MET-Rx Xtreme Size Up Review
4.0Overall Score
Reader Rating: (5 Votes)

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Met-Rx’s latest mass gainer attempts to solve a problem that has been plaguing ectomorphs (naturally skinny people) for decades. How on earth do you avoid becoming ‘skinny fat’?
‘Skinny fat’, or the appearance of being overweight while still lacking any sort of muscular definition, has always been an issue for people trying to pack on muscle mass quickly. With that in mind, Met-Rx decided to take a shot at creating a mass gainer called Met-Rx Xtreme Size Up. Their goal?  To helped people gain the most muscle possible, while putting on the least amount of fat.


Taste and Mixability:

As superficial as it might seem at first, taste and mixability (and by extension, texture) are critical aspects of any supplement, especially by supplements that meant to be consumed so frequently. Throughout our Met-Rx Xtreme Size Up review, we experienced a solid taste from both flavors. Granted, after a few weeks, the flavor might feel a bit repetitive, but it’s hardly noticeable.

Mixability of this supplement could be an issue for some people. The shakes are consistently pretty thick and we found ourselves having to pour in a bit more than the 16 ounces of water or milk. That being said, once you find the right consistency level, the actual texture of this mass gainer should be pretty smooth.


When deciding whether or not to buy Size Up, an important question that you need to ask yourself is ‘what do I want from a mass gainer?’ Frankly, you could probably pick up a low quality mass gainer for a few dollars less. So, if you want a mass gainer that will save you money (at least in the short run), go ahead and get your hands on a different supplement. Oh, and in case you were wondering, Met-Rx Xtreme Size Up should cost you about $2.50 a day.

Of course, if you’re looking to buy a mass gainer that actually works well, you’ve found the right supplement. You see, value is not always about how much money you have left in your pocket. Supplements are an investment in the greatest resource you have: yourself. And trying to cut corners now is a lot like trying to cut corners when building a house. It feels good now, but those decisions will catch up with you eventually.

The best price we found for a 6 lb tub was $43.99 at



Just in case our ‘Value’ section didn’t make it clear enough, we’ll say it here. Met-Rx Xtreme Size Up works. It works well, even by our standards (which are pretty high. Check out some of our other mass gainer supplement reviews so you know what we’re talking about). First off, we’re looking at 60 grams of protein per serving, which is an impressive statistic on its own. The real beauty of this supplement lies in its calorie count (600 calories per serving). Instead of adopting the mentality of ‘bigger is better’, Met-Rx kept in mind the main issue of ‘skinny fat’ individuals: too many calories.

Think about it. The reason that ectomorphs gain weight in all the wrong areas is because they increase their caloric surplus (a.k.a. the amount of calories you have beyond the amount you need to survive) by way too much. Unfortunately, putting on lean mass can feel like an impossible challenge considering that most mass gainers on the market today seem to think that fat is as satisfying as muscle. Met-Rx chose to address this issue by keeping their calorie amount relatively low for a mass gainer, something we can’t help but respect.

If that hasn’t impressed you enough, just take a quick look at their ingredient list. Creatine for increased energy, L-Glutamine for…basically everything (gastrointestinal wellness, aiding muscle growth and even brain health), plenty of Vitamins and even a bit of fiber thrown in, for good measure. During our Met-Rx Xtreme Size Up review, we noticed a noticeable decrease in muscle soreness after workouts, without the bloated feeling usually associated with mass gainers.


Side Effects:

Met-Rx doesn’t really have any serious side effects that you should look out for. Of course, if at any point you feel ill, stop using this supplement immediately and consult your doctor.

For For

  • Plenty of protein
  • High quality ingredient profile
  • Low calories to avoid ‘skinny fat’ dilemma
  • Solid taste

Against Against

  • Consistency can be quite thick


Met-Rx Xtreme Size Up – Our Verdict:

At first glance, Size Up might look like an incomplete mass gainer. With only 600 calories, this supplement seems to be an underwhelming supplement. However, after taking a look at the ‘skinny fat’ dilemma, it becomes clear that the people at Met-Rx knows exactly what they’re doing. With an impressive amount of protein and a comprehensive ingredient list, Met-Rx Xtreme Size Up has all of the tools it needs to become one of the most effective mass gaining supplements on the market.

Still not sure what to buy? No worries; we’re got plenty of reviews for you to check out. Remember to share this on Facebook if you liked it! We appreciate the love 🙂

Remember to look at today’s best deals for Met-Rx Xtreme Size Up before parting with any of your hard earned cash!

Per Serving (4 Scoops):

Calories 600
Calories From Fat 50
Total Fat 6g 9%**
Saturated Fat 4.5g 23%**
Cholesterol 65mg 22%**
Total Carbohydrate 80g 27%**
Dietary Fiber 8g 32%**
Sugars 5g ***
Protein 59g 118%**
Vitamin A(50% As Beta Carotene) 4500IU 90%
Vitamin C 60mg 100%
Vitamin D 240IU 60%
Vitamin E 45IU 150%
Vitamin K 40mcg 50%
Thiamin 0.9mg 60%
Riboflavin 1mg 59%
Niacin 20mg 100%
Vitamin B6 1.2mg 60%
Folic Acid 400mcg 100%
Vitamin B12 3mcg 50%
Biotin 180mcg 60%
Pantothenic Acid 4mg 40%
Calcium 1230mg 123%
Iron 8.1mg 45%
Phosphorus 1170mg 117%
Iodine 60mcg 40%
Magnesium 110mg 25%
Zinc 6mg 40%
Selenium 28mcg 40%
Copper 0.8mg 40%
Manganese 1mg 50%
Chromium 48mcg 40%
Molybdenum 60mcg 80%
Chloride 220mg 6%
Sodium 370mg 15%
Potassium 1750mg 50%

Other Ingredients: Complex Carb Optimizer Blend(Maltodextrin, Barley Flour, Oat Fiber, Oat Bran Concentrate), Metamyosyn®Muscle Mass Optimizer Blend ( Whey Protein Concentrate, Milk Protein Concentrate, Calcium Sodium Caseinate, Creatine Monohydrate, Dried Egg White), Cocoa(Processed With Alkali), MultiVitamin Optimizer Blend(Di-Potassium Phosphate, Potassium Chloride, Calcium Lactate, Di-Calcium Phosphate, Tri-Calcium Phosphate, Potassium Citrate, Beta Carotene, Salt, Sodium Citrate, Dl-Alpha Tocopheryl Acetate, Ascorbic Acid, Ferrous Fumarate, Niacinamide, Zinc Oxide, Vitamin A Palmitate, Calcium D-Pantothenate, Copper Sulfate, Manganese Sulfate, Pyridoxine Hydrochloride, Thiamin Hydrochloride, Riboflavin, Cholecalciferol, Folic Acid, Chromium Picolinate, Biotin, Sodium Molybdate, Potassium Iodide, Phytonadione, Sodium Selenite, Cyanocobalamin), Cocoa Powder, Natural And Artificial Flavor, Partially Hydrogenated Coconut Oil, Corn Syrup Solids, Cellulose Gum, Xanthan Gum, Lean Lipid Optimizer Blend(Medium Chain Triglycerides, Sunflower Oil, Flaxseed Powder), Guar Gum, Carrageenan, Acesulfame Potassium, Soy Lecithin, Sucralose, Mono- AndDi-Glycerides.

Contains Milk, Egg, Soy And Tree Nut (Walnut) Ingredients.