A carb blocker is a supplement that slows down or prevents the absorption of carbohydrates into your body.
Given the rising tide of evidence suggesting that carbohydrates have a particularly harmful effect when it comes to weight gain and the metabolic problems that come along with it, carb blockers are becoming increasingly popular among people looking to shed pounds or fend off weight gain.
Confused about your options? We’ve had our research team investigate and rank the ten best carbohydrate blocking supplements on the market.
Read on to see our rankings and for more details on how these supplements can help you lose weight.
1. Arazo Nutrition White Kidney Bean Carb Blocker
Among the multitude of brands that use white kidney bean extract as the main or only ingredient in their carb blocking supplements, Arazo Nutrition’s supplement stands out due to its high dose and simple, pure supplement design.
If you are looking to keep things minimal, this is a great choice: you get 600 mg of white kidney bean extract per vegan-friendly cellulose capsule, with a minimum of extra ingredients.
2. Irwin Naturals 3-in-1 Carb Blocker
Irwin Naturals 3-in-1 Carb Blocker takes what you might call a “maximalist” approach to blocking carbohydrate absorption.
This supplement uses a range of active ingredients to block the absorption of carbohydrates. These range from familiar ingredients like white kidney bean extract and chromium to more unusual ingredients, like cinnamon extract, flaxseed oil, and the enzymes lipase and protease, which help break down fats and protein.
It’s also got the proprietary black pepper extract BioPerine, which should assist with improving the absorption of many of the active ingredients. If other carb blockers aren’t doing the trick for you, give Irwin Naturals a try.
3. Base Carb Crush Cheat Meal Solution
Base Carb Crush Cheat Meal Solution is designed to blunt the effects of “cheat” meals when you are on a diet. The idea is that this supplement can make it so that you won’t take quite the same hit that you’d take if you splurged on pasta, bread, or other starchy foods while on a low-carb diet.
Base Carb Crush accomplishes this with a combination of grape seed extract, maqui berry extract, and chromium, each of which is designed to either increase your metabolism or block carbohydrate absorption. Among the multi-ingredient carb blockers, many people find it quite effective.
4. BioGanix Pure White Kidney Bean Extract
BioGanix Pure White Kidney Bean Extract uses the same 600 mg dosage of white kidney bean extract that you’ll find in many other carb blockers, though its supplement design is quite pure—there are zero additional ingredients, other than the vegetarian-friendly cellulose capsule used to deliver the supplement.
Because of the large number of capsules per bottle, it’s a good choice if you want to incorporate carb blockers into your diet on a regular basis instead of as an occasional “cheat meal” solution.
5. Phytoral White Kidney Bean
White kidney bean extract is one of the most popular carb blockers due to its ability to shut down carbohydrate absorption.
Phytoral makes one of the most popular white kidney bean supplements, thanks to its fairly high dose (600 mg per capsule) and fairly straightforward supplement design.
If you are looking for a fairly simple way to block carbs, this is a solid choice.
6. Code Age Keto Carb Blocker
Code Age Keto Carb Blocker uses a three-pronged approach to reduce carbohydrate absorption. The first is by using white kidney bean extract, which is a common and effective strategy among carb blockers.
Next up is cinnamon extract and green tea extract, which both might have beneficial metabolic effects when it comes to weight loss, but whether or not they have an effect on carbohydrate absorption specifically is unclear.
While Code Age Keto Carb Blocker may be an effective way to reduce carbohydrate absorption, it’s not going to totally block carbohydrates, so if you are trying to stay in ketosis, you still can’t go crazy with carbs.
7. Sheer Strength Sheer Block
Sheer Strength Sheer Block uses a unique combination of white kidney bean extract (445 mg per capsule) and green tea catechins, which are compounds that may be related to the weight loss potential of green tea.
This carb blocker is a good candidate for trying if plain white kidney bean extract carb blockers aren’t doing the trick for you, though the dosage of kidney bean extract is somewhat lower than what you’d get in a different product.
8. Nature’s Design White Kidney Bean Pro Enzymes
Nature’s Design White Kidney Bean Pro Enzymes is a pretty typical carb blocking supplement: it delivers 600 mg of white kidney bean extract per capsule, with a reasonably clean supplement design.
However, without much to set it apart from the rest of the competitors with similar products, it’s hard to rank this supplement any higher.
9. Natrol Carb Intercept
Natrol Carb Intercept uses a combination of white kidney bean extract, chromium, and dibasic calcium phosphate to block the absorption of starches.
It’s an innovative product, as most white kidney bean supplements are presented without any additional active compounds.
However, the efficacy is hampered somewhat by a lot of additives in the supplement, and the fact that it contains both milk and soy ingredients, which will turn off some users.
10. Slimgenics Alpha Slim
Slimgenics Alpha Slim claims to block up to 300 calories per meal, backing this up with a long list of active ingredients.
These range from vitamins A, C, and E to a proprietary blend of white kidney bean, gymnema leaf, ginseng, ginkgo, and other ingredients.
Unfortunately, it’s not possible to evaluate the efficacy of these compounds given that the exact dosage is shrouded in secrecy.
Slimgenics Alpha Slim may have a niche use, but most people would be better off with a different option.
Carb blocker benefits and side effects
Carb blockers are supplements that are used to blunt the negative effects of carbohydrates in your diet.
There are a number of ingredients that carb blockers might use to achieve this effect, but the goal is the same: eliminate or slow down the absorption of carbohydrates in your diet so your body doesn’t have to deal with a surge in blood sugar and the negative after-effects.
Nutrition research is increasingly focusing on the negative metabolic effects of excessive carbohydrate consumption, and these negative effects appear to be magnified when carbs are absorbed quickly. Could a carb blocker help you avoid some of these adverse effects?
Carb blockers might be able to reduce the negative effects of excessive carbohydrate intake. One increasingly prominent scientific theory related to weight gain is the “carbohydrate insulin model” of obesity, which focuses on going beyond the idea of weight maintenance being a matter of calories in versus calories out.
A 2018 scientific article in the Journal of the American Medical Association Internal Medicine by researchers at Boston Children’s Hospital outlines the evidence behind this hypothesis and the implications of it (1).
Under this theory, the primary driver of obesity and weight gain is the consumption of large amounts of carbohydrates, especially sugars and refined carbohydrates.
These carbohydrates have a low glycemic index, meaning they create a sharp rise in blood sugar levels. In response, the body pumps out insulin, a hormone which controls blood sugar.
As a result of rising insulin levels, the blood sugar circulating in the blood gets pulled into fat cells where it is stored as new fat, and finally, blood sugar levels crash.
This process takes several hours after a carbohydrate-rich meal, and explains a number of phenomena, such as the “carb crash” that many people experience in the hours following a meal with a lot of carbohydrates.
Under this theory, hunger and overeating are actually symptoms, not causes, of obesity: the crash in blood sugar drives you to consume more food, and if that next meal is rich in carbs, the cycle starts all over again.
If a carbohydrate blocking supplement could interrupt this process by slowing down or blocking the absorption of carbs, there is firm grounding that it could be quite beneficial for weight loss and weight loss maintenance.
Carb blockers that include white kidney bean can directly inhibit the absorption of carbohydrates. One of the most popular ingredients in carb blockers and other weight loss pills is white kidney bean extract, thanks to some very solid science on its biochemical properties inside your body.
White kidney beans contain a compound that blocks a specific enzyme that helps your body process the carbohydrates in your stomach, leading to decreased absorption of carbs for a given meal.
A study published in 2007 in the British Journal of Nutrition by a team of researchers in Spain demonstrated the precise mechanism of action (2).
Their study gave rats a dose of either white kidney bean extract or a placebo, both in conjunction with a standardized starch meal.
The researchers were able to demonstrate that the white kidney bean resulted in lower blood sugar levels and even a reduction in food intake.
The rats given the white kidney bean extract may have been less inclined to continue eating because of the increased amount of carbohydrates that remained in their stomach (as they were not absorbed), which suggests that white kidney bean could have a synergistic effect: less caloric absorption, as well as less caloric intake.
Carb blockers with cinnamon might reduce the negative metabolic effects of carbohydrate-rich meals. Cinnamon is rich in biologically active compounds, some of which look like they have beneficial effects on carbohydrate metabolism.
A study published in the journal Hormone and Metabolic Research by researchers at Nagoya University in Japan analyzed the effects of these compounds on insulin resistance, one of the biggest negative metabolic effects of a carb-rich diet (3).
Their study used mice to demonstrate that mice fed a high-sugar diet supplemented with cinnamon extract did not experience the same metabolic deficits as mice not given a cinnamon extract. More specifically, the insulin resistance of the rats fed cinnamon was not nearly as bad.
While cinnamon may not directly block the absorption of carbohydrates, it does look like it could help your body cope with a “cheat meal” more effectively.
As such, including cinnamon extract in a carb blocker could make it more effective, especially for occasional use.
Though many carb blockers use slightly different ingredients, the scientific research behind the most common ingredients like white kidney bean extract and cinnamon suggest that they are quite safe.
Additionally, clinical trials in humans that have examined commercial preparations including white kidney bean extract, such as one published in 2011 in the Nutrition Journal, have reported no adverse side effects (6).
As for cinnamon extract, early clinical reports indicate that it is well-tolerated and generates minimal side effects (7).
For carb blocker supplements that contain white kidney bean extract, there is a considerable body of research that has evaluated various doses of white kidney bean extract.
Anything between 500 and 3000 mg per day appears to be effective, though as is usually the case, it’s better to start on the low end first (X).
Cinnamon has mostly been studied at doses ranging from 40 to 80 mg per day (X), though it’s less clear if this is the optimal range for weight loss and weight maintenance.
A carb blocker might be an effective way to protect yourself from some of the negative effects of high carbohydrate intake.
Slowing the rate of carbohydrate intake looks like a good bet when it comes to blunting the negative metabolic effects of high carb intake, like the blood sugar spikes.
Carb blockers that use white kidney bean extract seem particularly effective, as the active ingredient in this supplement interferes with your body’s ability to process carbs in your stomach, leading to a slower rise and lower peak in blood sugar after a carb rich meal.
Cinnamon extract seems to be a useful extra ingredient, as it can help protect you from some of the negative metabolic effects of high carb intake, even if your body is still absorbing the same amount of carbs.
While there’s no replacement for actually reducing your dietary intake of carbohydrates, a carb blocker can come in handy on cheat days or on occasions where you don’t have much of a choice but a carb-heavy meal.