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Phentaslim Review - 11 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 17 ingredients. 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/. 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

Beyond Raw LIT
Lipo 6 Black
Phedra Cut Ultra XT

Phentaslim Claims

Phentaslim claims include:


Phentaslim Ingredients

This supplement contains the following ingredients:

  • Green Tea (15:1) (375mg)
  • Caffeine Anhydrous (270mg)
  • L-Theanine (225mg)
  • N-Acetyl L-Carnitine (200mg)
  • L-Tyrosine (200mg)
  • Korean Panax Ginseng (40:1) (1200mg)
  • Guarana Extract (4:1) (400mg)
  • Ginkgo Leaf Extract (120mg)
  • Magnesium (80mg)
  • Cayenne Powder (8:1) (50mg)
  • Black Pepper extract (4:1) (24mg)
  • Vitamin B12 (as Cyanocobalamin) (10mcg)
  • Vitamin B6 (as Pyridoxine HCL) (1.8mg)
  • Niacin (Vitamin B3) (20mg)
  • Riboflavin (Vitamin B2) (1.3mg)
  • Thiamine (Vitamin B1) (1.3mg)
  • Zinc (15mg)

Guarana Seed

This is an ingredient that we extract from 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 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 It Work?

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 and 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.

Bottom Line

The Bottom Line on Phentaslim

Phentaslim is formulated with some popular ingredients, which means it really doesn’t stand out from the crowd. We expect you may see increased energy and possibly lose some water weight, but it’s critical to eat a healthy diet and exercise to truly lose weight.

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 is Phentaslim?

Phentaslim is a dietary supplement that claims to help with weight loss, mental clarity, reducing cravings, boosting energy, and overall health.

How does Phentaslim work?

Phentaslim works by using a combination of ingredients that target fat burning, calorie burning, mental clarity, reducing cravings, and boosting energy levels.

Does Phentaslim actually work for weight loss?

While there are reviews and research supporting the effectiveness of some of the ingredients, the effectiveness of a supplement varies from person to person, and results may not be guaranteed.

What are the benefits of using Phentaslim?

Phentaslim claims to help with fat burning, reducing cravings, burning calories, boosting energy, mental clarity, and overall health.

What are the side effects of Phentaslim?

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

Where can I buy Phentaslim?

Phentaslim can be purchased using their Official Site.

What are the ingredients in Phentaslim?

Phentaslim is an all-natural weight loss supplement that contains some of the best fat-burning ingredients available, including green tea extract, caffeine anhydrous, guarana seed extract, Synephrine HCl, pine bark extract and chromium. These ingredients are scientifically proven to help boost metabolism and energy levels while suppressing appetite and reducing cravings for unhealthy foods. Phentaslim also contains a blend of soothing herbs such as green coffee bean extract, black pepper extract, ginger root powder and licorice root to help reduce stress levels and improve mood.

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.

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.

How long does it take to see results with Phentaslim?

The time it takes to see results may vary depending on the individual and how their body reacts to the supplement.

32 Phentaslim Reviews

  • Best product 4 me.
    Nev Richards (Verified Purchase)

    I’ve lost over 40pounds since I started using phentaslim. I sometimes only need 1 with a mouthful of water. Lost my belly fat in no time.

  • AVOID !!!
    Julie Kennedy-Mcgregor (Verified Purchase)

    This stuff is terrible. Made me feel really I’ll and certainly no weight loss
    When I asked to return the product, I foundvout ,they deducted so much for not returning it in original packing, more deducted for no invoice, more for p and p and even more for not returning all the pills !! I reckon I would have been lucky in I got £5. BEWARE OF THIS COMPANY!!!

  • Disappointed
    Anonymous (Verified Purchase)

    I eat a very healthy diet,exercise twice a day and,unfortunately,not list an ounce with taking this product for a month. So disappointed.

  • Expensive and useless
    Sarah (Verified Purchase)

    Waste of money. Doesn’t do a thing it claims to and money back guarantee is a complete lie. Company ignores messages. Avoid.

  • Phen
    Terence (Verified Purchase)

    Complete waste of money I bought 5 and if anything I have put weight on first and last time for this rubbish

  • Jackie Corbett

    Just received my bottles taken 1st one this morning I have weighed my self I am 18 stone 6 pounds I am sticking to a calorie controlled diet and will be moderately exercising lets see if they work 😁

  • Do not work
    Julie Houghton (Verified Purchase)

    I didn’t lose any weight at all. Took 3 a day and finished the full bottle. Feel I’ve wasted money.

  • stephanie McCormack

    can you take Phentaslim with other vitamins ? I’m currently taking a multivitamin to help with hair growth, skin and nails.

    • Taylor Izzo

      Hi Stephanie,

      Ask your physician before taking this product

  • My journey with Phentaslim starts now!!

    Today is the first day beginning my journey with Phentaslim.
    I am very excited and at the same time curious about the possibility that I may be successful in my plight to lose weight given being overweight for the majority of my adult life.
    I will keep you posted.. Mary ??

  • Dissapointed
    Miss Sewell (Verified Purchase)

    I have used phentaslim every day for the last 3 weeks and have not even lost a pound. So disappointed. £39 wasted.

    • Anonymous


      • Anonymous

        Same on phentaslim really disappointed

  • Dewi Klaessen (Verified Purchase)

    4 years ago i used to take these every day for 3 months straight i had so much energy and i could go for 2 hours to in the gym. you don’t get side effects as long as you eat a meal before taking it when you take it on an empty stomach you will get a headache also when you don’t drink enough water make sure you build it up and not to take too much because it’s a huge adrenaline rush kicking in you feel more energetic. For the people who say i only lost 5 pounds next to taking this pill you need to regularly exercise and eat healthy only then you will lose weight don’t expect this to be a magic pill only you need to put more effort in it !! i recommend it to people only be careful if you have a high blood pressure other then that i do advice this product just ordered 4 of them again!

  • Waste of money and no refund.
    Elaine Collins (Verified Purchase)

    I purchased the 3+ one free package so my husband and myself could use this product. My husband is 120kg – neither of us lost any weight taking these tablets despite following the instructions properly. It gave us a little more energy but no more than taking the vitamin B supplements. If the product is based on enhancing energy so you can get out and exercise it will not work if you are sitting in an office hours per day. On contacting the company for a refund, we are not eligible as we opened two bottles not the one stipulated. We gave it a really good trial for almost 2 months but my husband had to stop as they made him feel slightly nauseous. there are hundreds of bad reviews on various websites including reports of heartburn nausea etc.

  • Unhappy (Verified Purchase)

    I have used one bottle and haven’t dropped a pound! The product is a waste of time. I have been eating healthy and exercising 3 times a week. Don’t waste your money. It does however replace a cup of coffee in the morning! Good caffeine boost but that’s about it

  • Fast results?

    How long before I would expect to see results?

    • Alana

      I’ve been taking them for almost a week now. I’ve had loads of energy and am able to go for brisk, half hour walks.yes I can feel my clothes getting looser. I have been drinking lots of water and peppermint tea and eating healthy, small portions throughout the day. Feel fine so far. It’s like anything. Can work for some people, maybe not others. I’ve also read many good reviews on other sites.

    • Maribel (Editor)

      Hello. All users are different and can experience different weight-loss results. If you feel like you’ve reached a plateau, you might want to try other products if this one doesn’t work out for you. Another product that helps with burning fat is Dietspotlight Burn.

    • Marie

      I have been taking 3 months and only lost 5 pounds
      Don’t bother waste of money

  • Fantastic :)

    well i ordered my 1 month supply and i had received these tuesday just gone… i have taken one in the morning and one round my lunch time. i dont take the 3rd one as i wanted to adjust slowly to them..since being on these tablets i feel my body already reacting positivly to these . not only less appetite now but im going to the toilet more lol..sorry to go a bit gross but since going toilet more i notice old poo aswell leaving my body and my stomach doesnt feel as bloated aswell and actually looks flatter.. i do suffer with IBS badly and these do help with spasams for some reason (maybe with some of the herbal ingrediants)..im drinking 2 literz a day or even more now when before i would only drink a cup at night. i also feel more energy… i am a 38 year old woman and 2 kids.. full time job and housewife aswell… these tablets are defo doing something positive FOR ME… fantastic 🙂

  • Happy happy!

    i really like it im so happy im losing weight finally happy happy

  • 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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