Do Carb Blockers Work? Complete Guide

This content has been Fact-Checked by a Certified Nutritionist in our Publishing Team. Learn more here. Always consult a medical professional before commencing any diet.

Do Carb Blockers Work? Carb blockers are made for blocking complex carbohydrates from being digested.

As a result, your body doesn’t absorb calories from these carbs, which can result in weight loss.

Carb blockers, also known as starch blockers, are popular supplements for those who want to boost their weight loss without having to go on a low carb diet.

In order to use these supplements, it is important to understand what they do, how they work and if they are safe.

Let’s dive in to find out!

What Are Carb Blockers?

Carb blockers are designed to prevent some unwanted effects of taking too many carbohydrates.

Unlike typical weight loss pills, carb blockers can prevent carbohydrates from being digested.

In essence, carb blockers (also known as starch blockers) are made for facilitating weight loss without strict dieting. As you know, consuming carbs is often detrimental to weight loss. Many people simply cannot remove carbs from their diet. This is where carb blockers come in handy.

Carb blockers are made to block the enzymes needed to digest specific types of carbs. Many contain alpha-amylase inhibitors. These compounds are naturally found in certain foods. The most popular carb blockers are those found in white kidney beans.

While there are certain starch blockers that are prescribed by doctors as medications, most people can buy carb blockers without prescription because they are considered to be a supplement.

How Do Carb Blockers Work?

Man eating burger

In order to understand how carb blockers work, it is important to learn more about carbohydrates and their role.

There are two main types of digestible carbohydrates: simple and complex carbs.

Simple carbs are found in many foods, such as dairy products and certain fruits.

These simple carbs are not so much of a problem because their quantities in these foods are limited. However, a bigger problem is simple carbs in processed foods. These foods are packed with simple carbs in levels that are too high to be useful.

Foods that contain extreme quantities of simple carbs include sodas, desserts, frozen foods, flavored yogurts and other types of processed foods which could lead to obesity and heart problems

Complex carbs are found in other types of food, such as bread, rice, pasta and starchy vegetables, such as beans, potatoes, and broccoli.

These carbohydrates are made of simple carbs that are linked together to form chains. In order for your body to digest them, this chain has to be broken. This breakage happens through specific enzymes.

As soon as you eat food rich in complex carbs, your body starts producing digestive enzyme alpha-amylase.

This happens as you start to chew your food. The enzyme is responsible for breaking complex carbs into simple carbs so your body can digest them.

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Where do carb blockers come in handy?

These supplements contain special enzyme inhibitors.

They prevent the breakage of complex carbs. As a result, complex carbs can simply pass through the digestive system without being absorbed.

This means that they do not contribute to any calories and will not cause weight gain. At the same time, these carbs will not raise blood sugar.

By using these carb blockers, you are essentially removing complex carbs from your calorie intake.

This means fewer calories per day, which in turn improves your weight loss chances. By blocking complex carbs, you are essentially taking them away from your total calorie intake, all while being able to eat food that contains these carbs.

Do Carb Blockers Work?

woman checking weight scale

Now that you know the theory behind carb blockers – Do carb blockers work? Is it really possible to lose weight by taking starch blocker supplements?

They only work for complex carbs. They can’t prevent the digestion of simple carbs.

Remember, simple carbs are commonly found in processed foods, sodas and desserts. It means that carb blockers cannot help you against these types of foods.

If you continue to eat these foods, you can’t expect effective weight loss results.


Research shows that carb blockers only block around 50% to 65% of enzymes needed for digesting complex carbs. It means that 45%-50% of complex carbs will be digested by the body; carb blockers won’t block 100% of the carbs consumed.

One study reported that one group lost 2 to 5.5 pounds more than the control groups.

Another study showed a more remarkable 8.8-pound weight loss more than the control group.

On average, people managed to lose between 4.4 and 6.6 pounds over a 4-12 week period just by consuming carb blockers.

It is interesting to point out that the group who lost more weight, were the people who ate the most carbs. This is where carb blockers made the most difference.

On the other hand, other studies stated that carb blockers have no significant effect on weight loss or starch digestion and absorption.

Please note these studies were small and more high-quality research is needed to study the effects of carb blockers.

So, that is science.


Many people report excellent results using carb blockers.

There are users reporting various levels of success. According to consumers, carb blockers can be very effective for weight loss.

If you wish to try carb blockers, it is best to consult your doctor first. Your doctor can give you the best advice on dietary supplements you can consume safely.

Carb Blockers Benefits

lose weight belly jeans

There are numerous benefits potentially associated with carb blockers. While there is not enough scientific data to prove all of this, carb blockers are made for the following benefits:

1. Carb Blockers May Help With Weight Loss

One of the main purposes of starch blockers is weight loss. This is how carb blockers are primarily marketed: as an effective supplement for weight loss.

Many companies advertise these starch blockers as a supplement that will allow you to eat as many carbs as you want without packing on calories.

However, it is important to understand that this refers to complex carbs only. Simple carbs cannot be eliminated with these blockers.

Since simple carbs are those commonly found in processed foods and sweets, it means you cannot consume these foods if you want to achieve weight loss.

2. Carb Blockers Assist in Decrease of Appetite

Another potential benefit of carb blockers is that they may decrease appetite. They may slow digestion, which makes you feel full for longer.

There are certain indicators that starch blockers can affect hormones involved in the feeling of hunger.

As a result, you will not feel hungry for longer periods of time. This will decrease your appetite and can help with weight loss in the long run.

There are some scientific studies pointing out that this effect is due to the main ingredient of popular carb blockers, the white bean extract.

This extract also contains phytohaemagglutinin. This is a compound that increases the levels of hormones that make you fill full.

A study with rats shows a significant decrease in food intake. The rats that were given this compound ended up eating 25% to 90% less food.

Another way in which carb blockers can help decrease appetite is by decreasing the amount of food that is rich in fats and sugars. Rats from the study ended up being less interested in fatty and sugary food.

While these effects are not well-researched in humans, carb blocker consumers claimed to have lost weight due to a decrease in appetite

3. Carb Blockers May Help Control Blood Sugar

blood sugar levels

Most carb blockers are marketed as weight loss supplements.

However, there is an added benefit that is more proven than weight loss: blood sugar control. By preventing or slowing down the digestion of complex carbs, starch blockers lower blood sugar levels.

Generally speaking, when the body absorbs complex carbs into the bloodstream, there is a spike in blood sugar levels. With carb blockers, this spike doesn’t happen. In addition, carb blockers affect hormones involved in controlling sugar levels.

Studies showed that carb blockers prevented healthy people from getting high blood sugar levels after eating food rich in complex carbs.

Also, carb blockers assisted blood sugar levels to return to normal faster.

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4. Carb Blockers Provide Beneficial Resistant Starch

There is another unexpected benefit to carb blockers: they can increase the amount of resistant starch in the large intestine.

By decreasing the amount of carbs absorbed in the small intestine, they increase the starch that gets to the large intestine.

These are known as “resistant starches”. They are very similar to fiber.

These are foods that cannot be digested by the enzymes in the small intestine. You can find these starches in legumes, certain whole grains, raw potatoes and unripe bananas.

Why is this beneficial? They may promote healthier gut. Once they pass into the large intestine, gut bacteria ferment them to release gasses and short-chain fatty acids.

These resistant starches may also help you burn more fat after a meal. Resistant starches are also known to bring additional health benefits.

Carb Blockers Main Active Ingredient

kidney beans

There are many different carb blockers out there. However, the most popular active ingredient in most of these supplements is white kidney bean extract.

If you are interested in starch blockers, you need to understand what white bean extract is and what it can do for you.

White Kidney Bean Extract

White kidney bean extract, known as Phaseolus vulgaris extract, is the main active ingredient of the most popular carb blockers.

It is the only natural ingredient that is somewhat backed up by scientific evidence. This extract works by preventing your pancreas from producing alpha-amylase.

This prevents your body from producing the enzymes that are needed to digest complex carbs.

Generally speaking, white kidney bean supplements are sold in capsules. You should take 1 or 2 capsules before each meal, according to the manufacturer’s instructions.

Before taking white kidney bean supplements, make sure to understand how and when you should take your pills.

This translates to about 1,500 to 3,000 mg of white bean extract per day, which is the recommended dose for this ingredient.

White kidney extract is generally safe for use. It is a natural ingredient that doesn’t come with significant side effects.

The only thing to keep in mind is that you shouldn’t exceed a daily limit (10,000 mg). Since a typical supplement capsule contains 600 mg, it is not easy to go above this limit.

What is Phase 2?

Phase 2 is a nutritional ingredient with white kidney bean extract as the main ingredient. It is marketed as the first kidney bean extract that is clinically proven to reduce the digestion and absorption of carbohydrates.

This extract is clinically shown to reduce the digestion and absorption of complex carbs up to 66%.

This supplement is all-natural and non-stimulant. It is a safe way to block complex carbs found in foods such as potatoes, bread, pasta, rice, crackers, and many other foods. It is one of the most popular carb blockers on the market.

Recommended use: Take 2 tablets (500 mg each) with a full glass of water 5-10 minutes before a meal that contains starch. Make sure not to take Phase 2 too early or it will pass through your body before it can interact with food.

Never exceed more than 6 tablets per day.

Are Carb Blockers Safe?

The good news is that carb blockers are considered to be safe.

They are taken from a natural ingredient (most commonly, white bean extract) and as such, do not contain any dangerous elements.

However, it is important to remember that using starch blockers can produce certain side effects. After all, these supplements are made to alter the carb digestion, and this can produce side effects for some people.

It is best to consult your doctor before you try any of these supplements.

Tips: Make sure to always do your research before buying supplements and try to find a reputable and reliable source to buy your supplements from.

Carb Blocker Side Effects

unwell girl

Not all people will experience side effects while using starch blockers. Generally speaking, how often and how much of it you use will determine your chances of experiencing side effects.

It is shown that the body adjusts to carb blockers after a while. This means that those who use these supplements regularly may stop experiencing side effects after a while.

Carb blockers most common side effects:

1.Gastrointestinal problems

Starch blockers cause increased fermentation in your large intestine. This may result in discomfort and a feeling of fullness that doesn’t go away.

2.Bloating and flatulence

Carb blockers result in more resistant starches in your large intestine. They are broken down to release gasses. This can sometimes lead to a feeling of bloating, cramping and increased flatulence.


Some people who use starch blockers will experience diarrhea. This problem should go away in time. If diarrhea persists please consult your doctor and stop taking the supplement.

4.Low blood sugar levels

While carb blockers can regulate blood sugar levels, people with diabetes need to be careful. You may end up with dangerously low blood sugar levels if your insulin dose is not adjusted.

If you have diabetes, you should talk to your doctor before taking any carb blockers.

It is extremely important to let your doctor know about this, so they can advise you on how to proceed and to adjust your insulin dose if needed.

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Carb Blockers Pros and Cons


As you can see, carb blockers can bring certain benefits and drawbacks.

Before you start using any starch block supplements, it is important to understand all of the pros and cons of using these supplements.

Carb Blockers Pros

Here are the main pros of using carb blockers:

1.Weight loss

This is the main benefit of carb blockers. While these supplements don’t work the same for all people, there are many users who claim that carb blockers can help you lose weight, decrease appetite and make you burn more fat.

2.Natural ingredients

The most popular carb blocker ingredient is white bean extract. This is a natural ingredient that is safe for use. Carb blocker supplements don’t have to use complex chemicals to work.

3.Easy to use

Most carb blockers are made for ease of use. These supplements are easy to take so you don’t have to worry about how and when to consume them.

4. You can eat your carbs

Perhaps the best benefit of carb blockers is that they allow you to eat complex carbs. You don’t have to switch to a low carb diet in order to lose weight. With carb blockers, the complex carb will not contribute that much to your overall calorie count.

Carb Blockers Cons

Here are the main cons of carb blockers:

1. Only complex carbs affected

Starch blockers can only work on complex carbohydrates. It means that you will still have to eliminate process foods and sweets from your menu if you wish to lose weight.

2. Not all complex carbs affected

Even with complex carbs, only 50% to 65% of enzymes are affected. It means that carb blockers will mainly work on people who consume a lot of complex carbs. If you don’t fall into this category, carb blockers might not work for you.

3. Not ideal for people with diabetes

Since carb blockers lower blood sugar, they may be dangerous for people with diabetes. If you have diabetes, make sure to consult your doctor before using starch blockers.

4. Supplement regulation

Keep in mind that supplement companies are responsible for the safety of their products. Not all supplements truly contain what is written on the label. In order to stay safe, you need to choose your supplements carefully. Only use carb blockers made by reliable companies.

Popular Carb Blocker on the Market

taking pills

Dietrine Carb Blocker

Dietrine is an effective starch blocker that uses Phase 2 white kidney bean extract as an active ingredient. This is an all-natural supplement that is made to neutralize the digestive enzyme alpha-amylase, preventing the digestion and absorption of complex carbs.

Arazo Nutrition White Kidney Bean Carb Blocker

This is yet another carb blocker that uses white kidney bean as an active ingredient. This supplement has higher doses of the extract: 600 mg per capsule. Keep this in mind so you never go above the recommended dosage.

BioGanix Pure White Kidney Bean Extract

This is yet another supplement that uses 600 mg dosage of white kidney bean extract. What makes this supplement stand out is that it contains no additional ingredients. This is one of the purest forms of kidney bean extract you can get.

Irwin Naturals 3-in-1 Carb Blocker

This is a complex carb blocker that includes multiple ingredients, such as white kidney bean extract, cinnamon extract, and chromium. It is made for maximum effectiveness by combining different active ingredients.

Base Carb Crush Cheat Meal Solution

This carb blocker is designed to prevent the effects of “cheat” meals when you are on a diet. The active ingredient in this starch blocker is grape seed extract and maqui berry extract. This is a multi-ingredient carb blocker you can try if white bean extract blockers don’t work for you. Check out Best Carb Blockers Ultimate List.


stop hand

Carb blockers are supplements that impact your digestion. Just like with any other supplement, it is important to consult your doctor before using carb blockers.

If you take insulin or another medication for diabetes, talk to your doctor before using carb blockers.

People with diabetes are at danger of low sugar levels while taking carb blockers; this can be very dangerous.

In order to prevent serious medical consequences, people with diabetes must consult their doctor before using carb blockers.

Remember: you are using carb blockers at your own discretion. There are no scientific studies proving the effectiveness of these supplements, nor studies demonstrating their complete safety.

Finally, carb blockers are not magic pills.

While they may help you lose some weight, they will not allow you to eat large quantities of sweets and processed foods.

You will still need to adjust your diet in order to lose weight. These supplements will only work on complex carbohydrates. You will still need to eliminate processed foods and sweets if you wish to lose weight.

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This content has been Fact-Checked by a Certified Nutritionist in our Publishing Team. Learn more here.

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