Bupropion vs Phentermine for Weight Loss


I need to become thinner and lighter as my body mass index is above 30.0. I have heard that phentermine and bupropion are both a prescription appetite-suppressant drug that can promote weight loss. My question is, which weight loss medication is better and what are the pros and cons of each medicine? My body mass is excessive and so is my hunger for food. I need a drug which reduces my appetite so that I can lower my food consumption and decrease body weight.

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Tamira 3 years 2020-12-12T04:27:46+00:00 5 Answers 2396 views Beginner 4

Answers ( 5 )


    Image: (Left) Bupropion SR 150 mg tabs. (Right) Phentermine 37.5 mg tablets.

    This is an easy answer. Phentermine is a FDA approved prescription appetite-suppressant and prescribed for obesity. It is a controlled substance used to promote weight loss when used for a short time.

    If you have high body fatness phentermine will not help you lose the amount of poundage you need to achieve your weight loss goal and become healthy. Your body will quickly develop a tolerance to the medication and your food craving will return within three weeks.

    In contrast, bupropion, an antidepressant drug that is also used to relieve nicotine withdrawal, has been shown in studies to provide substantial weight loss for people adhering to a calorie-restricted diet. Bupropion is better than phentermine because it can be used long-term.

    Here is the reality of weight loss. When your body starts to undergo a reduction in body weight, your thyroid starts converting T4 into reverse T3 (rT3). Reverse T3, a metabolite of T4, binds to T3 receptors on cells and competes with T3 on a cellular level.

    High serum reverse T3 slows the metabolism, and subsequently, puts the brakes on your weight loss target. In other words, to curb hunger and lose weight, you will need to choose a weight loss medication that you can take for a considerable amount of time because losing 40, 50 or 80 pounds of fat takes months of diet and exercise.

    Phentermine will stop working after 3 weeks.

    Best answer

    I have been bodybuilding for 27 years. I have never been overweight but I have used phentermine, Contrave and bupropion to lose excess fat when preparing for bodybuilding competition.

    Phentermine works great to decrease appetite and to quickly drop a small amount of blubber, but it will not help obese or chunky people in dropping mass.

    Contrave is a good weight loss pill. It is a diet pill that contains naltrexone and bupropion (Zyban). Although, it is too expensive, and in my opinion, not really better than taking bupropion by itself.

    I don’t think bupropion is technically FDA approved for weight loss but most weight loss doctors will prescribe it for off-label use. Bupropion is much cheaper!

    Contrave or bupropion is clearly the better choice for long-term weight loss.


      I want to drop 20 pounds of fat in three weeks with a starvation diet. I will be using a half tablet of Phentermine in the morning and afternoon. Is it possible to lose that much weight that quickly? And is this medication addicting?


        Sure it is possible to lose weight that fast. Is fasting or starvation a good method for losing weight? You’d have to ask your doctor that question.

        Anything that makes you feel good can be psychologically addicting, but I didn’t find it to be physically addicting.


    This disadvantage of bupropion is that it often causes some level of sexual dysfunction in men. Although “supposedly” Wellbutrin and Zyban patients report that it increases libido. I think that is a flat out lie pushed by makers of the drug.

    The advantage is that it can be used long-term and it does a really good job at suppressing your appetite. Oh, and the sexual dysfunction goes away after discontinuing the meds.

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