Yes, Vitamins can most definately make you tired, that do that to me also, and many other people as well. I've tried different vitamins, including the Mega vitamins, and they make me very tired. I am going to stop taking vitamins for a while, to see how I feel, and just eat better. You can get vitamins thru fortified foods, such as cereals, oatmeal, etc....and also fruits and veggies as well. I think maybe vitamins cause an im-balance in our delicate system.
I don't eat any processed foods.
Try not taking them for a while to see how you feel. I mean, if you feel worse, more tired taking them, that's telling you something.

I have just been getting over a case of food poisoning. In which case, I have not taken any of my Mega Men's Gold for the past couple of days. I felt like I had the energy of my 20's while not on the pep pills. I took one of my vitamins for the first time this morning and I was out like a light. I have been through A&P classes, and have no clue why this happens.

OMG I'm taking the same exact vitamins and experiencing the same thing, I'm going to stop taking them.

I am having the exact same effect. I noticed it happens as well when I have taken a fruitdrink with lot's of vitamine C.

i take my vitamins - multi, iron, c and echinacia every morning at 9:30 and by 11 I can't keep my eyes open. I am goint to switch it to night and see what happens!

We don't necessarily need all that is in a multi vitamin & mineral tab for example magnesium some tablets etc have different forms of magnesium in them, magnesium oxide is only absorbed at a rate of 4% where chelated magnesium in different forms is absorbed much more efficiently depending on the functionability of our digestive systems & other levels of co contributing nutrients. An educational web site that teaches you about the balance of nutrition is ithyroid.com
hope it helps!

I am a female, I also work out regularly, and I eat pretty well but don't always get my fruits and veggies into my diet. I was feeling just fine, but I thought taking a multi would be more beneficial. I took the Women's Ultra Mega from GNC, which made me feel very relaxed. I have a part-time job for which I need to be very active, and thought the Women's Ultra Mega Active would give me some energy. Wrong! I'm exhausted - can barely lift my usual weight at the gym, or do my 45 mins of cardio, tired while at work, and at my part-time job...no energy to be found. Can't find anything else online about this topic except this website. Maybe I don't need all those vitamins, but which ones specifically? I'm thinking the B's, but who can say? I stopped taking them and I feel like a million bucks.

I am so glad that I am not the only one feeling this way. I have a very active lifestyle and just a week agao started taking the GNC Mens Sport Vitamin. I thought I was nuts thinking that the vitamins made me tired. Like the earlier post, I feel exhausted about 15 minutes after taking the vitamins. Has anyone tried to take them right before bedtime to see if that makes it any easier?

Hi,

No, l have not tried to take them before bedtime but maybe l'll try taking them in the early hours of the evening. But than again, not taking them at all makes me feel like the earlier post, a million bucks. I have untold energy don't matter how tired l am. I think my body is telling me that l don't need them. I am going for a blood test soon and if l am not low in anything, than l'm not going to take them anymore. Found even l can not do the simpliest of things anymore.

I'm so glad I found this post, I thought I was going nuts! I recently changed my diet to very healthy, at least 3 veggies, one fruit and lean protein at each meal. I have super energy...UNTIL I take my vitamins, and then I am dead tired. I take them at night, and can barely get up or function the next day. The nights I skip them, I am back to energetic the next day! Some of them I need to take for a medical condition, but I am going to try removing those that are not for anything specific, and see if I can avoid the "vitamin fatigue"!

i have been very lethargic in the past 3 years; which i put to post-pregnancy and/or hormonal imbalance... i work out regularly; strength train, cardio, yoga and never thought vitamins could cause tiredness! i have slowly decreased the amount of vitamins over the past 3 years; owing to side effects. evening of primrose oil caused acne breakouts and increased appetite; multi-vitamins with high B concentration caused insomnia; etc. i stop all vitamins but vitamin C; but the lethargy continued... however, for the past week, i have not taken any; and though i do not feel energetic; i feel somewhat better; less tired!! i have been pulling my hair out trying to correct my lethargy; i eat healthily; work out regularly; and currently (apart from last week) take only vitamin C. i am thinking of drinking fresh orange/apple juices in place of synthetic vit C? if anyone knows for fact that vitamin C (1000mg) can cause tiredness or general unwell being, please do advise

I am glad that I found this post. I am not taking GNC vitamins, but, the ones that I am taking still make me sleepy.

JayGeo and others
My guess is that your body metabolizes vitimins or additives differently, that the process of breaking them down drops your blood pressure enough that you feel weary, kind of like eating a nice thick steak makes you feel a bit lethargic.

If you are taking nothing more than multi-vitamins it would be very unusual for your body not to metabolize them easily. It could be a sign of illness. You should talk to a doctor about this if it proves to be an issue with other brands of vitamins.

Like everyone else, I'm glad to find that I'm not crazy for having "vitamin fatigue". When I first started taking multivitamins, I felt great -- cut way back on my caffine intake, was more productive, etc. But after a few months is when the fatigue set in to the point of almost passing out some mornings. I also suspect that the metabolization of all those vitamins is what does it. So what I've been trying for the last month or so is switching from a multivitamin to specific vitamins that I need. For example, I actually get plenty of vitamin A, calcuim, and even iron in my regular diet. So I tried taking just a total B complex which really made me pass out. So now I'm focusing on just folic acid and vitamin D and that seems to work for me. I'm also considering getting chewable multivitamins (even if it's the kids kind) and biting off little pieces during the day to avoid that one big mega dose.

I too had this experience! I did some looking into it, and like others here have already posted, this seems to be a natural side effect, and from what i read drowsiness seems to have a link to b12 and other high b vitamin doses. i havent tried to the chewable pill, but i read on the above site that a way to control the drowsiness may be to spread out your intake throughout the day instead of a one time 'loading' dose.
hope this helps!

Wow thank god for this post im taking gnc mega men sport and its making me dead tired gonna stop right now thought i was sick are somthing i had ton of energy before guess if it aint broke dont try to fix it.

Is there such a thing as taking to much vitamins is bad for you?

I am experiencing the same thing, I'm taking GNC Mega Women, and extra Iron because of severe Anemia. I was wondering if I might be getting TOO MUCH Iron... Although I used to take Mega Women and it really made me feel GREAT... I'm now post menopausal and still Anemic & nothing's helping my tiredness, if not the vitamins iron might be making me worse... I did research all other Medications I was taking to see if any caused Anemia and SURPRISINGLY ONE DID... I thought I was CRAZY until I found this BLOG... THANK YOU ALL SO MUCH FOR SHARING...
ONE THING THAT MAKES ME FEEL 100% is CARROT/APPLE/CELERY JUICE...

I like the rest of you seem to be suffering from "Vitamin Fatiuge" so I wrote GNC and below you will see the message I sent to them. If they respond I will gladly share with everyone.I need to get to the bottom of this.

Dear GNC,
I am a 42 year old female and I had gone to my local GNC in Peekskill,NY and bought a few of your products.I had purchased Ultra Mega Womens, 5000mcg B12 subligual, and liqid D3 and since I've started them I am so tired, totally exhausted and usually I have too much energy and require very little sleep. Now I cannot get enough sleep and need a nap.
I was told from blood work that I needed Vitamin B12 and D3 now I figured I should also take a multi as I probably need everything that wasn't tested for as well. Help what is going on??? All my other labs came back normal and just about everything that would cause anything was checked.
What is going on with me and your Ultra Mega??? It seems I am not alone from this forum!!!! If you could please advise it would be greatly appreciated!!!!!
Thank you in advance