What You Need to Know About Sodium Bicarbonate Side Effects

Anyone who’s done interval or hill workouts or lifted heavy knows the feeling—that achy, burning sensation in your muscles that grinds your workout to a halt. It’s painful, annoying, and pretty much impossible to push through.

Fortunately, there’s a science-backed solution to this common roadblock: Ingest sodium bicarbonate beforehand to prolong the arrival of that dreaded burn. Also known as baking soda, sodium bicarbonate is a well-studied, legal performance enhancer that athletes have been relying on for decades. So why isn’t it more mainstream?

Well, the major caveat is that for some folks, downing baking soda preworkout can seriously screw with your stomach and cause a host of GI issues including bloating, nausea, and vomiting. If that sounds unpleasant, it is—and it can overpower any benefit you’d gain from loading up on sodium bicarbonate.

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Ahead, all you need to know about the link between sodium bicarbonate and athletic performance, including the benefits and downsides, as well as info on a new product by raved-about sports fuel company Maurten, which promises the best of both worlds: performance enhancement with minimal GI distress.

What is sodium bicarbonate?

In simple terms, sodium bicarbonate is baking soda—a household staple that many of us use to make cookies and cakes, tamp down stinky fridge odors, and clean various surfaces. When taken for athletic performance, sodium bicarbonate is often ingested in a capsule form or by drinking the powder mixed with water, and sometimes other flavors to mask its bitter taste.

Maurten’s new product, marketed as the Maurten Bicarb System, offers sodium bicarbonate in the form of mini tablets. The product includes their water-based gel. So when you order the product, you receive the hydrogel component, the bicarbonate component, and a mixing bowl so you can combine them.

How can sodium bicarbonate help athletic performance?

Decades of research support the idea that taking specific doses of sodium bicarbonate before certain types of workouts can improve athletic performance. In fact, as Maurten points out in its marketing materials, the International Olympic Committee recognizes sodium bicarbonate as one of five legal supplements “with good to strong evidence” of performance benefits in specific scenarios. (The other four substances are caffeine, creatine, nitrate, and beta-alanine.)

A 2021 review published by the International Society of Sports Nutrition (ISSN) concluded that ingesting sodium bicarbonate can boost performance across a number of different workouts, including combat sports, muscular endurance activities, and high-intensity bouts of cycling, running, swimming, and rowing. The benefits of sodium bicarbonate are most established for high-intensity bursts of exercise lasting between 30 seconds and 12 minutes, per the ISSN.

How, exactly, can sodium bicarbonate enhance your workout? Put simply, it helps enhance your blood’s ability to maintain optimal pH levels during anaerobic exercise (basically, any form of high-intensity exercise that lasts between 30 seconds up to several minutes). When you perform anaerobic exercise, your muscle cells produce hydrogen ions rapidly that can accumulate within your muscle cells. These hydrogen ions lower the pH of your cells, making them more acidic.

To reduce this acidity, your cells attempt to buffer against this hydrogen ion accumulation. One buffering process is to push some of the hydrogen ions into your blood, where your body then uses its own natural supply of sodium bicarbonate to combat acidity while maintaining a normal blood pH range, says Fabio Comana, faculty lecturer at San Diego State University and master instructor for the National Academy of Sports Medicine.

Thing is, your body only has so much sodium bicarbonate available, so once the supply runs low, your blood stops accepting hydrogen ions from your muscle cells. As a result, it builds up in your muscles, causing that burning, achy feeling we all know too well. This is your body’s way of telling you to slow down or stop exercising altogether so that it can have a chance to regenerate its sodium bicarbonate supply, Comana explains.

By taking sodium bicarbonate as a supplement before your workout, you can increase the amount of this compound in your blood and therefore be able to tolerate more hydrogen spillover before your muscles yell at you to stop, says Comana. In other words, you’ll be able to perform at a higher intensity and/or for a longer period of time before having to take a break.

The benefits of sodium bicarbonate are most proven to help athletes who participate in anaerobic-based events, like sprinting or heavy lifting. That said, people who partake in endurance events, like steady-state running or cycling, could still get some boost from taking sodium bicarbonate if their event includes sprints during or at the end of the competition, per the ISSN.

So, cyclists participating in any race that requires a sprint, or major push in pace, could see some perks to taking sodium bicarbonate. Even athletes partaking in longer events may benefit: A 2020 study involving 11 male cyclists found that when athletes took sodium bicarbonate before and during a three-hour race, they exerted 3 percent more power during a 90-second sprint at the end of the race, compared to when they took a placebo.

What are the side effects of sodium bicarbonate?

Here’s the thing: Ingesting sodium bicarbonate can lead to a number of GI issues, including bloating, nausea, vomiting, and abdominal distress, says Comana. Indeed, the ISSN lists these as the most common side effects of sodium bicarbonate supplementation and notes that they can harm exercise performance.

These side effects arise because sodium bicarbonate is alkaline and so when you put it into your stomach, which is very acidic, your body reacts by producing more gastric acid. This results in a release of gasses that those unpleasant side effects, explains Comana, who speaks from firsthand experience.

He’s taken sodium bicarbonate before a workout three separate times. “I didn’t want to throw up, but I just didn’t feel right, I just didn’t feel good,” he recalls. “My general perceptions of it were, yeah, this wasn’t too much fun.” But, he adds, “for every one of me, there’s probably others that had no effect and they loved it.” Indeed, per the ISSN, the incidence and severity of sodium bicarbonate side effects “varies between and within individuals, but it is generally low.”

If sodium bicarbonate messes with your stomach, you can try prolonging the period during which you consume it as a way to reduce the risk of GI upset, says registered dietitian Marisa Michael, RDN, CSSD, board certified specialist in sports dietetics. “Sip it mixed with water slowly over two to three hours before your event, rather than drinking it quickly immediately beforehand,” she advises.

Additionally, a 2011 study involving 13 athletes concluded that ingesting sodium bicarbonate along with a carb-rich meal could reduce GI symptoms.

What’s with the new Maurten product?

The Maurten Bicarb System promises to deliver the performance benefits of sodium bicarbonate while reducing the risk of GI issues. That’s because the product is formulated to stay intact in the stomach—thus bypassing that acidic environment—and only break down once it reaches the small intestine, Joshua Rowe, a performance scientist at Maurten, tells Runner’s World.

Essentially, the gel creates a protective structure around the mini tablets of sodium bicarbonate to prevent them from breaking down in the stomach. Additionally, the small diameter of the tablets helps them pass easily through the stomach and reach the small intestine still intact, Rowe explains.

Based on internal testing with employees and Maurten athletes—including ultrarunner Killian Journet, who consumed the product during a 100-mile race in Sweden as well as the Ultra-Trail du Mont-Blanc, and Olympic speed skater Nils van der Poel, who used it during the 2021-2022 season—the formulation has so far proved successful at boosting performance while quashing GI issues.

Just keep in mind: There’s no independent research (at least not yet) that validates these claims. Moreover, the product is significantly pricier than baking soda: $65 for a box of four servings versus about $7 for a 1-pound box of Arm & Hammer.

“There is no evidence I am aware of that this product is useful, and it could potentially hamper the useful ergogenic effects of sodium bicarbonate if it is ingested in a slower-digesting gel form,” Michael says.

According to Rowe, a university in the United Kingdom is currently studying the effectiveness of the Maurten sodium bicarbonate product compared to traditional sodium bicarbonate supplementation and plans to publish its results later this year.

What should you know before taking sodium bicarbonate?

Curious to try sodium bicarbonate yourself? Start with a small dose, suggests Comana. “It’s a good idea to wean yourself onto it,” he says. “Don’t just dive into a big dose because you may get the side effects.”

The ISSA recommends taking between 0.2 and 0.3 grams of sodium bicarbonate per kilogram of bodyweight as a single dose about one to three hours before a workout or competition. So, a 165-pound athlete would aim to ingest 15 to 22 grams prior to their event.

That said, you may consider starting with a smaller dose—say, 0.1 grams per kilogram bodyweight—and “see how that feels,” says Comana. Though any amount less than 0.2 grams per kilogram bodyweight has not been proven to enhance performance, per the ISSA, starting with a low amount could help you ease into sodium bicarbonate consumption while minimizing your risk of side effects. If you tolerate it okay, then you can try upping your dosage, says Comana.

Another approach is to gradually load up on smaller doses of sodium bicarbonate for multiple days before your big workout or competition, per ISSA. This can reduce the risk of side effects during your event. Instead of taking just one dose of sodium bicarbonate the day of your workout, you’d consume 0.4 or 0.5 g/kg per day for three to seven days prior to race day. You’d break these daily doses into smaller amounts throughout each day—say, 0.1 to 0.2 g/kg taken at each meal.

However you choose to ingest sodium bicarbonate, avoid adopting the mindset of “more is better,” says Comana. Research points to 0.3 grams per kilogram as being the optimal one-time dose for performance benefits, per the ISSA. Down any more than that, and you may just end up with intensified side effects without any additional performance benefit, Comana warns.

If you try Maurten’s product, follow the use instructions provided with the product, as they differ slightly from the ISSA recommendations.

When considering whether sodium bicarbonate is worth a try, take stock of whether you want to devote the time and mental energy to implement it, whether you need a performance enhancer, and if you are doing an event where it could be helpful, says Michael. For example, a cyclist who sprints will benefit more than someone who does long, casual rides.

Lastly, be aware that sodium bicarbonate, as the name suggests, does contain sodium, says Michael. Depending on factors like your blood pressure, sweat rate, and current diet, this product may not be safe to take daily. “Always check with your healthcare provider before undergoing a diet or supplement change,” Michael advises.

The bottom line on sodium bicarbonate

If you’re able to stomach sodium bicarbonate (pun intended), it “would be a very viable supplement to take before those intense workouts,” says Comana, such as hill repeats, speed intervals, or a heavy weight lifting session.

But it may not be worth it for every athlete. “As with any nutritional intervention, it takes some dedicated time, mental energy, and cost to implement,” says Michael. “You can decide if this is worth it for you to try. If it feels overwhelming or not worth the effort, then it probably isn’t.”