GNC AMP Mass XXX, Clinically Proven Weight Gainer Protein Powder With Micronized Amino Acids, Creatine, Betaine, 780 Calories, 50g Protein, Strawberry, 13 Servings
GNC AMP Mass XXX, Clinically Proven Weight Gainer Protein Powder With Micronized Amino Acids, Creatine, Betaine, 780 Calories, 50g Protein, Strawberry, 13 Servings
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GNC AMP Mass XXX, Clinically Proven Weight Gainer Protein Powder With Micronized Amino Acids, Creatine, Betaine, 780 Calories, 50g Protein, Strawberry, 13 Servings

4.1 stars out of 119 reviews
(4.1)|
119 ratings
GNC AMP Mass XXX, Clinically Proven Weight Gainer Protein Powder With Micronized Amino Acids, Creatine, Betaine, 780 Calories, 50g Protein, Strawberry, 13 ServingsGNC AMP MASS XXX with MyoTor Strawberry 13 ServingsGNC AMP MASS XXX with MyoTor Cookies and Cream 13 ServingsGNC AMP Mass XXX with MyoTOR Protein Powder Targeted Muscle Building and Workout Support Formula with BCAA and Creatine Chocolate 13 ServingsGNC AMP Mass XXX with MyoTor Vanilla 13 Servings
Flavor:Strawberry-Out of stock

Key item features

  • Clinically Proven Gainer: Mass XXX mass gainer combines high-quality protein powder, key nutrients, and science-backed innovations—including MyoTOR, creatine, and BETAPOWER—to fuel proven results and performance
  • Increase Mass with 40% Fewer Sets: Delivers 50g of protein, including naturally occurring EAAs, plus carbs, and healthy fats—and it’s clinically proven to help get better results out of workouts
  • Improve Muscle Strength in As Early as 2 Weeks: MyoTOR® is clinically proven to accelerate improvements in strength with as little as 2 weeks of training and included in every serving of Mass XXX mass gainer
  • Improve Stamina: Take resistance training to a new limit with MyoTOR’s clinically studied support for improved muscle endurance and BETAPOWER’s athletic performance benefits
  • Banned Substance Tested: Product was tested and monitored for over 220 banned substances on the 2020 World Anti-Doping Agency (WADA) Prohibited list via LGC skip lot testing.
  • Backed By Science: Since 1935, GNC has been committed to meeting the highest standards of quality, safety, and efficacy while applying the most up-to-date advances in nutritional science so you can live well.
Current price is $84.99
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Customer ratings & reviews

4.1 out of 5 stars
stars119 ratings70 reviews
How item rating is calculated
  1. 5 stars68% (81)
  2. 4 stars9% (11)
  3. 3 stars7% (8)
  4. 2 stars3% (3)
  5. 1 star13% (16)
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Showing 1-3 of 70 reviews

Aug 11, 2025
AnthonyS
5 out of 5 stars review

Good stuff

Works as advertised. I'm adding reps and putting on some weight

Review from GNC
Helpful?6M9X8LJJ5FAE3218940318
Oct 1, 2024
LakeishaC
5 out of 5 stars review

I love everything about this protein powder. It has great taste and I have seen amazing results in body and strength. Most definitely worth the buy.

Review from GNC
Helpful?6M9X8LJJ5FAE3218940318
Jul 19, 2023
MorganJ
5 out of 5 stars review

Great to help you get started or restarted after a long hiatus from the gym.

[This review was collected as part of a promotion.] If you are starting out in the gym or coming back after a long hiatus, take this stuff. You will gain mass and you will see bigger lifts at the gym. The taste isn't too bad either, just make sure you shake it really well. I usually get allergic to headaches from general why protein, but I had no problems taking this. If I took a break for a bit, I would use this to help me build back mass for sure.

Review from GNC
Helpful?6M9X8LJJ5FAE3218940318