Fat Burners FAQ – 33 Most Common Questions Answered

Are you having a hard time losing weight? If you do, then you may have considered taking a supplement advertised as a fat burner. 

Fat burners are weight loss pills that can help enhance fat loss and work in a variety of ways. They help curb appetite, increase your core temperature so you burn more calories, boost your metabolism, boost your energy, promote fat loss and use it for energy.

But before you buy any fat burner, read through this list of frequently asked questions about fat burners to make sure you’re buying the supplement that helps and does not harm your health. Let’s get started!

Table of Contents

Fat Burners 101 – Frequently Asked Questions About Fat Burners

1. Are fat burners bad for your kidneys?

A high-quality fat burner should not affect and is not bad for your kidneys. If used according to the instructions, high-quality fat burners can even improve your kidney health by reducing the filtration workload.

Still, diet pills and fat burners can affect your kidney functions in various ways. Obese and overweight people often have much protein in their body so using weight control pills, diet pills, or fat burners pushes the kidneys to filter more byproducts (nitrogen byproducts) and work harder.

2. Are fat burners bad for your liver?

In moderate doses, there have been no safety issues reported to high-quality fat burners. So, generally, it is not bad for your liver. However, some fat burner ingredients may damage the liver. 

Green tea extract is a common ingredient in fat burners. One study has noted that large doses of green tea extract can be toxic to the liver. Consuming too many fat burners may also lead to acute liver failure. At best, proceed with caution. 

3. Can I take a fat burner before sleep?

The best nighttime fat burners are designed to be taken about 30 minutes before sleep, giving your stomach enough time to absorb the ingredients. These nighttime weight loss pills even contain ingredients, such as melatonin and Gamma-Aminobutyric Acid (GABA)  that help you stay asleep with ease.

Make a point of taking the fat-burning containing caffeine early in the day or at least five hours before bed so it won’t interrupt your sleep.

[Related post: Best Time to Take a Fat Burner]

4. Can I take a fat burner with whey protein?

Yes, of course! A fat burner will boost your metabolism while whey protein is meant for building muscles, improving body composition, and bulking up. Whey protein even outperforms any other protein powders as it contains all the nine essential amino acids for health and muscle building.

If you wish to mix them both, consider taking them in the morning to kick start your day and allow you to do a more intense workout than taking it in the afternoon when your body starts to slow down preparing for sleep.

5. Can a 15-year-old teenager take fat burners?

No, fat burners are not recommended for anyone below 18 years old. Teenagers are still developing and growing so their biochemistry is vulnerable to disruption. For parents concerned that their child may be overweight and wondering whether a fat burner is safe, it’s important to talk with their physician.

6. Can a fat burner cause hair loss?

Although uncommon, hair loss is one of the side effects of fat burner supplements. Some ingredients in a fat burner may increase the cortisol hormone in the body, which leads to stress and anxiety that can lead to unwanted hair loss.

7. Can fat burners cause erectile dysfunction?

Fat burners, if taken in proper quantity and are made of high-quality ingredients, do not cause erectile dysfunction. It will instead complement your overall weight loss efforts and may contain ingredients (like Yohimbe) that will improve your sexual performance.  

But watch out for appetite suppressants that contain phentermine ingredients as they may cause ED in men. Consult with your doctor first if you need to lose weight fast for a medical reason to make sure any medications will not interfere with your sex life.

8. Can fat burners cause headaches?

Most people tolerate thermogenic fat burners just fine, but there are few who experience unpleasant side effects, like headaches. Fat burners containing more than 400mg of caffeine may cause headaches as well. 

9. Can I take a fat burner on an empty stomach?

Yes, you can. Few benefits of taking a fat burner on an empty stomach before breakfast include providing your body the necessary metabolism to boost in the morning, increasing the absorption of some thermogenic compounds, which means the ingredients will reach your bloodstream faster, and supporting better appetite control as it keeps your insulin levels balanced early in the day.

There may, however, be potent compounds in a fat burner supplement that could cause digestive issues.

10. Can you drink alcohol while taking a fat burner?

A glass of beer once in a blue moon will not likely be a problem while taking a fat burner.  But alcohol and the fat burner is a match made in hell. Alcohol slows your body down while a fat burner helps melt your body fat. Combining the two will make you feel exhausted and your weight loss efforts just wasted.

11. Can you drink a fat burner while intermittent fasting?

Sure, it’s okay. The key is just to make sure that you are taking the right fat burner. You may even lose some extra fat when you combine a fat burner and intermittent fast.

When you do intermittent fasting (specifies when you should eat your food), it can break into your muscle mass to be used as fuel. It’s because your body needs the energy to keep it working and if it’s not getting enough from your diet, it will look elsewhere: both muscle mass and fat mass. Taking a fat burner while you fast helps preserve that lean muscle mass.

12. Can you drink fat burners while breastfeeding?

No, taking a fat burner may be unsafe for your baby. Most fat burners use stimulants, such as caffeine, and those may pass from the mother to baby through breast milk. And don’t worry about losing weight because you are already burning fat the natural way by breastfeeding. 

13. Can you take fat burners while trying to get pregnant?

Studies have shown that weight loss supplements contain substances that can affect a woman’s fertility and pregnancy. Caffeine is one example. Rule of the thumb, avoid taking a fat burner supplement or consult your OB-GYN first as he or she may allow you to take it if it’s plant-based or 100% organic.

14. Can you use a fat burner while bulking?

Yes, if you are taking a fat burner that builds more mass. Most fat burners in the market contain ingredients that promote metabolism or suppress appetite and these two will be counterproductive when you’re on a calorie surplus to build muscle mass.

Good thing there are now fat burners for bodybuilding meant to help you burn fat and gain muscle at the same time. Some potent fat-fighters in fat burners you can look for on your quest for mass are carnitine, caffeine, CLA, forskolin, and green tea.

15. Do fat burner creams work?

Yes, fat burner creams work. Fat burner creams help you lose fat by absorbing it into the skin, blocking cellulite formation, and burning excess fat but they are not as effective compared to actual fat burners in the natural route or in the form of supplements and powder. 

Choose a fat burner cream that is paraben-free or natural. Have a look at the minerals and vitamins the cream consists of as well to assess the safety level of the product. The more natural the ingredients are, the safer and healthier it is.

16. Do fat burners cause diarrhea?

Not all, but some caffeinated fat burners can cause diarrhea. This may be caused by the way the supplement increases the rate your body uses and processes foods and energy.

17. Do fat burners make you pee?

Yes, fat burners may make you pee because when you shed pounds, your body either sweats, breathes, or pees it out. The byproducts of fat metabolism leave your body either as water – through your kidneys when you urinate or through your skin when you sweat – or as carbon dioxide, through the lungs when you exhale.

18. Does nighttime fat burner work?

Depending on the product, night-time fat-burning supplements work just as well as the best fat burners designed to be consumed in the morning. It’s just that nighttime fat burners increase fat oxidation and promote a good night’s sleep at the same time while most fat burners keep you stay awake.

19. Fat blocker vs fat burner – what’s the difference?

A fat blocker is a supplement that prevents your body from absorbing fat from the food you eat. While fat burner supplements help you burn fat, fat blockers prevent you from storing fat in the first place.

20. Is it OK to take expired fat burners?

Expired fat burners are still okay to take after their expiry dates. Expiration dates on fat burners generally serve as a guideline on how long the product, especially its active ingredients, remains effective and potent but not an indication of the true shelf life of the fat burner.

If mold has, however, developed in the solid or powder form product, throw it out immediately because it could make you sick.

21. Will a fat burner break my fast?

As long as the fat burner doesn’t contain proteins or carbohydrates, it will not break your fast. Supplements that break a fast are those that will spike your blood sugar levels, such as the BCAA or collagen supplements .

22. Can I take a fat burner without working out?

Sure, you can. But taking a fat burner in addition to exercise and healthy eating will give you an edge on altering your body composition, increasing energy, and boosting your performance. All these make considerable weight loss possible.

23. Can I use a fat burner on keto?

Yes, you can take a fat burner on a keto diet. Of course, if it’s a sugar-filled fat burner, it may knock you out of ketosis – where the body burns stored fat for energy- and negate the effects with the added calories.

[Related post: Best Fat Burner for Keto Diet]

24. Can I use a fat burner with creatine?

Yes, it’s fine to use a fat burner with creatine – a compound often used to improve muscle mass and exercise performance. Just be aware that some creatine does the opposite so it all depends on the type, brand, and how your body responds to it. 

Fat burners and creatine have different functions in the body. Fat burners help you burn more calories and raise your metabolism so you lose fat fast while creatine increases lean muscle mass, increases energy levels, and super hydrates the muscle cells with water. 

At best, avoid ephedrine-based fat burners if you’re also taking a creatine supplement. That’s because ephedrine-based fat burners get rid of water from the muscle cells while creatine supplements bring water into those cells. Hence, ephedrine-based fat burners and creatine are working in the opposite manner.

25. Can you drink coffee while on fat burners?

Yes, consuming caffeine while on fat burners may even lead to more fat being burned during exercise than a fat burner alone. But too much caffeine may cause insomnia, increased blood pressure, nausea, nervousness, and other problems.

If you’re taking a stimulant fat burner supplement, watch your total caffeine intake over the day to avoid burning out your adrenal response quickly.

26. Can you take a fat burner after breakfast?

Yes! Taking a fat burner after breakfast is one of the best times to take a fat burner supplement and the other one is before your workout. Taking the fat burner in the morning is best because your metabolism is still at its slowest due to it slowing down during sleep.

If it’s your first time taking a fat burner, start with the lowest dose and begin that for at least two weeks. Only then can you bump up if it’s needed. Finally, any fat burner is designed for short cycles – two to three months. Avoid taking it for longer than what the manufacturer designed it to be because it will gradually stop working as your system gets used to it.

27. Can you take a fat burner after pre-workout?

For safety, avoid taking a fat burner after a pre-workout supplement. If you do, you will be subjecting your body to a high dose of stimulants and because these two supplements act differently in the body, you may experience side effects, like vomiting, nausea, and diarrhea. 

Why not opt for a pre-workout fat burner instead? This type of pill or powder helps your body burn fat and achieve better exercise performance. 

If you want a jolt of energy to deepen your exercise regime and give you that kick you need, then choose a fat burner with a stimulant. Anything above 200mg of caffeine is already powerful enough.

28. How long do fat burners last in your system?

Fat burners stay in a healthy system anywhere from one hour to several hours, depending on the ingredients.  Caffeine stays in your system between 1.5 to 9.5 hours while the elimination half-life of yohimbine is 36 minutes. Half-life is the time it takes from the maximum concentration to reduce to half.

A good fat burner must increase the metabolic rate, break down the fat cells, and burn the stored fats. A longer-lasting fat burner does not always equate to being more effective. 

29. How long do fat burners take to work?

In most cases, fat burners work within minutes after ingestion or up to 45 minutes, depending on the bioactive ingredients on the fat burner. 

Fat burner supplements come in different formulas and blend. On average, it takes 30 to 90 days to achieve noticeable results. To test the effects of the fat burner, take a photo or measurements of yourself and review it after three to five weeks since taking the fat burner.

30. How many calories do fat burners burn?

How many calories you burn on an average day while taking a fat burner depends on your metabolism. What fat burners do is increase your metabolism, causing you to burn more calories. 

A calorie is a unit of energy, not a measurement that only has to do with weight loss and food. It can be applied to lots of energy-releasing mechanisms outside the human body. 

Some factors affecting calorie burn each day include age, sex, amount of daily activity, body size, body composition, thermogenesis, pregnancy, and breastfeeding. An average person burns about 1,800 calories daily doing nothing at all. 

31. What are the side effects of fat burners?

The common side effects of fat burners are constipation, gas, diarrhea, nausea, and black stools. Infrequent side effects include vomiting, abdominal pain, and abdominal bloating. Most of these symptoms are linked with things like the chemical makeup of the green tea extract or the caffeine content in the fat burner itself. 

So, are fat burners safe? Generally, they are, so long as you take them following their nutritional use and guidelines and not over-consume them. Of course, if you are pregnant or nursing, it is best to consult with a healthcare professional or physician before supplementing.

32. When to take a fat burner?

The ideal time to take a fat burner is in the morning, about 30 to 40 minutes before your breakfast because your metabolic rate is still at its slowest. This makes the active ingredients of the best fat burners kick your metabolism into gear and it helps manage your appetite within the day.

Some fat burners, however, can upset an empty stomach. You may try consuming a meal with a fat burner to avoid side effects. Another option is to take it before your workout so the fat burner will work as a pre-workout supplement, providing you that extra oomph with no additional calories.

33. Will a fat burner burn muscle?

No, a fat burner does not burn muscle. Fats and muscles are two different things and cannot be converted from one to the other. The muscle tissues remain the same when the fat burner is in your system. Only the fat cells get burnt. 

Taking a fat burner, like Burn Lab Pro, that contains Hydroxymethylbutyrate ingredient may even help a person retain and build muscle while getting rid of love handles

The Bottom Line

It’s time to stop putting off your weight loss and workout goals. Now is the time to take back your energy, prevent mood swings, control your hunger, and jumpstart your weight loss!

By taking a high-quality fat burner, it will help your body burn fat in a healthy and natural way. And don’t worry if you don’t see the result too soon. Your best bet for keeping weight off is a gradual and steady weight loss, which is about 1 to 2 pounds per week.

We hope you find this guide to fat burners/ fat burners FAQ helpful and best of luck on your weight loss journey!

For more fat-burning tips, you might want to read our other reviews at ExpertFitness.org.

Nathan Lloyd, MSc

I’m a personal trainer, based in Boulder, Colorado.
I service clients physically in the Boulder area, mainly in the ONE Boulder Fitness Gym, but am also available for online consulting and coaching.

If you’re interested in my personal coaching programs, please contact me via the contact page.