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Phentaslim Review - 12 Things You Need to Know

Phentaslim claims, “In less than one minute a day, you can supercharge your life.” The supplement offers “powerful” ingredients targeting weight loss. However, our research team wanted to better understand the connection between the ingredients and weight loss.

After focusing on the benefits of the ingredients, our team studied reviews and testimonials. Then, we highlighted research supporting or disproving the claims. Finally, we gathered the facts to give you need.

Phentaslim can be purchased through their Official Site.

Phentaslim Readers: Noom is offering our readers a risk-free trial, for a limited time. Click here for more information!

Phentaslim Video Review


What is Phentaslim?

Phentaslim is a dietary supplement claiming to “destroy your hunger pangs and annihilate your body fat.” The supplement contains nine ingredients, vitamins, and minerals. Here’s a little research into some of the ingredients.

Customer Service Contact Information

You can contact their customer service information through their form online https://www.optimumnutra.com/contact-us/?_ga=2.141338034.1844221072.1632820837-753399305.1632820837. They are located at Optimum Nutra LLC. 680 S Cache Street, Suite 100-8640 Jackson, WY 83001, USA.

How Did Phentaslim Start?

The company behind Phentaslim is OptimumNutra. Founded in 2011, OptimumNutra is on a mission to provide “pure and potent” ingredients and supplements to maintain health and well being.

Phentaslim Competitors


Phentaslim Claims

Phentaslim claims include:


Phentaslim Ingredients

This supplement contains the following ingredients:

  • Green Tea (15:1) (375mg)
  • Caffeine Anhydrous (270mg)
  • L-Theanine (225mg)
  • Acetyl L-Carnitine (200mg)
  • L-Tyrosine (200mg)
  • Korean Panax Ginseng (40:1) (1200mg)
  • Guarana Extract (4:1) (400mg)
  • Ginkgo Leaf Extract (50:1)
  • Magnesium (80mg)
  • Cayenne Pepper (50mg)
  • Niacin (Nicotonic Acid) (20mg)
  • Zinc (as Zinc Acetate) (15mg)
  • Black Pepper extract (4:1) (24mg)
  • Vitamin B6 (as Pyridoxine HCL) (1.8mg)
  • Riboflavin (Vitamin B2) (1.3mg)
  • Thiamin (Vitamin B1) (1.3mg)
  • Vitamin B12 (as Cyanocobalamin) (10mcg)

Guarana Seed

This is an ingredient that we extract from a fruit. It contains caffeine that can cause adverse reactions to people sensitive to it. People take guarana to lose weight, improve mental and athletic performance.


This is a significant component since it boosts the metabolism and curbs hunger while retaining and elevating the energy levels. This ingredient, however, can cause jitters.

Panax Ginseng

According to the Annals of Pharmacotherapy (2002), panax ginseng “improves aspects of mental health and social functioning after four weeks.” There’s no current research supporting the claims of panax ginseng improving mental health.


While magnesium is commonly used in supplements for its laxative effects, there’s research showing magnesium is “required for energy production,” according to the National Institutes of Health.

Black Pepper Extract

According to the journal Critical Reviews in Food Science and Nutrition, the key alkaloid in black pepper extract, piperine, may assist in “cognitive brain functioning, boost nutrient’s absorption and improve gastrointestinal functioning.” However, there’s no current research supporting the claims of black pepper extract.

Green Tea Extract

The Journal of Oral and Maxillofacial Pathology concluded, green tea is a “cheap habit to maintain a healthy lifestyle.”

Vitamin B6

Vitamin B6 is found in foods such as fish, potatoes, poultry, bananas, and chickpeas. The vitamin may also help with muscle growth by boosting the absorption of amino acids, claims the NIH Office of Dietary Supplements.

Vitamin B2

Vitamin B2 plays a role in the development, function and growth of cells. Sources of riboflavin include meat and dairy, legumes and beans, eggs, and some seeds and nuts.

Vitamin B1

You can find thiamine in foods such as grains, yeast, nuts, beans, and meat. Thiamine plays an essential role in energy metabolism.

Does Phentaslim Work?

So, does Phentaslim work? There are reviews offering support of this dietary supplement. There’s even research supporting the effectiveness of some of the ingredients. However, the effectiveness of a supplement varies from person to person.


Phentaslim Benefits

Based on the official website, benefits include:

  • Burns fat
  • Reduce cravings
  • Burn calories
  • Boost energy
  • Mental clarity
  • Boost health

How to Use Phentaslim

You’ll take one capsule twenty minutes before breakfast, lunch, and dinner. You’ll need to take each capsule with a full glass of water. If you’re sensitive to caffeine, take the third capsule earlier in the evening or late afternoon.

Side Effects

Potential Phentaslim Side Effects

The official website doesn’t address Phentaslim side effects. However, there’s a chance some users may experience side effects from ingredients, including:

  • Jitters
  • Nausea
  • Headaches

Phentaslim Pricing

Phentaslim pricing depends on the package purchased on the official website. Pricing is:

  • Single bottle – $49
  • Two bottles + One free bottle- $98
  • Three bottles + Two free bottle – $147

What’s the Phentaslim return policy?

If you want to return the supplement to the manufacturer, you have 60 days from the date of purchase to return Phentaslim.

Pros & Cons

Phentaslim Pros and Cons


  • 60-day money-back guarantee
  • Natural ingredients


  • No current research is supporting claims.

Phentaslim Alternatives

Phentaslim alternatives include:


Phen 375 is an appetite suppressant just like Phentaslim, and its ingredients are very similar. They include stimulants like caffeine and cayenne pepper.

Superfruit Slim

Superfruit Slim is a dietary supplement from the same company. While both claim to promote weight loss, there’s no research supporting the effectiveness of the supplement.


PhenQ is a supplement containing ingredients similar to the supplement. The supplement also claims to promote weight loss and increase energy levels.


Phenocal is a dietary supplement offering clinically-researched ingredients; similar to Phentaslim. But, there’s no clinical evidence the combination of ingredients is more effective than the others.


Abidexin claims to promote weight loss by suppressing appetite and boosting energy levels. While there’s research supporting the effectiveness of some of the ingredients; there’s only anecdotal evidence Abidexin works.

What Users Are Saying

What Users Are Saying

“This was bought for a friend & they’re very happy with it.”

“Phentaslim is it just another fat burning product.”

Bottom Line

The Bottom Line on Phentaslim

Do clinically-proven ingredients, supportive comments, and an affordable price tag make Phentaslim the real deal? There’s a chance that this one will help you lose weight and reach your goals. The only concern we have is over a few comments about its effectiveness. However, those users didn’t specify if they followed directions in terms of diet and exercise.

While there are some benefits, there are also alternatives to add to your existing weight management plan, like a clinically proven weight-loss app.

One of the best apps we’ve seen this year is Noom. The program is backed by years of research and clinical proof it works to help you lose more weight and keep it off. There’s human coaching, personalized meal plans, expert advice and more.

Also, the team behind Noom wants everyone to take the app for a test drive, so Dietspotlight readers can access the app as part of a free trial offer.

Learn More About Noom »
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What are the side effects of Phentaslim?

Phentaslim side effects, based on user reviews, were mild.

What are the ingredients in Phentaslim?

Phentaslim ingredients are green tea, caffeine, l-theanine, l-carnitine, l-tyrosine, panax ginseng, guarana seed, magnesium, cayenne pepper, niacin, zinc, black pepper extract, vitamin B6, riboflavin, thiamin, and vitamin B12.

Does Phentaslim work?

The Phentaslim formula is not bad. It contains green tea and caffeine, two important ingredients. However, you can find these in hundreds (if not thousands) of other products.

How much does Phentaslim cost?

Phentaslim costs are the following:

  • Single bottle – $49
  • Two bottles + One free bottle- $98
  • Three bottles + Two free bottles – $147
How should I take Phentaslim?

You should take Phentaslim three times a day, once 20 minutes before breakfast and lunch and once in the late afternoon. It is not suggested to take Phentaslim after 5pm.

Where can I buy Phentaslim?

Phentaslim can be purchased using their Official Site.

Can I take Phentaslim if I have a health condition?

You should ask your physician if you are under the age of 18, if you are taking prescription medications, have other underlying health problems, are pregnant, or nursing.

Does Phentaslim come with a guarantee?

Phentaslim has a 60-day money back guarantee.

27 Phentaslim Reviews

  • Karen Redrup

    I have been eating healthy and exercising frequently and I haven’t lost a thing – complete waste of money.

    • Victoria (Editor)

      Hi Karen, we’re sorry that you had no results with this product. All users are different, and sometimes, don’t achieve the weight loss results they were hoping for. If you’re looking around for other alternative fat burners or metabolism boosters, you might want to check out Dietspotlight Burn.

  • Waste of money
    Marie (Verified Purchase)

    Don’t bother buying phentaslim. Iv been taking this product for 3 months taking 1 tablet 20 mins before breakfast 1 tablet 20 mins before lunch and 1 tablet 20 mins before evening meal with a full glass of water before each tablet and kept to a strict diet and excersize but only lost 5 pounds in 3 months.
    I’m not convinced it was the tablets that made me lose the 5 pounds but the strict diet and excersize that did.
    Expensive product and a waste of time

  • What happens if I CAN'T wait 20 minutes to eat after taking a pill?
    Ro (Verified Purchase)

    I’ve been taking Phentasilm for 1-week. I’ve lost one pound. My appetite seems suppressed. What I’ve found difficult is waiting 20 mins. Before the time is up I get jittery and slightly dizzy. So I have started taking it 5-10 mins before meals….with no less than 16 ounces of water

  • My experience
    Curvy redhead (Verified Purchase)

    I used this product after doing a lot of research and checking reviews. I needed something that would suppress my sugar cravings that had little or no side effect. I only take 2 a day so a bottle has lasted me 45 days ( although some days I’ve not taken it). I am doing Weight Watchers but cravings got so bad and I was spending £1-3 a day on chocolate, the weight was piling back on. Phentaslim was the last resort and for me it has worked, I knew it wasn’t a diet suppliment or meal replacement. I purely needed help with irrational cravings and thankfully it worked for me. I had no side effects other than having no sugar cravings and feeling fuller meant I didn’t snack between meals and most of time started wanting to have healthier meals.

    • Anonymous

      I have been taking this product for a week. I have stopped taking it bc of the profuse sweating, nausea and dizziness that I have experienced since day one.

      • Taylor Izzo


        Please make sure to contact your physician if you continue to experience side effects with this product

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