The first supplement created specifically for runners to stop bathroom issues before they start.
Clinically effective doses of 4 ingredients scientifically shown to improve gut health and reduce gastric distress to ensure you never need to carry toilet paper again.
4.9/5.0 513+ Happy Athletes
4.9/5.0 513+ Happy Athletes
Clinically effective ingredients scientifically shown to improve gut health & reduce gastric distress to ensure you never need to carry toilet paper again.
The first supplement created specifically for runners to stop bathroom issues before they start.
I honestly can’t believe this product worked so well. Before using flush, I’d be scrambling back home to go to the bathroom at least 3 days per week. It made me scared to go to group runs or even try out new trails for fear of not having a bathroom nearby. I’ve been using for 3 weeks now and not once have I had to go to the bathroom once I started running. This is such a relief!
I tried this product during the beta launch because I really struggled with stomach pain when racing and even after hard workouts. There were times after hard workouts that it would take hours for my stomach to feel normal. MAS Flush changed everything. I’ve been using it for a month and I haven’t had any stomach pain after workouts. I’m so glad I found this.
I’ve tried countless gut products, but this is the one that actually worked. For the first time in years, my digestion feels normal. No more discomfort, bathroom urgency, or unpredictable bloating. It’s been such a relief. This formula actually works.
I honestly thought needing to go to the bathroom within the first few miles of a run were just something all runners needed to deal with. I was given MAS Flush as a gift during a running retreat and I was definitely skeptical, but I didn’t need to go to the bathroom during the 3 runs we did at the retreat, which is unusual, so I kept using. It’s been working every day for the last 3 weeks. I can’t believe I didn’t look into something like this sooner.
Every runner fears starting a run without nearby bathrooms.
Frequent needs to go to the bathroom early in a run are usually caused by not being able to quickly digest the foods you ate for dinner or when your digestive system isn’t able to keep up and you have inconsistent bathroom times.
MAS Flush contains Psyllium seed husks, which when taken in the evening helps make bowel movements easier and more consistent.
It can also help add bulk to stool, which helps relieve the feeling of needing to go to the bathroom. This is especially helpful due to the jostling that occurs in the digestive tract during running.
Taking just two MAS Flush capsules after dinner will make it easy to go to the bathroom as soon as you wake up so you can virtually eliminate needing to go to the bathroom during your runs.
Put an end to stomach pain and cramping during and after hard workouts that lead to you slowing down and not getting the most from your performance.
Stomach issues during races and hard workouts often happen for two reasons.
First, endotoxins (bacterial toxins) are released during strenuous, long-duration exercise which lead to cytokine release, oxidative stress, and altered gastrointestinal function.
Second, internal and exertional heat stress causes blood to be redistributed away from the digestive system to help with thermal regulation. As a result, lack of blood supply stresses the gut, which results in bathroom and stomach issues.
MAS Flush’s combination of Bifidobacterium Longum and New Zealand Blackcurrant have been shown in research to
Despite eating a healthy diet, research has shown that we often don’t properly absorb all the vital nutrients we eat because we fail to properly digest.
The bioavailability of the foods we eat is determined by a number of factors, but probiotics such as ProbioSEB® and Bifidobacterium Longum have been shown in research to…
MAS Flush helps ensure you actually absorb the nutrients you need from your diet.
One of the most difficult things about racing half, full and ultra marathons is taking in enough fuel to keep your glycogen levels topped off without causing stomach issues.
All that simple sugar is difficult for your body to process quickly, which is a main contributor to why many runners suffer to fuel properly during races.
The included Bifidobacterium in MAS flush has been shown in research to improve carbohydrate absorption and metabolism during endurance races, potentially sparing muscle glycogen during prolonged exercise.
Additionally, Bifidobacterium may help maintain gut barrier integrity, reduce gastrointestinal distress, and improve nutrient absorption.
There’s a reason we often refer to hard workouts as “gut-busting”. That’s because they often leave us with stomach discomfort after the workout.
But, these intense workouts won’t mean a thing if you’re not able to properly recover; and recovery starts with refueling.
The probiotics in MAS Flush have been shown in research to reduce post-workout stomach discomfort so you can jump start your recovery process with the nutrients your muscles need.
Many runners knowingly or unknowingly suffer from stomach issues from difficult to digest foods such as legumes, lactose, soy, various grains, and meats.
Usually, this is caused by not producing enough of the enzymes that help break down these foods.
Our formula of ProbioSEB® and other probiotics helps your body naturally digest these foods by stimulating the production of digestive enzymes and improving gut microbiota to create a more favorable environment for your stomach to properly digest all the foods you need to eat to fuel your training and recovery.
The included bifidobacteria is specifically targeted to digest fiber and other complex carbs your body can’t digest on its own.
Every runner fears starting a run without nearby bathrooms.
Frequent needs to go to the bathroom early in a run are usually caused by not being able to quickly digest the foods you ate for dinner or when your digestive system isn’t able to keep up and you have inconsistent bathroom times.
MAS Flush contains Psyllium seed husks, which when taken in the evening helps make bowel movements easier and more consistent.
It can also help add bulk to stool, which helps relieve the feeling of needing to go to the bathroom. This is especially helpful due to the jostling that occurs in the digestive tract during running.
Taking just two MAS Flush capsules after dinner will make it easy to go to the bathroom as soon as you wake up so you can virtually eliminate needing to go to the bathroom during your runs.
Put an end to stomach pain and cramping during and after hard workouts that lead to you slowing down and not getting the most from your performance.
Stomach issues during races and hard workouts often happen for two reasons.
First, endotoxins (bacterial toxins) are released during strenuous, long-duration exercise which lead to cytokine release, oxidative stress, and altered gastrointestinal function.
Second, internal and exertional heat stress causes blood to be redistributed away from the digestive system to help with thermal regulation. As a result, lack of blood supply stresses the gut, which results in bathroom and stomach issues.
MAS Flush’s combination of Bifidobacterium Longum and New Zealand Blackcurrant have been shown in research to
Despite eating a healthy diet, research has shown that we often don’t properly absorb all the vital nutrients we eat because we fail to properly digest.
The bioavailability of the foods we eat is determined by a number of factors, but probiotics such as ProbioSEB® and Bifidobacterium Longum have been shown in research to…
MAS Flush helps ensure you actually absorb the nutrients you need from your diet.
One of the most difficult things about racing half, full and ultra marathons is taking in enough fuel to keep your glycogen levels topped off without causing stomach issues.
All that simple sugar is difficult for your body to process quickly, which is a main contributor to why many runners suffer to fuel properly during races.
The included Bifidobacterium in MAS flush has been shown in research to improve carbohydrate absorption and metabolism during endurance races, potentially sparing muscle glycogen during prolonged exercise.
Additionally, Bifidobacterium may help maintain gut barrier integrity, reduce gastrointestinal distress, and improve nutrient absorption.
There’s a reason we often refer to hard workouts as “gut-busting”. That’s because they often leave us with stomach discomfort after the workout.
But, these intense workouts won’t mean a thing if you’re not able to properly recover; and recovery starts with refueling.
The probiotics in MAS Flush have been shown in research to reduce post-workout stomach discomfort so you can jump start your recovery process with the nutrients your muscles need.
Many runners knowingly or unknowingly suffer from stomach issues from difficult to digest foods such as legumes, lactose, soy, various grains, and meats.
Usually, this is caused by not producing enough of the enzymes that help break down these foods.
Our formula of ProbioSEB® and other probiotics helps your body naturally digest these foods by stimulating the production of digestive enzymes and improving gut microbiota to create a more favorable environment for your stomach to properly digest all the foods you need to eat to fuel your training and recovery.
The included bifidobacteria is specifically targeted to digest fiber and other complex carbs your body can’t digest on its own.
MAS Flush is more than just a probiotic. We’ve carefully chosen the specific strains of bacteria and yeasts proven to help the most for athletes. Then we combined them with cutting-edge ingredients that help improve all the unique aspects of gut health runners and endurance athletes face.
Psyllium, derived from the plants known as ispaghula, is a primarily soluble, bulk-forming fiber supplement shown in research to help improve digestive and metabolic health.
Compared to similar fibers, psyllium is less fermentable in the gut, which means it’s less likely to produce flatulence, stomach pain, and nausea.
Research has demonstrated that psyllium makes bowel movements easier and more consistent which can help alleviate the issue of runner’s trots by ensuring you’re able to go to the bathroom before your run1.
Psyllium has also been shown in research can help add bulk to stool, which helps relieve the feeling of needing to go to the bathroom. This is especially helpful due to the jostling that occurs in the digestive tract during running.
1. Jalanka J, Major G, Murray K, Singh G, Nowak A, Kurtz C, Silos-Santiago I, Johnston JM, de Vos WM, Spiller R. The Effect of Psyllium Husk on Intestinal Microbiota in Constipated Patients and Healthy Controls. Int J Mol Sci. 2019 Jan 20;20(2):433. doi: 10.3390/ijms20020433. PMID: 30669509; PMCID: PMC6358997.
ProbioSEB Duo can help restore a healthy balance of microflora.
Unlike other probiotic formulas, ProbioSEB Duo withstands extreme conditions to successfully reach its destination within the body at full power.
The probiotic bacteria in ProbioSEB Duo create a favorable environment for the growth of “good microflora” in the large intestine, supporting normal functioning such as absorption of water and nutrients and passage of waste products.
One of the most common reasons runners experience bathroom issues later into runs and races is due to internal and exertional heat stress. This is because blood is redistributed away from the digestive system to help with thermal regulation.
As a result, lack of blood supply stresses the gut, which results in bathroom and stomach issues.
Recent research has shown that New Zealand blackcurrant…
1. Willems MET, Flood TR, Kuennen MR, Lee BJ. Anthocyanin-rich New Zealand blackcurrant extract reduces treadmill running-induced gastrointestinal symptoms in the heat: pilot observations. Res Sports Med. 2025 Jul-Aug;33(4):440-447. doi: 10.1080/15438627.2025.2471380. Epub 2025 Feb 25. PMID: 39996414.
2. Lee BJ, Flood TR, Hiles AM, Walker EF, Wheeler LEV, Ashdown KM, Willems MET, Costello R, Greisler LD, Romano PA, Hill GW, Kuennen MR. Anthocyanin-Rich Blackcurrant Extract Preserves Gastrointestinal Barrier Permeability and Reduces Enterocyte Damage but Has No Effect on Microbial Translocation and Inflammation After Exertional Heat Stress. Int J Sport Nutr Exerc Metab. 2022 Mar 14;32(4):265-274. doi: 10.1123/ijsnem.2021-0330. PMID: 35287112.
Bifidobacteria are a type of probiotics, which are healthy bacteria found in your intestines that help digest fiber, prevent infections, and produce important compounds, such as B vitamins and healthy fatty acids.
One of the main functions of bifidobacteria is to digest fiber and other complex carbs your body can’t digest on its own, which can lead to bathroom issues.
Specifically, bifidobacteria supplementation has been shown in research to significantly lower the incidence and severity of GI symptoms in marathon runners1.
Research has also shown that runners who supplemented with bifidobacteria saw a reduction in the severity of GI symptoms during training2 as well as a reduction in the duration of GI symptoms post-race3.
1. Kekkonen RA, Vasankari TJ, Vuorimaa T, Haahtela T, Julkunen I, Korpela R. The effect of probiotics on respiratory infections and gastrointestinal symptoms during training in marathon runners. Int J Sport Nutr Exerc Metab. 2007 Aug;17(4):352-63. doi: 10.1123/ijsnem.17.4.352. PMID: 17962710.
2. Roberts JD, Suckling CA, Peedle GY, Murphy JA, Dawkins TG, Roberts MG. An Exploratory Investigation of Endotoxin Levels in Novice Long Distance Triathletes, and the Effects of a Multi-Strain Probiotic/Prebiotic, Antioxidant Intervention. Nutrients. 2016 Nov 17;8(11):733. doi: 10.3390/nu8110733. PMID: 27869661; PMCID: PMC5133117.
3. Pugh JN, Sparks AS, Doran DA, Fleming SC, Langan-Evans C, Kirk B, Fearn R, Morton JP, Close GL. Four weeks of probiotic supplementation reduces GI symptoms during a marathon race. Eur J Appl Physiol. 2019 Jul;119(7):1491-1501. doi: 10.1007/s00421-019-04136-3. Epub 2019 Apr 13. PMID: 30982100; PMCID: PMC6570661.
While almost any probiotic will help improve your gut health, you have unique challenges and needs as a runner that generic probiotics just don’t address.
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|---|---|---|
| Helps alleviate needing to go to the bathroom as soon as you start running | ||
| Formulated to target endotoxins to eliminate stomach pain during races | ||
| Designed to reduce heat stress, a major cause of GI distress when racing and working out hard | ||
| Specific ingredients to improve carbohydrate absorption and metabolism while running | ||
| Advanced digestive enzymes to naturally digest fiber, complex carbs, and other difficult to digest foods |
Experience the benefits of a healthy gut, better digestion and no more bathroom fears
MAS Flush works best if you take it every day.
In addition to alleviating bathroom issues before and during running, the probiotics in MAS Flush help you more efficiently digest foods, absorb nutrients, and create a favorable environment for the growth of “good microflora” in the large intestine.
That said, if you only wanted to use on the days you run for the improvement of bowel movements, it will still work great.
Like almost any product, you should definitely use MAS Flush a few times during your training cycle before using it during a race.
The most significant results and changes often occur during the first few uses as your gut and digestive system experience ingredients for the first time.
However, we did specifically formulate the product to help with many of the digestive challenges we face during the race so it should be a significant aid during your most important performances.
Yes, MAS Flush is safe to take with any other probiotic or gut health product you may be taking.
The current medical literature has found that it’s difficult to overdose on probiotics or experience dangerous side effects from a large dose of probiotics.
You should not notice any side effects when taking MAS Flush.
That said, the most significant results and changes often occur during the first few uses as your gut and digestive system experience ingredients for the first time.
This means your bowel movements the first evening and the morning after you’re your first few doses may be more noticeable than they will be as you continue to use the product.
MAS Flush should be taken in the evening, ideally after your last meal.
That’s because one of the main ingredients, psyllium husks, takes at least a few hours take effect in the bowels.
This means that when you take it in the evening, it should make it easier to go to the bathroom as soon as you wake up. In addition, it helps improve bowel movements so you evacuate more during this first bathroom visit, making sure you don’t need to go as you start your run or during.
Probiotics and the ingredients in MAS Flush are generally considered safe, but if you have any concerns you should definitely contact your healthcare professional first.
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Try MAS Flush and if you don’t love it or you’re unhappy for any reason, just let us know via email or phone and we’ll refund your money. No product return needed or complicated policies.
04 Customer(s) recommended this item
I tried this product during the beta launch because I really struggled with stomach pain when racing and even after hard workouts. There were times after hard workouts that it would take hours for my stomach to feel normal. MAS Flush changed everything. I’ve been using it for a month and I haven’t had any stomach pain after workouts. I’m so glad I found this.
I honestly can’t believe this product worked so well. Before using flush, I’d be scrambling back home to go to the bathroom at least 3 days per week. It made me scared to go to group runs or even try out new trails for fear of not having a bathroom nearby. I’ve been using for 3 weeks now and not once have I had to go to the bathroom once I started running. This is such a relief!
I love how regular this makes my morning bathroom routine. I used to fear the mornings I’d wake up and not need the bathroom since I knew it was going to happen on the run. Since starting Flush I am so much more regular in the morning and it’s such a relief
I struggled for years with bloating and sluggish digestion. After 3 weeks on this product, my digestion is smooth, and I feel lighter every day! It’s like hitting the reset button on my gut health. I’m hooked!
Please email us at support@masedge.com with the word “Cancel Order” in the subject line. Please note that we cannot guarantee order cancellation as we ship very quickly – but we’ll do our best.
At this time, we are unable to make any changes or edits to orders once they have been shipped – this includes the shipping address. Please review your information before completing your order.
Many companies offer a money-back guarantee because they know the majority of dissatisfied customers aren’t going to go through the hassle of actually returning the product to get their money back.
We don’t play these games because we don’t have to, the quality of our products makes it unnecessary.
If you order any of our supplements for the first time and don’t like it, you can keep it. Just notify us and we’ll give you a full refund. No complicated forms and no return necessary.
To protect ourselves from fraud, the It’s-On-Us guarantee is only valid for first-time purchases of a product, and redeemable up to 365 days after purchase. If you bought more than one supplement and weren’t happy with your purchase, in some instances, we may ask that you send the products back to us for a refund. Don’t worry though, you’ll never have to pay for return shipping.
Yes, just login to your account here and you’ll be taken to the subscriptions page where you can modify your preferences.
Most US orders arrive within 3 to 5 business days, but can take up to 7 business days.
Orders to Canada and the UK usually arrive in 10 to 14 days. Orders to other countries generally arrive within 14 to 21 days. Customs clearance may add a few extra days to this as well.
Yes, you will receive a tracking number via email.
Some orders get marked as delivered by our fulfillment house when they’re actually a day or two away.
If your order hasn’t arrived within two business days of being marked as delivered, contact us and we’ll help you out.
Unfortunately, we can’t ship to some countries because they’re very strict on what supplements they will and won’t allow to cross their borders, and too many customers were losing their orders.
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