Supplements You Should Take (and AVOID) in 2026 — Transcript

Dr Karan reviews popular supplements for 2026, ranking their effectiveness and safety based on scientific evidence.

Key Takeaways

Avoid supplements with poor evidence like bovine colostrum and GLP-1 boosters.
Testosterone supplementation should be medically supervised and only for deficient individuals.
Turmeric supplements pose a small risk at high doses despite some benefits.
Nattokinase and glutamine show potential but require more robust research.
Healthy lifestyle habits are more effective than most supplements for cardiovascular and overall health.

Summary

Many supplements are overpriced and ineffective, but some have proven benefits.
Bovine colostrum is largely unsupported by high-quality human studies and considered a grift.
Testosterone boosters help only those with deficiency; otherwise, they may cause harm.
GLP-1 boosters in supplement form do not work like prescription drugs and should be avoided.
Turmeric has anti-inflammatory benefits but high-dose supplements carry a small risk of liver damage.
Nattokinase shows some cardiovascular promise but lacks strong randomized controlled trial evidence.
Glutamine is useful for specific medical conditions but not generally beneficial for healthy individuals.
Probiotics and other supplements like apple cider vinegar and adaptogens have mixed or limited evidence.
Lifestyle factors such as diet, exercise, and medical treatment remain the most reliable for health.
Supplements are tiered from S (best) to F (worst) based on current scientific data.

Chapters

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Most supplements out there are just expensive formulations of compounds that do nothing. But some are worth your time and money. And there's at least one I've changed my mind about and started taking recently. So in this video, I'm going to

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give you the science behind some common supplements and tell you exactly whether you should be taking it or not and what you should be doing instead.

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You might see redness, puffiness, irritation. What we developed is essentially beauty in a pill. So one differentiator about Wonderlow is the combo of colostrum and collagen. Beauty in a pill is just one of the claims made about colostrum, the first milk cows

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produce for calves and which is rich in antibodies, growth factors, and various immune signaling molecules. Given this nutritional profile, claims about colostrum range from gut health benefits to boosting immunity to anti-aging and even longevity. And essentially, none of

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them are supported by high-quality consistent human studies. And in my opinion, bovine colostrum is one of the biggest grifts going. I'll be happy to prove wrong as and when the evidence appears, but for now it is going on the

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E tier. Okay, next up are testosterone boosters. Which of you men wouldn't want increased libido, erectile function, muscle mass, and strength and improved mood? And research consistently shows testosterone supplementation can improve all these outcomes on one condition that

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the people taking the testosterone were deficient in the first place. In contrast, for adults whose testosterone is within a normal range, boosting it beyond that tends to have rapidly diminishing returns with extremely high levels of test being associated with

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negative outcomes like acne, mood loss, and even infertility. If you are low in testosterone, your doctor can prescribe TRT, and you can have more faith in that than most generic testosterone boosting supplements, which lack any kind of clinical trial data. And just a quick

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reminder that when you see outrageously ripped influencers selling you testosterone boosters, they're almost certainly the recipients of great genes and some particularly tasty juice, not just increased testosterone. Now, I am tempted to put testosterone boosters on the F tier, but it is true that many of

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them contain ingredients that have some published data supporting an effect on testosterone, but the final formulation hasn't often been studied. And so, for that reason, they're going on the E tier. Now, on the topic of boosting, what about GLP-1 boosters? We've all seen

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the amazing before and after pictures of celebrities who shed kilos thanks to GLP-1 agonists like Ozempic and Wegovy. And there's no doubt that these drugs are transformative for people with type 2 diabetes, obesity, and as we're beginning to see, a bunch of other

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conditions, too. But they're also extremely expensive. So, why not buy a much cheaper supplement instead? Well, because they don't work. GLP-1 drugs work by binding to the GLP-1 receptors, therefore making you feel fuller for longer. GLP-1 supplements work by

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encouraging your body to produce a tiny bit more GLP, which gets metabolized quickly by the DPP-4 enzyme, having a much smaller impact. It's like a sparkler versus the firework finale of a pharmacological agent. There is frankly no clinical evidence showing GLP-1

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boosters work because if there were, we'd all know about it and there'd be trials showing equivalent or superiority to actual GLP-1 medication and supplement companies would be making a killing. I mean, more so than they are now. Honestly, you'd be better off

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eating a bit more fiber or protein for the same feelings of satiety. So for GLP-1 boosters, even though there is a molecule of truth in the mechanism of action they propose, for the hyperbolic and frankly predatory marketing and

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trying to compare them to an actual pharmacological agent, they go in the bin. F tier, avoid. Next up is a compound with known anti-inflammatory effects.

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Turmeric. Turmeric's anti-inflammatory effects come from curcumin, which is thought to downregulate the production of certain inflammatory markers. The problem comes with bioavailability where much of the curcumin you consume gets metabolized too quickly to do anything.

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This means a typical curry might contain 20 to 300 milligrams of the stuff while turmeric supplements might have up to 1,500 milligrams. This amount approaches the levels of curcumin used in the clinical studies of osteoarthritis where it has

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been shown to reduce knee pain, improve joint mobility, and reduce the amount of medication needed. However, in just the last few years, reports have come in of certain individuals suffering from turmeric-induced hepatitis. Now, I need to be clear. Your absolute risk of

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suffering liver damage from turmeric is absolutely minuscule. But when it does happen, it can be severe and the evidence indicates it's most likely to happen in high-dose enhanced bioavailability form. So, if we're just talking about sprinkling turmeric on

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your food, I'd probably put it in the S or A tier. But given the risk from high-dose supplements, I'm actually putting turmeric on the D tier. Next up is nattokinase. Nattokinase is an enzyme extracted from natto, a traditional

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Japanese food made from fermented soybeans. The main claim is that it can improve cardiovascular health by helping to break down fibrin, a protein involved in blood clot formation. As a result, it's often marketed as a natural blood thinner or even nature's aspirin. A meta-

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analysis of randomized control trials published in 2023 found that nattokinase can modestly reduce blood pressure.

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Whilst a Japanese study found high doses of nattokinase was associated with significantly lower LDL cholesterol, total cholesterol, and triglycerides and even reduced thickening of the intima, the layer of cells in the arteries in contact with the blood. Unfortunately,

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this wasn't a randomized control trial, so we can't be certain it was the nattokinase that had this effect or something else. Now despite all this buzz online about nattokinase, the most reliable route to improved cardiovascular health is still all the

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boring stuff. Regular exercise, fiber, less saturated fat, not smoking, maintaining a healthy weight, and keeping your blood pressure under control. So the evidence about nattokinase is interesting, but ultimately not enough. I'm going to be putting it on the D tier and maybe C

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tier if the evidence comes out that it is good consistently. Now, let's talk about glutamine. Last time around in my video, I placed it on the E tier, but this one I'm definitely going to have to change. Glutamine is a conditionally

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essential amino acid, meaning you naturally make it, but occasionally if you're sick or injured, you might not be able to make enough, in which case you need to get it from a diet or a supplement. Doctors will prescribe

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glutamine in case of sickle cell disease and short bowel syndrome where in combination with other medicines and pharmaceutical-grade levels, it can improve nutrient absorption in the intestines. Another medical use of glutamine is where it's prescribed to anyone suffering from severe trauma like

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major surgery, injury, or cancer treatment to prevent intestinal hyperpermeability or leaky gut. But this is a far cry from saying healthy people should supplement glutamine. So what does the latest research say? Well, a meta-analysis of 10 different studies on

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glutamine found it did not significantly affect intestinal hyperpermeability or leaky gut except when prescribed at higher than 30 g per day for less than 2 weeks. So this suggests more research is required to identify ideal dosage and timing. All in all, for anyone with

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chronic GI issues related to their gut barrier, glutamine might be useful. So I'm moving it from E to C tier. However, for the average person with no GI issues, it goes in the D tier. Now, let's quickly talk about probiotics.

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I've made entire videos on probiotics before, and my views haven't really changed. Probiotic

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prepared to clinical standards and choose specific strains of bacteria to treat your symptoms. In contrast, probiotic supplements are unregulated, so you can never be sure exactly what you're getting. So, if you're just looking for a Hail Mary to boost your

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gut health, probiotics for you will be on the D tier. But for targeted outcomes, for specific conditions, if you're using a clinically studied, clinically researched probiotic with the named genus, species, and strain, I'm going to put it as a B tier. All right,

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I want to touch on apple cider vinegar. Now, the main claims about this supplement are that it assists in weight loss and reduces blood sugar spikes after eating carb heavy meals. Now, the evidence for these claims is somewhat

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reasonable, whereas the evidence for some of its other claims, like burning fat or detoxing the body is essentially non-existent. Maybe people like it because it's cheap and it's natural. But neither of these two things means it works. What apple cider vinegar can do,

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however, is cause tooth enamel erosion, heartburn, or at least worsen it, throat irritation if it's consumed neat or in excess. A 10-minute walk after lunch will help to reduce blood sugar spikes without you having to smell like a salad

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dressing. And so, for that reason, but also appreciating it's not really bad for you, I'm going to put apple cider vinegar on the C tier. Next up is a group of supplements that sounds like something from Transformers. They are

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adaptogens. The basic claim about adaptogens is that they are compounds that help you deal with stress. The most widely studied of them is Ashwagandha and a 2024 meta analysis of randomized control trials found it is effective in treating anxiety, perceived stress and

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cortisol. However, many of these studies were small and industry funded so it pays to remain skeptical and it doesn't invalidate them by any means. I think there is something there to Ashwagandanda specifically. Other adaptogens such as panax jinseng and

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rayi don't really have quality evidence behind them. Ultimately, if you want a free scientifically supported anti-stress technique, you might want to try diaphragmatic breathing. This type of breathing stimulates the vagus nerve and promotes parasympathetic activity which causes feelings of calmness. And

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studies have consistently shown this type of breathing reduces perceived feelings of stress and anxiety. Whilst I think there is tremendous potential in ashwagandha specifically given the general lack of solid research in other adaptogens and the free effective alternative, I'm going to put adaptogens

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on the C tier. But Ashwagandha specifically, I'm going to move it up higher. Maybe a B tier/ A tier. I think it needs even more evidence. Now, let's talk about mushroom blends. In case it needs saying, mushroom blends is not a

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scientific category. It is marketing talk. This means one mushroom blend could contain three mushrooms, another could contain 12. It also means you don't necessarily know if what you're taking comes from the fruitting body, the actual mushroom itself, or the

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mcelium, the rootlike network the mushroom grows from. Again, because this is a wide-ranging category of supplements, the evidence is mixed.

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Lion's mane is the best supported mushroom supplement. We know that compounds in lion's mane stimulate production of nerve growth factors. And when individual nerve cells are exposed to lion's mane, we see the growth of neurites, structures that mature into

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connections between nerve cells. And an increase in proteins related to synaptic density and function. But these studies are all done on animal models and petri dish studies. There's no evidence that lion's mane can grow new sinapses in humans. Studies involving humans taking

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lion's mane tend to be small and show modest improvements in cognition. Nothing we can draw any firm conclusions about. And as for mushroom coffee blends, yeah, you might feel calmer than normal, but that will probably be as there's less caffeine than normal

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coffee. And ironically, you'll miss out on the wellestablished benefits of coffeey's polyphenols by drinking mushroom blends. Bottom line is that the evidence that mushroom blends improve cognition in humans is weak. and the lack of transparency about ingredients means they're lucky to scrape on the C

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tier. Next up is NAD, the supplement that's becoming the darling of the longevity and biohacking world. The basic claim is that NAD levels decline as we age and that boosting them with NMN, the precursor to NAD, can improve

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energy production, cellular repair, and potentially even slow aging itself. Now, multiple studies have shown that NMN can successfully increase NAD levels in humans. However, when researchers look for meaningful real world benefits, things like improved cognition, physical performance, or slower aging, the

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results have generally been modest and inconsistent. Despite the hype, there is currently no convincing evidence that NMN slows aging or extends lifespan in humans. In medicine, we often look for mechanistic evidence. We want to know how and why something works. But in this

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case, that isn't enough. NAD is an example of a mechanism we understand pretty well, but it doesn't translate into meaningful differences in human trials. So for now, NMN and NAD both get a C tier from me. Now let's talk about

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uroliththn A. This molecule is made by your gut microbiome from compounds called elegantins and allergic acid found in pecans, raspberries, walnuts, and strawberries. Most people don't make a lot of uriththin A, which is why certain companies have started producing

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it as a supplement. The main claim is that uralithn improves the health of mitochondria, the main power units inside each cell, and it boosts the removal of damaged mitochondria. In fact, an RCT published in 2022 found uriththan A did result in increased

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biomarkers associated with mitochondrial health as well as reduced inflammation. However, it is worth pointing out that several of the authors of this study were employees of the company that developed the supplement, a proprietary brand of the supplement at least. Now,

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this doesn't invalidate the science, but personally, I'd like to see independent replication of these findings. And for that reason, Uralithn A is going to be another supplement on the C tier, potentially B tier as well. And I think

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it stands to go up even more with more independent trials. And now we come to the supplement with the most unfortunate name in the world, spermade. Look, I just need you to be grown up for at least the next 90 seconds. All right.

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Contrary to what you're probably thinking, you filthy animal, this compound is not only found in semen, but actually in many foods, including soybeans, mushrooms, legumes, a cheeses, and whole grains. So you don't necessarily have any explaining to do if

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you have high levels of it in a blood test. The main claim is that it promotes autophagy, the destruction and recycling of damaged cells and cell components. In laboratory studies, spermadine seems to promote autophagy and researchers have noted improved lifespan in multiple

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species given spermadine. But what about humans? Well, you can probably guess what the problem is when we observe that people who eat large amounts of whole grains, legumes, and fermented foods have lower mortality, better cardiovascular health, and improved

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cognitive outcomes. Now, is that because of the spermadine or because of the fiber and other nutrients? Or is it because these people tend to have other healthy habits? There's no human lifespan study for spermadine yet and certainly no evidence that you're better

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off getting it from a supplement than food. So unfortunately, it is going to go in the C tier. Like Uranus, interesting science, but it's hard to get past the name. Now, last time around, I placed magnesium on the B

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tier. And since then, I think it's fair to say that the research findings have become more nuanced, focusing on specific groups of people for whom magnesium benefits rather than universal claims. For example, magnesium seems to lower blood pressure, but to a greater

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degree for some people who are hypertensive than those with normal blood pressure. Magnesium bis glycinate can improve sleep quality and associated psychological parameters, but only for people with poor sleep in the first place. I think this is a pattern with

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many of the supplements I've already talked about so far. Increasingly, evidence is pointing towards these supplements being suitable for certain people with specific needs, but not for everyone. All this means that I'm keeping magnesium on the beat. Now,

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let's talk about something that might just help you with your local park run without any extra effort. Beetroot is a rich source of nitrates which get converted into nitric oxide in the body, which we know plays a key role in

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dilating blood vessels, increasing blood flow, and therefore improving oxygen efficiency. And it's precisely this mechanism that might help you to shave off a few seconds off your 5K time. And this does come with a wellsupported claim. However, it's the nitrate that

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drives this effect. The fact that it comes from beetroot is irrelevant. Just make sure any beetroot supplement that you buy has at least 800 milligrams of nitrate as this is the amount that's been used in studies showing a positive

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effect. And just a warning, antibacterial mouthwashes containing alcohol have been shown to reduce the effect of dietary nitrates by killing the bacteria involved in the conversion process to nitric oxide. So I'm going to put beetroot nitrate on the B tier. Now

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there is one supplement I've changed my mind on. And in fact, I've recently started taking it regularly myself every single day. Having become a dad over 2 months ago, everything about my life I'd had dialed in before has kind of gone to

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Sleep, which is why I've got bags under my eyes, training, nutrition, and if you have little gremlins in your life, you'll know exactly what I'm talking about. Whilst I can rely on LOM to fill gaps in my fiber, there are

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other things like vitamin D and magnesium that frankly I'm not sure I'm always getting in my current diet. And that's where taking a multivitamin can come in handy. Yes, it would be ideal to get all our nutrition from whole foods.

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But seriously, who can do that even some of the time? Never mind all the time. In fact, recent research has even suggested that taking a multivitamin can slow down biological aging, even just a tiny bit.

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The age your organs and cells appear to be compared to your chronological age. So, I'm going to revise my previous ranking and move multivitamins up from the D tier to B tier. And in fact, for some people like myself, at certain

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times in their life with tiny humans trying to destroy their lives and routines, it might even be 80. Now, let's talk about a supplement that's been claimed to improve heart health, improve energy, prevent chronic disease, and even extend lifespan. Your BS

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monitor should be ringing already. The best evidence suggests that this supplement is effective in reducing major cardiovascular events in people with heart failure, and there are studies showing it can also help to reduce statin induced muscle symptoms and migraine symptoms in some people, a

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fairly limited range of people. From there on in, the quality of evidence supporting any other claims falls away quicker than your resolve not to laugh about spermadine. I'm talking obviously about CoQ10. CoQ10 plays a key role in producing cellular energy and also has

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antioxidant effects. And given that it naturally declines with age, it makes sense that supplements might have an effect on energy levels or even lifespan. Problem is that the research shows little to no benefit from CoQ10 supplements in these areas. So, if you

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fall into any of the categories I just mentioned, it probably belongs on the A tier, but in general, I'm putting it down to B. Next up, prebiotics.

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Prebiotics are these substances your gut microbes preferentially use as nutrition, and in return, provide you with short- chain fatty acids that do wonders for your gut barrier integrity, blood sugar control, cholesterol, inflammation, and way more. The evidence supporting the beneficial effects of

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prebiotics is pretty much settled. And the only downside is some of these compounds might give you transient gas.

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Now, if you are choosing a fiber supplement, there are some definite red flags you need to watch out for. For example, many are low dose between 4 to 7 g. You want one that's ideally 10 g of fiber. You also want to avoid one which

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has things like inulin or fructosaccharides or other high doses of fast fermenting fibers because this can definitely cause gas and bloating. Look for one with slower fermenting fibers like PHG, partially hydrayed gu, or tapioca fiber. Interestingly, most fiber

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supplements have one type of fiber or at best two. You need diversity of fibers to feed a diverse microbiome. So look for a multifiber blend. In fact, in my years of testing fiber supplements, which is over 60 fiber supplements

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tested, I got tired of additives like maltodextrin being added to the mix. So make sure you pick one without exipients or bulking agents or any other additives because your gut microbiome doesn't need it. And finally, look to see who

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formulated it. Was it by a doctor? Was it by another expert? And does it have third-party testing? or has the company done a clinical study on the final formulation and not just relying on clinically backed ingredients. Something that checks all the boxes above is LOM,

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which I use. And in full transparency, I created it simply because I couldn't find something that did all the above in years of using other fiber supplements.

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However, just to show you that I'm acting in good faith, there is no link to buy LOM in the description of this video. Instead, there's a link to the LOM website page explaining the results of the first doubleb blind clinical

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trial of LOM that showed 30 days of taking it resulted in a flourishing microbiome. That's just one of two clinical trials that we did showing how effective LOM is, which is two more clinical trials than pretty much every

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other fiber supplement out there. So, based on the vast quantities of high-quality data we have, prebiotic fiber supplements go in the S tier because of all that evidence. Now, it is worth touching on the newest kid on the

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gut health block. Postbiotics are a group of supplements that cut out the middleman. Instead of feeding the microbes in order for them to make beneficial compounds, why not just supplement the beneficial compounds in the first place? For example, butrate is

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a short- chain fatty acid produced by gut bacteria when they ferment fiber, and it's now available to supplement directly. There is some evidence that supplementing butrate can confer benefits in IBS, inflammatory bowel disease, and for the gut barrier. But

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these studies are small and usually short-term. Realistically, we need more and better quality evidence that postbiotics can have lasting positive effects. I think it has potential, but the science isn't quite there yet. And in the meantime, your best bet is

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definitely to eat more fermentable fiber. And so, for that reason, I'm going to be putting it on the B tier.

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Right. So, here's a supplement I rated as S tier last time, which has since had a systematic review published in early 2026. Creatin. This paper looked at the results of six studies on the effects of creatin on cognition in older adults.

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Five of these studies found a positive relationship between creatin consumption and cognitive functioning, particularly memory and attention. And it didn't make any difference whether the creatin came from a supplement or diet. These findings need to be confirmed in further

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clinical trials, but there's no reason to downgrade my previous assessment of creatin. Creatin monohydrate will help your muscles do more work and seem to be clearly associated with some degree of improved cognitive functioning in a wide range of research. So for me, creatin

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stays right where it was on the S tier. If you want to learn more about health supplements, what I use personally, I cover all of this in my weekly newsletter. And I regularly write also about how to increase your fiber intake

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without supplements, such as a recent issue where I gave two simple suggestions for an extra 10 g of fiber per day. If all of that sounds interesting for you, it is completely free and you can sign up below. And I

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will see you beautiful walking bags of sentient microbes next week.

Topics:supplementstestosterone boostersGLP-1turmericnattokinaseglutamineprobioticshealthDr Karan2026 supplements

Frequently Asked Questions

Are testosterone boosters effective for everyone?

Testosterone boosters are effective primarily for individuals with clinically low testosterone. For those with normal levels, boosting testosterone further can lead to negative effects and diminishing returns.

Do GLP-1 supplement boosters work like prescription GLP-1 drugs?

No, GLP-1 supplements only slightly increase GLP-1 production and are quickly metabolized, making them ineffective compared to prescription GLP-1 agonists like Ozempic or Wegovy.

Is turmeric safe to take as a supplement?

Turmeric has anti-inflammatory benefits, but high-dose supplements with enhanced bioavailability carry a small risk of severe liver damage. Using turmeric as a spice in food is generally safe and beneficial.

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