How Long Does PhenQ Stay In Your System?

January 10, 2024 |

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For this article, I’ve looked into each of PhenQ’s ingredients to determine how long it takes to leave your system for good.

Key Points:

  • PhenQ ingredients may stay in the body from 3 hours to 4 days after taking the pill.
  • These ingredients do not cause adverse effects even if they stay inside the body for up to 4 days.
  • Find out more about PhenQ on its official website.

Since weight loss drugs and supplements contain ingredients in their concentrated forms, their metabolism can take a long time.

Hence they can stay in your body for several days and can interact with other drugs and natural metabolites produced in your body.

That is why knowing how long a supplement would last in the system before starting the medication is important.

As for PhenQ, half-lives of the ingredients vary, and the total time for elimination goes as long as 4 days. However, most of its nutrients are excreted or utilized within 24 hours of ingestion.

Keep reading to find out why its elimination time is prolonged and how you can calculate the elimination time using the half-life of a drug;

How Long Do Fat Burners Stay In Your System?

Usually, diet pills last for 1 to 5 days in your body.

However, the exact time a fat burner would stay in the human body depends upon the biological half-lives of its ingredients and, to some extent, on your age, health, and metabolism.

Using the half-life duration, we can calculate the time a compound will remain viable in the human system.

After one half-life, 50% concentration of the drug remains in the system; after two half-lives, 25% concentration is left. And after 5.5 half-lives, less than 1% concentration is left, which is often too less to affect the body’s functions.

Below this level, a drug is usually considered completely eliminated.

In short, you can calculate the elimination time of a drug component using this simplified formula;

Time required for 99% elimination = Component’s half-life x 5.5

To help you get a better idea, I checked the pharma catalogs about famous diet supplements, and here is the estimated time they would stay in your body;

How Long Do OTC Fat Burners Stay In Your Body?

Let’s consider popular fat burners like PhenQ PM, Phen24, and Trimtone, for example:

1. PhenQ PM

PhenQ PM nighttime burner

Nightime PhenQ is a stimulant-free fat burner formulated to melt away fats as you rest.

Its main ingredients are biotin, L-arginine, 5-HTP, chromium picolinate, and L-lysine HCl. These ingredients have half-lives of 15 hours, 1.5-2 hours, 7.4 hours, 4 hours, and 1.3 hours respectively.

Hence, most ingredients of this diet pill are eliminated from the body within 5-6 hours, but some of them, like biotin and 5-HTP, remain viable for longer.

The total time required for complete elimination is approximately 3.5 days.

Related: PhenQ PM Review

2. Phen24

Phen24 bottles and capsules taken by MaxhealthLiving

Phen24 dose consists of daytime and nighttime fat burners to keep metabolism running 24/7.

Most of their ingredients have a half-life of 1.5-2 hours. However, Guarana in daytime tablets and Griffonia in nighttime tablets have half-lives as long as 5.5 to 7.4 hours.

So, the peak activity happens in the first 8-10 hours of taking the pill, but it will take 1-2 days to completely remove its components from the body.

Related: PhenQ vs. Phen24

3. Trimtone


Trimtone is an OTC drug containing bioactive ingredients like phytol, fiber, and caffeine.

Among these ingredients, caffeine has the longest half-life (approx. 5 hours). So, it would last up to 27 hours after you took the supplement.

Related: PhenQ vs. Trimtone

How Long Do Prescription Fat Burners Stay In Your Body?

Now let’s have an idea of how long the prescription drugs take to leave your system for good.

1. Contrave

Contrave is a prescription drug having two active agents, Naltrexone and Bupropion. The Half-life of Naltrexone is 5 hours, and that of Bupropion is 21 hours.

Considering these values, you can expect that Contrave components will stay in your system for 4-5 days.

2. Phentermine

The famous weight loss drug, Phentermine, has a half-life of 19-24 hours.  Hence, it will take about 5 days for its complete elimination from your system.

3. Alli/Xenical

The active ingredient in Alli and Xenical is Orlistat, a compound that prevents fat absorption in the gut. Pharma analysis shows that Orilstat breaks into two metabolites that degrade in the body at different times.

Its primary metabolite has a half-life of about 2 hours (total elimination time= 11 hours), while that of the secondary metabolite is 13 hours (total elimination time= 71.5 hours).

So, the Orlistat’s overall elimination time is 3 days after ingestion.

The longer elimination time for highly potent, stimulatory drugs is concerning, but with health-friendly diet pills like PhenQ, longer elimination time is, in fact, beneficial for weight loss.

How Long Does PhenQ Stay In Your System?

PhenQ is a mixture of different appetite suppressants and fat burners. Hence, its components are metabolized at different times.

According to metabolic studies, half-lives of these ingredients are as follows;

  • L-carnitine half-life ranges between 15-17.4 hours.
  • With a half-life of 5 hours, each caffeine dose would stay in your body for about 27 hours.
  • α-Lacy’s Reset(Cysteine and Alpha Lipoic Acid) has different half-life values as their chemical properties differ.
    In adults, 50% of L-cysteine quantity is metabolically utilized in 5.6 hours.
    In contrast, it only takes 30 minutes for Alpha Lipoic Acid concentration to reduce to half and 3 hours to become less than 1%.
  • Niacin has a half-life of 20-40 minutes.
  • Chromium Picolinate half-life is quite short (only 23 minutes) when directly injected into the blood. However, when it is taken orally, like in PhenQ, its stability increases, and its half-life is extended up to 4 hours.

And using the equation mentioned above, the elimination times for these compounds turn out to be;

how long does phenQ stay in your system

Simply put, your body would need almost 4 days to completely remove PhenQ components from the system.

However, most bioactivity of the drug is seen within 4-6 hours of ingestion, as after this time, the quantity of active ingredients is significantly reduced.

And even the components that stay in the body for longer pose no health risk or make you fail a drug test.

However, the higher concentration of L-carnitine, chromium picolinate, and caffeine in the blood plasma may interfere with other drugs you are using.

So, I recommend talking to your physician first to confirm its compatibility with other medications.

Related: Does PhenQ Interact with any Medications?

What Happens When You Stop Taking PhenQ?

With PhenQ, you need not worry about withdrawal symptoms.

Though you may miss the energy boost and mental focus this caffeine and l-carnitine mixture used to give you, no serious effects are seen in users.

Simply put, you can start and stop taking PhenQ anytime.

How Long Does PhenQ Last?

One bottle of PhenQ has 60 pills. So, it will last a month with the recommended dose of 2 pills daily.

As it costs $69.99, some people think PhenQ an expensive supplement, but with a whole month in each pack, the price eventually boils down to be $2.33/day which is worth trying for its amazing fitness benefits.

And you can save even more with bulk purchases. When you order 2 bottles for $139.99, you get 1 for free. That means you get 3 months’ supply for the price of two.

Similarly, you get 2 extra bottles on ordering 3 bottles. Hence you get 5 months’ supply just for $209.99, and that too with free shipping.

A complete win-win, right?

PhenQ Cost & Bundles



How long does it take to see results with phenQ?

It depends upon your body type, physical activities, and diet, but on average, people see significant weight loss after using phenQ for 3-4 months.

However, those who stick to a restricted calorie diet and work out regularly start seeing the result in their first month.

Find out more about it in my detailed blog about how long it takes to see results from PhenQ here. 

How long can you take PhenQ?

As PhenQ is a 100% nature-based supplement associated with no severe side effects on long-term usage, you can use it as long as you need it.

So, you can use it even for months until you achieve your fitness goals and later on for maintenance.

How often do you take PhenQ?

You should take PhenQ pills twice daily, one with breakfast and the other with lunch.

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