Optimum Nutrition


A zinc monomethionine aspartate formula to help support your immune and restful sleep*
Support Testosterone Levels And Muscle Strength!*
8.6  out of 10  (403 Reviews)
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Product Overview

A synergistic combination of Zinc Monomethionine Aspartate, Magnesium Aspartate, and Vitamin B6 may significantly increase anabolic hormone levels and muscle strength in well-trained athletes.* The novel Zinc Monomethionine Aspartate formula may also help to support endurance, growth and restful sleep.*

Beyond The Basics
  • Contains the PATENTED BLEND of Zinc, Magnesium, and Vitamin B6
  • May Increase Testosterone Levels and Muscle Strength in Well-Trained Athletes*
  • May Offer Even Better Results When Stacked with Creatine, Glutamine, HMB, or Other Strength & Recovery Products*

Behind Optimum with Jennifer Delgado

For NPC Figure competitor Jen Delgado, intense training is everything. Learn why no one should fear lifting weights, how to train for explosive results, and check out Jen's first-rate, fully-loaded supplement stack. It's ON.

Video Length | 3:38

Ratings & Reviews

Overall Rating
403 Ratings
Verified Buyer Rating
115 Ratings
By clicking the button above, you agree to entering the Reviews section. Products in the Store are not intended to diagnose, treat, cure, or prevent any disease.
May 08, 2020
Verified Buyer

Works good for me. Feel more energized and no more mid day naps needed

Jun 24, 2019

Love love love ZMA! Definitely makes me feel like I have had a full night's rest even if I only end up getting 5-6 hours, it feels like I had 8 full hours. Its absolutely amazing!!! I can absolutely tell the difference the next morning when I don't take it. Glad to have this as a regular part of my workout/recovery stack. NOTE - this price is not the best (180 capsules). You can find it at least $10 cheaper (same exact product). Do your research.

Jul 25, 2018
Verified Buyer

The first time I took this product was in 2012 and it made a huge difference in my workout recovery time. Unfortunately I think over the years the product quality or effect has declined or due to my body changes maybe it just not works. I don't know. Not everyone has the same effect. It does not work for me anymore. I did read reviews that the product quality had changed but I still went ahead and ordered it and I can say for a fact that it doesn't work on my body anymore. I would not recommend ON ZMA but you're good to go with any other brand as I feel ON ZMA quality has significantly dropped.

Jul 13, 2018
Verified Buyer

Great product

Jun 10, 2018
Verified Buyer

Love having this as part of my recovery arsenal. I definitely notice the difference when I forget to take it. ZMA helps me recover by promoting better rest when I'm sleeping. There also seems to be a reduction of muscle soreness from heavy lifting which allows me to power through my next workout without stiffness

Mar 28, 2018
Verified Buyer

If I'm pretty awake I'll combine this with melatonin and I sleep like a baby through the night ready to attack the gym the next day.

Mar 27, 2018

Been using this for years!!! Love helps your muscles relax when you sleep!!!

Feb 22, 2018

I know the studies on ZMA are kind of hit and miss but from my personal experience I tend to feel better rested when using it and I seem to recover quicker as well. Could be placebo but it does seem to have positive benefits from my experience. (Also the crazy dreams bit is completely legit)

Jan 22, 2018

I didn't notice these help me get to sleep, but they certainly helped me stay asleep. Getting up in the morning after taking these is like trying to rouse a corpse. All of my muscles (even my eyelids) felt weak and stiff for a few minutes, almost like being partially paralyzed. Indeed, I once experienced sleep paralysis while taking these. I may try these again, but this time taking them earlier before bed.

Dec 31, 2017
Verified Buyer

Another overpraised and non effective ON product. This product is good if you want to have dreams and deep sleep, otherwise stay away as it does not provide any additional results! If you have a busy lifestyle and you sleep for 6 hours max - I would not recommend this product, because you will struggle to get out of bed - it knocks you out in the bed...

Aug 07, 2017
Verified Buyer

This works well to help me get relaxed and stay asleep at night. Works best if you take it every night at a routine time.

Aug 02, 2017
Verified Buyer
No written review.
Jul 08, 2017
Verified Buyer

love this. bought the second bottle already

Jun 18, 2017
Verified Buyer
No written review.
Jun 07, 2017

I've only used this three nights in a row so far, but my sleep has been way worse? I keep waking up in the middle of the night, and have been getting up an hour or two before my alarm goes off, where I can't fall asleep. I"m going to take a few more times to see if I need to get used to it or something, but currently after using for 3 days I'm a zombie.

2 Sizes
90 Capsules
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Support Testosterone Levels And Muscle Strength!*

What's in Optimum Nutrition ZMA

90 Capsules
Serving Size 3 Capsules
Servings Per Container 30
Amount Per Serving % Daily Value
Vitamin B6 (as pyrodoxine HCl) 10.5 mg 525%*
Magnesium (as aspartate) 450 mg 113%*
Zinc (as aspartate and monomethionine) 30 mg 200%*
* Percent Daily Values are based on a 2,000 calorie diet
Other Ingredients:
Gelatin, Microcrystalline Cellulose, Magnesium Stearate, Magnesium Oxide, Zinc Oxide

Directions For ZMA: Men: Take 3 capsules, preferably on an empty stomach, before bed.
Women: Take 2 capsules, preferably on an empty stomach, before bed.

Warnings: Consult your physician before using this product if you are taking any medications or are under a physician's care for a medical condition. Not for use by those under the age of 18 or women that are pregnant, trying to get pregnant, or nursing.

* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
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