Updated May 22, 2019.
Published Nov 16, 2017.

Phen24 is dietary supplement designed to help you lose weight more effectively. It is considered a 2-in-1 supplement because it uses a unique day and nighttime formula to promote weight loss. Its regular use is supposed to increase your metabolism and suppress your appetite during the day. It is also said to keep you from waking up in the middle of the night because of hunger, and promote sound sleep to keep you healthy. Although it contains glucomannan (which has genuine scientific backing) and has a money-back guarantee, these are the only real plus points about Phen24.


  • Natural ingredients
  • Contains glucomannan
  • Money-back guarantee


  • Lacks scientific evidence for support
  • Contains loads of caffeine
  • Under-dosed ingredients
  • Several side effects
  • Expensive than other similar supplements
Phen24 Day & Night
Phen24 is a weight loss supplement that claims to be different from other supplements, because it not only works during the day but also keeps working when you are asleep. The idea sounds impressive, but the question is, can you really trigger weight loss by increasing your metabolism?

Can Phen24 help suppress cravings and improve sleep quality? Here is our review to help you decide.

Phen24 Overview

What you need to know about Phen24

Phen24 is a combination of different natural ingredients. This 2-in-1 dietary supplement includes one pill for the day and one for the night-time. It is supposed to increase your metabolism during the day and help prevent nighttime cravings at the same time. It is supposed to make the weight loss process more effective, by promoting thermogenesis and raising your body temperature. Ingredients like cayenne pepper, guarana extract, and caffeine help in this regard.

It also contains glucomannan, a dietary fiber that is backed by many studies to help promote a feeling of fullness and control your calorie intake. The problem is that most of the ingredients in Phen24 do not have sufficient scientific evidence to support their use, and the presence of so many ingredients has actually made the formula less effective.

What are the side effects of Phen24?

Phen24 contains a long list of ingredients, so it is possible to experience several side effects. The most common side effects come from the presence of caffeine in this supplement. There is caffeine found in the blend, and there is guarana extract that also increases the caffeine content of Phen24. Many people may develop insomnia, irritability, increased heart rate, and elevated blood pressure because of caffeine. Refer to our “Side Effects” section to learn more.

How much does Phen24 cost?

You have to spend $74.99 to order a pack of Phen24. Each pack contains 30 day pills and 60 night pills.

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Phen24 Key Features

Phen24 contains two types of pills – each comes with different ingredients. You have to take a pill in the morning and two at night. It is supposed to help you burn calories during the day, and prevent nighttime cravings at the same time. While both types of pills contain different ingredients, they are supposed to increase your metabolism and suppress appetite. Unfortunately, most of these ingredients lack scientific evidence, which is why we believe that you will be better off avoiding it in the first place.

There is caffeine in Phen24, which is the reason why you may experience a slight boost in energy after taking the pill. Caffeine is a stimulant and works by masking the fatigue. However, you do not always experience that effect; in fact, caffeine may do nothing to increase energy or power output. For instance:

  • Caffeine was dosed at 2,4,6,8 and 10mg/kg bodyweight in a double-blind manner 1 hour before sprinting exercises on an erg bike. Caffeine was unable to increase time to peak power, peak power output, or average power during sprints relative to placebo and noted a reduction in blood lactate levels. Source

Even if it helps, you are likely to feel worse once the effects wear off, and that is why we do not believe it is a good idea to stick to a caffeine-based fat burner. Guarana extract also adds more caffeine to the blend, but it does little to promote weight loss. Some evidence suggests that caffeine may help increase thermogenesis, which in turn makes it possible to burn more calories, but you need to take larger doses of caffeine to experience that effect. Just keep in mind that if you increase the dose, you may end up experiencing side effects, such as restlessness, insomnia, increased heart rate, dizziness, shortness of breath, and more.

Phen24 Key Points

  • 30-day supply
  • May suppress appetite
  • Money-back guarantee

Other ingredients are not that impressive either. For instance, it contains cayenne powder, which is supposed to increase fat loss by increasing your body temperature, but there is insufficient evidence that cayenne powder can cause a significant reduction in weight. Similarly, there is phenylalanine in the blend, which is supposed to help prevent issues like lack of energy, depression, decreased alertness, and memory problems. However, you can get enough of it by paying attention to your diet. Phen24 also includes iodine. It is important for a healthy thyroid function, as thyroid problems can lead to weight gain. If you are not already deficient in it or your weight gain is not due to a thyroid problem, there is no point in taking Phen24. In case you are deficient in it, you are likely to see effects if you take more than 1,100mcg a day. We really have no idea if you are going to get this much of iodine in each service of Phen24 or not.

If you talk about the night pills, you will notice that the main ingredient is chromium picolinate, which is included to prevent hunger pangs. It is supposed to work by regulating your blood sugar levels. However, it may not always work. For instance:

  • At least 12 placebo-controlled studies have compared the effect of chromium supplementation (172-1,000 g/day of chromium as chromium picolinate) with or without an exercise program on lean body mass and measures of body fat. In general, the studies that used the most sensitive and accurate methods of measuring body fat and lean mass (dual energy x-ray absorbtiometry or DEXA and hydrodensitometry or underwater weighing) did not find a beneficial effect of chromium supplementation on body composition (PubMed) (PubMed)

How to Take Phen24

Here is what the official site says about taking Phen24:

  • Take one Phen24 Day capsule each morning with breakfast. Take two Phen24 capsules with one or two glasses of water 15 minutes before the evening meal.

In order to experience any benefit, you need to take larger doses of chromium picolinate. For instance:

  • Recently, a meta-analysis of 11 randomized, double-blind, placebo-controlled trials in 866 overweight or obese subjects found a significant 0.50-kilogram (1.10-pound) reduction in body weight with supplemental chromium (most exclusively in the form of chromium picolinate) at doses between 137 g/day and 1,000 g/day for 8-24 weeks (PubMed). However, such a small change did not reach a clinically significant weight loss of 5% of the initial body weight.

The problem is that you are not going to get this much from each serving of Phen24. Similarly, it includes green tea extract that is supposed to increase metabolism and suppress appetite because it contains EGCGs. It is true that catechins in green tea are beneficial, but not everyone is going to see weight loss benefits by including green tea in their diet.

  • A 2012 Cochrane review analyzed the results from 14 randomized controlled trials of green tea preparations in a total of 1,562 overweight or obese participants (Source). The trials lasted from 12 to 13 weeks, and doses of green tea catechins ranged from 141 to 1,207 mg. Green tea supplementation reduced body weight by a mean of 0.95 kg more than placebo.

Moreover, how effective it proves depends heavily on the amount of catechins found in the formula. Phen24 offers not details about it, so it is better to avoid it. There is biotin in Phen24, but you do not need to supplement with it if you are already following a balanced diet. Similarly, molybdenum is not going to help a lot in terms of weight loss. Pantothenic acid or vitamin B5 is also beneficial for your health, but you should take it only when you are deficient in it. It helps break down carbs and fats, but these effects appear when you are severely deficient in it and take larger doses on a daily basis.

Phen24 Concerns:

  • Ineffective ingredients
  • Lack of scientific evidence
  • No information about the amount of ingredients
  • High in caffeine
  • Possible side effects
  • Quite expensive

One relatively beneficial ingredient that may help suppress your appetite is glucomannan. This water-soluble dietary fiber swells in your stomach and promotes a feeling of fullness. This way, you are less likely to worry about overeating, especially at nighttime. However, an important thing to keep in mind is that studies show that you may have to take up to 4g of glucomannan a day to see its positive effects. Also, it works when you combine it with a low-calorie diet. For instance:

  • Two published studies have tested glucomannan in dieters who were consuming 1,200 calories a day. (The typical American eats 1,500 to 2,750 calories a day, depending on sex and age.) Those who took 1.5 to 4 grams a day of glucomannan before meals lost three to four more pounds over five to eight weeks than those who took a placebo. But in seven other studies where the participants didn’t cut their calories, glucomannan had no effect on weight. So much for no change in lifestyle needed.

Now, if you have no idea about how to be in a calorie deficit mode, supplementing with glucomannan may prove ineffective. And if you can make and follow a healthy diet plan along with a workout program, you do not always require a supplement like Phen24 to lose weight. Therefore, it would not be wrong to suggest that Phen24 is not an effective dietary supplement, and is actually a waste of money. Look for something that is not laden with stimulants, and helps increase energy production naturally to make it possible for you to lose weight in a healthy way.

What does Phen24 claim to do?

Phen24 has a unique take on how to lose weight effectively. It comes with day pills and night pills that you need to take daily to enjoy several benefits. Here are some of its claimed benefits:

  • Helps you get better results from your exercise
  • Increases your metabolism
  • Burns fat and calories
  • Increases energy production
  • Eliminates night-time cravings
  • Helps you sleep better to promote weight loss

Does Phen24 work?

Phen24 is a dietary supplement with a combination of several natural ingredients. It contains green tea extract, caffeine, guarana, and many other ingredients that are supposed to help by increasing thermogenesis and boosting your metabolism. There is insufficient scientific evidence available to confirm these claims.

Similarly, it includes pantothenic acid, biotin, and other vitamins that may be beneficial for your overall health, but may not play a direct role in burning additional fat. It includes glucomannan, and like other forms of dietary fiber, it helps increase a feeling of fullness. But, you will not experience its benefits if you do not stick to a clean diet. Overall, there is nothing in Phen24 that makes it better than other stimulant-based dietary supplements currently available in the market.

phentatrim bottle
The most popular appetite suppressant in 2021 is Phentatrim.

Its ingredients are scientifically proven to aid weight loss and you are covered by a full 60-day money-back guarantee from a trusted company, making Phentatrim a very popular choice in the diet world.

Phentatrim is the best thing to hit the supplement market in a long time, with thousands of customers already seeing the benefits. That’s why it's our editor's top pick.

Read the Watchdog Phentatrim review here.

Phen24 Ingredients

Phen24 contains a long list of ingredients. Here is what the official site says about its ingredient profile:

  • Caffeine: Caffeine isn’t just a great ingredient to reduce fatigue and increase alertness and focus (as would your favorite cup of coffee). It also stimulates thermogenesis, slimming you down by turning up your body’s internal temperature. It can even reduce your appetite, helping you stay on track with your healthy eating choices.
  • Guarana Extract: In addition to caffeine itself, the Guarana Extract in Phen24 Day provides a further energy boost even better than that of coffee. A popular energy supplement, Guarana Extract offers one of the highest concentrations of caffeine among any plant. In fact, it can contain up to 3.6 to 5.8% caffeine by weight, whereas coffee has only up to 2%.
  • Cayenne Powder: Cayenne powder isn’t just an ingredient for your favorite dishes. Spicy food increases your body temperature, forcing the body to expend energy (calories) to cool down. Consumed daily, Cayenne powder can increase metabolic rates by up to 25%. By also promoting healthy digestion and maintaining healthy blood pressure, the cayenne powder in Phen24 helps support your new, healthy lifestyle.
  • Iodine: There is a complex relationship between your weight, thyroid, and metabolism. After all, the hormones secreted by the thyroid gland directly regulate your metabolism. Increasing your iodine intake can improve your thyroid function, which in turn, can boost your metabolism, helping you lose weight.
  • Glucomannan: The key ingredient in Phen24, Glucomannan keeps you feeling fuller for longer. As a dietary fiber, Glucomannan absorbs water and maintains a feeling of satiation, effectively reducing cravings. It means you’ll be less likely to eat later in the evening, keeping the cravings that can compromise your diet at bay.
  • Chromium Picolinat: If you’re into strength training, you may know chromium picolinate as a supplement useful in building muscle, burning fat, and metabolizing carbohydrates. Beyond these benefits, chromium moves blood sugar, also known as glucose, from your bloodstream into your cells. Here, glucose can be used to transform the macronutrients you eat – fats, carbohydrates, and proteins – into energy.
  • Molybdenum: Your body’s cells can’t produce energy on their own. But with molybdenum, they can use broken-down macronutrients to create energy. This kind of energy doesn’t just fuel your day and workouts. It also helps you digest your food, regulates your heartbeat, promotes healthy muscle functioning, and creates new, healthy cells.
  • Pantothenic Acid: More commonly known as vitamin B5, pantothenic acid helps your body metabolize food into energy, while assisting your liver in metabolizing toxins that can stall your weight loss efforts.

Phen24 contains some other ingredients as well, but it seems that most ingredients lack the sufficient scientific evidence to support the claims they make. Other possibly effective ingredients like glucomannan seem under-dosed, as customer reviews are not that impressive for this dietary supplement.

Phen24 Side Effects

Phen24 contains many different ingredients, so there is always a risk of developing certain side effects. For instance, it contains caffeine that can cause problems like irritability, increased heart rate, high blood pressure, nausea, and insomnia. There are many vitamin included in it, but you are going to experience gastrointestinal symptoms when you are not deficient in those vitamins.

Similarly, phenylalanine can cause problems like jitteriness, anxiety, heartburn, nausea, and headaches. Some people have also complained about upper stomach pain, which could be due to the addition of phenylalanine in Phen24.


Avoid Phen24 when you are pregnant or breastfeeding. You should also stay away from this stimulant-based dietary supplement if you already have a medical condition.

Phen24 Customer Feedback

Phen24 offers a combination of day and night pills that you need to take daily to help lose weight. Unfortunately, it is hard to find positive reviews for Phen24. For instance:

I have been taking these pills for a couple of weeks now, but I have not noticed any change in my appetite or weight.

It did help increase the feeling of fullness to a certain extent, which I guess is due to glucomannan, but it really did nothing to help me lose weight. I will try something else now!

Phen24 Money-Back Guarantee

Yes, Phen24 comes with a money-back guarantee, but it is not easy to get a refund.

Where To Buy Phen24

You can buy Phen24 directly from the official website, or order through third party retailers.

Watchdog Verdict

Phen24 is advertised a weight loss supplement and it claims to be different, because it uses a 2-in-1 formula to help you burn calories during the day and prevent hunger pangs at night. You have to take pills during the day and at night to help lose weight effectively. While some ingredients like glucomannan and green tea extract have their benefits, they are not going to work unless you know how to be in a calorie deficit mode.

The ingredient profile is actually quite extensive, but most ingredients like cayenne powder, guarana, phenylalanine, chromium picolinate, and different vitamins are not going to promote weight loss. The price of this dietary supplement is also on the higher side.

Our verdict: avoid it!

How does Phen24 compare to Phentatrim?

Criteria Phen24 Comparison Phentatrim comparison
Clinically Proven Ingredients
Side Effect Free
Positive Customer Reviews
24/7 Support
Money-back Guarantee

Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.

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