Updated: 11/17/2015 - Sponsored by Leptigen

Diet Fuel Review - Does This Weight-Loss Supplement Really Work? Are ineffectiveness and customer complaints deal breakers?

Editor's Review: 2.8 / 5.0

diet-fuel-product-imageWell over half of weight-loss products out there have absolutely ZERO scientific backing. Let’s see if Diet Fuel is one of those. We conducted a detailed review, examining the ingredients, side effects, overall customer service and clinical studies. Plus we sorted through countless user reviews and dieter responses posted online. Finally, we summarized all the facts to give you the bottom line.

EDITOR'S TIP: Substitute Diet Fuel with a proven fat burner such as Leptigen for better results.

What You Need To Know

To start off, Diet Fuel is available online for $42.99 (90 capsules). This product contains green tea leaf, raspberry ketones, caffeine anhydrous, guggulsterones, green coffee, kelp, dendrobium noble stem extract, fucus nodosus, capsimax, citrus aurantium, dulse powder, nettle root, bioperine, diiodotyrosine and brassica campestris root extract. It is touted as an “advanced thermogenic.” This supplement is part of the pro series available from TwinLab. The directions suggest taking it daily as 1-2 capsules. It aims to burn off fat, suppress appetite, boost energy levels and increase thermogenesis. With the size of the bottle we see no issues with taking this one on the go.

TwinLab was founded in 1968, and it appears that Diet Fuel was initially released in 2013. This supplement can be used by women and men alike. Moreover, this it contains some natural ingredients and is available at discounted rates through online stores, but read on…

Ineffective – “What’s Up?”

Our first concern was with Diet Fuel ingredients. “While examining the label, we noticed that this weight-loss aid contains fad elements such as raspberry ketones, which have not been clinically proven to assist with fat loss,” said our Research Editor. “This may be part of the reason dieters are not reporting the results they wanted to see.”

One customer said, “Slight boost in energy, nothing special.”

Another stated, “Did absolutely nothing for weight loss. Not buying again!”

Scroll below for one of the best products we’ve seen in 2015.

Customer Complaints – “Another Concern”

There are definitely a number of customer complaints regarding Diet Fuel. In fact, one user said, “Not for me. Made me vomit and break out. I threw them away.”

Another complained, “It did not work for me because it made me feel like I was under the influence of speed. It was way too intense and made me sick to my stomach a lot of the time.”

Our research has shown that if a specific facet of a weight-loss pill is especially burdensome (side effects, too many customer complaints, fad ingredients) the probability of success for the long-term is pretty low. So, if Diet Fuel does lead to a lot of consumer issues, this could be problematic.

The Science – “Any Validity?”

We couldn’t find any documented science listed on the official website supporting Diet Fuel as an effective weight-loss product. Green tea and caffeine have been the subject of such research with some positive results, but you can buy these online for less than $5 a bottle. There are also studies on ingredients like citrus aurantium showing some negative side effects like increased heart rate and elevated blood pressure, especially when taken with a stimulant. We at DietSpotlight have to see published proof supporting the product. Unfortunately there is nothing backing claims made about Diet Fuel.

The Bottom Line – Does Diet Fuel Work?

Alrighty then, what did our detailed look into Diet Fuel reveal? It’s always nice to see a weight-loss product that uses natural ingredients, but we are hesitant to suggest you use it. Aside from the fact that this supplement is not supported by clinical studies, it appears to have been discontinued as well. We’re also concerned that synephrine may be associated with some potentially negative side effects.

If you’d really like to shed more pounds and slim down quickly, we suggest you try out a supplement that contains ingredients that are supported by clinical studies with no reported side effects. Customer reviews are also a huge part of the equation with positive experiences being the same as a green light.

Among the best products we’ve seen in 2015 is one called Leptigen. Its formula is a blend of four key ingredients, which have been proven in documented scientific studies to help increase fat loss and elevate metabolism. Moreover, we didn’t find any discussion of harmful side effects and user comments posted on the internet indicate people are seeing amazing results.

Also, the company behind Leptigen are so confident in the ingredients that they’re offering a Special Trial Offer, a nice surprise.

Learn More About Leptigen »
GD Star Rating

How Does Diet Fuel Compare?

Previous Diet Fuel Review (Updated April 2, 2014):

What You Should Know

Click Here To See Our Highest Rated Review

It is prudent to investigate any diet product prior to taking it for weight reduction purposes, or any other reason. One issue that constantly arises is ingredient safety. If you are not aware of Ephedra (also called Ephedrine), then you should know that it is not legal in the US. Therefore you do not want a diet product containing this substance. One weight loss product that we are going to scrutinize at this point is Diet Fuel by TwinLab. How would you like to have more energy, lose unwanted pounds, and feel great? This is what Diet Fuel is supposed to do for users. It contains the ingredient Green Tea Extract, just like many other weight loss products nowadays. This is a form of caffeine, which is claimed to boost energy levels. However, you should know that caffeine is a diuretic that pulls water off of the body.

List of Ingredients

Guarana Seed Extract 800mg, Thermogenic Energy Enhanced Complex 685mg, Citrus Aurantium Fruit Extract, St John’s Wort Extract, L Phenylalanine, Green Tea Leaf Extract, Quercetin, Citrus Bioflavonoid Complex, Ginger Root, Cayenne Fruit, Gelatin, Purified Water, MCT Silica, and Magnesium Stearate.

Product Features

Diet Fuel is one of the several dietary supplements offered by TwinLab. This product in particular is supposed to aid users with weight reduction. It sells for a retail price of $39, which amounts to 120 capsules. Along the lines of many other weight loss formulas available, this supplement is to be taken prior to each major meal of the day. While two capsules should be taken each time, the user should not exceed six capsules of Diet Fuel in one day. There are a number of warnings that should be examined prior to taking this weight loss formula. Some health concerns that restrict certain individuals from taking Diet Fuel are as follows; liver disease, thyroid problems, pernicious anemia, depression, nervousness, prostate enlargement, and diabetes. Women who are nursing or pregnant cannot take this diet product. There are not many reviews presented online for Diet Fuel capsules, and some of them are not positive.

See Our Featured


  • A full list of ingredients are presented for this weight loss supplement.
  • It is easy to find Diet Fuel on sites like drugstore.com.


  • There is no scientific research presented to support Diet Fuel.
  • This weight loss formula has a lot of warnings, which may turn some dieters away.
  • Some of the reviews for Diet Fuel are not positive.


When all is said and done, there is really not a lot supporting Diet Fuel as a stellar and effective weight loss product. First of all, some reviews posted online for this supplement are negative, which is something to keep in mind. Secondly, Diet Fuel contains caffeine, which is a known diuretic that may lead to nervousness and jitters. Be sure to compare Diet Fuel to some other weight loss products before choosing to buy it.

Diet Fuel FAQ:

We narrowed down hundreds of user comments about Diet Fuel into this helpful FAQ.

What are the side effects of Diet Fuel?

Some potential side effects of Diet Fuel include jitteriness, nausea, increased heart rate and sleeplessness.

What are the ingredients in Diet Fuel?

Diet Fuel ingredients are green tea leaf, caffeine, raspberry ketone, gum guggul resin, green coffee fruit, camellia sinensis leaf, loranthus parasiticus stem, polygonum multiflorum root, kelp, dendrobium nobile stem, fucus nodosus, capsicum annuum fruit, citrus aurantium fruit, dulse powder, nettle root, brassica campestris, piper nigrum fruit, diiodotyrosine, gelatin, microcrystalline cellulose, magnesium stearate and silicon dioxide.

Does Diet Fuel work?

There’s no scientific research proving Diet Fuel is effective. We found research supporting weight-loss claims of caffeine and green tea, but not linked to this particular formula. You may want to consider changing things up and substituting Diet Fuel with a supplement like Leptigen, which contains ingredients clinically proven to work.

How much does Diet Fuel cost?

Diet Fuel costs $12.45.

How should I take Diet Fuel?

You should take two Diet Fuel capsules per day. The company recommends using one to test your tolerance and warns not to take more than one serving, two pills, in a 24-hour period. One bottle lasts a little more than 30 days.

Can I take Diet Fuel if I have a health condition?

Woman who are pregnant or nursing or people who take prescription medication, have health conditions of any kind or are under 18 years of age should contact a healthcare provider prior to using weight-loss supplements, including Diet Fuel.

What do users like about Diet Fuel?

Some users like that Diet Fuel is affordable and that the small size of the pill makes it portable.

What do users NOT like about Diet Fuel?

We found that some users didn’t like the side effects associated with Diet Fuel. Additional concerns were ineffectiveness and difficulty reaching the customer service department.

How do I contact the Diet Fuel customer service department?

You can contact the Diet Fuel customer service department by mailing correspondence to Twinlab 600 East Quality Dr. American Fork, UT 84003, calling the hotline at 1-800-645-5626 or using the customer feedback form on the official website.

Are the raspberry ketones in Diet Fuel clinically proven effective?

No, the raspberry ketones in Diet Fuel isn’t supported by clinical research. The ingredient is often considered a ͞fad͟ ingredient.

What is the amount of caffeine in Diet Fuel?

There’s no mention of the amount of caffeine in Diet Fuel.

Does Diet Fuel come with a guarantee?

Diet Fuel doesn’t come with a guarantee. The product isn’t sold on the official website, only through online retailers.

Do you know of any special deals or discounts on Diet Fuel?

We didn’t find special deals or discounts on Diet Fuel. However, the past few months have been a whirlwind with our readers taking advantage of Leptigen’s Special Trial Offer, which is just the cost of shipping and handling. Click here to try it out.

4 User Reviews About Diet Fuel

Leave comments below
  • 1
    Travis Hall

    Everything is very open with a precise description of the issues. It was really informative. Your site is very useful. Thank you for sharing.


  • 2

    Does this realy give.u weight loss


    Your Name

    Yes I have lost 12 lbs and haven’t exercised a bit



    Does it make you go a lot to the bathroom?


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