What to look for in a weight gain supplement
Calorie-dense supplements can support healthy weight gain when you want an easier way to add more nutrition to your routine. A strong option should deliver meaningful calories, quality protein, and a macro profile that helps fuel your body consistently. That is exactly where GNC Pro Performance® Weight Gainer Protein Powder fits in.
This formula is built for healthy weight gain goals with targeted macros and a high-calorie profile designed to help replenish energy stores. It also includes BCAAs, making it a practical choice for anyone pairing nutrition with a structured training plan. If your goal is to add size and support muscle mass, getting enough total intake matters, and a calorie-rich shake can help fill that gap more efficiently than trying to eat more food at every meal.
Protein quality matters too. This product delivers 50g of protein from whey protein concentrate and micellar casein, giving you fast-, medium-, and slow-releasing protein sources in one serving. It also provides all 20 amino acids needed to build muscle mass. That combination makes it useful for supporting your routine before or after training, or anytime you need a more substantial shake during the day.
For shoppers who value clarity, the formula also features a transparent label, all-natural colors and flavors, and third-party testing for purity and potency. That makes it a disciplined choice for building a routine you can stick with.
Why this formula supports your goals
GNC Pro Performance® Weight Gainer Protein Powder is designed around the core needs of a weight gain plan: more calories, more protein, and dependable daily use. Instead of focusing on one single nutrient, it brings together targeted macros to help support a more complete approach to adding size.
- High-calorie support: The formula is designed to help fuel your body while supporting healthy weight gain goals.
- 50g of protein: Protein comes from whey protein concentrate and micellar casein to provide fast, medium, and slow-releasing protein.
- All 20 amino acids: A complete amino acid profile helps support muscle mass goals.
- BCAA-rich formula: Built to help replenish energy stores while supporting your training routine.
- All-natural colors and flavors: Great taste with a cleaner approach to flavor and color.
Trust is another major benefit. This formula is third-party tested for purity and potency and features a banned substance tested label. That matters if you want confidence in what you are using day after day. The transparent label also makes it easier to understand exactly what is in your shake.
For anyone starting fresh or getting back into a consistent routine, this product keeps the approach straightforward: add meaningful nutrition, stay consistent, and support your progress with a formula built for the job. Performance Starts Here.
How to choose a calorie-focused supplement for weight gain
Choosing the right product starts with your goal. If you want support for adding body weight and muscle mass, look for a formula that does more than just add calories. The best fit should also provide substantial protein and a macro profile that works with your training and eating habits.
- Start with calorie density. A supplement should help you increase intake without forcing extra meals into your day. A high-calorie shake can make your routine more manageable.
- Check the protein source. A blend of whey protein concentrate and micellar casein gives you a mix of release speeds, which can help support your intake across the day.
- Look for amino acid support. BCAAs and a full amino acid profile are useful if your plan includes exercise and muscle-building goals.
- Choose transparency. A clear label and third-party testing can help you feel more confident in your daily supplement choice.
- Think about consistency. Taste and mixability matter because the best routine is the one you can maintain.
GNC Pro Performance® Weight Gainer Protein Powder checks those boxes with targeted macros, 50g of protein, all 20 amino acids, and all-natural colors and flavors. It is especially useful for people who want a simple, reliable way to support a structured eating and exercise plan without overcomplicating their stack.
Fuel your progress with GNC
Since 1935, GNC has been committed to high standards for quality, safety, and efficacy while applying the latest advances in nutritional science. That long-standing focus gives shoppers a trusted place to turn when their goals call for more than guesswork.
GNC Pro Performance® Weight Gainer Protein Powder reflects that commitment with a transparent label, third-party testing for purity and potency, and a banned substance tested formula trusted by athletes around the world. It is a straightforward solution for people who want dependable nutrition support as they work toward healthy weight gain and muscle mass goals.
At GNC, the focus is on helping you build momentum through informed choices and consistent effort. When your routine calls for more calories, quality protein, and a formula designed to support progress, this is a confident next step. Performance Starts Here.
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THE BIGGER PICTURE OF WEIGHT-GAIN
Serious weight gain requires serious calories. However, those who need the extra calories most, often have the toughest time consuming enough of them. For many aspiring to be bigger, highly-active metabolisms, weaker appetites, and on-the-run lifestyles make consuming sufficient calories through whole foods alone a real challenge. With Serious Mass, you've got nothing to lose and lots to gain. We've consolidated over 1,250 calories, 50 grams of protein, 250-plus grams of carbohydrates, and 25 vitamins & minerals with added glutamine and creatine into every serving. It's time to stop thinking small; get serious – Serious Mass.
BEYOND THE BASICS
- 1,250 calories per serving in water; 1,630-plus calories when made with low fat milk.
- 50 grams of protein from a combination of faster and slower digesting sources including Whey, Casein, and Egg.
- 250-plus grams of carbohydrates to support fueling of intense workouts and aid in the replenishment of glycogen stores - with NO ADDED SUGAR.
- Enhanced with Creatine, L-Glutamine & Glutamine Peptides, Choline, Inositol, PABA, and MCTs.
- 25 Vitamins & Essential Minerals with an emphasis on B-Vitamins and Antioxidants.
From The Brand
Complete Your Goal
Recent Reviews
Nice
Qualities are the best
Delicious, filling, energizing, & it works!
I have been using Optimum Nutrition Serious Mass for 30 years. It is delicious, filling, energizing, and builds & sustains muscle mass! Strawberry, banana, vanilla, & chocolate are all delicious.
Does exactly what it's supposed to do!
Does exactly what it's supposed to do: adds mass while giving you extra "umph" when strength training! The key is consistency. It's definitely not bad tasting especially if you're a true fan of whatever flavor you select and easier to drink than some other mass gainers I've tried. Make sure to keep hydrated with plenty of water as this product may make you feel constipated over time. It's up to the user on how to adjust to the obvious results of extra body mass but I do guarantee that it works. I've personally used this product off and on (when I can afford it) for two years and going.
AWESOME
Very good price tag, fast shipping, I have no complain, buy again
Serious mass
I love the chocolate version a lot, reminds me of instant carnation breakfast mix. I can drink it consistently day in and out, gives me lots of energy and helps pack on the weight.Its nice to have a switch up every once in a while and the vanilla flavor for the summer time seems even easier to get down. Two thumbs up
Buy it
Adding this to my weight gain journey has made a significantly positive impact. The flavor tastes amazing. I do feel like I am gaining and maintaining weight.
Se tardó muchísimo
Se tardó demasiado en llegar
Great product
Has been working wonders for my weight gain & keeping the gained weight on. I've noticed visional results for me two weeks after first starting. I drink two 22oz shakes a day.
Get it gurrrrl
Good stuff
Completely satisfied
Great product , fast delivery service.
Serious muscle
I've been using this for about 4 years and it works well at helping me build muscle.
Best weight gainer shake!!
The best weight gain shake I've had. It actually works. I put on 20lbs in three months! It's great and the taste is great too!
For beginners
If you have to, this is probably the best flavor. But don't do it if you're confused this isn't a great thing to be doing
It works great product
Excellent product i've gained ten pounds in two months well need it for health reasons.
I like it!!
Easily dissolved, great tasting.
Congratulations GNC
Excellent service, best protein
Best protein ever!
My first protein and it tastes amazing and does not disappoint, would buy again and again, tastes really amazing with banana
That it will work great !!
Haven't tried it but I'm giving it a 5 star cuz I know I'm my heart it'll wrk!! Thanks again GNC I'll keep u posted
I'm confident it'll work
I still haven't tried it yet but I know it'll work great I'll keep u posted when I do try
Excelente 100%
Producto de calidad y ayuda a mejorar el peso del athleta lo recomiendo es el mejor ganador de peso que he tenido que usar para mi hijo con problema para ganar peso
Impressive results, great taste.
I needed to add macros and this supplement is perfect. The taste is great, along with fruit and almond milk. The two scoops are large when blended, so I do 1 morn, 1 even.
Not great
Has a bad after taste and doesn’t taste like peanut butter at all. It’s trying to, but it misses the mark.
About Serious Mass? - Vanilla (8 Servings) Rated 1 out of 5 Purchased on Dec 12, 2025 I dont enjoy it, would love a refund. Rihanna R Verified Purchaser Jan 3, 2026 Was this helpful? 1 1 Flag Review by Rihanna R has been flagged Flag
About Serious Mass? - Chocolate (8 Servings) Rated 5 out of 5 Purchased on Jul 22, 2025 Absolutely amazing Ryan T Verified Purchaser Aug 13, 2025 Was this helpful? 0 0 Flag Review by Ryan T has been flagged Flag
About Serious Mass? - Strawberry (8 Servings) Rated 4 out of 5 Purchased on Mar 2, 2025 It's good, however you can't really taste the strawberry. Edouard F Verified Purchaser Mar 27, 2025 Was this helpful? 1 0 Flag Review by Edouard F has been flagged Flag
About Serious Mass? - Chocolate Peanut Butter (8 Servings) Rated 1 out of 5 Purchased on Jan 30, 2024 Too expensive for such little amount Chelsea S Verified Purchaser Jun 20, 2024 Was this helpful? 9 7 Flag Review by Chelsea S has been flagged Flag
About Serious Mass - Vanilla (16 Servings) Rated 5 out of 5 Purchased on Dec 11, 2023 Great product, my only gripe is it's a little difficult to mix. I have to split it into two blender bottles if I want to make one full serving. Other than that it tastes great and is filling. Christopher J Verified Purchaser Jan 2, 2024 Was this helpful? 0 0 Flag Review by Christopher J has been flagged Flag
About Serious Mass? - Vanilla (8 Servings) Rated 5 out of 5 Purchased on Nov 27, 2023 This is for my Grandson and he thinks it's great. Frances Z Verified Purchaser Dec 22, 2023 Was this helpful? 0 1 Flag Review by Frances Z has been flagged Flag
About Serious Mass? - Chocolate Peanut Butter (8 Servings) Rated 5 out of 5 Purchased on Sep 4, 2023 Great product Michael R Verified Purchaser Sep 30, 2023 Was this helpful? 0 0 Flag Review by Michael R has been flagged Flag
About Serious Mass? - Chocolate Peanut Butter (8 Servings) Rated 5 out of 5 Purchased on Jul 11, 2023 My son loves this flavor! I wish it was available in the 12lb bag in stores!!!! Leonnette M Verified Purchaser Aug 2, 2023 Was this helpful? 0 1 Flag Review by Leonnette M has been flagged Flag
About Serious Mass - Vanilla (16 Servings) Rated 4 out of 5 Purchased on May 4, 2023 Wasn't so bad , definitely needs improving in terms of nutrition factors. Erick R Verified Purchaser May 26, 2023 Was this helpful? 1 0 Flag Review by Erick R has been flagged Flag
About Serious Mass? - Vanilla (8 Servings) Rated 5 out of 5 Purchased on May 1, 2023 I very happy with the product Miguel D Verified Purchaser May 24, 2023 Was this helpful? 0 2 Flag Review by Miguel D has been flagged Flag
About Serious Mass Rated 5 out of 5 Purchased on Jan 9, 2023 Excellent product for weight gain and delicious taste Hamad A Verified Purchaser Mar 6, 2023 Was this helpful? 0 0 Flag Review by Hamad A has been flagged Flag
About Serious Mass - Vanilla (16 Servings) Rated 5 out of 5 Purchased on Feb 3, 2023 Awesome product my favorite! JOSE R Verified Purchaser Feb 25, 2023 Was this helpful? 0 2 Flag Review by JOSE R has been flagged Flag
About Serious Mass? - Chocolate (8 Servings) Rated 5 out of 5 Purchased on Jan 20, 2023 Great supplement Ronisha B Verified Purchaser Feb 18, 2023 Was this helpful? 1 0 Flag Review by Ronisha B has been flagged Flag
About Serious Mass - Vanilla (16 Servings) Rated 5 out of 5 Purchased on Dec 29, 2022 Been buying this for years, love it when I need to gain mass and strength. Nicholas M Verified Purchaser Jan 20, 2023 Was this helpful? 3 0 Flag Review by Nicholas M has been flagged Flag
About Serious Mass? - Vanilla (8 Servings) Rated 5 out of 5 Purchased on Dec 7, 2022 It’s was amazing jose m Verified Purchaser Dec 29, 2022 Was this helpful? 0 1 Flag Review by jose m has been flagged Flag
great protein shake
Perfect flavor and impact!!!!
It is so hard for me to GAIN weight. I've gained a couple lbs. S.Mass has at least stopped the weight loss! Thank you
Wow, serious Mass is every thing that is says it is. Taste is like chocolate malt,very smooth,easy to blend,,I would recommend .
Very pleased
Tastes good and blended well
Wish it came in strawberry
Good taste
My son loves this stuff he's gained 15 pounds in two months
Solid protein
Has a great overall chocolate taste and mixes well in blender or bottle. Plus creatine already in.
I'm starting to see results
I love it I'm starting to see results great product
protein
nice, and delicious.
Gains
It needs more carbs like 2000
Love it!
Great mass gainer! ON is a good brand. Contains whey.
Amazing
Love it lots of calories and protein. Tastes fantastic with milk and some ice cream. Was not expecting a 3 foot tall bag but whatever
Mounir alami
The product was good and on time I picked it up with no problem
Like it!
It is great! I have been using it for about 1 year and I love it! It has helped me to gain weight and to build muscles!
Great taste
My favorite gainer! Tastes great
Serious Mass
Serious Mass is excellent but in the last online purchase the store had an error charging me for the product and then making me a return
Great
Love it. Recommend buying , personally have it shipped every month
10/10 but only with oatmeal, Milk and Peanut butter
Gets u nice and chubby u have to take it with milk and peanut butter and oatmeal
Can't eat 5,000 calories? Drink it.
Put on 15lbs in 3-4 months putting 2 scoops of this, 3 scoops of ice cream, 2 spoonfuls of peanut butter, and finishing that off with whole milk in a shake, in addition to eating until I wanted to puke everyday (whatever high caloric/high protein meal works best for you.) Not a clean bulk and not for everyone, but if you're lanky and need to bulk for football or any athletic activity, this might be right for you.
GREAT if you have a fast metabolism
Amazing product, haven't been able to put on weight ever. Added this to my diet once a day and made a HUGE impact. Finally putting on weight and muscle. Feeling much better in my skin. Struggled with having an extremely fast Metabolism all my life it's great to finally find something that works ?? will definitely continue to purchase ?? thanks
Great For Bulking
I used to weigh 130 for 8 years I had struggled with gaining weight my whole life. I started taking creatine ashwaganda and whole foods multivitamins and serious mass protein. Currently weigh 150 i had to take a break from the mass gainer as I was gaining weight faster than I wanted so I have been off it for about 3 seeks and I am still 150 and now I am caught my strength up to my body weight and now will continue the bulk to hopefully 160 by the end of the year the ultimate goal is 170 for me personally 5'10 male.
Question
How much pounds of muscle will you gain if you go 6 times a week to the gym or will you gain mostly just fat?
Mass Gainer
this product has helped me gain 3 pounds in just a week! will definitely continue using it to help me hit my goals
Great product for swimmers
Helped me to reach my macro goals daily, tried blending with some carbs worked out well.
tastes amazing with fruits and milk
Great taste/weight gainer
I really like the peanut butter flavor. It tastes great with milk. You have to drink it cold in order to have a better taste going down. I have been adding a spoon full of peanut butter to the mix as well for extra calories. I have gained a few pounds, but nothing to noticeable yet. I will keep drinking it though since it tastes good.
Flag
About Serious Mass - Vanilla (16 Servings) Rated 5 out of 5 Purchased on Jun 9, 2023 This review was collected as part of a promotion Great...truly the gold standard BRANDED INSTANT I Verified Purchaser Jul 16, 2023 Was this helpful? 0 1 Flag Review by BRANDED INSTANT I has been flagged Flag
Rated 1 out of 5 Purchased on Mar 21, 2023 This review was collected as part of a promotion Gave me stomach problems. Miguel G Verified Purchaser Apr 12, 2023 Was this helpful? 7 4 Flag Review by Miguel G has been flagged Flag
^When used in conjunction with an exercise program
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.