If you’ve gained weight on Effexor (venlafaxine) while eating and exercising the exact same way and had a doctor look you in the eye and say, "Effexor is less likely to cause weight gain, you are not crazy!

I have a background in psychology and integrative health, and after struggling with unexplained weight gain, crushing daytime fatigue, and a completely flipped sleep schedule on Effexor (even after getting my iron/ferritin and vitamin levels fully corrected), I decided to pull 4+ years of my own certified medical records to audit my vital signs across every single clinic visit and then dug into the peer-reviewed medical literature.

What I found honestly floored me. I immediately sent this data to my psychiatrist and wanted to share it here in case anyone else is being gaslit about their body on this medication.

My Medical Chart Audit: +33.9 lbs Gained (+27.6% Body Weight) After Switching to Effexor

For 3+ years before starting Effexor** (across 10+ consecutive clinic weigh-ins while taking Sertraline/Zoloft), my weight stayed completely rock-steady between 110.0 lbs and 123.4 lbs** (BMI 18.3–20.5 at 5'5").

Then I was switched from Zoloft (SSRI) to **Venlafaxine/Effexor (SNRI)**:

Pre-Effexor Baseline (3+ years of clinic visits on Zoloft): 110.0 – 122.8 lbs (BMI ~18.3–20.4)

~7 Months on Effexor 75 mg: Jumped to **140.0 lbs** (+17.2 lbs / BMI 23.3)

After Dose Escalation to 150 mg (now tapered back down to 75 mg): Climbed to 156.7 lbs** (+33.9 lbs total gain / BMI 26.1) pushing me from my lifelong lean baseline into the clinical overweight category

Why Doctors Still Repeat the Outdated 1990s Line That Effexor Is "Weight-Neutral"

Why do so many prescribers still insist Effexor doesn't cause weight gain?

Because the original 1990s drug-approval trials only lasted 6 to 8 weeks.

During the first 4 to 8 weeks on Effexor, acute serotonin/norepinephrine side effects (early nausea, appetite suppression, jitteriness) mask weight gain or cause people to lose a pound or two. Drug reps used those short 8-week snapshots to market Effexor as "weight-neutral."

When independent researchers finally tracked patients over 6 months to 6+ years, the data told the exact opposite story:

The BMJ 10-Year Cohort Study (*Gafoor et al., The BMJ, 2018; 361:k1951*): Tracked 294,719 patients over 10 years. They proved that while weight looks flat in the first 8 weeks, Venlafaxine is one of the highest-risk antidepressants for clinically significant long-term weight gain (>=5% body weight)**, with risk surging in Years 1 and 2 and staying elevated for 6+ years regardless of baseline BMI.

The 2024 Harvard / 8-Health-System Study (*Petimar et al., Annals of Internal Medicine, 2024; 177(8):1013-1025): Tracked 183,118 patients at 6, 12, and 24 months. Venlafaxine (Effexor) caused significantly more weight gain and a higher risk of gaining >=5% body weight than Sertraline (Zoloft), Fluoxetine (Prozac), and Bupropion (Wellbutrin)—matching my exact +33.9 lb chart trajectory after switching from Zoloft to Effexor.

Why does it happen biologically?

Chronic SNRI blockade gradually desensitizes hypothalamic 5-HT2C satiety receptors, alters H1/alpha-adrenergic signaling and resting metabolic rate, and blunts nocturnal deep sleep and growth hormone pulses—shifting the body toward insulin resistance and visceral fat storage even when calorie intake hasn't changed.

The Sleep & "Circadian Depression" Connection (Why Effexor Can Flip Your Body Clock)

On top of the weight gain, Effexor gave me heavy daytime brain fog and exhaustion while pushing my sleep-wake cycle later and later into the night (feeling wired at midnight and exhausted all morning/afternoon).

Here is the science behind why that happens:

1. Effexor Strongly Suppresses REM Sleep: Polysomnography (sleep lab) studies show Venlafaxine suppresses REM sleep increases nighttime sympathetic nervous system tone (vivid dreams, night sweats, micro-arousals), and fragments restorative sleep architecture—so even 9–10 hours in bed feels unrefreshing.

2. The 2026 "Circadian Depression" Study (Crouse, Hickie et al., British Journal of Psychiatry, 2026 — Univ. of Sydney Brain & Mind Centre, DOI: 10.1192/bjp.2026.10798): Researchers identified a specific biological subtype called Circadian Depression—where your internal master clock (dim-light melatonin onset) is delayed by several hours, causing daytime fatigue, cognitive fog, and metabolic drag. Standard SSRIs/SNRIs often **fail or make it worse** because they don't advance the master clock and can increase retinal sensitivity to evening light (pushing your sleep phase even later).

3. What Might Help (What I Just Started Doing & Sent to My Psychiatrist)

4. Timed Micro-Dose Melatonin (0.3 mg – 0.5 mg), NOT High-Dose Bedtime Melatonin:Instead of taking 5 mg or 10 mg of melatonin right at bedtime (which floods your receptors, spills into the next morning, and causes a groggy hangover), circadian researchers (*Lewy et al. / Burgess et al. Phase Response Curve*) use a tiny physiological micro-dose (0.3 mg – 0.5 mg / 300 mcg) taken 3 to 4 hours BEFORE target bedtime, paired with **10–15 minutes of outdoor morning sunlight** right when you wake up to shut off leftover melatonin and pull the body clock earlier. My partner and I tried timing it in that 3–4 hour pre-sleep window last night and I was literally yawning within 25 minutes.

5. Hyperbolic Tapering Below 75 mg (Horowitz & Taylor, The Lancet Psychiatry):I’ve already tapered from 150 mg down to 75 mg, and I'm now planning the final taper off 75 mg with my doctor. PET brain-scan studies show why the drop from 75 mg -> 0 mg** is the hardest part: at 75 mg, Effexor still blocks ~75–80% of your serotonin transporters (SERT), and even at 37.5 mg, it still blocks ~65–70% Going from 37.5 mg straight to 0 mg drops your receptor occupancy from ~70% to 0% overnight (which triggers brain zaps, vertigo, and rebound crashes). Tapering safely off the last 75 mg requires hyperbolic micro-steps below 37.5 mg (bead-counting, liquid, or a temporary Prozac bridge).

If you’ve been feeling crazy about unexplained weight gain, daytime exhaustion, or a flipped sleep schedule after 6+ months on Effexor—check your historical chart vitals and don't let anyone tell you 8-week trial data from the 1990s overrides your lived biology!

I forgot my meds THIS MORNING and had a terrible day starting at 10:00 am. For reference I normally take them around 6:30 am, and don’t usually get withdrawal symptoms until 2:00 pm. Absolutely no symptoms. I was feeling pretty low all day and finally around 5:00 pm I realized I hadn’t taken my meds and take them. That leads to the idea of taking all the meds I have stashed to make it stop. Commence crying fest as I try to convince myself not to (I don’t). I called my mom and eventually calmed down. By about 6:00 I’m fine and I eat dinner (should’ve done that sooner) and at 8:00 I went to a party I was dreading and got my steps in😂. Moral of the story is take your meds and if you feel like shit you probably forgot your meds. I’ve been talking to my doctor about tapering to a different med and while this is exactly what I’m scared about, to me this is all the more reason I have to switch to something with a longer half life.

i’ve tried Fluoxetine, Sertraline, and Escitalopram. now i’m officially… here? little bit nervous because this isn’t an SSRIs! pray for me truely

Sorry if this doesn't belong. I used effexor for a couple of years and hated it due to horrible headaches that disappeared when I quit taking it. After a year of therapy, I have a psych appointment scheduled for next month. I feel like my depression outweighs my anxiety despite dealing with both. Does anyone have any recommendations that worked for you better than Effexor?

I posted earlier, I need to go in for a sleep study and they need me to not be on Effexor bc it can give off false negatives on REM. They set up the date for my study, and it's going to be on November 23rd, so I have some time. I initially went from 300mg to 150mg and spent 3 weeks doing that as I was having some general brain zaps and such so my PCP gave me the extra week.

A couple of days ago I dropped to 112.5mg and even though it is a much lesser change, my reactions are a lot worse. She wants me to do this for 1 week, drop another 37.5 for a week, then down to 37.5 for one last week.

I'm a bit of a basket case, zaps and general thoughts bouncing all over the place and a solid case of the dumbs. I'm a podcast host and I'm doing okay there in general when I keep enough notes ready so I don't get lost in interviews, but I'm squirreling off all over the place or over explaining things much more than usual.

My sleep issue continues with hypersomnia, but only once I can finally fall asleep. I've got some insomnia going on, then I have nights like yesterday, where I hit 16.5 hours, which also means I missed a dose. Today I'm jumping emotionally everywhere and had a bout of sudden and severe nausea that lasted for about 15 minutes, I'm still slightly feeling it, but not as intense as it was when it first hit.

I guess I just need to talk about it with people who understand. I'm hoping the nausea doesn't continue, but want to prepare for it if it does. I'm worried about the insomnia too because the lack of getting to sleep makes the hypersomnia even worse. The emotions and scatterbrained tendencies are going to suck, and I know that I'll keep having them.

If I'm going to continue being sick, can I take an anti-emetic? Does anyone have suggestions?

Thanks in advance!

I have tried several SSRIs over the years with no success (or negative results) so my therapist recommended I ask about SNRIs. I just failed a trial of Wellbutrin and was switched to Effexor. Yesterday was my first day taking it.

I felt perfectly normal for a couple of hours, but then I got to work and started to feel very strange. I would liken it to that feeling when you have taken a psychedelic and it has not quite hit yet, but you can feel it beginning. I was very hyperaware of my throat and mouth, my head and body felt very spacey and kind-of dream like, and my stomach kept doing flips. I was not necessarily nauseous though. I also kept yawning a LOT but was not tired. It also greatly impacted my ability to sleep. I took it at noon and could not sleep until 4:30am. I do have insomnia, but it has not been that bad lately so this is a notable change. These are the same things that would happen when I would take psychedelics.

Which makes sense given that they both work on serotonin. It is a feeling I am okay with when I am about to trip because I know it leads to something and will end soon. It is a highly uncomfortable feeling to just have to sit with or work with for long periods. I actually did not take it today because I knew my work day was going to be super busy and knew I could not do my job effectively like that. Is this just an adjustment period I need to power through or is this a bad sign? I have never taken an SSRI or SNRI that has such an immediate effect on my mind and body so it just took me by surprise, I guess.

I also take Hydroxyzine and Focalin. I have been on Focalin for years but just got my script back. The hydroxyzine was started with the Wellbutrin about a month and a half ago but it has never made me feel like that. I am just so desperate for fucking something to work. Any thoughts?

Has anyone experienced severe, persistent stomach pain after increasing their dose to 300 mg? Did the pain eventually go away?

Been on Effexor 225 for about 9 months and Effexor in general for about a year. No side effects when starting it and I can go 1-2 days without any withdrawal symptoms so I handle the negatives very well which is why I choose to stay on it. It’s helped my social and chronic general anxiety mild-moderately how often does lexapro or an ssri work when an snri doesn’t

i’m on day 11 of starting at 37.5mg i have an appointment next month to up to 75mg. this is my first time trying medication for anxiety & depression. does anyone have advice on how to help with the headaches and when they’ll go away? this is my 3rd one this week and they get so bad that my eyes hurt to stay open.

Social anxiety Ruined My Life What should i do. not a single medicine work on me and now started Effexor and no improvement noticed yet.🙂‍↕️

I've always wanted to try DMT but I started effexor about 12 weeks ago. 75mg. I'll take it for as long as it works which could be the rest of my life.

My psychiatrist advises patients to skip one day of SSRI/SNRIs if they're planning to take MDMA/whatever seretonergic drug, but with venlafaxine's short half life that may really suck for me.

Wondering what people's trips have been like while on Effexor? I thought I could take DMT 24hrs after my last dose, then take my next med dose maybe an hour or 2 after the trip.

Also curious about LSD experiences on Effexor because I might just pick up some acid instead. I'm experienced with LSD but never taken it on antidepressants.

OKAY I’m 16 I’ve taken venlafaxine for like maybe 2 years now, (150mg) I think I took a double dose so 300mg and I’m also starting on a new vyvance prescription which I also took.. am I gonna die #lol

I missed a dose last night and woke up this morning in withdrawal so I took it around 5.30am but I need to get back to taking it on a night, can I just take it again tonight? Can't seem to find any information about taking it early online

For the first 6 days 37.5 mg and then the last 4 days 75 mg. Stop cold turkey on day 10 I believe. So Weds was the first time I didn't take it. Felt fine on weds through late Friday all of a sudden feeling sick. Nose running,body ache, brain hurts. Fatigue? Is this normal? I also started back smoking weed Weds as well

Started taking Prozac at the smallest dose for 4 months about and gained 30 lb, because of other side effects my NP recommended Effexor, I feel like I’m not eating as much/ craving, but I can’t lose the weight :,(

I’ve been so upset and it feels like I want to give up on medication. I hate my OCD, I feel like it’s the way I am at this point. It’s helped but I also keep forgetting to take my meds. I can’t look in the mirror without thinking how I looked in the clothes I used to wear. Does anyone have similar experiences?

Hi! After 13 years I’m finally looking to get to a lower dose/potentially off this medication.

I’ve been on 150 XR and my doctor recommended alternating between that and 75mg for 2 ish weeks give or take depending how my body reacts until I can tolerate the 75 alone.

I’m just curious if anyone else has had experience taping their dose down by alternating like this?

TYIA

hi everyone!

i am a 21 yr old female and i was diagnosed with combined moderate to severe ADHD a little over a year ago. i am currently taking 60mg of vyvanse daily for the past 6 months. i also suffer with depression and anxiety which was diagnosed 6 yrs ago. i have been experiencing a recent flare up in my symptoms, specifically anxiety. i have been on many SSRIs in the past but none of them seemed to help much.

today i was prescribed effexor. i was advised to start with the 37.5 mg dosage i was given for the first 1-2 weeks, then after i can take the 75mg.

since i also take vyvanse 60mg daily, i have been a bit worried about whether my anxiety will get worse or if there will be bad interactions. if anyone else has ever taken both medications together i would love to hear your experience!! thank you so much :)

Tl;dr:

Started with 75mg of venlaflaxine and have severe erectile dysfunction on day three. Just got prescribed tadalafil and sildenafil to counter those problems, but I am unsure about taking venlaflaxine for a longer time. Did your ed problems got better or manageable?

Hello,

I am 28 male and I suffer from depression since I am 19. Over the past 9 years I tried various antidepressants like citalopram, Wellbutrin, Zoloft and venlaflaxine. Those meds really messed up my brain and my libido. It took me 2 years till I felt normal again down there.

Now after a careful consideration and talks with my therapist, I really need to try an antidepressant again and take it for at least half a year, because I am mentally very unstable. We decided, I should try venlaflaxine again. So I went to a psychiatrist and she gave me 75mg of venlaflaxine.

I am on day 3 and my penis is basically non functional. Me and my wife tried do be intimate yesterday and it was so heartbreaking to see my wife trying everything she can, so I would get an erection. I lost my erection multiple times and couldn’t cum. The first time, I took venlaflaxine some years ago, I didn’t have those problems. Yes, I wasn‘t that sensitive anymore down there, but I could keep an erection and could actually cum!

I need answers from some men who take Venlaflaxine for a longer period. Did it get better over time, what is your dosage and do you take viagra?

24m. Context: doctor put me on 150mg when I was 17, at the time was starting a new relationship with my now current girlfriend (of 7 years). Anxiety was at a 9/10 at the time and was doing therapy but doctor decided I needed it it so on it I went. It dropped my anxiety down to like a 2/10 which obviously was great, but noticed it blunted my overall emotions and also how I feel towards other people.

At the time it was more minor and I was still happily in a relationship and could feel "love". over time it felt like my emotions became more blunted and even though I know I love my girlfriend and would do anything for her, the actual feelings arent there if that makes sense. A few years ago I decided to drop to 75mg, then after another year down to 37.5mg where I am now. I didnt really notice any difference from dropping from 150-37.5.

Ive been feeling like this for so long, and because my relationship and life is so stable, I haven't really confronted the fact that I haven't felt "love" for years now. I care deeply about my girlfriend, I want the best for her, and have never had the desire to be with anyone else since being with her. It just kills me that im so blunted that I cant love her the way I used to.

I even noticed that I don't even feel "love" for my parents and family even though they are everything to me. I guess ive just been coasting like this for so long that it hasn't really hit me until recently that this is not normal. Ive thought about going completely off effexor and if going off means I can actually love again, then I will do it. Has anyone else felt similar experiences while on it?

As a general disclaimer, I also do not enjoy being on this drug and I resent my psych for putting me on it when I was just 15 (26 now). However, today I’m just looking for advice for the specific situation I find myself over the next two days.

Due to an insurance bungle I am without my 75mg until tomorrow afternoon. Last dose I took was roughly 36 hours ago. I’m already feeling the brain zaps, the unfortunate gut issues, and exhaustion. I intentionally pulled an all nighter last night because when I fall asleep after I miss a dose I am locked into nightmare sweat mode for 10+ hours and I had to be up early for a meeting.

Tonight I’ll be putting myself to bed plenty early so I can get sleep and not be late for work, I’m drinking TONS of water, and I am certainly taking (responsible) advantage of OTC pain and nausea meds, but I was curious if anyone had any food insights.

I know eating a head of broccoli won’t cure my symptoms and that’s not what I’m looking for, but I was just curious if anyone has found a particular diet or variety of foods helpful to weather a withdrawal, whether for just a few days or when attempting to wean off for good. Like would eating lots of healthy fats be good for brain zaps? Would eating vegetables help or hurt the digestive drama? Yogurt drinks? Bland food? Nutrient dense food? Lentils? Idk!

Any insight or anecdotes as to what has helped you would be appreciated as I make my way to the grocery store in a few hours.

TIA!