Skip to main content

Phentermine and Tremors: What Users Say

Brand names: Adipex-P, Lomaira, Atti-Plex P

Tremors: mentioned by 81 users (2.7%)

Based on user experiences from 3,014 Phentermine reviews, the following table shows the most commonly mentioned side effects.

All user comments are moderated by Drugs.com. Each review is verified for relevance and screened for inappropriate content. Side effects are user-reported and not clinically verified.

dry mouth 26.7%
insomnia 9.8%
headaches 6.9%
anxiety 6.4%
constipation 4.5%
increased heart rate 3.6%
loss of appetite 3.0%
dizziness 2.7%
tremors 2.7%
nausea 2.6%

Reviews for Phentermine

Commonly mentioned side effects
  • cwa...
  • February 3, 2021

For Weight Loss (Obesity/Overweight) "I went to a weight loss clinic on January 4, 2021. The doctor put me on an old-fashioned low-fat diet and phentermine. Wow! I went from 218 lbs on January 4 to 210 lbs this morning. The dry mouth is lessening. No more jitters or anxiety. I really don't think about food. The doctor told me not to spend too much time in the gym because I am not training for athletics, and most people get into routines they will not sustain. He told me to walk a bit every day and to continue my yoga daily, even if for just 15 minutes. I take trazodone for sleeplessness. It's not a sleeping pill but an antidepressant. It doesn't have the harmful side effects of regular sleeping pills. When combined with melatonin, it really helps. I don't take phentermine every day. I think it accumulates in my system and keeps me awake unless I mix it up a bit. Some days I take half a dose, and today I took none. I believe I will sleep better tonight and still get the benefits of a reduced appetite."

10 / 10
Was this helpful?YesNo
76 Report
  • AGa...
  • Taken for 1 to 6 months
  • January 31, 2020

For Weight Loss (Obesity/Overweight) "I was prescribed phentermine as a way for me to boost losing the weight I had gained while on antidepressants. At the start of taking the medication, I must say I did feel a little shaky or jittery for about 1-2 days, but then all was fine. My energy was high and my hunger was suppressed. I even had to remind myself to eat! I was averaging losing 1 pound a day! I did incorporate moderate daily or every other day exercise and watched what I ate, and the weight kept coming right off! Within the first month, I had lost 16 pounds and dropped a pant size! I only took phentermine for three months and then stopped. In total, I lost 34 pounds and dropped two pant sizes. I absolutely recommend this as a short-term weight loss booster for anyone needing to lose some weight quickly."

9 / 10
Was this helpful?YesNo
85 Report
  • Ser...
  • February 27, 2014

Phentermine for Weight Loss (Obesity/Overweight) "I just started using Fastin and I like it better than other diet pills I've tried, such as Hydroxycut, because it doesn't make me feel sick or nauseous. However, it definitely makes my heart rate skyrocket, so for the first couple of days, I would only take half a pill at a time. A full pill makes my hands tremble, and I can hear my pulse in my brain."

7 / 10
Was this helpful?YesNo
147 Report

Frequently asked questions

  • Mag...
  • April 1, 2009

Phentermine for Weight Loss (Obesity/Overweight) "I started using phentermine (Adipex-P) in the later part of February 2009. My first weigh-in was 233 pounds. I now weigh 203 pounds. The only side effect I had was a slight case of the jitters that lasted about a week. Other than that, everything has been great. I do exercise a few times a week, most of the time. Nothing crazy, just the treadmill and weights, when I feel like it. I do have high blood pressure, and I take lisinopril 10mg for that. I also keep up with the calories and sodium I take in, and I only drink water. If I need flavor, I buy the pour-in packs (e.g., Crystal Light, or Sam's Choice). Just the fact that I don't drink ANY sodas is a big accomplishment for me because I was a Pepsi-holic."

10 / 10
Was this helpful?YesNo
137 Report
  • Ano...
  • January 29, 2021

For Weight Loss (Obesity/Overweight) "5'2", female, 28. Sedentary (desk job, gyms closed). Pre-existing PTSD, depression, and ulcerative colitis. 37.5 mg phentermine for 3 months. Doc did not stack it with fluoxetine or topamax as I'm already on 450 mg of Wellbutrin. After gaining 15 lbs in the first few months of COVID isolation, I decided to take this. Yes, I got the jitters for the first few days. Yes, it made me anxious for the first few days. Yes, my breathing pace and heart rate were up for the first few days. It went away. I didn't experience constipation per se, but I ate so little that bowel movements were few and far between. I took it between 6:30 am and 8:00 am every morning, otherwise I didn't get enough sleep. August 2020: 136 lbs, size 28/7 jeans, m/l shirts, 34B bra. November 2020: 112 lbs, size 23/3 jeans, xs/s shirts, 32C bra. This was combined with an Atkins variety keto diet, with 2 shakes and 1 big meal/day on most days. I kept my carbs under 20/day and struggled to eat 1200 calories."

10 / 10
Was this helpful?YesNo
48 Report

Are you taking this medicine?

Your review helps others make informed decisions.
Write a review
  • JJM...
  • October 14, 2014

Phentermine for Weight Loss (Obesity/Overweight) "I am borderline average/overweight for a 5'3 woman. I just wanted to lose about ten pounds. Extremely effective, but as the other reviews state, two pills for me was way too much! Uncontrollable shaking, but the heart pounding was nothing less than frightening."

8 / 10
Was this helpful?YesNo
107 Report
  • Che...
  • Taken for less than 1 month
  • October 24, 2014

Phentermine for Weight Loss (Obesity/Overweight) "I took this and it's the best thing I have ever tried. The first couple of days I went by the directions, then I doubled the dose. And I lost 20 pounds in 2 weeks. It did make me feel very jittery and my heart rate was going 90 to nothing, but I was determined to lose weight! And a little information, DO NOT, I repeat (DO NOT), take Fastin before you get in a tanning bed. Tan first, then take it. It made me very, very strange in a bad way. I'm no doctor but when I increased my dose, I had the shaking and the increased heart rate. But it never harmed me."

10 / 10
Was this helpful?YesNo
91 Report
  • Kai...
  • Taken for 1 to 6 months
  • March 10, 2016

Phentermine for Weight Loss (Obesity/Overweight) "I'm 5 ft nothing, weighed 155.4 when I started. I tried dieting, exercising, Weight Watchers, and kept gaining weight. I was prescribed Adipex on Nov 18th, 2015, and the pounds started falling off. I took the whole pill and felt anxious and shaky for about 3 hours, and after that, no bad symptoms. I took it for 2 months and lost 26 lbs. I stayed off for a month, and I didn't gain a single pound back. After a month off, I got back on, following instructions from the doctor when I first started, and by the first week, I lost 5 lbs. I have 10 days left, and I am at 118. My goal weight is 115. Adipex changed my life, and losing 30+ lbs in 3 months is amazing. I would recommend it to anyone! Also, it is not expensive at all, with or without insurance."

10 / 10
Was this helpful?YesNo
64 Report
  • bcl...
  • Taken for less than 1 month
  • March 18, 2013

Phentermine for Weight Loss (Obesity/Overweight) "I have been taking Adipex for 4 days now. I have lost 13 pounds somehow. I changed my eating to only intake 1000 calories a day. I take half a pill in the morning and half a pill at noon. I have severe dry mouth and drink about 10 bottles of water a day. I am having trouble sleeping for the last 2 days. I get the jitters really bad about 30 mins after I take the pill, it lasts for a few hours. No issues with my heart rate! I am hungry until my stomach hurts. I was an overeater, so it's pretty painful! With all that, this pill is worth it. I am excited about my progress so far and can't wait to see what I can get down to in a few months!"

9 / 10
Was this helpful?YesNo
78 Report
  • Zor...
  • Taken for less than 1 month
  • September 15, 2021

Phentermine for Weight Loss (Obesity/Overweight) "I was always wary about weight loss pills due to the jittery effect they give you. I decided to try the Adipex-P, and it was the best decision I had ever made. It gives no anxiety or jitters, on the contrary, I felt relaxed. Not like a drug relaxed, it made me feel as if I had slept so well that I felt perfectly healthy. By the way, it had been many years since I felt that well. It just curbs the appetite, and you start cleaning and getting on with life, as one is supposed to do. I went from a whopping 400lbs to 165lbs in 1 year. I only used it for the first month, after that, my body took off on its own, but it was the perfect start."

10 / 10
Was this helpful?YesNo
30 Report
  • Mic...
  • September 8, 2015

Phentermine for Weight Loss (Obesity/Overweight) "I tried Fastin for the first time today, which I purchased over the counter. Within 20 minutes, I experienced a slight euphoric feeling. After 30 minutes, however, my heart started racing, my body and hands began shaking, and I felt as though I was going to pass out when standing. I had to sit down until I felt in control. After 45-50 minutes, the shakiness and racing heart improved, as well as the dizziness when standing, but didn't disappear completely for over an hour. My mood still remained lifted. I may just be sensitive to the initial dosage, so I recommend that anyone sensitive to stimulant medications begin with a half dosage to minimize the initial negative effects until your body gets used to the drug."

8 / 10
Was this helpful?YesNo
61 Report
  • Sli...
  • Taken for less than 1 month
  • October 26, 2015

Phentermine for Weight Loss (Obesity/Overweight) "Oct. 16th - 5'8, 256 lbs, Male. Oct. 26th - 240 lbs even. 16 lbs - 10 days. Loss of appetite, which makes it easy to control how, what, and when you eat. Dry mouth only if you don't drink lots of water, which is absolutely necessary to dispose of the fat you're losing. 1/2 pill - modest energy. Whole pill - a bit shaky, but I love shaky. Feels like a miracle is happening. Getting my life back slowly but surely."

9 / 10
Was this helpful?YesNo
55 Report
  • Aim...
  • June 5, 2017

Phentermine for Weight Loss (Obesity/Overweight) "I work at an endocrinology clinic. And there, I have seen crazy stories about Adipex - from 191 lb in 1 year to 30 lb a month. So, I said to myself I'm going for it. In the first 3 days, I am 4 lb down. I have plenty of energy, I do have a dry mouth, and one time after I stood up from the bed I felt dizzy. Now, my post is more for the people who are taking it - please take 1200 cal per day. If you take less, you will have jitters, and you would start doubting the medication. And yes, I push myself to eat because I want to eat, but I eat small portions. From day one, I want to adjust my portions, always small portions. After 1 month after my medication finishes, I will continue small portions and won't exceed 1200 cal. Good luck."

10 / 10
Was this helpful?YesNo
44 Report
  • Ono...
  • Taken for 1 to 6 months
  • July 23, 2015

Phentermine for Weight Loss (Obesity/Overweight) "I am now exactly one month in. My start weight was 301, and I am now at 278! Hooray! The only side effects I still have are dry mouth, nasty taste in my mouth, and jitters from time to time. I will update again in one month :)"

10 / 10
Was this helpful?YesNo
51 Report
  • Yer...
  • Taken for less than 1 month
  • December 4, 2019

For Weight Loss (Obesity/Overweight) "I was prescribed Phentermine. By day 9, I had lost 11 lbs and I was ecstatic. But that night, I ended up in the ER. My resting heart rate was 180, I was shaking, pale, and my lips were blue. They did blood work and EKG. Both came out fine. I was told to stop taking the medication and that things would get better, but they didn't. Everything I do elevates my HR. Even laying in bed, it goes up to 120 (norm is 60-100). Seven days later, I ended up in the ER again. I spent the day getting every test done: blood work, X-rays, EKGs, ultrasounds. Every test came out perfectly fine. They sent me home. But still, everything I do elevates my HR. I am exhausted, feel like I can't breathe. I am terrified to do anything because as soon as I do, my HR goes up. I need to see a cardiologist. Had I known this pill would cause all of this harm, I would have never taken it. I don't even feel like myself. I’ve been off of the medications for seven days with no improvements."

1 / 10
Was this helpful?YesNo
39 Report
  • dai...
  • June 16, 2016

Phentermine for Weight Loss (Obesity/Overweight) "I used to take Fastin/Fastin XR in 2012. Within a few short months, I went from a size 9/10 to a 4. I kept the weight off for 3 years after stopping this product. I’m only 5’3″, so all the extra weight on me was really noticeable. I didn’t like the side effects at all: shaking, racing heart…but it definitely worked. I just started taking this product again a few days ago because I’ve gained 35+ lbs within 4 months due to major lifestyle changes. I’m trying to get back on track again. Hopefully, I’ll get similar results this time around too."

10 / 10
Was this helpful?YesNo
49 Report
  • Nik...
  • Taken for 1 to 6 months
  • March 8, 2017

Phentermine for Weight Loss (Obesity/Overweight) "On 1/24/2017, I started taking 1 pill of Adipex 37.5 mg once a day. I started at 262 lbs. As of today, 3/8/17, I now weigh 247 lbs. It gives me energy without the jitters. I also suppress my appetite, I force myself to eat 5 small meals a day. I also do at least a 30 min workout 4 times a week. Adipex works! My normal doctor will not prescribe this medication, so I see a weight loss doctor. I pay 100.00 a month for the meds."

10 / 10
Was this helpful?YesNo
44 Report
  • lib...
  • Taken for less than 1 month
  • March 11, 2016

Phentermine for Weight Loss (Obesity/Overweight) "I started this medication on 3/4/16. Starting weight was 208. After a week of taking it, I've lost 10 lbs. I weigh now, is 199. This pill works! I've been eating small snacks and working out. So far, the only problems I've experienced are dry mouth, dizziness, restlessness, and slight tremors for the first few days. I'll give an update in about a month."

9 / 10
Was this helpful?YesNo
47 Report
  • Kru...
  • January 10, 2017

Phentermine for Weight Loss (Obesity/Overweight) "I heard from a lady I work with about Fastin, and she told me it worked well for her. So I came on this site and read the reviews. I was concerned with a lot of reviews stating that there were side effects such as pounding/racing heart and jitters. Despite the reviews, I still ordered the pills. After receiving the pills, I still waited a few days before starting because I was terrified of the side effects. So I finally started taking the pills a week ago. I started taking just half a pill in the morning and half after lunch, like recommended in a review I read. After a couple of days, I began taking a whole pill after breakfast and a whole after lunch. I have had no side effects at all and have lost 5 lbs in 1 week."

10 / 10
Was this helpful?YesNo
45 Report
  • Tra...
  • April 25, 2017

Phentermine for Weight Loss (Obesity/Overweight) "I've been taking a low dose of Adipex for about 2 weeks now. I am 5'7" and started around 165 lbs. I haven't been taking Adipex regularly, as I am a nurse and work rotating shifts, and it suppresses my appetite so much that when I want to go out for nice meals/enjoy weekends, I also don't take it. I have not experienced any jitters or vision effects, but I am much more focused and have much more sustained energy that I actually save for night shifts. I eat like a toddler, being constantly on the go and rarely have time for the gym. I do, however, spend 36-48 hours on my feet, running around at work. So far, without any effort, I am down 7-8 lbs. I highly recommend this, and I'm sure results would be exaggerated with diet and exercise."

8 / 10
Was this helpful?YesNo
40 Report
  • des...
  • Taken for less than 1 month
  • October 31, 2015

Phentermine for Weight Loss (Obesity/Overweight) "I just tried this medicine because I had continuously heard it worked. I will say I felt a lot of energy for the first couple of hours after taking it, and I did lose 5 lbs the first two days, which was GREAT! But... I experienced terrible side effects. Other than the normal dry mouth, some jitters, and restlessness, I experienced severe mood swings, irritability, and I became angry out of nowhere. I know side effects are different for everyone. This was my personal experience. I think the medicine could've really helped me with losing weight, but I'm not willing to have the side effects. Good luck to everyone!!"

3 / 10
Was this helpful?YesNo
43 Report
  • Ski...
  • January 29, 2020

For Weight Loss (Obesity/Overweight) "I have been on these phentermine for 4 months, 115 mg a day, amazing energy. I wanted to fit into my suit that I haven't worn in a while and see how far I could take this. Boy, did I take it far, basically way too thin for all my suits, and people at work and my wife call me skinny, and I've lost enough, they tell me. I don't even understand where they're coming from, as I haven't heard that my whole life. Sure, there are side effects, it affects your sleep, somewhat dry mouth, shaking, and sometimes I had dizziness before, but that's gone."

10 / 10
Was this helpful?YesNo
30 Report
  • La-...
  • Taken for 1 to 6 months
  • December 13, 2015

Phentermine for Weight Loss (Obesity/Overweight) "I was prescribed Fastin for weight loss. The prescription pills worked great, not a single bad side effect. I lost over 50 lbs in about 4 months. It gave me energy to start working out, and WOW did my concentration for work improve. However, the pills were costly and given out in the office only. So every month it was $40 for the doctor visit and weigh-in, and another $40 for 1 month's worth of pills. When I was unable to afford this regimen, I looked for cheaper alternatives. I got some over-the-counter bottle of Fastin, I bought 2 bottles. These are unhealthy, way over-caffeinated crap! I had gotten very ill halfway into taking the first bottle and had to stop because of jitters, headache, paranoia, racing heart!!! My advice, pay for the real stuff."

9 / 10
Was this helpful?YesNo
43 Report
  • tni...
  • March 31, 2016

Phentermine for Weight Loss (Obesity/Overweight) "I started taking Adipex on 11/14-4/15, and without diet and exercise, I instantly lost 25 lbs. I weighed 150 lb (only being 5'2). By the end of the first month, I was down to 126 lb, my goal being 125 lb. I stopped for a while and ended up gaining all but 3 lbs back. Now I am back on it and I'm excited to see where I'll be a month from now. The side effects I have had both times are dry mouth, shakes, and a short temper. I'll report back in about a month, maybe sooner."

10 / 10
Was this helpful?YesNo
38 Report
  • Pon...
  • Taken for 1 to 6 months
  • November 15, 2019

For Weight Loss (Obesity/Overweight) "I started phentermine on October 10, 2019. The first week, I had dry mouth, insomnia, and jitters. After the first week, all of the side effects seemed to go away as I became more used to it. Today is November 15, 2019, and I have lost 16.4 lbs. I have had enough energy to do 6-7 HIIT classes a week and a low enough appetite to not have cravings. I have also incorporated intermittent fasting as well as cutting all grains, flours, sugars, rice, etc. Only carbs are from vegetables. The first week of the diet change was difficult, but being on the medication makes it easier. Before starting this drug, I’d be lucky if I lost 5 lbs a month with regular diet and exercise."

10 / 10
Was this helpful?YesNo
24 Report

Are you taking this medicine?

Your review helps others make informed decisions.
Write a review
Reviews may be edited to correct grammar/spelling or remove inappropriate content. Reviews appearing to come from parties with a vested interest are not published. This information is not intended to endorse any medication and should not replace the expertise and judgment of healthcare professionals.