How long do Appetite Suppressants take to work?

January 9, 2024 |

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In this article, we will discuss the absorption time and half-lives of different diet pills and how much time they can take to help you with weight loss.

Different appetite suppressants take different times to become biologically available, and their weight loss effectiveness also becomes visible after different durations. On average, most dieting drugs show results after 3-4 months’ usage.

In the next section, we have provided an estimate of the time a famous anorectic substance would take to work, and then we will discover a highly effective weight loss drug.

So let’s get in and see when your diet pill efficacy would be visible;

How long does it take for appetite suppressants to kick in?

Every medicine takes a different time to absorb into the bloodstream, become available to body tissues, and start influencing the biological processes.

So is the case with appetite suppressants; each requires a different time to become effective.

To simplify this, we have researched the pharmacokinetics of most common appetite suppressants, and the results for their absorption bioavailability and half-life are presented below;

1. Phentermine

Phentermine formula

This famous appetite suppressant – Phentermine – works by manipulating the level of stress hormones, which interfere with the hunger cycle and reduce the temptation to eat.

How long does it take Phentermine to absorb?

When a phentermine 15 mg tablet is taken, its active ingredient shows maximum bioavailability after about 6 hours.

How long does Phentermine stay in the body?

Phentermine lasts for about 2-3 days in your body because its terminal half-life is approximately 19-24 hours.

How fast do you lose weight with phentermine?

When on phentermine, you will notice small weight changes after the first few weeks.

However, evident weight loss results are only visible after 2.5 to 3 months.

On average, it is expected that you would lose about 3-5% of your initial weight with phentermine.

2. Topiramate


Topiramate is an antiepileptic drug often combined with phentermine and other anorectic substances to induce appetite suppression.

How long does Topiramate take to absorb?

It becomes fully available to the body via absorption through the gastrointestinal tract. After 2-3 hours of ingestion, its plasma level reaches its peak.

How long does Topiramate stay in the body?

Topiramate takes almost two days to be eliminated from the human body as its half-life is about 20-30 hours.

How fast do you lose weight with Topiramate?

Although results vary from person to person, most people have reported a difference in their body mass after four months of using Topiramate-containing medicines.

3. Sibutramine


It is another nervous system simulator, leading to a higher concentration of certain neurotransmitters in the brain. Resultantly, these neural compounds affect the sensation of hunger, causing lower calorie intake.

How long does Sibutramine take to absorb?

A pharmacokinetic study shows that Sibutramine is absorbed in the gut and becomes maximally bioavailable 1.2 hours after intake.

How long does Sibutramine stay in the body?

Sibutramine’s appetite suppressant stays in the body for only a small duration, and most of it is gone after a few hours because its half-life is only about 1.1 hours.

How fast do you lose weight with Sibutramine?

After a month of Sibutramine treatment, you would see a small reduction in weight, like about 2 kg or lesser. However, a notable weight loss is reported to take place in up to three months.

A recent study revealed that most people achieve a 5% loss in their weight after three months of diet therapy with Sibutramine.

4. Diethylpropion

Diethylpropion is a sympathomimetic amine compound, just like phentermine. As a result, its mode of action is essentially very similar, producing appetite suppression through neural stimulation.

How long does Diethylpropion take to absorb?

This anorectic compound is absorbed maximally into the blood after 2 hours of administration because it is readily absorbed from gastrointestinal walls.

How long does Diethylpropion stay in the body?

Despite having similar chemical nature, diethylpropion is eliminated from the body sooner than phentermine because it has a shorter half-life span of 4-6 hours.

How fast do you lose weight with Diethylpropion?

Diethylpropion therapy is approved for the short term only due to its potential side effects. Thus, it is usually prescribed for four weeks. In this duration, an average weight reduction of 4 pounds is expected.

5. Liraglutide

Liraglutide is a lipopeptide used for weight loss and diabetic therapies. It enhances satiety by stimulating the increased production of insulin.

How long does Liraglutide take to absorb?

The pharmacological study infers that it takes 8-12 hours for Liraglutide to reach its maximum concentration in blood plasma.

How long does Liraglutide stay in the body?

This peptide stays in the body for almost 1-2 days as its biological half-life is reported to be 13 hours.

How fast do you lose weight with Liraglutide?

A good weight difference (4.7% reduction) is usually visible after using Liraglutide for four months. However, it shows the best weight loss results after almost 12 months, reaching up to 7% weight loss.

Here’s a quick that might make it easy for you to understand how it all works:

how long do appetite supressants take to work - a summary

Looking for a safe yet effective Appetite Suppressant?

We’ve got your back!

Phentermine and other suppressants are effective, but they are also associated with some side effects.

Most of these effects are due to the stimulatory nature of these substances. The common ones are palpitation, nausea, dry mouth, increased heart rate, and in severe cases, stroke and heart arrhythmias can also occur.

Resultantly, the quest for an effective and safe dieting medicine becomes more of a hassle, but with our years-long fitness expertise, we have a safer recommendation for you.

Enter: PhenQ

(A diet appetite suppressant pill formulated with plant-based, natural, and benign substances)


With a balanced mixture of anorectic amino acids, vitamins, and fiber extracts from capsicum and cactus, it provides benefits over traditional appetite suppressants with only one or two active ingredients.

As its effectiveness is unmatched and no serious side effects are known to date, you will find PhenQ at the top of most “best appetite suppressants’’ reviews.

Following, we have listed the features which make PhenQ more beneficial than other products;

Traditional appetite suppressants vs. PhenQ

Appetite suppressants usually focus on a single factor in weight loss, i.e., reducing calorie intake to limit fat build-up and induce energy deficit.

In contrast, PhenQ is a holistic weight loss solution, offering hunger suppression, fat loss, and a decrease in the future fat build-up.

Furthermore, metabolism improvement is a better weight loss strategy than just cutting down your calorie intake, and anorectic drugs usually play a minor role in metabolic reactions.

But PhenQ is a solution for your lower metabolic rate because it induces thermogenesis, enhancing the speed of fat consumption in bioreactions.

The efficacy of PhenQ is also higher as users have reported 5 to 6% weight loss in just one month, while most suppressants would take 3 or 4 months to reach the same level.

Likewise, the safety level of PhenQ appetite suppressant is much higher than traditional diet tablets, which stimulate the nervous system and release stress hormones to suppress appetite.

Instead, the Wolfson brands’ product reduces ghrelin (hunger hormone) levels to curb eating temptations safely. Due to this reason, it is approved as an over-the-counter product.

Another trouble while taking appetite suppressants is that you are likely to feel cranky and tired due to a lower food intake.

But PhenQ comes with a solution for this, too, as its key component, l-carnitine, is known to improve mood and cognitive stress. Hence, you will feel motivated and happy when using PhenQ.

What makes PhenQ the best of all? The answer is its ingredients

PhenQ is a mixture of L-carnitine fumarate, niacin, caffeine, capsimax powder, and chromium picolinate.
The α-Lacys reset (a blend of ALA and cysteine) is the miracle ingredient in PhenQ because it increases fat consumption, reduces fat production, and minimizes hunger.

The anorectic efficiency of cysteine makes the product different from most suppressants in the market as it interferes with the production of the hunger hormone instead of stimulating neurotoxins.

It also contains a bulking proportion of L-carnitine fumarate, which is a natural fat buster.

The caffeine content of its formulation provides multiple fitness benefits as it boosts energy, speeds up metabolism, and reduces fatigue.

Plus, this product is entirely vegan and includes extracts from capsicum, piperine, and nopal cactus, known for their thermogenic and anorectic properties.

Also, it comes with financial incentives and a 60-days money-back guarantee. There are 60 tablets in one bottle, providing a month-long supply.

It is available from the official online store according to the following pricing structure;

  • 1 bottle for $69.95
  • (2 bottles+ 1 free) is $139.90
  • (3 bottles + 2 free + free Advana cleanse) is $189.95


  • Effective fat burner
  • Blocks fat production
  • Reduces appetite
  • Enhances mood


  • It cannot be used at night
  • Not suitable for pregnant and breastfeeding women

Learn more about about PhenQ here


Appetite suppressants are an effective medication for losing weight faster. They provide a fullness sensation for a long time, restricting the amount of food intake, which eventually leads to weight reduction.

But all suppressants are not the same; hence, they get absorbed and excreted from your body differently.

Similarly, you will see varied weight loss results from different products depending upon the respective efficacy of their mode of action and their correspondence with your body systems.

Before choosing a weight loss supplement, analyze its effectiveness period according to your fitness goals and also consider the side effects to ensure health safety.

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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