Does Phentermine Make you Feel Happy & Good? (why?)

January 9, 2024 |

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Yes, phentermine may make you feel happy because it increases the level of neurotransmitters like dopamine and norepinephrine in your brain.

I get that phentermine is a stimulant, and you may think that it will help to brighten your mood, but in some cases, this stimulation of the central nervous system may also be the reason why you start feeling the blues as well.

However, phentermine has a similar effect to amphetamine and anti-depressants, so it may make you feel happy. The stimulant effect of phentermine helps overcome the deficiency of neurotransmitters like dopamine and norepinephrine that alleviates low mood.

In this article, we will discuss how phentermine may impact the way you feel during the day and whether you should take it if you are diagnosed with anxiety and depression.

So keep reading to know all about phentermine and its effect on one’s mood.

Can Phentermine change your mood?

If so, how?

Yes, phentermine does have different effects on your mood, but these effects may vary from person to person. In fact, mood changes are one of the most common side effects of phentermine.

In addition to being an appetite suppressant and anorexiant drug, phentermine is basically a sympathomimetic amine that works by mimicking the endogenous agonist of the sympathetic nervous system to stimulate it.

people mood

The term endogenous agonist refers to the neurotransmitters like epinephrine, norepinephrine, and dopamine in the brain.

(And for a fact, an increase in the norepinephrine concentration in the hypothalamus (a region in the brain) caused by phentermine is what keeps your hunger pangs and cravings away.)

Phentermine is also suspected of having an indirect effect on serotonin, but there is still a lack of significant research to prove this hypothesis.

Nonetheless, since it messes with your brain, neurotransmitters, and the nervous system, it may also induce mood changes.

On the one hand, some people might feel motivated or happy; others might start getting mood swings or feel ‘phentermine rage.’

Phen Rage is a term that is used to describe feelings of frustration, anger, irritability, hostility, anger, and impatience that the users feel after taking phentermine.

Phentermine’s effect on mood has not been assessed as a primary outcome in scientific studies performed on it. But it has been reported as a secondary outcome in participants of the studies and in case reports.

Anyhow, let’s dive deep into the details of both the positive and negative impact of phentermine on your mood without any further ado.

The positive effect of phentermine on mood

Phentermine is believed to have a similar mechanism of action to bupropion, a common anti-depressant, as it increases the level of dopamine and norepinephrine in the brain.

And this is why you should not take phentermine with MAO inhibitors, which are a powerful class of anti-depressants.

Remember that I mentioned above, phentermine influences a region of your brain called the hypothalamus, which is involved in the regulation of appetite, and this, in turn, causes appetite suppression.

A number of studies have reported that HPA (Hypothalamus Pituitary Adrenal) axis dysfunction may cause major depression. As phentermine is modulating the function of the hypothalamus, so it may help to normalize your mood as well.

Studies have found that imbalances in neurotransmitters like serotonin, norepinephrine, and dopamine may cause depression.

And as phentermine increases the levels of these neurotransmitters in the brain, it may help make you feel happier.

A high level of dopamine in the brain is linked to better concentration, motivation, and feelings of euphoria and bliss.

On the other hand, low levels of norepinephrine are linked to depression and attention deficit hyperactivity disorder (ADHD).

And since phentermine increases the level of norepinephrine in the brain, it may help enhance your attentiveness, increase energy, and relieve depression.

Nonetheless, an improvement in mood cannot be linked to serotonin. A comparative study was performed on rats to check the effect of phentermine on dopamine and serotonin in them. And according to it, although phentermine increases the level of dopamine in the rat brain, it does not affect serotonin.

The negative effect of phentermine on mood

There are multiple reports of individuals who ended up developing a depressive illness, and for many others, phentermine worsened their anxiety.

The scary part is that numerous case reports also suggest that taking phentermine may present a risk for you to develop a mood disorder like psychosis. But for those who reported it, discontinuing the prescription resolved their symptoms.

The action of phentermine on dopamine and serotonin is about 10 (dopamine) and 100 (serotonin) times weaker than its effect on norepinephrine.

And thus, this may be why there is a longer list of phentermine’s negative impact on mood rather than its positive impact.

An early study was performed to assess the adverse effects of the plasma phentermine levels. It reported that phentermine had to be withdrawn from seven out of thirty-four women because they developed side effects, including depressive illness and irritability.

Multiple case reports have reported an occurrence and worsening of the depressive illness in already diagnosed patients with depression or in others who had a family history of any affective disorder.

However, individuals with no previous history of any psychological disorder or depression have also reported symptoms of depression after taking this drug.

And since phentermine is acting on your sympathetic nervous system, it may also worsen anxiety symptoms.

The effect of phentermine on depression and anxiety is discussed in detail below.

Can phentermine make you feel depressed?

Yes, appetite suppressants like phentermine are linked to causing depressive illness.

(We have an entire article about it where I have already discussed in detail the scientific evidence that has documented cases in which depression was caused by taking phentermine.)

So, phentermine may make you depressed either as a withdrawal symptom or as a side effect. It might also trigger an underlying depressive illness, and sometimes the link might not be so evident at all.

The scientific evidence that I am referring to is a 2011 publication that includes 4 case reports in which depressive illness occurred within two weeks of taking phentermine.

The cause cannot be generalized because some of them had a family or self-history of psychiatric disease, but others had no such history.

Moreover, according to a phase IV clinical trial performed on FDA data of side effects reported in 13,858 people, phentermine-caused depression is more prevalent in 40-49-year-old women who had been taking the drug for over one month.

I have also fetched evidence from user experience, and this is what I found;

A user ‘Beckalou’ shared on the medhelp forum that she took phentermine for about a year, and it helped her lose around two and a half stones.

But soon after she discontinued the prescription, she started facing withdrawal symptoms like depression, paranoia, panic attacks, and heart palpitations. And she had to take a year off from university because doctors had put her on anti-depressants.

phentermine depression forum

Another user, ‘scrawdad1365,’ also wrote that depression runs in his family, but he had been fine without medicine for the last three years.

However, after taking phentermine, his depression relapsed, and he suffered from symptoms like shortness of breath and a fast heartbeat in the form of a severe side effect of the drug.

Can you take phentermine if you have anxiety?

No, it is better to avoid phentermine if you have anxiety.

However, if nothing is making you achieve your desired weight loss progress, and you want to support your diet and exercise with some appetite-suppressing and fat-burning pills, then PhenQ is one of the safest phentermine alternatives out there that you can opt for.

The reason why you should avoid phentermine if you have anxiety is that phentermine is a sympathomimetic amine.

It may make your anxiety worse because it has a stimulating effect on the sympathetic nervous system.

And this is the exact reason why side effects related to anxiety-like breathlessness, increased heart rate, restlessness, and insomnia are reported in patients put on phentermine.

On the other hand, PhenQ is an all-natural alternative that is free from any speed, phentermine, amphetamines, and toxic chemicals.

The a-LACYS RESET is the key ingredient in PhenQ.

Other ingredients are the dietary fiber nopal cactus, the thermogenic ingredients like caffeine and capsimax powder, the mineral chromium picolinate, etc.

Moreover, contrary to the speculation that PhenQ might cause anxiety-like symptoms due to high caffeine content, the caffeine in PhenQ is only 150mg which is fairly below the maximum safe quantity of 400 mg caffeine per day.

So, just by taking one pill, you can have a risk-free weight loss and get a boost in energy and an improvement in mood, concentration, and motivation.

It also promotes fat burning and prevents fat accumulation in your body, and phentermine does not offer these benefits.

Moreover, it is an over-the-counter drug that you can easily and directly order from the website and get quality pills made in the FDA and GMP-approved facility delivered free of cost right at your doorstep.

Also, the company also offers a 60-day money-back guarantee. But on the other hand, you have to show a doctor’s prescription to purchase phentermine, and buying phentermine online isn’t safe as you may get fake pills delivered.

The price of phentermine varies between $30 to over $200 depending on the different brands, but a bottle of PhenQ contains 60 tablets and costs only around $70.

Now, coming back to the evidence that shows the effect of phentermine on anxiety;

According to a phase IV clinical study regarding anxiety and phentermine performed on the FDA data of 13,858 people, anxiety is most commonly reported in 50-59-year-old women who had been taking the drug for 1 to 6 months.

And if we consider user experience, many people have reported that phentermine made their anxiety worse.

A patient, ‘cunkie 830’ wrote on the medhelp forum that she was diagnosed with anxiety and bipolar disorder but had been free of anxiety for the past year.

However, she had been taking phentermine for the last four months. And since the previous month, she has felt that her anxiety symptoms such as panic attacks and depression have returned, so she is giving up on the phentermine pill and has to start her anxiety medicines now.

Multiple Reddit stories reinstate the same fact.

For instance, a Reddit user-initiated this Reddit thread by writing a post in which he shared that he took a full dose of phentermine, which is about 35 mg, for five days and then discontinued it, but this gave him an anxiety attack that lasted for three days.

Ever since then, he hasn’t had the courage to resume the prescription.

Then, ‘beargin’ is a Reddit user who replied to this thread and agreed that phentermine may make anxiety worse and that she too has experienced symptoms of anxiety, like vomiting, panic attacks, and dizziness, and had to discontinue the prescription as well.


To conclude, phentermine can alter your mood, and thus, you may feel happy, motivated, and energized when you take it.

However, on the flip side, the same increase in neurotransmitters that lifts your mood might also become a reason to dim your spark because an over-stimulation of the sympathetic nervous system is linked to causing irritability, nervousness, and other negative emotions.

To be clear and precise, phentermine has the potential to induce changes in your mood, but since there is a mixed user experience, so, your experience with it may vary.

And for now, there is a lack of significant research that can settle the argument that either this drug has a positive or negative effect on mood.

Thus, to be on the safe side, your doctor may recommend that you avoid phentermine if you were pre-diagnosed with or have a family history of affective disorders as it may worsen both your anxiety and depression.

So, you must communicate your psychiatric history with your doctor if they discuss that they want to put you on phentermine for treating your obesity.

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