My order arrived very fast!! I didn’t have any special shipping method and it arrived quick! I could DEF notice my first dose of Diamond hard also
Fruit Punch: OUT OF STOCKWatermelon: OUT OF STOCK
ONYX Preworkout
Onyx — Stimulant Pre-Workout by Kinstone Labs
Some pre-workouts give you energy. Some give you pumps. Onyx gives you both, at full volume.
Built for lifters who want to walk into the gym and immediately feel it, Onyx is engineered for massive blood flow, skin-splitting fullness, and locked-in focus that carries you from your first rep to your last drop set.
Formulated by Kinstone Labs with caffeine and paraxanthine, Onyx delivers fast-hitting energy alongside smoother, longer-lasting focus — so you get the jolt without the jagged crash that comes from caffeine alone.
Why lifters are switching to Onyx:
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Massive, Lasting Pumps — engineered to maximize nitric oxide production and vasodilation, so blood keeps flowing where you need it, set after set.
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Dual-Source Energy — caffeine for the fast hit, paraxanthine for smoother, more sustained focus without the harsh comedown.
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Locked-In Focus — dialed in and driven from warm-up to the last rep.
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Built Like Onyx — dense, dark, and unyielding energy for training sessions that demand everything you've got.
Whether you're chasing max pumps, max energy, or both, Onyx is built to deliver the full experience in every scoop.
Kinstone Labs. Solid nutrition. Built different.
These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
Supplement facts & ingredient lab specs
Shipping & returns
Free shipping on orders over $75. Orders placed before 2pm PT ship the same business day. Unopened products can be returned within 30 days.
Customer Reviews
Overall rating: 4.5 / 5 from 27 reviews.
I have been using a lower dose than prescribed since I am only using this for PE and to boost nocturnal erections for recovery. Usually I take one capsule at night before bed with my L-citrulline supplement. When wanting to boost EQ for the sake of pumping, I will take two or three capsules ideally an hour beforehand. It's hard to quantify how effective the product is but I really believe it is working. No side effects to my knowledge. Shipping was timely and very discreet. No complaints.
Another one! I feel like I can pump to higher vac pressure without getting petechiae. This also seems to work better than the other pre-workout from that other company that shall not be named. I prefer unflavored, but it actually tastes quite good
I’ll be back
Store owner replied: Hello, And we will be waiting! -Red
So far so good
The best non stim pre-workout i have ever tried. Unbelievable pump in the gym and with the "other workouts", great taste, fast shipping, I couldn't be happier.
So, this stuff works! The pump is real. I was really hoping the fruit punch flavor was the same as a previous product, and it is!
It came right on time. Looking forward to using it! Have complete trust and faith in the products
Great product but slow and unreasonable explosive shipping .
It hasn't done anything, it's really too much money for something with zero results, I've been taking for over a week now and nothing. When's it supposed to start working?
tastes delicious! Looking forward to the results
So far so good
Great product but slow and expensive shipping
Absolutely fantastic product. Does exactly as the label says and them some. Reminded me of my early 20's
Very nice supplement. I have been taking the product before the gym.
Shipped very fast. My actual results are still inconclusive. Have only been using 2 weeks.
Flavor is great, the pumps are off the charts with this one. Stacked it with a caffeinated one it was amazing, as it is by itself. Try it for yourself. Buy you 30 of em b*#$hes (anyone know the reference)?
I really wasn't sure what rating to give it because it doesn't come with enough info on how to take it. Is it something you take daily so that it can build up in your system? Do you take it as needed before sex ? I took it on an empty stomach and felt kind of nauseous. I can't say I noticed anything, because I wasn't going to have sex and just wanted to see how I felt. The next time I won't take it on an empty stomach, that way I'll be able to give a better review.
Store owner replied: Hello Michael, We will add a small list of guidelines on how to take the supplements as this will be an excellent way to prevent any future issues for guest who may have any issues when taking these supplements on an empty stomach. Thank you for taking the time to write a review! -Red
This is a great product and would definitely recommend it.
My first order came damaged. I emailed customer service with pictures and they got another sent out to me. The only thing they could have done better was to have expedited my order or given a discount on my next order. I haven't been taking it long enough to say how good the product is. Customer service great, the product so far so good.
I spoke with a married women who told me that her husband had asked her to take 4 Diamond Hard capsules before sex - without telling her the name of the supplement, what it was supposed to do or ingredients. After sex she told me that she told her husband that if she never had another O as long she lived, she would live the rest of her life a completely satisfied woman! She also told me that she told her husband that it was was the longest O she ever had and that it was also her most "energetic" (energy-based) O she ever had! Quite a testimony for only her first use pf Diamond Hard!
I enjoyed having products that work
Great product got me diamond hard!
Great products!
I got the Blue Raspberry and it tastes pretty good... The shipping was really fast .. Thanks Kinstone
Great product! Kinda strange to ask for a picture of Load Maxx results but happened to get some overhead video. Image quality not great, maybe next time!
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The Kinstone Promise
No shortcuts. Just results.
Premium ingredients
Only the highest quality, clinically dosed ingredients.
Made to perform
Formulated for maximum absorption and results.
Fuel your legacy
Built for those who demand more from themselves.
No compromises
No fillers. No gimmicks. Just pure performance.