Hank: Last year, SciShow did a video about whether some popular supplements actually work or not, and a lot of people have comments with suggestions for others to read up on. So we decided to do that. We looked into the supplements you're most curious about to see if they are worth your money or even good for you.

Plus, we revisited a few that we talked about last time to supplement our coverage. So here are ten more over-the-counter pills and potions, and whether or not they do what they say on the bottle.

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Now, since we're gonna be talking about things that impact your health, a quick disclaimer: it's always good to check with your healthcare provider before you start taking any supplements. Even if we say there's good evidence for anything on our list, there may be reasons why it's still not right for you. We are not doctors. We're certainly not your doctor. We're a YouTube channel.

And your provider might also be able to give you more information that can make certain supplements more effective. For one example, there's evidence that taking iron supplements on an empty stomach and with vitamin C helps absorption, but whether or not you wanna do that also depends on why you're taking those supplements in the first place.

And you just can't get that kind of tailored advice just by reading the labels. So even if we give a supplement a gold star, make sure you check with your provider first before you add it to your cart.

With all that our of the way, let's start with a supplement that's pretty fishy, but that's a good thing. Omega-3 fatty acids are molecules most famously found in fish, but you can also find them in things like soybeans and flax seeds. You've probably seen commercials for omega-3 supplements all over the place, which is good, since there is a boatload of evidence that they're great for your cardiovascular health.

They can reduce the risk of heart attack, stroke, and cardiovascular-related deaths, lower your triglyceride levels, and keep your blood pressure in a healthy range. But the evidence-backed pros don't end there. A 2020 review looked at 38 studies to see how omega-3 supplementation affected skin health, and most of the studies saw significant improvements in conditions like dermatitis, acne,

psoriasis, and skin cancer. Some researchers are looking at whether omega-3s reduce the risk of other cancers, too, like breast and colorectal cancer, but there isn't a whole lot of data on this yet.

There are, however, more studies on how omega-3s affect the brain. A 2022 review article looked at nine randomized clinical trials and reported improvements in memory, learning, cognitive well-being, and even the physical flow of blood to the brain when taking certain omega-3 fatty acids. They seem to be neuroprotective and anti-inflammatory, which can help improve brain health. Studies also report that omega-3s can help with managing chronic diseases related to inflammation, reducing the risk of preterm birth, aid in childhood cognitive development, and might even reduce the risk of memory-related disease in older folks.

And unfortunately, most people don't have enough omega-3s in their diet. Globally, over three-quarters of people are likely omega-3-deficient, and it's estimated that only 3% of Canadians had adequate omega-3 levels. And that means that, if you're not regularly, like, eating a bunch of salmon, an omega-3 supplement could be "a mega" win, and omega-3s get a five out of five.

Our next supplement, taurine, is an amino acid found naturally in your body. It is abundant in the muscles, which is probably why it's a popular exercise supplement. There is some evidence that increased taurine levels from supplements can help with reducing exercise-related DNA damage, decreasing muscular fatigue and soreness, and increasing strength and muscle power, but a lot of these studies were pretty small, so until there's larger ones, we can't really know how accurate that really is.

Plus, not all the taurine claims are supported as strongly. For instance, it doesn't seem to decrease inflammation, even though some proponents might say it does. Still, based on the evidence we could find, we'll give taurine a bronze medal and a three out of five. There's worse out there.

Co-enzyme Q10, or CoQ10, is an antioxidant naturally found in your body, but levels decrease with age,

and diet usually isn't enough to maintain sufficient levels, which is where supplements come in. CoQ10 supplements have been explored for treating a bunch of conditions, with mixed results. For instance, it generally does not help with symptoms or disease progression in Parkinson's.

It seems like CoQ10 might help control insulin levels in Type 2 diabetics and improve conditions relating to heart disease, like lowering blood pressure or recovering from heart-related surgeries. And a 2020 review article suggests it can improve fertility in women. They found that 28.8% of patients with infertility who took it got pregnant during the study intervals, versus only 14.1% of control patients.

There's also pretty strong evidence that CoQ10 might be useful for treating migraines. A 2025 review article concluded the supplements are associated with decreased migraine frequency, duration, and overall feelings of pain. Research also shows it can enhance the efficacy of other treatments for various conditions, so there's, like, a lot of potential pros for CoQ10.

But research is not definitive, and it can have some negative effects, too, like making blood thinners not work as well or causing nausea or sleep problems. So take that as your Co-"cue" to proceed with caution. Sorry, that was not our best pun of all time. Let's give CoQ10, like, a 3.5. It's good for specific situations.

Next, this supplement comes from an ancient source: ginkgo, also known as ginkgo biloba or the maidenhair tree. It's a very old species of tree that is native to China--old as in ginkgo trees were around when non-avian dinosaurs were still stomping the Earth. Well, let's fast forward from then to when humans showed up on the scene.

Ginkgo leaves have been used medicinally for centuries, and extracts are used and sold globally. The central claim is that taking ginkgo supplements can help improve brain function. The extracts are usually from the leaves, because they have high concentrations of flavonoids and terpenoids.

Flavonoids are a type of antioxidant, which means they may be able to help limit damage to the cells of your body. These potential effects are everything from

reducing information to fighting cancer. Terpenoids can do that, too, but they also keep your blood moving by counteracting clotting factors so you don't end up with more clots than you should have.

So, in general, both of those chemical classes fall into the "good" category. The catch is that, even with those promising ingredients, the research on ginkgo extracts improving memory is a bit dodgy. A double-blinded, placebo-controlled study in the journal Physiology and Behavior looked at how five days of ginkgo extract supplements affected memory and test performance in 30 volunteers and found no difference in memory performance compared to controls.

But that study was small; it was brief. Surely, bigger and longer studies could find benefits, right? Well, that doesn't seem to be the case, either.

A six-week study looked at over 200 participants ages 60 and up and found that the ones taking ginkgo weren't any better at the cognitive tests than the placebo group was. Another study on thousands of older adults across several years of ginkgo supplementation found no difference in the development of dementia between the treatment and placebo groups. They also didn't reduce the risk of cancer development or cardiovascular disease.

So, even with some ingredients that might sound like they might do something, you might wanna "leaf" the ginkgo supplements at the store. We give them a one out of five.

Now, we talked about collagen supplements in our last video, but some of you were curious about whether taking collagen could do anything for your joints. Most of the studies about collagen supplementations for joint health look at patients with osteoarthritis, since current drug treatments just focus on pain management and aren't necessarily safe for long-term use.

But a review from 2021 explains that, while some studies find that collagen supplements lead to significant improvements in pain or joint function, others do not. Part of the problem here is that there are several types of collagen, including hydrolyzed type II collagen, non-hydrolyzed collagen, and ultra-hydrolyzed collagen, and they all affect your joints a little differently. Depending on which one you're using, you might get different results.

So, because the jury's still out on whether collagen will keep your joints springy, we're gonna give this one a three out of five for now.

Next! In the last video, we also covered the value of vitamin D when you are deficient. This time, we wanna talk about how to take it. So, if you go to the pharmacy looking for vitamin D, you'll see that doses range from a few hundred international units, or IUs, to tens of thousands. And if you need prescription-strength vitamin D, you might be told to take it once a day, once a week, or even once a month for really high-dose stuff.

So the question is: do those high doses taken less often really make a difference? Well, a 2017 study found that taking 1000 IUs of vitamin D daily, 7000 IUs weekly, and 30,000 IUs monthly all resulted in statistically equal increases in vitamin D levels in people previously deficient. So it seems like going for the once a day option is just about as effective as less frequent mega-doses would be. However, it's important to still follow the rules on the package, because it is possible to accidentally get too much of good stuff.

You could also do some things to make your vitamin D supplement better. If you pair it with your largest meal of the day, you can increase your serum levels of vitamin D by up to 50%. And vitamin D also has some friends that you can consider pairing your pills with.

For instance, taking vitamin D with vitamin K can support your bone health, and getting adequate zinc and magnesium can also improve the way your body actually utilizes vitamin D. Just make sure to talk to your doctor about which dose to pick, and take it only as directed. Like, if you started taking the 30,000 IU dose every day, that would be very bad.

You can get too much of this stuff. Overdosing on vitamin D can lead to hypercalcemia, or too much calcium in your blood, and that can be fatal. But, because it is so important, we once again give vitamin D top marks at a five out of five.

Now, before we get to the next item on our list, we need to supplement our income, so here's a quick break.

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Hank: Feverfew, a flowering plant native to Asia, has long been used as a medicinal herb, and now it's touted as a preventative for headaches. But definitive results for this supplement are feverfew and far between. A systematic review from 2015 found that studies reporting positive outcomes

were on the smaller side, while the larger ones found no difference between the treatment and placebo groups. The most recent large study in that review did find a reduction in migraine frequency, but the intensity and duration of migraines was the same across both groups.

But a 2025 meta-analysis found that feverfew didn't even reduce migraine frequency compared to placebos. Still, a different 2025 article suggested that migraine frequency and duration can be reduced with feverfew prophylaxis, but other symptoms like pain and nausea weren't affected.

All of this back and forth is giving me a headache and is usually a sign that the effect size is not particularly big, if it exists at all. So the results are mixed and weak, probably due to small sample sizes, variations in doses, and poor study quality. There are some negative side effects that can come with feverfew supplements, like upset stomach and mouth ulcers, which is why we knocked some points off, giving feverfew two out of five.

Next! Ginseng is another popular traditional herbal medicine that's been used for all kinds of things from increasing your energy to lowering your blood sugar. But our commenter wanted to know about ginseng and ADHD, so that is what we're gonna talk about here.

There are a couple of studies that suggest children who take ginseng along with omega-3s can have improved attention, executive function, and memory, and reduced hyperactivity symptoms. A 2024 review article found that inattention specifically might benefit from ginseng supplementation. But the "why" is a little more difficult to figure out.

Scientists initially thought ginseng might affect hormones made by your adrenal glands, like cortisol, but a 2014 paper did not find any change in the levels of those chemicals after supplementing with ginseng. What they did find was a huge difference in brain activity compared to both the baseline and the placebo group; essentially, the treatment group's brain activity looked less like they had ADHD by the end of the study.

The "how" is still pretty unclear. And keep in mind that these studies were all small and only including children, so it might not have the same effect on adults.

That said, ginseng supplements also have very few side effects, so if you wanna give it a shot, the risk is pretty low. Ginseng gets a three out of five from us.

The next supplement is one that you typically take as an adult. Folate, or vitamin B9, is involved in DNA synthesis and cell division, but it's better known for how important it is during pregnancy. Folate is key for building and developing a fetus's neural tube during the first trimester of pregnancy.

Our diet alone doesn't usually provide as much as we need during that crucial window, so folate supplements are recommended during pregnancy, and before pregnancy, and even if you simply can get pregnant at all. The neural tube forms so early in pregnancy that you might not even know you're pregnant yet, so in case of accidental pregnancy, it's still important for anyone that can become pregnant to have that folate.

And that's at least partly why a lot of women's multivitamins have a bit of extra B9 in them, too. So, in this case, we have literal decades' worth of studies about how important folate supplements are. In the last few years, there's been a lot of discussion about what form the folate should be in.

Key word here is bioavailability, or how much of a chemical actually gets to where it's going in your body. See, there's more than one kind of folate. There's the form that we find in our foods, and there's also a synthetic version called folic acid.

Your body can absorb both forms, but that doesn't mean that they are equally available. Folic acid is absorbed about two times better than natural folates, which sounds like it should be more bioavailable, but once you've soaked it in, that folic acid has to be converted into the active form that's actually used in the body, called 5-MTHF. And up to 40% of people have mutations to the gene that codes the enzyme responsible for that conversion, called the MTHFR gene.

So for people with a mutation, all that folic acid can build up in their blood and can't really go anywhere. Plus, they might still be deficient in the active form of folate, since it isn't turning into

what you need when you need it. Low bioavailability strikes again.

Usually, supplements have that synthetic folic acid version, since it's the most shelf-stable folate. For most people, that should get the job done. But some newer supplements let you skip the conversion steps altogether and just include 5-MTHF ready to go. There are some studies that show this form can be a good option for people with the MTHFR mutations.

As far as protecting against a neural tube defect, the evidence is clear: folate supplements are incredible important. So anyone who wants to get pregnant should definitely take them in some form, so we give them a five out of five. Just chat with your doctor about whether you might need a different form of the stuff.

Our last item on this list simply sounds like something I maybe should be putting on my pizza, not something that is a supplement, but there are plenty of people who think that oregano oil might be more than just a tasty treat. It is rich in phenols and flavonoids, which are both antioxidants.

And a double-blind study in humans showed oregano oil extracts failed to reduce oxidative stress, which is the thing that an antioxidant is supposed to do. There is some evidence that oregano oil has antioxidant potential, but so far, the studies that suggest that are on in vitro cell culture as well as various livestock, but nothing in actual living humans.

Also, the effects can vary based on the type of oregano used to make the oil and what parts of the plant are used as well. Plus, high concentrations of the stuff can be toxic, which means that you have to be careful about what oils you are using as supplements. We're not saying it's snake oil; we're saying it's oregano oil, and it's probably best for oregano to keep its day job seasoning food. One out of five.

When it comes to supplements, I think the biggest takeaway is that there is no one-size-fits-all super-pill. You should definitely talk to your doctor before taking anything on this list, even the five out of five best pills in the aisle. Health is complicated; the system that maintains you is extraordinarily complex.