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(Out of 10, after 25 reviews)

Ranks #3 (better than 95%)
In: Growth Enhancers > Nighttime Sleep Formulas

ZMA is a Nighttime Sleep Formula manufactured by Optimum. It is designed to be used before bed time. It promotes restful sleep, increases REM sleep and helps the body attain an optimal state for muscle recovery and growth.

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Growth Enhancers > Nighttime Sleep Formulas


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The supplement industry is notorious for agressive marketing and misinformation.

Rep: +499
Trust: 100%
TROOPer Level: 31
  January 9, 2017


ZMA is not unique to O.N.-- there are many companies that make this potent mix of Zinc, Magnesium, and B6. To some that may be obvious, but I know many people who have never heard of this. Including myself until relatively recently. Zinc and Magnesium are the important things in this compound and since the brand manufacturing only matters as much as their manufacturing practices, I want to provide an overview of why.

To explain the need for magnesium you really need to start at the cellular level. ATP is the main energy source for our cells--it's what makes everything run. Without ATP you'd simply drop dead, and ATP must be bound to a magnesium ion to become biologically active. Very few of us get as much Magnesium as we should. A diet rich in Magnesium will include dark leafy vegetables, avocados, bananas, as well as things like oysters or walnuts which are loaded with it. Unfortunately, there are many things that cause magnesium to be excreted from our bodies, or rendered unavailable. Things like carbonated beverages, pastries and sweets, caffeine, and alcohol all negatively impact magnesium levels. If you eat well, chances are you already get a good amount of magnesium

Zinc meanwhile is a huge component of our immune systems. It plays a part in cellular division, cell growth, healing wounds, and is even involved in the senses of smell and taste. Without Zinc you would find yourself becoming sick very easily, and very slow to recover. When you consider that the act of lifting weights involves the tearing of muscle fibers that are then repaired stronger, thicker, and more malleable, it's not hard to imagine why this would be important.

Bringing it altogether, ZMA has some scientific studies that back it's efficacy. Plug ZMA into Wikipedia and you'll quickly find the most commonly cited study of ZMA conducted at Western Washington University where they studied 12 football players who took ZMA nightly for 8-weeks during spring training, along with a control group that took a placebo. The athletes taking the ZMA had strength gains 2.5x greater than the placebo group, and had a 30% increase in testosterone levels compared to 10% in the placebo group. The asterisk on this study is that one of the scientists conducting the study holds the registered trademark for ZMA's original formula and funded the research. It's a BIG asterisk, and also a small study size, but the logic behind the effects of the compound is enough to make me want to try it all studies aside.

Ingredient Profile

In O.N.'s blend you get:
10.5mg B6
450mg Magnesium
30mg Zinc
per serving

For comparison, that's amount of magnesium found in about 3.5 cups of ground walnuts, or 39 medium-sized oysters-- two of the most potent natural sources.


3 white pills, taken at night.


This does seem to help me sleep, and my recovery time is much better. I do feel a little bit of grogginess some mornings, but I noticed that's more common when I take it immediately before bed. If I take it 30 minutes or so prior to heading to bed I'm fine. It's not going to knock you out by any means. It just seems to relax you.

Recovery times are good while taking it too. I feel good and rarely am sore for more than a day, even after the heaviest lifts. I never have days where I worry about stairs after legs day or that sort of thing.

The biggest effect is the improved immune response. I just don't seem to get sick. I don't drink much anymore, but if I have a few beers I noticed diminishing effects, that's the only thing to keep in mind-- it will drain your zinc. Otherwise, if I get the slightest symptom towards the end of the day, it's gone by morning.


Incredible. On Amazon ON's ZMA costs $16.87 for 60 servings. $8/month is in almost anyone's budget.

Side Effects

A little grogginess in the morning. Easy to shake off though.


I honestly think that ZMA is something everyone should take, regardless of whether or not they're even training. There are just so many benefits of zinc and magnesium for the general population, and even more for athletes. I don't really buy into the claims of this being responsible for boosting testosterone by any means, but for maintaining a healthy lifestyle and strong immune system it's a no brainer even before the price. Other manufacturers are similarly priced as well.
  • Great Value
  • Helps Recovery
  • Makes You Healthier
    Rep: +160
    Trust: 100%
      December 28, 2015


    I've been using a zinc and magnesium supplement ever since I stumbled upon its great effects while studying various supplements, so for a few years now. I haven't thought about it's effects on me for a while, but I recently went without it for about 3 weeks (I ran out and I was too lazy to buy more). MAN, I will NEVER be without this stuff again. I'll talk about my experience and ZMA's benefits in this review.

    Ingredient Profile

    Optimum's ZMA contains two major components: Zinc (monomethionine and aspartate) and Magnesium (aspartate). Vitamin B6 is thrown in as well, I suppose for fun. For most people taking a daily multivitamin, you'll already get a little bit of zinc and magnesium. This is usually in the form of the "oxide" salt, (zinc oxide and magnesium oxide) which isn't a very absorbable form. ZMA contains forms of zinc and magnesium that are much more absorbable and in higher doses than what you will find in your daily multi, which is a great reason for supplementation.


    ON's ZMA is dosed in gelatin capsules, and therefore don't have much of a flavor. The recommended dosing is 3 capsules for men, and 2 for women. I'm not sure why exactly women get a lower dose, perhaps due to women usually having a lower bodyweight in males? Purely conjecture on my part, I know that's not always the case.

    The bottle recommends taking ZMA at night on an empty stomach (that also means no other supplements). Some foods can interfere with the absorption of zinc, so this is good advice. I try to take it with water instead of milk, as the calcium in milk will compete for absorption of the zinc (this is important, and I feel that many people that have tried ZMA in the past and haven't responded to it did not follow these recommendations). Since it helps with sleep the nighttime dosing makes sense as well.


    I have always found zinc and magnesium supplements to be helpful in reducing recovery time, promoting restful sleep, and improving my overall well-being (I just feel better, ya know?). Optimum Nutrition's ZMA is no exception. During my three week "washout" period with no ZMA (with all my other supplements, training, and food remaining the same) I noticed a dramatic increase in fatigue in between workouts, to the point that I would add an extra rest day here or there for more recovery time. I felt more run down and more groggy getting out of bed in the morning. Another unexpected symptom was low libido, which would return when I added more rest days. When I got back on the ZMA, all of these symptoms went away. Recovery time is back to what it was, sleep is better, and libido is back to normal. Yee haw!

    Some people will take ZMA for "testosterone support", which is more difficult to measure objectively without blood testing. Most of the literature that I have read says that there's no significant change in testosterone levels while on ZMA, so it's effects on recovery and libido may be unrelated to the hormone. Even so, my personal experimentation is enough for me to continue taking it and enjoying its effects.


    At around $22 for 180 capsules (two months for the "men" dose and three for the "women" dose) this stuff is a steal. It will probably be one of the cheapest and most effective supplements you can take (in my own personal opinion). You'll pay more for a tub of pre-workout that only lasts a month!

    Side Effects

    Some people report having vivid dreams while taking ZMA, but I didn't experience anything out of the ordinary. I did find that on the night following a heavy leg day (squats or deadlifts) I would be awakened at night by, shall we say, "libido-related urges". No other problems that I experienced.


    I always try to be as objective as possible when putting a supplement on trial, since I don't want to pay good money for something that doesn't work. I also don't want to be a source of supplement misinformation, since I have a fair amount of people that come to me asking for advice on them. That said, I can't say enough good things about ZMA. I feel that it's one of those overlooked supplements that, when taken as recommended, will complement ANY training regimen.
    • Great Value
    • Very Effective For Sleep
    • Helps Recovery
    • Very Absorbable Forms Of Zinc And Magnesium
    • Libido Support
      Rep: +59
      Trust: 10%
        August 10, 2015

      I'm a 25 year old hard gainer and my goal is to add lean mass. This product helped me to achieve that mainly by helping me with recovery and optimizing my natural testosterone levels.

      *Ingredient Profile
      Zinc 30 Mg (200%)- Great way to get this micro-nutrient which is essential for optimizing natural test levels. Also this helps improve the release of IGF-1.
      Magnesium 450 Mg (113%)- Another micro-nutrient that is key to testosterone. It improves the body's anti-oxidant capacity and also decreases inflammation. It's good for joints along with many other benefits.
      Vitamin B6 (525%)-Another essential micro-nutrient, don't always get it in my diet.

      No taste it is capsules. I took the three capsules about five nights a week and still got benefits although it recommends 7 nights a week. I still noticed it helped my recovery.

      *Effectiveness (7/10)
      I really didn't notice it helping with my sleep much. I got a little drowsy but for me that feeling wore off quickly (30 minutes to an hour). I have trouble sleeping anyway though and everyone is different. I had to use melatonin to sleep. It did help with recovery though, I was noticeable less sore and able to really get after it in the gym consistently. I was able to lift heavy and lift in high volume without joint pain or excessive soreness. This helped me to continue progressing without additional recovery days or deload weeks. I got stronger and added mass with this product.

      *Value (9/10)
      It is 90 servings for $13.55, you can't beat that! Basically it is $13.55/month for men because the recommended dosage is 3 caps a night. For women a month and a half. The recommended dosage is two caps a night for women.

      *Side Effects
      No negative side effects. I did notice an increase in libido though.

      I would recommend this to someone who doesn't always get these micro-nutrients ZMA has (B6, zinc,and magnesium) in their diet. And for anyone who is looking to improve their recovery. The most noticeable effect for me was definitely improved recovery.
      • Provides Decent Amounts Of Very Inportant Micronutrients
      • Optimizes Natural Test Levels
      • Great Value
      • Helps Recovery
      • Didn't Have A Major Effect On My Sleep
      Rep: +22
      Trust: 0%
        May 3, 2013

      Hello all!

      First review here so hopefully this fits in with the correct format of reviewing.

      I've been using ZMA now on and off for the past two years. I've tried ZMA products from MyProtein (UK), BodybuildingWarehouse (UK), Holland and Barrett (UK) and now this bottle, from ON.

      Whereas there isn't a great deal of difference necessarily between the proportions of ingredients used between each, the ON product is good value for money.

      For some context, I lift 6 days a week; 3 days of lifting in the morning and in the evening and 3 days of lifting in the morning and running in the evening, alternating each day. With such a high volume of exercise and a full-time job, I need to make sure I can get the quality sleep I need to perform both well, hence why I decided to start supplementing with ZMA.

      The results I experienced from ZMA were improved recovery by inducing much deeper sleep cycles than normally. I take 3 tablets between 20-30 minutes before bed, seem to fall asleep much more quickly and into a deeper sleep, too. The benefit of this is that I have been able to wake up much earlier to lift and get all my other tasks done before starting the day, as my sleep was more efficient.

      Negative side-effects? Some people, including me occasionally, do get pretty vivid dreams from this stuff. And this isn't your average clear dream but dreams where I would wake up the next day, remember a situation or something I needed to do before realising that it didn't happen in real life but just in a dream the night before.

      I would highly recommend ZMA as a supplement in general for anyone who lifts or plays sport regularly, especially if it's physical exercise putting a lot of pressure on the CNS. The quality of sleep this product grants is well worth the price, just be prepared for an odd dream or two!

      • Great Value
      • Very Effective For Sleep
      • Helps Recovery
      • Vivid Bloody Nightmares
      Rep: +215
      Trust: 100%
      TROOPer Level: 5
        April 16, 2013

      Hi. This is my second review. I hope you'll find it useful.

      A brief recap of who I am: a regular guy, 41, work full-time at a desk job. Been working out consistently for the past 9 1/2 months. I discovered this site, did some research and entered the world of supplements cautiously - starting with Optimum Nutrition's Opti-Men, which I wrote my first review on.

      Now about that ZMA. I came across it when I was being a human sponge reading all of the great reviews from everyone here at and I put it down, with a number of other items to try.

      So why ZMA? I've always had problems sleeping, so that was my initial attraction to using it as the reviews suggested my sleep could be better. Second, as I was now getting more confident in my ability to push myself at the gym, and I was moving from 3-4 times a week to 4-5 times, I was dealing with a sore body and a lack of energy, which I felt could turn into a negative quickly if I didn't take steps. My third reason was because I wasn't taking anything else besides the Opti-Men and my diet was something I hadn't addressed yet - I'm taking baby steps because I don't want to flame out - and I thought this would be a decent supplement to try.

      To this point I've already used a full 180-count bottle and I'm a few weeks into my second 180-count bottle.

      Here is my experience with it.

      Dosing: I take 3 pills each night with a full glass of water, about an hour or so before I think I'll be ready to sleep and this is generally a couple hours since I last ate. I was going to bed late, 2:30am or sometimes later as this is a habit that I've formed over the years.

      I became aware of the effects of the pills after a couple days. These are a slight sleepiness and a relaxed feeling, like I want to lie down, not sit or stand. My sleeping habits as I mentioned are bad, generally I wake up 5-6 times during the night. With the ZMA this went down to 1-2 times a night and I fall into a deeper sleeping pattern quicker and for longer. I also sleep over a slightly longer period of time, 7 hours as opposed to the maybe 6 from before. So, not quite the home run I was hoping for but, it is an improvement. I'll be adding Melatonin to my routine in a couple days because the lack of uninterrupted sleep is an ongoing issue I want to solve.

      When I wake up in the morning, I have no problems getting out of bed or being alert. No mushiness or fuzziness. I also - and this is what I know the ZMA did - felt less soreness and I was able to push myself hard in the gym without feeling like I was stiff and lethargic.

      So, what qualifies as push myself? I was averaging 60 minutes of cardio 30 minutes of light weights before the ZMA.

      I have now moved to 60 minutes of higher intensity cardio where I sweat constantly and 30 minutes of moderate weights, and from 3-4 days a week to 4-5 days a week; this was big for me, because mentally I had the desire, and now my body wasn't too sore when I went to the gym and tried heavier weights.

      I was 173lbs when I started using ZMA, I'm now 171.5lbs. Not a lot, but because I had made no other changes to my diet - which admittedly is not the best but, like I said baby steps - this is all the result of consistent hard work and recovery.

      Now for the extra result that I noticed from the ZMA. Morning wood. Every day without fail once I actually get some good sleep in it's there. I think it's also made my libido rise because my girl has been beating me off with a stick and she also noticed the early morning drama; sometimes cause it's poking her when she stays over. I can also say there's been an increase in my performance - now this last may just be a combination of working out consistently + supplementing - but, it's changed moreso since I've been taking the ZMA.

      So for my ratings:

      Value - I got the bottle for $23 and that was about on par with most others I've seen, give or take a couple bucks. I say it rates a 9.

      Effectiveness - I had good recovery and morning wood + I think libido increase but, as I didn't get the full sleep effect I really wanted, I rate it a little lower than I might have otherwise, so an 8.

      Overall - I'd say an 8. I'm not sure how many people would really need this as a supplement, and for someone younger it may not even be necessary. However, I would totally recommend this for anyone in the late 30s upwards, or perhaps for someone who is now starting to work out and make diet corrections and wants to take baby steps, like myself. I'm going to keep taking it personally because I am feeling the results and I think it's worth it.

      I'm going to get my dad to use it because I think he'll have a great result with it.

      Finally, in closing I'll say I wrote this review for all you guys and gals out there who have helped me by providing your own valuable experience with the products you use.
      • Good Value
      • Supports Sleep
      • Helps Recovery
      • Morning Wood
        Rep: +19
        Trust: 0%
          February 26, 2013

        So I don't know how to feel about this one. It's affected me very strangely.

        I have to wake up for class at 6:30 every morning. I normally wake up feeling rather lethargic and tired. I have very bad insomnia and already take melatonin and valerian root to help me get to sleep. I wanted to try out ZMA as well. I'm currently cutting, so I'm keeping volume low and maintaining a 3-day split that's working quite well.

        The first night I got these, I took the recommended dosage and fell asleep instantly. Slept like a rock. Woke up voluntarily without an alarm at 6:15 and felt like a damn champion, went to class and had 2 tests that day; aced both of them. I didn't even drink any coffee, and I normally have 2 cups before I do anything. I didn't feel like I needed it. "This is a miracle supp!" I thought. Well, now I'm not so sure.

        Next night, I took the same dosage. No calcium before bed either night. That night I stayed awake and felt extra-energized all night. Normally when I have insomnia, I'll feel tired but unable to fall asleep. This stuff made my body extra hot - I was sweating like a mofo. Sometimes I would go into these states of "half-sleep"; I was still conscious but I would start seeing visions on the inside of my eyelids, but I could easily control my body and look at the clock/take a drink of water if I wanted to.

        All that said, I got out of bed the next morning still feeling energized even though I got no deep sleep. It wasn't until later in the day that I felt ridiculously tired and run-down.

        Must have been a fluke, I thought, so I took it for 5 more nights. Same experience every night. Quit taking it on the 6th night and haven't taken it since then. I really would like to try it again and maybe try and figure out how to get to sleep, because that one night I actually got to sleep I woke up feeling like a king. Weird.

        Just thought I'd share in case anyone else has had a similar experience.
        • Good Value
        • Helps Recovery
        • Bad Sleep
        Rep: +14
        Trust: 20%
          November 5, 2012

        Hey guys,2nd review here. ZMA's a pretty straight forward supplement and a definate necessity in anyones staple stack trying to pack it on. I could notice the difference in sleep quality after a night or two taking the Max dose of 3 caps.
        I ordered the bottle for my girlfriend who has no sleep issues,unlike me,and she even attests to having deeper quality of sleep.

        I used to swear by Puritans Pride supplements(in this case,their Magnesium/Calcium product) I replaced with ZMA,just due to the fact I've read alot of hype on it and have been tempted to try it. Im happy I made the switch.

        I will probably be taking this product for the rest of my life,even if weight lifting ceases for any reason,just for the pure fact of it being an all around great mag/zinc supplement and the awesome quality it delivers.
        I battled no negative side-effects. I remember waking up at 2:30am realizing I forgot to take the usual doze 50 mins before bed,and took them then. I had no groggy issues waking up 4 hours later,if anyone wonders about grogginess.

        Thank you,take care.
        • Great Value
        • Very Effective For Sleep
        • Optimizes Natural Test Levels
        • Deep Sleep
          Rep: +11
          Trust: 0%
            August 7, 2012

          Stacked with a bunch of other products.

          bought a month for about 20 buck which isn't too bad. I couldn't give ten because it didn't give me the sleep I wanted. I woke up with boners every day so it may have helped me get a deeper sleep.

          Product is basically just zinc magnesium asparate. This is the most bioavailable form of zinc so your body really absorbs it more than eating red meat.

          One thing is make sure to stay away from calcium or milk anytime around zma because the calcium blocks zincs absorption to a point.

          Overall 9/10
          No reason not to throw in stack if you are working out really hard
          • Great Value
          • Helps Recovery
          • Optimizes Natural Test Levels
            Rep: +92
            Trust: 10%
              May 1, 2012

            Value: 9/10
            I got 180 capsules ( recommended use is 3 capsules a day) so this is a two month supply for $24. This comes out to .40 cents a day which is a great value.

            Effectiveness: 7/10
            The product claims to help increase testosterone levels and improve sleep. There really isn't much conclusive evidence out there that states that this product directly can increase testosterone. Although having low zinc levels which most people who are carnivores don't have will decrease testosterone production. I noticed no changes in sleep quality or feeling fresher in the morning. The one thing that I noticed was CRAZY dreams while taking this product. I am giving this a 7 because I didn't notice substantial changes in how I feel (probably because I regularly eat red meat which is high in zinc) but I felt pretty good while taking ZMA. The magnesium is supposed to help relax the body and mind but I always sleep pretty good so it made no difference.

            Overall: 8/10
            Optimum is always reliable in my book. I can always trust them as a company and they always come through with great products and prices. I recommend taking ZMA during hard training cycles because intense exercise can definitely deplete your body of crucial vitamins and minerals especially zinc and magnesium. If your diet is not perfectly on point or you are a vegetarian, this product is a must for athletes and intense lifters.

            Fair and Honest,
            • Great Value
            • Helps Recovery
            • Deep Sleep
            • Vivid Dreams
            • Vivid Absurd Dreams
            Rep: +21
            Trust: 46%
              April 25, 2012

            Optimum Nutrition is one of the top three companies out there right now...hands down. With that being said, when I want supplements with very simple ingredient profiles I look to Optimum, and have done so for the past year on the advice of Olympic trainers and nutritionists.

            Taste: 10, I say 10 because it's a swallow it and it has no aftertaste. This should not be an issue for anyone.

            Value: Wow..$15 for a supplement that works as advertised? Sold

            Timing: I think the timing of supplements is extremely overlooked and can be the most difficult part of supplementing properly so that maximum bioavailability of the substance can be obtained. I was informed to take three pills on an empty stomach before going to bed. I personally refuse to go to bed on an empty stomach and usually have a casein shake before I sleep. I take my ZMA before I drink the shake.

            Effects: Give this product a week to feel enhanced recovery time. The difference in recovery time is very noticeable and helpful, this may be due to the deep sleep that it can induce. Also very vivid dreams, this will take effect immediately, often with first dosage.

            Testosterone booster: I couldn't tell you if this worked or not. I think it is very very difficult to gauge this without having blood work done which I did not.

            Unwanted Side effects: IF YOU ARE PRONE TO ECZEMA, the magnesium in this product WILL dry your skin out. I manage mine really well with medication and lotion, however, it's still there. so figure out if this product is worth it to you. I had a great time on it, but I can not use it again because my eczema gets unbearable. When I stopped taking ZMA my skin issues went away within three days.

            Overall: For 99% of the population this product is absolutely wonderful and helpful, and at a price like this should be tried at least once.

            Thanks for your time and consideration, good luck on reaching your goals.
            • Great Value
            • Very Effective For Sleep
            • Helps Recovery
            • Deep Sleep
            • Vivid Dreams
            • Eczema Become Aggravated

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