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White container labeled Momentous Fiber in Pure Cinnamon flavor, 13.1oz dietary supplement powder.
White cylindrical jar with white lid containing Momentous Fiber dietary supplement, 12.3oz net weight.
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Fiber+ Exclusive powder in a beige container displayed next to a glass of water and a mixed tan-colored beverage.
Clear glass with water being poured from a pitcher, held in a person's hand showing the product in use.
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Supplement Facts label for Pure Cinnamon Fiber+ Exclusive showing serving size, calories, carbohydrates, dietary fiber, and i
Supplement Facts label for unflavored fiber powder showing 2 scoop serving with 6g dietary fiber and ingredients including ps
White container labeled Momentous Fiber in Pure Cinnamon flavor, 13.1oz dietary supplement powder.
White cylindrical jar with white lid containing Momentous Fiber dietary supplement, 12.3oz net weight.
Man wearing black aviator sunglasses and dark t-shirt holding a cylindrical metallic container outdoors.
Muscular man flexing biceps in profile against gray background, black and white.
Fiber+ Exclusive powder in a beige container displayed next to a glass of water and a mixed tan-colored beverage.
Clear glass with water being poured from a pitcher, held in a person's hand showing the product in use.
Muscular man flexing outdoors in black and white, wearing black shorts against mountainous background.
Supplement Facts label for Pure Cinnamon Fiber+ Exclusive showing serving size, calories, carbohydrates, dietary fiber, and i
Supplement Facts label for unflavored fiber powder showing 2 scoop serving with 6g dietary fiber and ingredients including ps
4.7
Rated 4.7 out of 5 stars
177

Fiber+ Exclusive

30 Servings Per Container: $1.42/Serving

Exclusive first-batch offer of our new complete fiber supplement for Pump Club members: only 500 available

  • Comprehensively targets gut health
  • Soluble and insoluble fibers + resistant starch
  • Digestion, gut microbiome diversity, and energy
Select Flavor: Pure Cinnamon
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"The product is excellent! It really helped me to get regular, drop my blood sugar levels and helped me to control hunger."

Pietro (Verified Customer)

"Solid foundational product that covers all the important fundamentals. Lab tested so the label matches ingredients."

Robert (Verified Customer)

"Cool to see how they crafted this formula to have a few different types of fiber to maximize results."

Emil (Verified Customer)

More than just fiber, Fiber+ targets comprehensive gut health

A blend of soluble and insoluble fibers, including psyllium husk, plus resistant starch to support comfortable + regular digestion, gut microbiome diversity, and steady energy.

In a category that hasn’t seen evolution in decades, we’re introducing a new kind of gut health formula: one containing both soluble and insoluble fibers in addition to resistant starch, for a truly comprehensive approach to gut health that can keep up with high performance demands.

  • Complete Digestive Support

The comprehensive combination of soluble fiber, insoluble fiber, and resistant starch promotes digestive regularity without bloating or discomfort.

  • Full-Spectrum Gut Health

Resistant starch acts as a prebiotic to feed healthy gut bacteria, which in turn support the production of short-chain fatty acids (SCFAs) that strengthen the gut barrier and promote long-term gut and metabolic health.

  • Steady + Stable Energy 

Helps maintain balanced blood sugar levels throughout the day, with no spikes or crashes, for steady and stabilized energy. 

  • Made to The Momentous Standard™

Fiber+ is made without unnecessary additives or artificial or natural flavors. The Pure Cinnamon flavor system uses only real Cinnamon Bark Powder and Reb M (a natural sweetener).

Supports Digestive Regularity and Comfort

Psyllium husk and rice bran work together to promote healthy digestive function. Soluble fiber from psyllium forms a viscous gel that increases stool hydration and eases motility, while insoluble fiber from rice bran adds bulk for smoother transit. Together, they help reduce occasional bloating and constipation and support regular, comfortable digestion.

Contributes to a Diverse Gut Microbiome

Resistant potato starch acts as a clinically validated prebiotic that escapes digestion in the small intestine. Once in the colon, the starch is fermented by beneficial bacteria into short-chain fatty acids (SCFAs) like butyrate—a key energy source for intestinal cells that strengthens the gut barrier and fosters microbial diversity. Studies show Solnul™ resistant potato starch increases Bifidobacterium and Akkermansia abundance and enhances digestive comfort.

Helps Maintain Steady Energy and Blood Sugar

Soluble fibers, like the ones in Fiber+, slow the breakdown and absorption of carbohydrates, reducing post-meal glucose spikes and preventing rapid energy drops. Meanwhile, the SCFAs produced from the resistant potato starch fermentation improve insulin sensitivity and overall metabolic efficiency. Together, these actions support steadier energy and more balanced blood sugar throughout the day.

Mix 2 scoops (6g fiber) with at least 12–16 fl oz of liquid daily. Can be added to water or your protein shake. Drink shortly after mixing to maintain texture.

If you’re new to fiber, start with 1 scoop for the first few days, then increase to the full serving as tolerated.

To support absorption, take Fiber+ at least 2 hours before or after medications. Adequate fluid intake is important when using fiber supplements.

*Experts recommend a daily fiber intake of 22–34 grams, depending on age and body composition.Consult a healthcare professional if pregnant, nursing, taking medication, or if you have a medical condition.

Pure Cinnamon: Psyllium Husk, Resistant Potato Starch (Solnul®), Rice Bran Hull

Other Ingredients: Maize Starch, Cinnamon Bark Powder, Sunflower Lecithin, Reb M*

Unflavored: Psyllium Husk, Resistant Potato Starch (Solnul®), Rice Bran Hull

Other Ingredients: Maize Starch, Sunflower Lecithin

*Reb M is a natural, plant-based sweetener with zero glycemic response or aftertaste. Our Reb M is made from fermented sources and is 250× sweeter than sugar without bloating, 2.5× sweeter than monk fruit, and made sustainably with less land, water, and crop rotation.

Take Fiber+ daily to support regularity and gut health — morning, before meals, or in the evening all work. Whenever is most consistent for your schedule. 

You may notice easier, more regular stools within 12–48 hours, with fuller microbiome and metabolic benefits building over 1–4 weeks of steady use.

Expect improved bowel comfort, better stool quality, reduced bloating over time, and added satiety/steadier blood sugar when your intake is consistent.

Frequently Asked Questions

Momentous Fiber+ was designed in partnership with Arnold Schwarzenegger’s Pump Club for those pursuing Performance for Life™. In celebration of the partnership, we wanted to offer a first batch exclusive of our Fiber+ prototype to Pump Club members to try before the general public. In an effort to provide exclusive access as soon as possible, we shipped this prototype straight from the production line. 

Professional athletes should note this prototype version has NOT YET been NSF Certified for Sport®.

Adequate fiber supports gut health, nutrient absorption, sustained energy, metabolic stability, and long-term digestive resilience—all essential for maintaining high performance as you age.

Yes. Consistent fiber intake helps keep your system moving smoothly, even when travel, training, stress, or inconsistent meals might otherwise disrupt digestion.

Take Fiber+ daily to support regularity and gut health - morning, before meals, or in the evening all work. Whenever is most consistent for your schedule. 

You may notice easier, more regular stools within 12–48 hours, with fuller microbiome and metabolic benefits building over 1–4 weeks of steady use.

Expect improved bowel comfort, better stool quality, reduced bloating over time, and added satiety/steadier blood sugar when your intake is consistent.

Take Fiber+ at the time of day you can be most consistent — that’s what drives the biggest digestive and metabolic benefits. Morning hydration, with your first meal, in a protein shake, or evening wind-down all work.


If you want targeted effects:

  • Before meals can support fullness and steadier post-meal energy
  • With meals or shakes makes it easiest to build a habit
  • Anytime of day is effective for gut health and regularity

Fiber+ is gentle enough for an empty stomach, and the microbiome benefits build with daily use, not specific timing.

Fiber is foundational nutrition. Daily intake mirrors what your body expects from a high-quality diet and helps maintain long-term digestive and metabolic health.

Yes, Fiber+ mixes well with protein, creatine, and most supplements, and normal daily fiber intake doesn’t block nutrient absorption. You can take it alongside your morning stack or add it directly to your shake.

If you’re new to fiber or have a sensitive stomach, you can start with 1 scoop for the first few days, then increase to the full serving.

For habit-building, pair Fiber+ with an existing routine cue like pouring your morning water, making a shake, sitting down to breakfast, or evening routine — whatever helps you take it daily.

As a celebration of the Momentous x Arnold’s Pump Club partnership, we wanted to give a first batch exclusive of our Fiber+ prototype to Pump Club members so they can try the formula before it launches to the general public. As a result of wanting to give exclusive access as soon as possible, we shipped this prototype straight from the production line. The NSF Certified for Sport® process takes an additional 4-6 weeks.

Professional athletes should note this prototype version has NOT YET been NSF Certified for Sport®.

4.7
Rated 4.7 out of 5 stars
Based on 177 reviews
Total 5 star reviews: 150 Total 4 star reviews: 17 Total 3 star reviews: 6 Total 2 star reviews: 0 Total 1 star reviews: 4
94%would recommend these products
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Reviews Summary
Customers say this fiber supplement has excellent taste, especially the cinnamon flavor which many compare to cinnamon cereal or toast. Users find it mixes easily into smoothies, protein shakes, oatmeal, yogurt, and water without becoming gritty or clumpy. Many appreciate that it helps with regularity and keeps them feeling full longer. The unflavored version is described as tasteless and versatile. Some mention the powder can have small chunks or needs to be consumed quickly after mixing to avoid texture changes. Most users report positive digestive results within days or weeks of use.
Customers Talked About
177 reviews
  • J
    Joseph
    10 hours ago
    Reviewing
    Fiber+
    Rated 5 out of 5 stars
    5 Stars

    Works. Tastes good. Will continue to buy.

  • TK
    Tracy K.
    Verified Buyer
    Product Standouts Taste + Texture, Ease of Use, Results, Trust and Transparency
    13 hours ago
    Product Standouts Taste + Texture, Ease of Use, Results, Trust and Transparency
    Reviewing
    Fiber+
    Rated 5 out of 5 stars
    Great product

    As usual, Momentous delivers quality products and this is no exception. Provides all of the benefits as advertised. I switched from a product that I used for years and have no regrets

  • JC
    john c.
    Verified Buyer
    Product Standouts Results, Trust and Transparency, Taste + Texture
    Yesterday
    Product Standouts Results, Trust and Transparency, Taste + Texture
    Reviewing
    Fiber+
    Rated 5 out of 5 stars
    Good quality

    Very good quality product, works week

  • EM
    Elizabeth M.
    Verified Buyer
    Yesterday
    Reviewing
    Fiber+
    Rated 5 out of 5 stars
    Working

    Really

    Makes a difference with stomach issues

  • MS
    Michael S.
    Verified Buyer
    Product Standouts Results, Taste + Texture, Ease of Use, Trust and Transparency
    3 days ago
    Product Standouts Results, Taste + Texture, Ease of Use, Trust and Transparency
    Reviewing
    Fiber+
    Rated 5 out of 5 stars
    Feeling full!

    I take it every day first thing in the morning. I didn’t think I’d enjoy taking a fiber supplement, but this one really has good flavor and not too grainy. I am on a GLP-1 and adding this supplement has only been a positive. Not only do I feel more full, it has spared me from a lot of the gastrointestinal side effects of the shots. I used to get a little bound up in the days after taking a shot. Now, I stay regular!