Fastin vs Phentermine: Which one’s better? (plus otc alternative)

January 8, 2024 |

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If you’re serious about losing a lot of weight but fail to do it through diet and exercise, your doctor might recommend using weight-loss pills.

You might have heard about Fastin and phentermine. These pills can help you shed off over 5% of your body weight in 12 weeks.

What are some of these pills, and which one’s the better choice in terms of efficacy and safety?

Phentermine is an FDA-approved appetite suppressant for obesity and weight loss. It’s a popular diet pill but you can’t easily get your hands on phentermine because it’s a controlled substance. On the other hand, the original Fastin diet pills were simply a type or brand of phentermine, but it has been discontinued.

Why were Fastin diet pills discontinued and why can you still see some of these products being sold to this day? Are these new Fastin diet pills similar to the original one or are they formulated differently?

If phentermine needs a prescription, do you still need one if you want to buy the new Fastin weight-loss pills?

You can get answers to these questions, and more about Fastin vs. phentermine, in this article we prepared especially for you.

Original Fastin Diet – Pills vs Phentermine

What is Fastin?

The original Fastin diet pills were made of phentermine hydrochloride and were used as a prescription-based weight reduction regimen based on caloric restriction.

This drug worked by suppressing appetite, making you feel full, and reducing your calorie intake.

It doesn’t directly burn fats or prevent fat absorption. However, because you eat less, then your body is forced to use up your fat stores for energy, ideally making you lose weight.

Its recommended dose is 30 mg (one capsule) per day, usually taken around 2 hours after breakfast. Because it can cause insomnia, users are advised against taking Fastin late in the evening or at night.

Some of the possible side effects of taking Fastin:

  • Changes in sex drive
  • Constipation
  • Diarrhea
  • Dizziness
  • Dry mouth
  • Elevated blood pressure
  • Euphoria,
  • Fast heart rate (tachycardia)
  • Feeling uneasy
  • Headache
  • Hives (allergic reaction)
  • Impotence
  • Insomnia
  • Nausea
  • Overstimulation
  • Palpitations
  • Restlessness
  • Tremors
  • Unpleasant taste in the mouth
  • Vomiting

What is Phentermine?

Phentermine formula

As the active ingredient of Fastin, all the information above can also apply to phentermine (including the side effects).

We previously wrote a comprehensive article on phentermine, but if you haven’t read through that one yet, don’t fret. Let’s briefly discuss this topic to help you make an informed choice if you’re still trying to decide what weight-loss pill to get.

Phentermine HCl is the common active ingredient in phentermine supplements.

However, these pills also have various inactive ingredients, including dyes, fillers, and binding agents.

What’s the effect of phentermine on weight loss?

The diet pill isn’t designed to burn fats. A stimulant, phentermine stimulates your brain to produce more neurotransmitters that can trick you into thinking that you’re already full.

The potential risks of phentermine (and Fastin) can include serious withdrawal symptoms such as the following:

  • Diarrhea
  • Headaches
  • Heart palpitations
  • High blood pressure
  • Insomnia
  • Irritability
  • Lack of energy
  • Memory loss
  • Menstrual irregularities
  • Stomach pain
  • Vomiting

Both Fastin (original) and phentermine are scheduled drugs because of their potential for recreational abuse.

Also, they aren’t ideal for pregnant women, anyone below 16 years old, and people with underlying medical conditions, including the following:

  • High blood pressure
  • Tachycardia (abnormal or irregular heartbeat)
  • Heart failure, heart valve disorder, or coronary artery disease
  • Stroke
  • Thyroid problems, such as hyperthyroidism
  • Kidney disease (especially those undergoing dialysis)
  • Parkinson’s disease
  • Tourette syndrome
  • Seizure disorders
  • Diabetes or high blood sugar
  • Glaucoma (abnormally high pressure in the eye)
  • Depression

Core Differences

Here are the major differences between Fastin and Phentermine:

  • Phentermine continues to be sold as a generic or branded drug (including Adipex-P, Suprenza, and Lomaira), but the original Fastin diet pill has been discontinued since 1998.
  • Phentermine is available in different dosage options: 8 mg, 15 mg, 30 mg, or 37.5 mg

New Fastin Diet Pills vs Phentermine

The new Fastin diet pills are manufactured by Hi-Tech Pharmaceuticals who reportedly bought the Fastin name and trademark from the original prescription manufacturer in 2007.

Hi-Tech Pharmaceuticals produced the new Fastin diet pills without phentermine, and they’re now marketed as a “herbal stimulant.”

Surprisingly, the manufacturer only recommends using the product for up to 8 weeks.

That’s 4 weeks shorter than the recommended 12 weeks for phentermine.

So, is Fastin still prescribed? As you can guess, the new Fastin products no longer require a prescription because it doesn’t contain the controlled substance, phentermine.

Although you can’t buy Fastin diet pills on Amazon (subject to availability), you can get them directly from Hi-Tech Pharmaceuticals and other online sources.

Is the new Fastin a stimulant like the original? The answer is YES! Although it’s now made with phenylethylamine, this active ingredient is still a stimulant that acts by amplifying or increasing neurotransmitters in your brain.

As a stimulant, Fastin can uplift your mood, improve alertness, and increase physical drive.

It increases the following:

  • Dopamine (your body’s “feel-good” hormones)
  • Norepinephrine (your brain’s stimulant for higher performance and wakefulness)
  • Acetylcholine (helps improve memory and mental activity)
  • Serotonin (elevates mood and helps in impulse control)

Today, these new products are sold in two forms: Fastin and Fastin XR.

Learn more about their differences below.

Difference From Phentermine

As a dietary supplement, the new Fastin pills aren’t controlled by the FDA (Food and Drug Administration). They’re considered as food products rather than medication, so they don’t undergo rigorous clinical testing to prove that they’re effective and safe.

In contrast, phentermine is a controlled, prescription-only drug. It’s FDA-approved for use as a weight-loss and obesity drug.

Although the phentermine active ingredient might make you feel worried, some people think they’d rather choose that because they know exactly what’s in the pill.

With a dietary supplement, you might never know.

That’s not to say that dietary supplements are bad, of course. Just make sure you’re buying products from a trusted brand or manufacturer.

What Is The Difference Between Fastin And Fastin XR?


First, let’s talk about Fastin.

What is the generic name for Fastin?

This new diet pill’s generic name is phenylethylamine HCl. Don’t confuse it with phentermine. They might have similar spellings but they’re two very different amines.

What are the ingredients in Fastin?

The manufacturer declares the following ingredients in Fastin in what they call “Thermo-Rx”:

  • Phenylethylamine HCl
  • Methylsynephrine HCl
  • Theobromine anhydrous
  • 2-Aminoisoheptane HCl
  • Synephrine HCl
  • N-methyl-B-phenylethylamine HCl
  • Yohimbine HCl
  • Caffeine – 200 mg in anhydrous form

Fastin XR

It’s the extended-release form of Fastin.

According to Hi-Tech Pharmaceuticals, Fastin XR contains an identical ingredient profile of stimulants as Fastin but also includes Senegalia Berlandieri and another 150mg dose of caffeine.

Fastin XR also has 5-Methoxytryptamine HCl (5-MOT), an ingredient not found in Fastin. It can support neurotransmitter serotonin activity, which makes your brain’s hunger center think that you’re already full.

While Fastin only contains 245 mg of the proprietary blend, Fastin XR is available in a higher dose of 425 mg.

How Do You Take Fastin XR?

Both Fastin and Fastin XR are taken in the same manner.

Take 1-2 tablets/capsules in the morning and another tablet (just one) after lunch. Don’t exceed 4 tablets daily.

Is Fastin Good For Weight Loss?

Hi-Tech Pharmaceuticals claims that Fastin can be good for weight loss because it contains eight active ingredients (listed above), including caffeine.

What’s The Best Diet Pill: Fastin vs Phentermine?

As you’ve read above, Fastin (the original and the new formulations) and phentermine have different advantages over each other.

Choosing the right one depends on your needs and preferences.

Since the original Fastin is no longer available, you can only take your pick from the new Fastin and Fastin XR or phentermine.

If you prefer a dietary supplement that you can buy anytime, without a prescription, and free from a controlled substance, then the Fastin products are the ideal choice.

If you want an FDA-approved diet pill, then phentermine might be the one for you (as long as you don’t mind regularly going to your doctor for a prescription).

What’s Our Recommendation?

It’s up to you to pick between Fastin and phentermine, but note that both are stimulants.

That’s why we recommend PhenQ.

Due to their mechanism of action and the way they directly affect the brain, Fastin and phentermine can only be used for a few weeks. The limit is 12 weeks for phentermine. Although off-label use (over 12 weeks) is sometimes done, this isn’t recommended because it can be unsafe.

In contrast, PhenQ is made of natural ingredients that work to help you burn fats, without the use of stimulants. Thus, you can take PhenQ for as long as you want and need.

The brand claims that it hasn’t received any reports of adverse or side effects from its customers.

As a diet pill, PhenQ can help you:

  • Lose weight
  • Maintain your new weight

For best results, you can use PhenQ to help you lose weight. Note that 2 lbs per week are considered a healthy, sustainable weight loss rate. How much you lose (or gain) depends on several factors, including your activity level and calorie intake.

Then, once you achieve your weight loss goal, you can opt to continue taking PhenQ to increase your likelihood of maintaining your new weight.

In case you stopped using the diet pill but discovered you gained weight again, you can go back to using it to shed off your regained weight.

There’s no need to ask your doctor for a prescription because you don’t need one to buy this product.

What’s In PhenQ?

This diet supplement contains their patented a-LACYS RESET as the main, active ingredient.

It boosts your slimming efforts naturally because it’s made of alpha-lipoic acid and cystine, which can encourage your body to burn excess fats naturally.

It also has other natural ingredients that boost metabolism to further promote weight loss:

  • Caffeine – for heat production to burn calories and shed off excess fat stores
  • L-carnitine fumarate – helps shed off excess fats; can also combat mental and physical exhaustion
  • Chromium picolinate – appetite suppressant (like phentermine) that curbs cravings for carbs and sugars
  • Capsimax powder – promotes natural fat-burning and thermogenesis
  • Nopal cactus fiber – binds with dietary fats for natural elimination, which makes you feel full even with eating less food

You don’t need a prescription to order PhenQ because it doesn’t contain phentermine. Plus, it’s made of 100% natural and safe ingredients for your peace of mind. It’s even suitable for vegans and vegetarians.

Final Thoughts

Fastin and Phentermine are both prescription medications used to suppress appetite and treat obesity.

While Fastin is a newer medication, Phentermine has been around for many years and is available in a few countries. And both can only be obtained with a prescription.

However, they have similar side effects, including constipation, dry mouth, and headache.

This is why we highly recommend an effective appetite suppressant, try PhenQ. It contains clinically proven ingredients that have been shown to help you lose weight quickly and safely. Plus, it comes with a money-back guarantee so you can try it risk-free.

Finally, don’t forget to always consult your doctor before using diet pills in your weight loss program. This helps ensure your safety, especially if you have an undiagnosed medical condition.

Important Disclaimer: The information contained on MAX HEALTH LIVING is intended for informational and educational purposes only. Any statements made on this website have not been evaluated by the FDA and any information or products discussed are not intended to diagnose, cure, treat, or prevent any disease or illness. Please consult a healthcare practitioner before making changes to your diet or taking supplements that may interfere with medications.

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