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Fastin Review - Does This Weight-Loss Supplement Work? Are lack of results and side effects deal breakers?

By Summer Banks on Oct 02, 2016
Fastin Review

Why is it that so few diet products are backed by science? Let’s find out if Fastin is one of the good ones. Our in-depth review examinied the ingredients, side effects, customer care and clinical studies. Additionally, we analyzed hundreds of dieter comments posted on the web. Then, we summarized and refined to give you the info you need.


What is Fastin?

To start off, Fastin is a “rapid fat-loss catalyst”. The ingredients include thermo-rx, phenylethylamine HCL, methylsynephrine HCL, theobromine anhydrous, 1,3-dimethylamine HCL, synephrine HCL, N-methyl-b-phenylethylamine HCL, yohimbine HCL and caffeine 100mg. You’ll take one or two tablets in the morning and another after lunch. It supposedly increases thermogenesis, energy and weight-loss.

Fastin was introduced around 2010 from Hi-Tech Pharmaceuticals. The supplement is sold through the official website and through trusted retailers. We like that it contains a few natural ingredients and that we found some positive customer comments, but read on…

Lack of Results – “No Weight-Loss?”

Our first concern with Fastin ingredients was the lack of results. “At first glance, the profile is promising,” said our Research Editor. “But, customer reviews are telling a different story.”

“I was stuck at the same weight for over 2 weeks and was working out over 60 min a day,” stated a user.

“No results. I thought this was supposed to provide rapid fat loss,” commented another.

We did located Fastin reviews talking about people seeing solid results.

“It curbs my appetite and gives me the energy I need to get up and go and lasts all day,” said a dieter.

Side Effects – “Complaints”

According to customer reviews, Fastin side effects are a major issue. One dieter said, “I took 1 tablet, my heart was racing. I then tried 1/2 tablet and still the same result. Not for me. I’m tossing them.”

Another stated, “After 30 minutes, however, my heart started racing, my body and hands began shaking and I felt as though I was going to pass out when standing. I had to sit down until I felt in control.”

While side effects are rare, we did find some Fastin reviews where customers reported no adverse reactions.

“I have had no side effects whatsoever. It never sped my heart up or gave me jitters at all,” reported a dieter.

“I just started using Fastin and I like it better than other diet pills I’ve tried because it doesn’t make me feel sick/nauseous,” said a customer.

After years of research, we’ve concluded that if a particular part of a weight-loss supplement is problematic, like being the cause of adverse reactions, long-term success is reduced. Is it worth it if you use Fastin and experience negative side effects?

The Science – “Based on Research?”

We did not find any scientific studies to support the weight-loss claims related to Fastin diet pills, but that doesn’t mean none of the ingredients are effective. Caffeine may boost metabolism, but there’s no connection between the ingredient and this particular formula. At DietSpotlight, solid science is critical to the review process. When there are no studies used to back the claims, we raise the red flag.

The Bottom Line – Does Fastin Work?

Ladies and gentlemen, the clock is up on this one. While it’s good to see that some Fastin ingredients are natural and that we found some positive customer comments, the lack of research used to support the claims is concerning. We’re also a bit hesitant about this one due to customer comments about the lack of results and negative side effects.

If you’re a dieter who wants to those extra pounds, we suggest going with a supplement that’s not connected to harmful side effects and backed by reviews showing it promotes weight-loss.

Among the best products we’ve seen in 2016 is one called Leptigen. The supplement contains four clinically-tested ingredients that have been shown to help ignite fat loss and accelerate metabolism. While there’s no mention of harmful side effects, dieter reviews reveal people are seeing outstanding results.

It’s a good sign that the makers of Leptigen are so confident in the supplement that they’re offering a Special Trial Offer.

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About the Author:

Summer Banks is an ISSA-Certified Fitness Nutrition Specialist and has reviewed over 2000 diet products. 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.

How Does Fastin Compare?

Previous Fastin Review (Updated November 19, 2014):

What You Should Know

Fastin was originally offered by prescription by the pharmaceutical company King Pharmeceuticals for Smith Kline Beecham. The company pulled the Fastin from the market in 1998, and Hi-Tech Pharmeceuticals acquired the rights to the formula and modified it to make it safe for over the counter sales. Also under this company's umbrella is the sibling supplement Fastin XR. Today, Fastin is available through the product website, although the powerful stimulant contained in the formula makes it a good idea to check with a doctor before taking this supplement. Fastin combines ingredients that will elevate the mood while stimulating the metabolism. The mood elevator makes it easier to stick with a diet and exercise program until weight loss goals are met. The powerful stimulants in the formula will offer an energy boost to help you make it through your workouts while boosting your metabolism. It should be noted that some stimulants have been pulled from the diet market because of potentially dangerous side effects that can occur. Regrettably dangerous side effects lead to litigious action as is the case with Estrin-d and Activia also. While the stimulant in Fastin is allowed in diet formulas, it is still a good idea to check with a doctor to ensure the ingredients are safe for you.


We are pleased to see that the Fastin website offers a complete ingredient list for their product. This list includes Phenylethylamine HCL, R-Beta-Methylphenylethylamine. methylphenylethylamine tartrate , methylsynephrine HCL , N-Methyl-phenylethylamine HCL, Synephrine HCL, Theobromine Anhydrous, Yohimbine HCL and caffeine. Phenylethylamine HCL is a powerful stimulant, but it is not the only one in the formula. As a side note, Triadalean is almost entirely made of phenylethylamine compounds. Dieters with heart conditions, hypertension, thyroid disorders or those on prescription medications should check with their doctor before taking this formula. It is not recommended for women who are pregnant or nursing. Those who are sensitive to caffeine may find that Fastin has undesirable side effects like jitteriness, anxiety or difficulty sleeping. The product should not be taken too close to bedtime because insomnia can occur.

Product Features

Fastin is available on a free trial through the product website. However, if you order the product and do not cancel within the first fourteen days after placing your order, you will be enrolled in the Fastin auto ship program. This means that you will receive a 60-day supply of the supplement bi-monthly and your credit card will be automatically charged. The current cost of Fastin is about $70 per month at the time of this review.

See Our Featured


  • Fastin has stimulants that will speed the metabolism and boost energy.
  • The product also contains mood elevators that can help you stick with your diet program.


  • Fastin does not contain an effective appetite suppressant.
  • The formula may have undesirable side effects in some people.
  • Fastin is not safe for everyone.
  • Initial order of the product will sign customer up for auto ship program.
  • The product is rather expensive.


Fastin may help some that are extremely overweight and have not seen success with diet and exercise alone. In that respect it is similar to Optifast. However, we prefer a diet supplement that contains a safe but effective fat burner and an appetite suppressant for best results.

Fastin Questions & Answers:

We picked apart hundreds of user comments about Fastin into this helpful FAQ.

What are the side effects of Fastin?

Some potential side effects of Fastin are dryness of mouth, euphoria, insomnia, dizziness, restlessness, jitteriness and increased heart rate.

What are the ingredients in Fastin?

Fastin ingredients are methylphenylethylamine tartrate, methylsynephrine hcl, n-methyl-phenylethylamine hcl, synephrine hcl, theobromine anhydrous, yohimbine hcl, caffeine, dextrose, microcrystalline cellulose, hydroxypropyl methylcellulose, stearic acid, magnesium stearate, sodium starch glycolate, starch and silica.

Does Fastin work?

There’s no scientific research proving the effectiveness of Fastin. We found studies linking caffeine to weight-loss, but not specific to this formula.

How much does Fastin cost?

One bottle of Fastin costs $49.95. When you order two, the price increases to $95.90. Three runs $134.85. A discount is applied when you purchase more than two bottles.

How should I take Fastin?

You should take one or two Fastin capsules in the morning and another after lunch. The company suggests not exceeding the recommended serving and not taking in the evening.

Can I take Fastin if I have a health condition?

Women who are pregnant or nursing, people with health conditions of an kind, those taking prescription medication or anyone under 18 years of age should consult with a healthcare provider prior to using a weight-loss supplement, including Fastin.

What do users like about Fastin?

Some dieters liked that the availability of Fastin and that the price was reasonable.

What do users NOT like about Fastin?

We found that users didn’t like the side effects of Fastin.

How do I contact the Fastin customer service department?

You can contact the Fastin customer service department by calling 1-800-310-9108, emailing a representative at customerservice@fastinsupplement.com or mailing correspondence to Hi-Tech Pharmaceuticals 6015 Unity Dr. Suite B Norcross, GA 30071.

Can I contact Fastin through social media?

Yes, you can contact Fastin through Facebook and Twitter.

Is Fastin the same as phentermine?

No, Fastin isn’t the same as phentermine. The latter is a prescription medication and the former is sold over-the-counter.

Are there any FDA advisories on Fastin?

Yes, there are FDA advisories on Fastin. The agency contacted Hi-Tech Pharmaceuticals in April of 2015 about the potential dangers of r-beta-methylphenethylamine.

How much caffeine is in Fastin?

Each serving of Fastin, one capsule, contains 100mg of caffeine.

Does Fastin come with a guarantee?

There’s no mention of a guarantee with Fastin. The official website sells the product, but doesn’t provide information on the return policy.

Do you know of any special deals or discounts on Fastin?

There are special deals and discounts on Fastin. If you purchase multiple bottles, you’ll receive money off the price.

Fastin is a strong fat burner from Hi-Tech Pharmaceuticals. The label is clear on the official website, but you won't find amounts for most of the ingredients. A proprietary blend is used to keep details of the formula with the company.

Fastin Ingredients and Supplement Facts

Serving Size: 1 Tablet
Serving Per Container: 60
Amount per Serving % DV
Proprietary Blend with ThermoRX 245mg *
- Phenylethylamine HCL * *
- Methylsynephrine HCl * *
- Theobromine Anhydrous * *
- 1,3-Dimethylamine HCL * *
- Synephrine HCL * *
- N-Methyl-B-Phenylethylamine HCL * *
- Yohimbine HCL * *
Caffeine 100mg *

Other Ingredients: None

We dug deep into the Fastin ingredients to give you the details you need.

Caffeine Anhydrous

Caffeine anhydrous is a dehydrated form of caffeine that’s naturally found in coffee and tea.

What is it Supposed to Do?

Because it’s a stimulant, it’s thought to help boost the metabolism so you can burn more fat.

Clinical Research

According to a study published in September 2007 in European Journal of Clinical Nutrition, “Only caffeine was thermogenic in the given dose and caused no haemodynamic side effects.”

Theobromine Anhydrous

Theobromine anhydrous is a dehydrated form of theobromine. It is the primary alkaloid found in chocolate, and is the chemical responsible for the “feel good” reaction we get when we eat chocolate.

What is it Supposed to Do?

Theobromine is used as a stimulant, a diuretic, and a vasodialator. It is a longer acting substance than caffeine.

Clinical Research

According to a 2013 study published in Psychopharmacology, “Theobromine responses differed according to dose: it showed limited subjective effects at 250 mg and negative mood effects at higher doses. It also dose-dependently increased heart rate.”

Synephrine HCL

Also known as bitter orange, this plant has stimulant qualities that make it similar to the now banned ephedra. Because of the potential for negative side effects, the National Collegiate Athletic Association (NCAA) considers it a banned substance.

What is it Supposed to Do?

It’s supposed to boost the metabolism to make it easier to loose weight. It affects the central nervous system and may increase heart rate and blood pressure.

Clinical Research

According to a study published in a 2005 issue of The American Journal of Medicine, “Ephedra-free weight loss supplements have significant cardiovascular stimulant actions, similar to ephedra. These effects are not likely caused by C. aurantium alone.” That could mean other ingredients may be required for optimal effect.

Phenylethylamine HCL

The salt form of phenylethylamine, this chemical is used to improve mood and alertness, as well as assist with weight-loss. It is found in chocolate and is known as the “love drug.”

What is it Supposed to Do?

This chemical helps to increase dopamine levels and block the actions of dopamine receptors. Its stimulant nature makes it behave similar to amphetamines to raise the blood pressure and blood sugar levels, while also boosting metabolism.

1,3-dimethylamine HCL

This is an over-the-counter stimulant made from geranium plants.

What is it Supposed to Do?

It is supposed to help improve energy levels and promote feelings of well-being.

N-methyl-b-phenylethylamine HCL

This is another form of phenylethylamine.

What is it Supposed to Do?

Like the other form of phenylethylamine found in the formula, it is supposed to help promote feelings of well-being.

Methylsynephrine HCL

This is an ephedrine alternative.

What is it Supposed to Do?

It’s a stimulant to boost metabolism and energy levels.

Yohimbe HCL

This is a form of yohimbe that is available as prescription drug in the United States. Yohimbe is an evergreen tree found in parts of Africa.

What is it Supposed to Do?

It’s supposed to help improve sex drive and function while taking an SSRI antidepressant medication, improve athletic performance and support weight-loss.

33 User Reviews About Fastin

Leave comments below
  • 1

    I’ve been taking fastin for a long time off an on an i love them i don’t have any complaints EVERYTHING AIN’T FOR EVERYBODY find something that agree with you an stop complaining about fastin i are the reason why i can’t go to GNC to purchase them


  • 2
    Your Namesheila

    Tell us yi was given these pills years ago from my doctor, but cant seem to get them anymore… please help me find a way to order…. no jitters, no side effects worked like a charm…. … thoughts about Fastin.


    Anna (Editor)

    Hi! For more information on where to purchase this product, please refer to the Fastin official website.


  • 3
    Lisaour Name

    I only take a half instead of coffee. But no one sells it at any drug stores or Gnc.Vitamin shop I’m a little upset


  • 4

    I bought mine last night otc at a local store. I read many reviews on the product. I took a half of one this am and my heart is racing no noticeable energy but I’m feeling like I’ll be thrown into a panic attack. Not suse what to think.


  • 5

    I just bought a bottle this afternoon. I took one after lunch, and was shaking so bad and jittery. I haven’t been hungry or thirsty. I need to lose about 50lbs. I will try 1/2 tab in the am, a d 1/2 at lunch tomorrow. I need to motivation and energy to work out.


    Mamie Brindley

    They do that. I love it. Wish I could afford them.


    Youannar Name

    I just used 1 pill this morning and, I worked out 1hr. non -stop and I liked it. I weight about 156lbs and I think that tomorrow, I will take 1/2 pill because still feel jumpy… but I am still going to work outside on our yard . I use to take 1 pill of Phentermine 30 MG capsule time release,and I lost lots of weight . It was a doctor prescription and it cost my $30 for 3o pills plus doctor visit of $75 . Where FASTIN cost me 60 ct capsules $49.99 = tx


  • 6

    severe side effects similar to heart attack/stomach virus due to the vomiting


  • 7
    Vikki M

    They have totally helped me to lose 40lbs using fastin. I will continue to use them until I hit my goal which is another 20lbs. I couldn’t be happier. Thank you


  • 8

    I’ve read a lot of good reviews on fastin. So I ordered some from the rite Aid Web site , 60 pills for 50 bucks! I can not wait to get them and along with my exercise routine, hoping to lose weight! My friend who recommended these lost 30 pounds in 2 months!



    I started a few days ago- I can only take a 1/2 tablet or I get MAJOR jitters for the 1st 1/2 hour. What I will say is that I am eating right regardless and it does curb your appetite. I am also doing 1 hour a day at the gym, and it has made me go insanely hard at the gym (and I hate the gym). I am hoping to get rid of the 15 pounds and then discontinue and continue the gym and eating right. I have tried Phentermine before and this is working the same as a prescription. So fingers crossed with eating right- gym daily this will provide the push I needed. But the jitters are no joke!


  • 9

    I needed help with energy for sure but mostly was looking for a strong appetite suppressant so I’m not thinking about food 24 hours a day & eating way too much. I have found that with Fastin. Even if my stomach is growling, I don’t FEEL like eating, which is a rare thing for me. I weigh 319 right now…have only been on it for a week or so..have lost 5 lbs so far. I know this is not a long term solution. I just need a jump start to my weight loss & to be able to eat less & get used to it. The only bad side effect is that about 20 minutes after taking one pill, it accelerates your heart, which can be scary. That issue stops about 30-45 minutes after taking it & then all is good. I only take one a day (around noon) & that works for me. I don’t think my heart could deal with another pill a day.


  • 10

    Hi every one,can any one help me,I checked on site for fastin,and they had a couple of different sorts.which ones are the best to take?does any one know.and I am not over weight,just midiumish want to loose about 2stones,does only over weight people take them? Or can anyone who wants to loose habit of weight can use them too?



    i like it . i do not get the jitters and i would start with the i like the blue white bottle that says fastin, phenylethylamine hci. i have alot of energy on these. alot.


  • 11

    I have stage 4 renal failure. Is this product safe for me?


  • 12
    Mamie Brindley

    I only need 30 at this time. If they are the same as a doctor prescribed they will work. I’ve taken before they did wonders for me. If anyone has any to pitch out send them my way. They are not high priced, but they are for me.


  • 13
    Angela Mannon

    I need to lose about 30 lbs. The one I have used before is now off the market. I need the extra help to get me back on track. Please email any information on this. I have heard the changed some things and it doesn’t work like it did. Can you clear that up? Thank you Angela Mannon


  • 14

    I really like it . It helped me lose at and gave me engery


  • 15

    Can you buy Fastin off the counter without a script? HOw much are they and do they really make one loose weight? I just ordered I thought it had phertermine in it and it doesn’t. I bought 6 bottles from the computer. It is like eating candy–IT HAS NO EFFECTS!!!!!!!!!!!!!!!!!!!!!!!!!!! DOes Fastin have phetermine in it? ANd where can one purchase it?


  • 16
    April Jones

    Is Fastin- original formula still available at GNC either in stores – preferably or via to order? I was under impression it was pulled from shelves? Someone please respond via Email thank you! Love GNC 🙂


  • 17

    I have been taking this product for 5 days and I have had increased energy as well as decrease appetite I have to force myself to eat even one meal a day. I only take one in the morning and one at lunch. this morning I had major issues i think it was dangerously low blood sugar as I have only been eating 1 healthy choice meal a day. I was down for most of the day I did not take the second pill and I will for now on eat a protien bar, egg, fruit or oatmeal before I take the pill in the morning. I have on the plus side lost 10 lbs so far but at what cost? I was freaked out this morning and so worried I was going to go into cardiac arrest. Force yourself to eat protien and veggies through out the day.


  • 18

    This stuff does jack you up. I’m used to drinking about six diet sodas per day, but this is unbelievable (and not necessarily a good thing.) I’m shaking like a leaf and nauseated unbelievably.


  • 19
    Alicia Smith

    I started taking Fastin three days ago. I have not weighed yet, but what I can tell you is I have more energy than I did and I am not very hungry. I do take it twice a day, but I do not take the recommended dosage. Right now, I am taking a half a pill around 8:30 and the other half around 12:30 or 1:00. I can tell a big difference in my appetite which is what I was looking for. It also gives me a push to work harder during my workouts. I have about 15-20 poinds left to use and I am hoping that this helps me achieve my goal. In the past, I have taken the prescription Phentermine whiuch worked for a while but the last time I got the pills it didn’t appear to have the same effect on me. So I went on a search for other supplements and I can honeslty day that this is the first one that has given me both an appetite supressant and the energy I need. If you are looking for a good product for the money…this is it!



    It has been several months since you wrote this review are you still taking the pill and if so what if any changes have you experienced.


  • 20

    I just took my first dose – two tablets of this Fastin supplement upon waking off an afternoon nap and then trying to see if it would jack me up like speed. As long time ago I used to abused PEA or Phenylethylamine HCL + Deplin (an MAO Inhibitor) that I would stay awake for days just like someone on methamphetamine. And that lead me to go into the delusional mode and my roommate called an ambulance that they strapped down onto a hospital bed as a result of overdoing Phenylethylamine HCL plus Deplin. Phenylethylamine HCL breaks down in your stomach but Deplin can prevent it from doing so leading to REAL amphetamines release into the brains creating powerful euphoria and energizing effects. Back to the story, after taking my first dose of Fastin on an empty stomach and it barely got me out of bed just like drinking two cups of coffee. No euphoria. No “high class” meth-like energizing effects. The overall effect is neutral and I’m still craving for foods. Perhaps adding the drug Deplin to this product can create mind boggling effects.


    Funk Shunning

    You stupid fucker, maybe you will jack your going nowhere self to the freezer in a nice big Baggie. You suck little nowhere man. You sound like such an idiot, you really do. This is not the place for your adolescent crap. Go back to the basement of your parents house where you live, at least get a paper route.


    Your Name

    I will pray for you, something is wrong with you and I hope you will find out what it is because , I hate for you to end up in a body bag. and if you have family their live will be destroyed Think about it please. :O(


  • 21

    i bought some from kroger and i opened iot and the pill came out like a pile of wet sand. wtf??



    The pills are highly sensitive to heat/light exposure, causing them to turn a slight brownish tinge and become VERY brittle. It does not harm the effectiveness of the drug. But if you just bought it, it was probably sitting on the shelf for some time. Just return it and attempt to get a fresher bottle.


  • 22

    I found it at my grocery store, Kroger. $25 for 20 pills.


  • 23
    Bernice Tweed

    I want to order some of the fastin diet pills


    Your Name

    It causes jitters


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