MASI supplements are very high quality which you can already tell just from their packaging, I just wish they were more affordable. No other complaints, the supplements work.
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It is my recommendation that anybody over 40 years of age starts supplementing with NMN, it has been proven to boost the NAD molecule which is responsible for all energy production in our body. This i... See more
Actually I was surprised with the quality of Masi supplements. Yes, they are not cheap, but this is what quality is about. German quality did not let me down. Bottles and packaging are so beautif... See more
Third party testing. Independent reviews backing up statements and claims of purity. Service. Ships on time. Arrives on time. This in spite of torturous journey from manufacture to third party testi... See more
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Company details
Written by the company
Trusted by over 352,000 longevity enthusiasts – MASI offers German-made, Swiss-tested NMN, Resveratrol, Spermidine, and Fisetin crafted to the highest anti-aging standards. Every supplement is produced in a state-of-the-art facility in Germany using raw materials sourced exclusively from top-tier German suppliers – never from China or India. Each batch is independently tested in Switzerland to ensure exceptional purity, safety, and potency.
The MASI Guarantee
German-made, Swiss-tested supplements crafted to the highest European standards.
We use only premium European-sourced ingredients – never from China or India. Every product is vegan, non-GMO, and free from fillers, allergens, gluten, and lactose. Pharma-grade quality. No shortcuts.
Contact info
Switzerland
- info@masi.eu
- masi.eu
4.1
Great
64 reviews
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I love my Masi supplements and have…
I love my Masi supplements and have been taking them for more than a year.I just had an amazing physical.My doctor was blown away by my test results
3 September 2026
Unprompted review
Absolute best products on the market…
Absolute best products on the market today! I’ve seen nothing but great results since I’ve been taking these products. Great customer support as well.
1 September 2026
Unprompted review
We are always excited to place an order…
We are always excited to place an order with the amazing team at Masi, they are very prompt, attentive and are always willing to do whatever it takes to deliver their anazing supplements to us!! Thank you VERY much team Masi!! We look forward to our next shipment!! Best regards,
Chris & Maria Herrington
Orange County California
14 August 2026
Unprompted review
Reply from MASI Longevity Science
Thank you!
Kindness, wisdom, and great help
They responded to my questions with kindness and wisdom. They also went the extra mile to help with my problem. I’m thankful and impressed.
Bill
14 August 2026
Unprompted review
Quality, Service, Communication
Third party testing. Independent reviews backing up statements and claims of purity. Service. Ships on time. Arrives on time. This in spite of torturous journey from manufacture to third party testing to customer.
Five stars!
20 April 2026
Reply from MASI Longevity Science
Thank you for your support!
I cannot assess the real benefit vs
I cannot assess the real benefit vs. price. Moreover, as I also have to take other substances ( selenium, zinc, magnesium, Vitamin B and D3) to support my tyroid, I fear that I take these substances twice.
5 March 2026
Reply from MASI Longevity Science
Here is a professional and reassuring reply:
Thank you for sharing your concerns. We understand that it can be difficult to assess the value when several supplements are taken at the same time. Clinical research suggests that at least three months of consistent use may be needed before the potential benefits can be properly evaluated.
To avoid taking overlapping nutrients, we recommend comparing the ingredient amounts on each product label and discussing your full supplement routine with your doctor, especially when supporting a thyroid condition.
FedEx dumped my order in the driveway…
FedEx dumped my order in the driveway where my dogs were. I lost half my order since they opened the box and ate 2 bags. Fedex failed to put my order in the designated box as always done in the
12 March 2026
Reply from MASI Longevity Science
We’re very sorry this happened. Your order should have been left in the designated delivery box, not in the driveway. Please contact us at info@masi.eu with your order number so we can investigate this with FedEx and find a solution for the damaged items.
As your dogs may have consumed some of the supplements, please contact your veterinarian as soon as possible and share the product names and estimated amounts they may have eaten.
One of the best products on the market
One of the best products on the market. Also, most importantly when you place an order that arrives in a timely manner. My opinion, this product is top tier with great Customer service.
17 February 2026
Reply from MASI Longevity Science
Thank you so much for your kind words and continued trust in MASI. We are delighted to hear that you are happy with both the product quality and our customer service. Your support truly means a lot to our entire team.
The product is great, but.....
The product is great, but I've had to cut back my budget and can't afford the subscription any more. I've tried multiple times to cancel my subscription but once I hit the button to cancel it just spins and never cancels. I'd give it more stars but I'm frustrated.
17 May 2026
Reply from MASI Longevity Science
Thank you for your honest feedback, and we’re sorry for the frustration this has caused. Cancelling your subscription should be simple and should not leave you stuck on a loading screen.
Product is great
Product is great, but took months to arrive if it even cleared customs at all I got a call from FedEx telling me * have to sign special customs forms to clear it for delivery? No thanks
13 February 2026
Reply from MASI Longevity Science
Thank you for your feedback. We’re glad to hear that you liked the product, but we’re very sorry about the delivery and customs experience.
Your case was resolved and the order was fully refunded. MASI prepays applicable taxes and duties and works closely with FedEx and US Customs, but unfortunately, customs may still occasionally request additional documentation from the recipient. We understand how frustrating this was and sincerely apologize for the inconvenience.
I mistakenly took two in the morning…
I mistakenly took two in the morning and two at night 😳 for the summer my blood work in the fall was lower sugar better cholesterol and my eye sight was improved . I am now taking the proper amount one morning and one at night but hmmmmmm
12 February 2026
Reply from MASI Longevity Science
Thank you for sharing your experience! We’re delighted to hear about the improvements in your blood sugar, cholesterol, and eyesight. Those are wonderful results.
Please continue with the recommended dosage of one capsule in the morning and one in the evening. Many customers also combine NMN with Resveratrol as part of their longevity routine, as NMN supports cellular energy while Resveratrol provides additional antioxidant and healthy-aging support.
We truly appreciate your trust in MASI!
Loving it!!!!
Good products. Both me and my husband have been on the MASI regimen and we are not going back to living without them.
MASI should improve their shipping times but it's not a dealbreaker for the quality that you are getting.
10 April 2026
Unprompted review
Reply from MASI Longevity Science
Thank you so much for sharing your experience! We’re delighted that both you and your husband are enjoying your MASI regimen and experiencing the quality of our products.
We also truly appreciate your feedback regarding shipping times. We are continuously working with our delivery partners to make the experience faster and smoother. Thank you for your patience and continued trust in MASI!
All the products are great
All the products are great, thoroughly researched and tested, and always arrive on time!
15 January 2026
Fantastic!!!
Fantastic!!!! I feel alive again, nmn has changed my life. Been on MASI nmn for the past 3 months, I've been struggling with anxiety for over 10 years and this supplement is the best thing I've ever added to my routine. It took about a month to TRULY kick in but once it did my I was finally able to sustain conversations without rising anxiety regularly! Love everything about this brand!!!
5 January 2026
Unprompted review
Wow!
Wow! Absolutely amazing Spermidine from MASI EU is top quality. I've taken it now for a month, the supplement overdelivered above my expectations, I was not expecting skin smoothness so fast! I first bought it after watching a clip online about spermidine cleaning your cells and now I can see the effects.
27 February 2026
Unprompted review
I would give zero
I would give zero. I had bought the gift for my wife expecting her to enjoy as it was already second by without any visibal effet, but believing that maybe after some tim ether will be some positive effect. When she opened the box, carton inside was crubled, as if someone had already opened the box before her. After few days of trying to use it she told me taht I feeel very bad like usežing someone had used it already. I have photos beu I do not have time tio waste, I was planning to buy for her more things from Masi, but after this experience it's absolutelly disappointing
19 December 2025
A real Supplement
It is my recommendation that anybody over 40 years of age starts supplementing with NMN, it has been proven to boost the NAD molecule which is responsible for all energy production in our body. This is something that naturally declines with age so supplementing with its pre cursor which is NMN works to lower your biological age in return. You can still get younger as you get older and that's fascinating. Great efforts from MASI brand, highest quality I've tested.
6 March 2026
Unprompted review
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