NMN supplements are trending – experts explain whether they really work
‘I'm going to NAD for the rest of my life, and I'm never going to age,’ said model Hailey Bieber to Kendall Jenner in an episode of The Kardashians back in 2022. This now much-shared clip featured the women being administered with an IV form of NAD – a much-raved about supplement that comes with a plethora of claims including slowing down the ageing process, to reducing inflammation in the body and improving fitness performance.
For most mere mortals, this was the first time they’d ever heard about NAD, but fast-forward to 2025, and talk of this naturally occurring compound has spread like wildfire.
While NAD may once have been written off as something only the rich and famous could enjoy (a single IV drip starts from around £250) the pure form of the molecule has now been made more readily accessible as an NMN supplement – a compound naturally derived from vitamin B3 which converts to the purer form of NAD+ in the human body. It’s also suitable for use via a capsule – so it’s far more affordable.
To find out more about how NMN supplements as capsules work and if the benefits are worth it, not only did I start taking it myself for several months, but I also spoke to several experts specialising in nutrition and science to find out their opinions. Read on to find out what I discovered.
What is an NMN supplement?
‘NMN, short for nicotinamide mononucleotide, is the latest in a line of popular longevity supplements in recent years to hit the mainstream health market,’ explains nutritionist Steph Baker, the founder of Stephanie Jayne Nutrition.
‘It is a compound naturally derived from vitamin B3 which converts to NAD+ in the human body,’ she says – adding that NAD+ is an enzyme that is a part of every single cell in the body. Contributing to many biological processes that improve human health, it’s also been studied on animals as an all-rounder anti-ageing, life-extending super supplement.
NMN supplement benefits
The claims on the product pages of NMN supplements such as those from vivanmn include; ‘increased energy that lasts the whole day and eliminates those pesky afternoon crashes, improved sleep quality leaving you feeling completely refreshed when waking, and enhanced mental clarity and concentration allowing you to increase your productivity.'
So far, so promising. It also claims to help elevate your metabolism, resulting in suppressed age-associated body weight gain.
But how accurate are these claims and can they be backed up with clinical research?
In short, not really and science still has some way to go. ‘There are animal studies in mice that showed improvement in insulin sensitivity, improved cardiac health, cognitive function and reduced age-related physiological decline,’ explains Harshita Kundarvalli a drug development scientist with over 13 years of experience in the field of medical research and innovation.
She’s also quick to point out that these are all animal study demonstrations and cannot be translated as benefits to humans without testing being conducted on people for a minimum of 10 years.
Put simply, while animal studies have shown exciting results, and there are potential benefits to humans, more human clinical trials and long-term data need to be gathered to understand the efficacy and safety of these supplements.
It’s also worth noting that NMN and other forms of NAD+ are also found in natural foods like cow’s milk, beef, shrimp, and vegetables like broccoli, edamame, cucumber, avocado, and tomato cooked at low temperatures. As every nutritionist will tell you, a food-first approach is always preferable.
Does NMN supplementation work?
While the claims and anecdotal reviews of NMN capsules are interesting, the unregulated nature of supplements means you can never take any of them as gospel. (A supplement business owner recently told me that there are greater restrictions on the marketing of beauty products in the UK than there are on supplements).
But, in the name of journalism (and to see if I could see any difference myself), I’ve been taking one capsule of Pure NMN by vivanmn for the last three months.
Pure NMN | 500mg Capsules
The results? In all honesty, I feel better than ever with improved energy levels and general immunity. However, I wasn’t starting from nothing and I eat a well-balanced wholefood diet comprising minimal alcohol and ultra-processed foods. I also exercise four times a week and walk over 10,000 steps most days. But after just a few weeks, I definitely felt that my fitness levels improved – particularly my stamina.
I’m 40 years old and have been working hard to build up my fitness after having two children, but I definitely feel stronger than I have in a long time. I’ve also not had so much as a cold all autumn or winter, which with two small children in the house is nothing short of a miracle. Is my current good health and PB in spin class down to the daily NMN supplement I take each morning, or just an accumulation of practising good health habits?
Experts such as nutritionist Steph Baker are sceptical of my findings. ‘Overall, NMN supplementation and the latest surge of positive reviews on social media about the effects on muscle health and sports performance could be because the supplementation is taken alongside an improvement in dietary and lifestyle factors,’ she says.
‘Studies need to be taken on healthy individuals taking the supplement without any changes to their regular long-term diet/lifestyle routines. Likewise, there is also a lack of data on the metabolic benefits of NMN supplementation, which it is praised for in the media. Several studies found no significant improvements in common metabolic health parameters including HbA1c (blood glucose), cholesterol, blood pressure and body composition.’
While research on humans is definitely limited, Baker says that there is one study on prediabetic menopausal women that found that taking 250mg a day of NMN improved insulin sensitivity. Another study found that muscle NAD+ of older adults was relatively similar to those of younger participants if they followed a consistently healthy diet and exercise regime. ‘The improvements in metabolic health from NMN supplementation, however, needs to be further explored,’ she says.
Raquel Britzke, a Doctify-rated registered nutritionist adds: ‘While NMN is exciting, it’s not a miracle solution and won’t replace the fundamentals of healthy living like a nutrient-dense diet, regular exercise, good sleep, and stress management. I encourage people to think of NMN supplements as part of a holistic approach to ageing well.’
NMN side effects
While I personally didn’t experience any side effects from taking NMN capsules, there are some to be aware of.
‘Side effects of taking NMN are mild and not very common but some users might experience digestive discomfort, nausea or abdominal pain, especially at the beginning when the body is adjusting to higher doses,’ says Britzke.
Before taking any new supplement, you should also speak to your doctor or nutritionist especially if you take other medications, have underlying health problems or are pregnant or breastfeeding.
The bottom line
So, is NMN the anti-ageing breakthrough it’s hyped up to be? Well, the science is still catching up, and while early research – mostly in animals – is promising, experts agree that long-term human trials are needed before we can make any definitive claims.
From my own experience, I have felt better since taking it once a day for several months but it’s hard to say how much of that is directly due to NMN. I was definitely taken in initially by the social media hype, and if anything, speaking to the experts for this piece has reminded me to consider published clinical research before making a purchase.
As far as continuing with NMN, I’ll definitely finish my current bottle and then stop for a while to see if my stint of good health and stamina is affected. I’m not entirely sure how I feel about taking a supplement long-term that’s not been tested on humans or has any proven benefits on people. As with any supplement, NMN could be a good addition to an already healthy lifestyle but should never be used to replace healthy habits such as eating well and exercising regularly.
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