Updated: 07/11/2017 - Site sponsored by Dietspotlight Burn
By Summer Banks Jun 17, 2017

There’s quite a buzz about Phentabz reviews, so we dug deep into the ingredients, side effects, scientific research and customer service. Additionally, we jumped into hundreds of consumer comments and reviews. We then condensed and summarized to give you the info you need.

PhenTabz Readers: Click here to find out why we're giving away samples of our product, Dietspotlight Burn.

What is Phentabz?

First off, Phentabz is a fat burner containing caffeine, DMAA [1] and synephrine. The recommended dose is one capsule per day, not to exceed two capsules. The supplement supposedly assists with burning fat and weight-loss. One benefit of the capsule is ease of use.

The product was introduced in 2001 by Gentech Pharmaceuticals. The company also sells the supplement under the banner of Lexium International. You can purchase it on the official website. We do like that the company has been in business for more than 10 years but read on…

Ingredients Unsafe – “FDA Says Yes”

The first concern for us was Phentabz ingredients. “Caffeine [2] is considered a safe and efficient weight-loss supplement,” said our Research Editor. “But, when a diet pill contains a banned substance like DMAA, there could be an issue.”

According to the FDA, “DMAA, especially in combination with other ingredients such as caffeine, can be a health risk to consumers. Ingestion of DMAA can elevate blood pressure and lead to cardiovascular problems ranging from shortness of breath and tightening in the chest.”

It’s also important to note, “DMAA-containing dietary supplements are illegal [3], and their marketing violates the law. Based on the scientific information reviewed by FDA, DMAA is not a dietary ingredient.”

PhenTabz Customer Testimonials

Phentabz Side Effects – “A Major Concern”

Based upon some customer comments, the adverse reactions with Phentabz RX can be severe. “I have not experienced weight loss yet, but there are side effects like feeling edgy and jittery and going to sleep at night has been difficult,” said a consumer.

“The only side effect was that it was making me jittery,” offered a dieter.

“I get these hot sweaty episodes with a heavy weight feeling on my chest, and it gets hard to breathe,” reported a user.

Our research shows that if an issue arises, like side effects, this could hinder long-term success. If Phentabz side effects does, in fact, cause adverse reactions, there is a problem.

The Science – “Is There Any Proof?”

While the official Phentabz customer reviews website makes the case that the supplement is an effective weight-loss pill, we can’t find any clinical studies speaking directly to the benefits of the ingredients, other than caffeine. We did locate several cases where the Food and Drug Administration has banned DMAA [4] from products. At DietSpotlight, finding science to back claims is critical. If there is no research, dieters should probably walk away [5].

Also: read our Dietspotlight Burn Weight-Loss Kit review »PhenTabz Ingredients

The Bottom Line – Does Phentabz RX Work?

So here’s our final take. You might be thinking what’s the better option, Phentabz vs Phentermine, but we have some news for you. There are some favorable aspects of the product, like the longevity of the parent company and some positive customer comments, but we can’t get past our reservations because of the lack of clinical research supporting weight-loss claims. Plus, we’re concerned about the combination of ingredients, the potential for Phentabz side effects and the “F” Better Business Bureau rating.

If you’d like to see real results, we recommend going with a product that contains ingredients backed by published clinical research, with no warnings from the FDA and no side effects mentioned in any dieter review.

Among the best products we’ve seen this year is our product called Dietspotlight Burn. The formula contains a four-ingredient proprietary blend. All clinically-tested with results commonly found in journals such as Obesity and The American Journal of Clinical Nutrition.

Also, we’re so confident that you’ll love our product that we’re offering a Special Trial Offer, which is a good sign.

Previous PhenTabz Review (Updated February 6, 2014):

What You Should Know About Phentabz RX

PhenTabz is a weight loss supplement that claims the only side effects from taking the supplement are increased energy and faster weight loss. The official website looks like a website for a prescription drug, which is exactly what the company is going for. According to the description, PhenTabz vs Phentermine sums up to the same results, but one is a prescription weight loss drug. There are three products described on the website: PhenTabz, PhenTabz Teen and PhenTabz RX. None of these products lists ingredients used to promote weight loss.

List of Ingredients

  • None listed.

Product Description of Phentabz

We looked through every link on the PhenTabz website and not one ingredient is listed for any of the three formulas Gentech Pharmaceuticals wants dieters to trust. There is mention of a proprietary blend in the FAQs section of the website, but the ingredients present in that blend are not listed. Weight loss supplement companies have a responsibility to list all ingredients so dieters can review ingredients and choose whether or not they want to try a product. Moreover, some natural ingredients are contra-indicated when prescription medications are taken. Gentech Pharmaceuticals expects the dieter to believe PhenTabz customer reviews on faith that none of the ingredients cause negative side effects and that’s not a responsible choice for dieters to make. The blatant use of medical images and the extension “RX” is something we consistently tell dieters to avoid. Diet supplements are not medical supplements. Prescription medications are reviewed and approved by the Food and Drug Administration. The same cannot be said for weight loss supplements. We are also concerned that Gentech Pharmaceuticals markets a diet supplement for teens. Ingredients commonly used in diet supplements are not tested on teens and thus should not be considered healthy or safe for teen consumption. Of course, we are assuming there are ingredients other than those found in common vitamin supplements because the company does not list ingredients.


  • PhenTabz can be purchased online.


  • No ingredients are listed for any of the PhenTabz products.
  • The marketing push is clearly toward dieters looking for phentermine without a prescription.
  • There is a product aimed at teens.

Phentabz - Conclusion

The first thing we look for when reviewing a diet supplement is an ingredient list. If a company is not willing to reveal the ingredients used in the formula, they are not willing to earn the trust of the consumer. We can only assume Gentech Pharmaceuticals is hiding something by not publishing the complete list of ingredients for PhenTabz, PhenTabz RX and PhenTabz Teen.

PhenTabz is a supplement that claims to increase metabolism and "mobilize" fat. Lexium International, the company behind the formula, uses terms like "prescription" and "Rx" to catch the eye of the customer. There is a table that compares PhenTabz to phentermine, but no research supporting the idea that the supplement is stronger, in some cases.

PhenTabz Ingredients and Supplement Facts

Serving Size: 1 Tablet
Serving Per Container: 60
Amount per Serving% DV
Proprietary Formulation250mg*
- 7-Methyltheophylline**
- Methyl Synephrine HCL**
- Octopamine HCL**

Other Ingredients: None

We dug deep into the ingredients to give you the details you need on this PhenTabz review.


Caffeine is easily considered the most popular drug in the world. It is a naturally occurring substance found in coffee and tea. It is often added to sodas and energy drinks, and can be found in supplement form on its own.

What is it Supposed to Do?

It is a stimulant drug that is supposed to help increase mental alertness. It is also thought to have some bearing on speeding up the metabolism.

Clinical Research

According to a study published in Cellular and Molecular Life Sciences, “Increasing evidence indicates that the psychomotor stimulant effect of caffeine is generated by affecting a particular group of projection neurons located in the striatum, the main receiving area of the basal ganglia.”


DMAA is closely related to amphetamine, and has been banned by the FDA.

What is it Supposed to Do?

Originally introduced to the pharmaceutical market in 1948 as a nasal inhaler for sinus and cold issues, it was withdrawn in the 1970s.

Clinical Research

According to a study published in New Zealand Medical Journal, “Dimethylamylamine (DMAA) is a synthetic stimulant and is one of the main ingredients of new ‘BZP-free party pills’. Though patented in the 1950s as a nasal decongestant, little is known of its pharmacology via the ingested route. This case report describes a 21-year-old male who suffered a cerebral haemorrhage shortly after ingesting two capsules of DMAA.” [1]


Synephrine is also known as bitter orange, or Citrus Aurantium. It is a plant used for a number of conditions, but is considered a banned substance by the National Collegiate Athletic Association (NCAA>)

What is it Supposed to Do?

It is a potentially harmful stimulant that is supposed to boost metabolism. It may cause side effects such as cardiovascular issues.

Clinical Research

According to a study published in Obesity Reviews, “While some evidence is promising, we conclude that larger and more rigorous clinical trials are necessary to draw adequate conclusions regarding the safety and efficacy of C. aurantium and synephrine alkaloids for promoting weight loss.” [2]

Weight loss can be an ongoing issue never finding the right balance of diet and exercise. Dietspotlight Burn is a clinically proven supplement suggested to help boost metabolism and fat loss. Dieting and exercise can be achieved with this product from studies supporting a boost in energy levels, absolving weight loss plateaus and weight loss.

PhenTabz Side Effects:

In the market of weight-loss supplements, it’s easy to think that natural solutions are one-in-the-same with being side-effect-free, but that isn’t always the case. With any formula there is a risk for a negative reaction, and although PhenTabz side effects are relatively uncommon, it doesn’t necessarily mean they don’t happen for some people.


Insomnia is the inability to fall asleep or to stay asleep throughout the night. Someone with insomnia may not be able to fall asleep for thirty minutes or more and often get less than six hours of sleep a night.

What causes insomnia?

Stress, anxiety, and depression are common causes of insomnia due to the brain’s inability to rest. Stimulants such as caffeine and nicotine can also contribute to insomnia as well as medical conditions like arthritis, hyperthyroidism, and Parkinson’s disease.


Heartburn, although not directly related to the heart, is described as a burning sensation in the chest. The pain is often worse when bending over, or lying down. [1]

What causes heartburn?

Heartburn occurs when stomach acid backs up into the esophagus due to a weakened or relaxed esophageal sphincter. It can be a condition on its own, caused by spicy food, overeating, and alcohol consumption. It can also be a symptom of another condition such as GERD, pregnancy, and esophagitis.

High Blood Pressure

High blood pressure (or hypertension) is when the blood flows through arteries at a higher than normal pressure. A systolic pressure below 120 mmHg (millimeter of mercury) and a diastolic pressure below 80 mmHg are considered normal for adults. A systolic pressure above 140 mmHg and a diastolic pressure of above 90 mmHg is considered to be hypertensive.

What causes high blood pressure?

All causes of high blood pressure are unknown, but several lifestyle habits and conditions may contribute. Some factors include poor diet, excessive weight, smoking, obesity, thyroid disorders, and chronic kidney disease.


Jitters are the sensation of feeling shaky or trembling inside the body or out. It can be the feeling of nervousness or slight, irregular movements to the hands, legs, and feet.

What causes jitters?

The most common causes of jitters are stimulants such as caffeine, nicotine, and certain medications that affect the nervous system. Another factor may be insufficient food consumption, causing your blood sugar levels to become too low, resulting in shakiness. [2]

PhenTabz side effects are rare, although there have been some reported, such as jitters, heartburn, and insomnia. In order to prevent any unforeseen complications, it’s always best to consult a doctor before taking any supplement, especially if you are pregnant or nursing, taking prescription medications, are under the age of 18, or have a medical condition of any kind.



PhenTabz is a supplement that uses DMAA, synephrine, and caffeine to promote weight-loss. Side effects aren’t always a guarantee, unfortunately, we found comments of people who have experienced them.


“It made me jittery [and] sweat.”    Dana


“Every time I take this pill I get sleepy.”    Stacey


“My [heart] started beating really fast, I started shaking and my hands were uncontrollable, I couldn’t concentrate in work as my mind was all over the place.”    Michka


“I cannot sleep when I take it.”    Arabella


“Did not lose weight, I gained!”    Susan


“They do give me trouble sleeping.”    Dayna


“They increased my blood pressure, I could feel my heart beating significantly harder, I’d get stomach cramps which made me need to visit the loo immediately. The worse thing was which was the deal-breaker was the crazy heartburn/acid reflux pains.”    Rose


“They do not curb appetite rather make you more hungry and chest pains are awful.”    Rain


“It was making me jittery.”    JoAnn


“I can’t sleep at night when I take two.”    Renee


When taking a closer look at weight loss supplements that work best for health and fitness, Dietspotlight Burn came across as a noticeable product with four ingredients clinically shown to boost energy levels and help the metabolism run at a faster pace, resulting in weight loss.

PhenTabz Questions & Answers:

We summarized hundreds of customer comments and user reviews about PhenTabz and put the information into this helpful FAQ.

What are the side effects of PhenTabz?

PhenTabz possible side effects include chest pains, sleeplessness, jitteriness, difficulty breathing and stomach pains.

What are the ingredients in PhenTabz?

PhenTabz ingredients are 7-methyltheophylline [1], methyl synephrine HCL and octopamine.

Does PhenTabz RX work?

The actual amount of each ingredient used in PhenTabz tablets is not disclosed, which makes it impossible to know how potent this weight-loss product is. There is simply not enough clinical research or solid science presented to support the claims regarding PhenTabz.

How much does PhenTabz cost?

A bottle if PhenTabz sells for $69 (60 tablets) on the official website.

What is PhenTabz’s BBB rating?

Gentech Enterprises, LCC (also Gentech Pharmaceutical) has an F BBB rating, which is the company that makes PhenTabz.

How should I take PhenTabz?

You should take Phentabz twice a day, 30 minutes prior to breakfast and lunch. It’s recommended to take this product on an empty stomach, with eight ounces of water. A single bottle of Phentabz will last for one month.



What do users like about Phen?

Some customers like that PhenTabz is available on the official website and there are some video testimonials posted on the website for review.

What do users NOT like about PhenTabz?

Some users do not like that there are numerous customer complaints posted online about PhenTabz reviews. Also, some users do not appreciate that PhenTabz can lead to unpleasant side effects [2] and the ingredients used in this product are not explained on the website.

Have the ingredients in PhenTabz changed?

The official website is unclear about the current ingredients used in this product. However, the only ingredient mentioned is Ampheta HCL (125mg), but this substance is not explained at all.

Is there a return policy for PhenTabz?

According to the official website, you can only return this product if it’s in unopened/new condition. Also, there is a 20% restocking fee that applies.

If you are looking for a supplement with clinically-tested ingredients that promote weight-loss without the harmful side effects, Dietspotlight Burn may be for you. It is one of the top fat burners out there with amazing user reviews.

PhenTabz Scientific Abstracts:

Bitter Orange

Bitter orange extract by itself (p-synephrine)or when combined with various other herbal ingredients didn’t produce substantial negative events as a raise in heart rate or blood pressure, or alter serum chemistry, electrocardiographic data , blood cell counts or urinalysis. Bitter orange by itself as well as combined with other products had displayed an increase in resting metabolic rate as well as energy expenditure. Increases in weight-loss were also observed with the p-synephrine extract when administered for 6 to 12 weeks. It was concluded that longer term studies were going to be needed to test efficacy of these products any further. [1]

After ephedrine had been pulled from the dietary supplement market, sales of citrus aurantium (bitter orange) products for weight-loss have increased significantly. The most frequently noted ingredient of bitter orange that is speculated to lead to weight-loss is synephrine, however citrus aurantium contains a number of constituents which are believed to be important in losing weight. There are six potential isomers of synephrine (meta, para, ortho; and for each a dor I form). Some studies have found citrus aurantium to possess only p-synephrine, while other studies have come forth stating m-synephrine as the main ingredient. This is found to be a crucial difference, since the two molecules have rather different pharmacological properties that could affect efficacy and safety. Further studies are needed to determine which synephrine alkaloids are indeed present in citrus aurantium as well as products supposedly containing these alkaloids from citrus aurantiumand the relative quantities of different isomers. [2]


Trials had shown that glucose tolerance is quickly reduced following ingestion of caffeine, which suggests that coffee intake could increase the risk of diabetes in humans. This contradicts epidemiologic studies over the last 4 years which showed ingestion of caffeine reducing the risk of diabetes. Weight-loss may be a factor, due to one study showing that ingestion of caffeine was succeeded by lower diabetes risks in participants who had lost weight. Another study had concluded that both coffee and caffeine ingestion were associated with weight gain. It remains a possibility that caffeine and constituents of coffee, like quinides and chlorogenic acid may be a trigger of weight-loss. Caffeine, as well as caffeinated coffee has been found to increase blood pressure, in turn, posing a further threat to those who are already at risk of cardiovascular disease. [3]

In one study, high caffeine consumption was found to reduce weight, waist circumference, and fat mass more so than in lower amounts. High caffeine consumption was associated with weight-loss through fat oxidation and thermogenesis and with suppressed leptin in women. In participants who ingested low amounts of caffeine habitually, green tea-caffeine mixtures had improved weight management through fat oxidation and thermogenesis. [4]

Learn More About Dietspotlight Burn »
Summer Banks Dietspotlight Author
About the Author:

Summer Banks, a content strategist at Dietspotlight, has researched over 5000 products in the past 10 years. She has years of nursing training, experience as a manager responsible for 15 supplement brands, and completed coursework on Food and Nutrition from Stanford University. full bio.

Rating: 3.7. From 168 votes.
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Leave a comment or review

Patricia thomas powell

I would like to ask if I could take this if I am on the kidney machine three times a day?

Cameron (Editor)

Hi, Patricia. Only your doctor would be able to say for sure if the ingredients may affect someone using a kidney machine.

  Is it safe with Zoloft?

Is the a problem taking PhenTabz with zoloft?

Victoria (Editor)

Hi Marsha! Because of possible interactions with your anti-anxiety medications, please make sure to consult with your physician before taking this product to make sure you can safely combine the two.

  keep the weight off? Side effects?
safa saleh

I am 17 years old this product does seem that it works but does it really keep the weight off? and would I get high blood pressure or anything like that after the weight is gone?

Cameron (Editor)

Safa, people under 18 years old are advised not to take these products.

Your Nameamanda Runyon

I’ve been taking them almost two weeks and I can’t tell any difference in my weight but yes they do give you energy

Lost 30 pounds in 1.5 months

I’ve lost about 30 pounds of weight in approx 1.5 months. I have also visibly dropped my waist size and have not felt jittery. With no exercise, just watching what I eat. However I seem to be having many loose bm’s while taking them (which is the reason I first started looking into their side effects).


I have PhenTabz and the ingredients is clearly stated in the bottle’s label. It says: Proprietary Formulation consisting of 7-methyltheophylline, Methyl Synephrine HCL, and Octopamine.I have not started them yet. I will repost when I do.


Every time I take this pill I get sleepy. Never gave me energy


Yep, I feel the same way! It does not give me energy, it makes me unmotivated, and i am not taking any other drugs…

Don't recommend it.
Monica (Verified User)

I actually did have shortness of breath and chest pain with these pills when I take a whole one. I would not recommend these to anyone but healthy people with no past medical history or on any other medications. Honestly probably shouldn’t take them period.


I’ve been using it for the last 3 months and it seemed to work amazing at first, I lost 9 lbs in about two months and felt great, however, the last couple weeks it’s not doing much. Guess i’ll stop taking them

Tabitha mccollum

I paid 77$

  This is the worst product
MMW (Verified User)

This is the worst product I have ever used, I took a tablet and then my started beating really fast, I started shaking and my hands were uncontrollable, I couldn’t concrete in work as my mind was all over the place, basically felt like I had took a drug.. so it DOES have side effects! DO NOT RECOMMEND.

arabella shah

I can not sleep when I take it. Doctor said it was because of the caffeine. wont be taking this anymore


I haven’t taken it yet. I read you shouldn’t take it if you have high blood pressure and I have that so I have been scared to start it. I did read, Arabella, that if you are having trouble sleeping while taking this, to drink 3 or 4 more glasses of water a day.


yes it works! i have lost weight on it and i do like it. at first it makes me quiet and i work all day. after i get use to it, its fine. i was gettting from a doctor but office vists and such but i found it here. i havent ordered it yet from online but i do know that i have had success with it with really no side effets.

  I take one pill in the morning
Crystal (Verified User)

I’ve lost 17 pounds in alil over a million nth and a half. I take one pill in the morning when I wake up. I cut my cokes out and almost no sugar in my morning coffee and drink lots of water. I was 161 now 143.

  No bad side effects
Brian (Verified User)

Works great for the first month, I lost 15 pounds and had way more energy to exercise, yes you must also exercise for it to make a difference. But once accustomed to it the benefits are less. No bad side effects and I’ve been using it for a year now