fat to lean tissue. [5]


Experts at WebMD say carnitine supplementation is ineffective for improving athletic ability, even in trained athletes. [6]

However, a study done on 10 resistance trained men showed carnitine supplementation is effective in recovery after exercise. [7]


L-Leucine is an essential amino acid thought to increase athletic performance and fat free mass.

One study showed leucine supplementation greatly increased fat free mass and strength. Researchers also found it significantly improved athletic performance. [8]

Lutemax 2020

Lutemax 2020 combines lutein and zeaxanthin. Lutein and zeaxanthin are both vitamins used to treat and prevent eye problems.

Lutemax 2020 has no apparent function in reducing fat or gaining muscle.

Papain and Bromelain

Papain and bromelain are both fruit extracts that have anti-inflammatory effects. Both extracts are shown to relieve pain when combined with other important ingredients. [9]

Flavors and Sizes

GNC GenetixHD Iso-Define comes in two flavors: Berry Sorbet and Swiss Chocolate.

The Swiss Chocolate contains 1.6 lbs. of powder, whereas the Berry Sorbet only has 1.5 lbs.


As a daily supplement take 1 scoop and mix with 6 oz. of your favorite beverage.

For a defined physique, lean muscle support and faster recovery, take 1 scoop right after a workout on training days. On non-training days take 1 scoop in the morning or between meals.

For a lean sculpted physique, faster metabolism, improved lean muscle growth and strength, take 1 scoop in the morning and 1 scoop after a workout on training days. On non-training days take 1 scoop in the morning and 1 scoop in the afternoon.

Side Effects

Because GNC GenetixHD Iso-Define is a new product, side effects have not been observed.

However, side effects for the ingredients included in GNC GenetixHD Iso-Define are as follows:

• Upset stomach
• Nausea
• Diarrhea
• Fatigue
• Vomiting
• Gas
• Heartburn
• Seizures [10]

Where to Buy GenitixHD Iso-Define

GNC GenitixHD Iso –Define is an exclusive GNC product that can be bought online or in their stores.

GNC GenetixHD Iso-Define costs $43.99, but members can buy it for $39.59.

About GNC

GNC is headquartered in Pittsburgh, PA and has more than 8,200 locations.

GNC has a 30-day money-back guarantee, as long as the item is returned in the original boxes with all the paperwork included therein. There are possible return policy exceptions that can be found on their website.

Final Thoughts

The ingredients contained in GNC Genitix HD Iso-Define appear to have muscle gaining and fat burning qualities. However, more research needs to be done to solidify these claims.

The lack of customer reviews due to newness of this product makes me skeptical that it works as claimed, at least until further research is done on the ingredients.

This supplement is meant to be taken along with a diet and exercise regimen; those looking for a quick solution to weight loss without the work should look elsewhere.

The GNC return policy is pretty good, so if you aren’t satisfied with the results, send it back!


[1] Hayes, Alan, and Cribb J. Paul. “Effect of whey protein isolate on strength, body composition and muscle hypertrophy during resistance training.” Clinical Nutrition and Metabolic Care 11.1 (2008). Web. 5 June 2013. <http://journals.lww.com/co-clinicalnutrition/Abstract/2008/01000/Effect_of_whey_protein_isolate_on_strength,_body.9.aspx>.

[2] Cribb, Paul J., Andrew D. Stathis, Christos George, Michael F, and Alan Hayes. “Effects of whey isolate, creatine and resistance training on muscle hypertrophy.” Victoria University Insitutional Repository . Web. 5 June 2013. <http://vuir.vu.edu.au/1441/>.

[3] Miranda, J, A Fernández-Quintela, M T. Macarulla, I Churruca, and C García. “A comparison between CLNA and CLA effects on body fat, serum parameters and liver composition.” Journal of Physiology and Biochemistry 65.1. Web. 5 June 2013. <http://link.springer.com/article/10.1007/BF03165966>.

[4] Bhattacharya, Arunabh, Md. Mizanur Rahman, Dongxu Sun, Richard Lawrence, and Walter Mejia. “The Combination of Dietary Conjugated Linoleic Acid and Treadmill Exercise Lowers Gain in Body Fat Mass and Enhances Lean Body Mass in High Fat–Fed Male Balb/C Mice.” The Journal of Nutrition (2005). Web. 5 June 2013. <http://jn.nutrition.org/content/135/5/1124.short>.

[5] “Medium-Chain Triglycerides.” www.med.nyu.edu. NYU Langone Medical Center, n.d. Web. 5 June 2013. <http://www.med.nyu.edu/content?ChunkIID=21809>.

[6] “L-CARNITINE.” WebMD.com. WebMD, n.d. Web. 5 June 2013. <http://www.webmd.com/vitamins-supplements/ingredientmono-1026-LCARNITINE.aspx?activeIngredientId=1026&activeIngredientName=L-CARNITINE>.

[7] Volek, Jeff S., William J. Kraemer, Martyn R. Rubin, Ana L. Gomez, and Nicholas A. Ratamess. “L-Carnitine L-tartrate supplementation favorably affects markers of recovery from exercise stress.” American Journal of Physiology (2001). Web. 5 June 2013. <http://ajpendo.physiology.org/content/282/2/E474.short>.

[8] Mero, Antti. “Leucine Supplementation and Intensive Training.” Sports Medicine 27.6 (1999). Web. 5 June 2013. <http://link.springer.com/article/10.2165/00007256-199927060-00001>.

[9] Shoskes, Daniel A., Scott I. Zeitlin, Asha Shahed, and Jacob Rajfer. “Quercetin in men with category III chronic prostatitis: a preliminary prospective, double-blind, placebo-controlled trial.” Urology 54.6 (1999). Web. 5 June 2013. <http://www.sciencedirect.com/science/article/pii/S0090429599003581>.

[10] WebMD.com. WebMD, n.d. Web. 5 June 2013. <http://www.webmd.com/>.