Fitness
Exercise Scientist Reveals His System for Ranking Muscle-Building Supplements
Dr. Eric Trexler, PhD – researcher, coach, and professional bodybuilder – recently appeared on the Renaissance Periodization podcast to share his evidence-based tier system for ranking muscle-building supplements. He emphasised that supplement rankings are goal-dependent, varying based on what you’re aiming to achieve with your training and supplementation.
Dr. Trexler then outlined his tiered approach specifically for those focused on gaining muscle and building strength, categorising supplements into five distinct tiers and providing examples of each along the way.
Tier-1 Supplements
‘Tier-1 basically means we have strong evidence. We know what this thing does, and what it does is good,’ says Dr. Trexler, who explains that for muscle-building, tier-1 supplements are in a class of their own. ‘It’s a short list – it’s creatine [assuming you’re not a non-responder] and it’s protein.’
Dr. Trexler caveats that protein supplements could be redundant if you’re able to get enough of the macronutrient from your diet. ‘If you’re eating enough from your food, who cares, forget it.’
Tier-2 Supplements
Dr. Trexler believes tier-2 supplements are the most interesting. ‘There is some evidence related to the supplement for the outcome we’re interested in, and it actually looks pretty good, but it’s not on tier-one because it has some shortcoming,’ he says. ‘Maybe the initial evidence is pretty good, but I’d like to see more of it before I get super stoked.’
He adds that in some cases, the evidence for a supplement may be very strong, but in the real world, its effects are small and inconsistent, or only work in people with deficiencies. ‘You can have a really solid evidence-based justification for this. However, you’re likely going to have to acknowledge this is a really marginal effect. Maybe this only matters for a competitive athlete.’
The supplements Dr. Trexler would include in tier-2 are: sodium bicarbonate, citrulline malate and nitric oxide supplements.
Controversially, Trexler says he would also put caffeine, one of the most heavily relied-on ergogenic aids in existence, into tier-2. ‘There are meta-analyses and umbrella reviews indicating it should have a positive effect on things like strength, strength endurance, and power. But caffeine is probably better for endurance sport than it is for resistance exercise.’
He does point out the potential dark side of becoming too reliant on the pre-workout shot of espresso. ‘We don’t know when you get to that point when you say, “I wouldn’t dare work out without my pre-workout.” Is that because it’s still giving you an ergogenic [performance-enhancing] effect? Or is it because caffeine withdrawal gives you an ergolytic effect and your performance sucks?’
(Ergolytic is science-talk for something that negatively impacts your performance.)
Tier-3 Supplements
‘Tier-3 is where the vast majority of supplements live’, Trexler says. ’It’s the tier where I tell someone I do not have enough evidence to say that there is a defensible use case for this but I also don’t have enough hard evidence to tell you there is no way this will work.’
So, if it’s not in any of the other tiers, with enough evidence for or against it’s use, consider it tier-3.
While Dr. Trexler doesn’t clearly define tier-3 supplements as he does with other tiers, examples might include Beta-alanine, which shows some promise for improving endurance but has inconsistent effects on muscle-building and strength, or Branched-chain amino acids (BCAAs). Once highly popular, recent research suggests their benefits are limited compared to complete proteins or essential amino acids, placing them in the tier-3 category.
Tier-4 Supplements
Dr. Trexler believes tier-4 is a tricky one – it’s the first category where we should consider actively swerving the compounds in question. ‘This is where we have evidence of a null effect. I can look at studies on it and say this is not going to achieve what you want it to achieve,’ says Dr. Trexler. His host, Dr. Mike Israetel, also an exercise scientist, offers a more concise and memorable definition: ‘It’s not hurting you; it just doesn’t do shit
When it comes to building strength and size, Trexler would include previously popular supplements like glutamine in tier-4. ‘For getting jacked and performing better, I think we’ve pretty much shut the book on glutamine.’
He’d also place arginine – an amino acid that was once popular in pre-workout mixtures and touted as a ‘pump enhancer’ – in tier-4, alongside some testosterone boosters and modern ‘new-and-improved’ creatines like ethyl ester and alkaline varieties, saying they don’t justify their cost when tier-1’s cheaply available creatine monohydrate is an option.
Tier-5 Supplements
Tier-5 is the group that Dr. Trexler strongly advises you avoid. ‘[These are] supplements where we have evidence that one of two things is going to happen – either this is going to literally harm your performance, or it is going to harm you.’
Trexler says he would include compounds like DMAA, a chemical extract previously included in now-banned pre-workout supplements such as the highly-memed JACK-3D. He jokes that although these compounds were widely available and not previously banned, the aim of manufacturers at the time seemed to be to get as close as possible to the effects of methamphetamine.
Another tier-5 chemical that was once the stimulant of choice for many bodybuilders is ephedrine. ‘It was the era of [high stimulant] pre-workouts. However, there were serious adverse events reported. I believe that there were a couple of deaths.’ Thankfully, sporting organisations and federations have helped to pave the way to a slightly safer supplement industry. ‘Once it’s banned by all the big federations, I say all right, we’re going to tier-5…’
With almost 18 years in the health and fitness space as a personal trainer, nutritionist, breath coach and writer, Andrew has spent nearly half of his life exploring how to help people improve their bodies and minds.
As our fitness editor he prides himself on keeping Men’s Health at the forefront of reliable, relatable and credible fitness information, whether that’s through writing and testing thousands of workouts each year, taking deep dives into the science behind muscle building and fat loss or exploring the psychology of performance and recovery.
Whilst constantly updating his knowledge base with seminars and courses, Andrew is a lover of the practical as much as the theory and regularly puts his training to the test tackling everything from Crossfit and strongman competitions, to ultra marathons, to multiple 24 hour workout stints and (extremely unofficial) world record attempts.
You can find Andrew on Instagram at @theandrew.tracey, or simply hold up a sign for ‘free pizza’ and wait for him to appear.
Fitness
How busy women can realistically hit 10 hours of exercise a week – and unlock the biggest health benefits
A huge new study published in the British Journal of Sports Medicine – which analysed the activity levels of more than 17,000 participants – suggests that to achieve a substantial (defined as greater than 30%) reduction in heart attack and stroke risk, adults should aim for 560–610 minutes of moderate-to-vigorous physical activity per week. That’s considerably more than the current 150-minute minimum guidelines for health benefits, so it’s perhaps unsurprising that only 12% of people in the study achieved it.
It’s not to say there wasn’t any reduction in risk for lower totals – just not what scientists class as ‘substantial’. And it’s also important to note that the study was observational, meaning it cannot prove any kind of direct link; just association. It could be the case, for instance, that participants were already healthier and fitter than the general population. Plus, neither sedentary time nor less vigorous exercise were measured.
When WH put the findings to personal trainers, they were very keen to stress that something is always better than nothing – and they also had some useful tips for giving it your best shot at getting those golden 10 hours in.
4 tips for adding more movement into your week
Olivia Horncastle is a personal trainer helping busy women and mums fit exercise into their schedules.
Habit stack
‘I get my busiest clients to habit stack movement – so every time they fill up a kettle, they might do some squats, when they brush their teeth, they might do a wall sit,’ says Horncastle. ‘Other small things like trying to take calls while walking, or stretching in front of the TV at night work well. It doesn’t need to always be adding a full workout – all small additions help.’
5-minute workouts matter
‘Even starting with a 5-minute bodyweight circuit and building that up over time starts a habit – something is always better than nothing.’
Set yourself daily or weekly challenges
That might be trying to do 50 squats throughout the day, increasing your steps by parking further away at the shops, or taking the stairs instead of the lift, says Horncastle.
Tie exercise into your social plans
‘Instead of drinks with friends, I might suggest we go for a walk and grab a drink at the end, or try a new Pilates class instead of brunch etc.’
What type of exercise should you prioritise?
Michael Baah is a strength coach and oncology exercise specialist working with busy professionals, athletes and people recovering from cancer. ‘All that protection for your heart works best if you maintain your muscle mass, too,’ he cautions. ‘If you walk a lot but never do any strength work, you actually lose muscle faster, and after age 30, women naturally lose about 1% of their muscle every year unless they use it.’
Baah recommends doing three 45-minute strength sessions a week, using simple, compound moves (think: squats and deadlifts) that work your whole body. ‘You should finish each exercise feeling like you could maybe do just one or two more reps – this is the safe and effective method we use in clinics.’
‘The rest of your target comes from walking,’ adds Baah. ‘Just 40-50 minutes of brisk walking every day gets you there easily. Add a swim, yoga or dance class once a week if you like, and you’re all set.’
But don’t forget to adequately fuel, notes Baah. ‘Once you’re moving regularly, food matters, too. You need enough protein every day to help your body get stronger – aim for 1.4-1.8g for every kg of bodyweight. Without this, you do the work but miss out on the best results.’
If you’re more deterred than motivated by the recent study results, Horncastle wants to leave you with a few words. ‘Start small and slow, whether that’s one workout a week and building up, or starting with a few small walks – that’s how you achieve long-term, consistent change.’
‘And don’t compare yourself – who cares if Susan does hot yoga five times a week? She isn’t living your life. You need to find what works for and benefits you, but is realistic, too.’
One of our most frequently asked questions here at Women’s Health? How to build muscle and burn fat at the same time. So, we asked superstar trainer Oyinda Okunowo exactly how to do it. In this 4-week plan – created exclusively for Women’s Health COLLECTIVE members – you’ll get the workouts and nutrition guidance needed to help you on your way to better body composition. Tap the link below to unlock 14 days of free access to Oyinda’s plan and start training today.
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Hannah Bradfield is a Senior Health and Fitness Writer for Women’s Health UK. An NCTJ-accredited journalist, Hannah graduated from Loughborough University with a BA in English and Sport Science and an MA in Media and Cultural Analysis. She has been covering sports, health and fitness for the last five years and has created content for outlets including BBC Sport, BBC Sounds, Runner’s World and Stylist. She especially enjoys interviewing those working within the community to improve access to sport, exercise and wellness. Hannah is a 2024 John Schofield Trust Fellow and was also named a 2022 Rising Star in Journalism by The Printing Charity. A keen runner, Hannah was firmly a sprinter growing up (also dabbling in long jump) but has since transitioned to longer-distance running. While 10K is her favoured race distance, she loves running or volunteering at parkrun every Saturday, followed, of course, by pastries. She’s always looking for fun new runs and races to do and brunch spots to try.
Fitness
The Best Fitness Trackers, According to Months of Real-World Testing
In the last few years, the fitness tracker market has grown exponentially. Now, you can find something for every taste, whether you prefer a discreet ring or a large screen, as well as for every personality, from the health metric-obsessed to the person who simply wants better sleep.
And in 2026, I tried many of the most popular devices on the market, from Apple, Oura, Garmin and more. Some days, I had a forearm-high stack of watches as I compared how they tracked my data for runs, strength training sessions, sleep and more. And I had some clear favorites.
Below, I’m sharing the top trackers that I tried last year, from screen-free options to the best pick for runners.
Best smart watches
Best affordable tracker:
If you’re looking for a fitness tracker that can give you all of the basics (and then some) at a relatively affordable price, the Fitbit Inspire 3 is one of the best devices out there, in my opinion. While it doesn’t have some of the bells and whistles that other gadgets offer, it really does quite a bit. Over the course of about a month of wear, I found the sleep, activity and general health data to be pretty accurate.
I also like that the device feels less bulky than many of the other trackers with screens that I have tried. The screen is 5 millimeters, which is just enough to show you the relevant stats during workouts, read notifications and texts and more without feeling like an eyesore on your wrist. However, that comes with the caveat that those with larger fingers may struggle with the small touchscreen.
To access all of your data, you’ll have to go to the app. It takes some playing around to figure out where to find everything, but once I did, it was easy to stay up to date on all my metrics. While you can access most of the basic data with just the app and watch, you’ll also get a six-month Fitbit Premium membership when you purchase, where you can see even more metrics and access additional workout videos as well.
Best for runners:
While I’ve tried a couple of Garmin’s devices and loved them all, for casual runners, the Garmin Forerunner 55 is a great entry point. That’s not to say you can’t use it for other activities. It allows you to log different activities and monitor sleep data, but I’ve found it to be the most helpful for running.
If you’re someone who regularly runs races, whether it be 10Ks or full marathons, you can find your race on the Garmin app and start a countdown and the app will even create a custom training plan for you with workouts that you can send to your device. I love the ability to create custom workouts with different pace and distance goals throughout your run (which is particularly great for anyone working on speed). If you’re running below or above your desired pace, the watch will send you an alert to keep you on track.
It has an impressive battery life of up to two weeks on a single charge, too, so I’ve been able to go on trips and leave the charger behind. In fact, on a 14-day trip, I got home and still had a day’s worth of charge left.
This is also the only device I tried without a touchscreen, which I really liked. That meant that I wasn’t fumbling with the buttons with sweaty hands on hot days or cold, gloved ones in the winter. The buttons are large enough that I could press them to pause or restart my workout, even when the watch was hidden by a jacket sleeve.
Best affordable Apple Watch:
The Apple Watch SE is the brand’s most affordable model, and I recommend it for the person who wants to stay connected, track workouts, monitor health and more, but doesn’t mind charging every day. (Though a big benefit of this new model is that it charges much faster than previous versions.)
New features include temperature sensing for more accurate vitals measurements, a daily sleep score to give you a better idea of how well-rested you are for the day, an always-on display and the ability to start workouts on your phone and track them on the watch.
Plus, if you have an iPhone, an Apple Watch is by far the best option out of all the available trackers for staying connected. You can easily respond to texts, check your email, use your Apple Wallet, answer calls and more. It makes functioning without a phone easy if I need to accomplish something without my phone nearby.
Best for iPhone users:
Lowest price ever
Apple released its Apple Watch 11 earlier this year, and for anyone questioning if they should make the upgrade, the new watch has one major perk: Extended battery life. According to the brand, you can get up to 24 hours of normal use from one charge, and I find that to be pretty accurate. But when you put it on low power mode (which I often do), you can get more than a day of use.
When looking at the other models, I would say the biggest draw of this one is that you get a much better battery life for just a little more money than the SE (considering that it’s on sale right now). Plus, like the other new models Apple released this year, the Series 11 includes the sleep score feature and can be used to spot signs of possible hypertension or high blood pressure.
I’ve also had issues with my Apple Watch screens scratching in the past, so I appreciate that the brand says this one is twice as scratch-resistant as the previous model.
Best for endurance athletes:
If it weren’t for the high price, I would recommend the Apple Watch Ultra to everyone. But for those who are active and willing to invest, I consider it to be the all-around best option among Apple’s watches.
The Ultra is designed specifically with athletes and adventurers in mind. It has the longest battery life of any of the Apple Watches, with up to 42 hours of battery life (and up to 72 hours on low power mode), so it will last through long races and backpacking trips — or even just a couple of days of going through your normal routine. It’s also designed to be much more durable than other models, as it has a titanium case and a display made from sapphire crystal (which Apple says is one of the strongest naturally occurring metals on Earth). It’s also said to have a better-than-average GPS, so your data won’t be as affected when running in urban areas where there are a lot of tall buildings.
Another thing that I really love about the Ultra is the additional Action button, which is customizable, so you can use it to control your workout, start a new interval or mark a segment. You can pause and end your workout using the buttons as well, so you don’t have to fumble with the touchscreen (which, if you have sweaty hands, you know is a big win).
If you spend a lot of time off the grid — say, trail running or climbing in remote areas — you can use the satellite feature to stay connected and send texts or your location, even if you don’t have WiFi or cell service. It can also be used to get help in case of an emergency.
Best screen-free trackers
Best for the data-obsessed:
If you’re a true wellness obsessive who loves data and seeing how behavior changes affect sleep, workouts and more, this is a great device to consider.
For each activity you do, you get an estimated strain score that tells you how taxing the activity was on your body (the score can range from zero to 21). These all factor into your strain score for the day, which includes everything from workouts to general daily movement, as well as stress and anxiety. After a night’s rest, you’ll also get a recovery score — a percentage between one and 100 — which factors in your activities and stress from the day before, your sleep performance, HRV, heart rate and respiratory rate. Each day, you also get the option to journal, so you can track behaviors, like stretching or taking supplements, and over time, you can track how the habits affect your recovery.
The Whoop provides you with a lot of interesting data, but it also has features to help you understand it better. It uses AI to create a daily outlook, which will give you activity recommendations based on your sleep and activity data. There’s also a Healthspan feature, which takes your data (after 21 consistent nights of wear) and gives you your Whoop Age (a measure of your physiological age, which can be different from your actual age) and Pace of Aging (which is impacted by your daily lifestyle choices and can range from -1x to 3).
The battery life is also pretty hard to beat. The brand shares that you can get up to 14 days, and I’ve found that estimate to be pretty accurate. In fact, I’ve even occasionally gotten more than two weeks of use out of it from one charge. To charge the Whoop, you charge its battery pack separately and then can slide it onto the device while you’re still wearing it to add juice, so you don’t even have to miss a minute of data.
As someone who is super interested in using data to optimize health, I love the Whoop. However, as a runner who spends a lot of time focused on proper pacing during workouts, for those activities, I also typically wear a device with a screen, like my Garmin or Apple Watch, to make sure I’m meeting my goals.
When you purchase using one of the above links, you’ll get a year-long membership. After that, you can choose from one of Whoop’s three membership options: One ($149 per year), Peak ($239 per year) or Life ($359 per year).
The most discreet fitness tracker:
Editor’s pick
The Oura Ring has become one of the most trendy trackers of the last few years, thanks to its discreet — and I would even say, stylish — design. The ring features sensors along the inner band, which measure things like blood oxygen levels, temperature, respiration, heart rate variability and more.
In my opinion, one of the best things about the Oura ring (outside of its look) is how simply it breaks down the data. Each morning, it takes your data from the night and day before, and gives you three scores: Sleep, Activity and Readiness, all of which fall between zero and 100. Each one provides you with a broader view of how well rested you are for the day and how ready you are to challenge yourself.
If you’re in it for the workout tracking aspect, this is not the best option. Aside from the fact that it doesn’t have a screen (so you can’t actively see your stats while you’re in a workout), it doesn’t always sense lower-intensity workouts, like yoga or Pilates, so you often have to go into the app and add them after. Plus, in addition to the cost of the ring, accessing your data and all the features on the app costs $6 per month.
How we chose
Last year, I tried over a dozen fitness trackers, wearing them each for at least a week straight (most of the time much longer) for workouts, sleep and everyday activities. Throughout the year, I trained for multiple races, including a marathon and two half marathons, so I used many of the trackers for workouts related to my training. When choosing the best trackers, I kept in mind a range of factors, including price, battery life, connectivity and general features.
Why trust Shop TODAY?
The Shop TODAY editors and writers search the internet to find the best products out there. We interview expert sources and use our own personal experiences with the product and brand to make shopping easier for our readers.
Emma Stessman is a writer for Shop TODAY. She has over a decade of experience in digital media — with nearly half of that time being focused on the health and wellness space. She has owned multiple fitness trackers from top brands over the years. At Shop TODAY she covers a range of topics, from new tech releases to expert-approved beauty trends. She is an avid runner and fitness enthusiast with a personal passion for health.
Fitness
The 150-minute Exercise Rule Helps Your Heart. But If You’re Serious About It, Better Aim for 600 Minutes
Public health advice says you should get at least 150 minutes of brisk walking, cycling, running or other moderate-to-vigorous exercise each week.
However, a new study suggests that the target is just the bare minimum.
The widely cited 150-minute goal is not wrong. The new study found it offers a reliable first layer of protection against heart disease. But for people seeking a much larger reduction in cardiovascular risk, the amount of exercise associated with that benefit was far higher: roughly 560 to 610 minutes a week, or about 80 to 90 minutes a day.
A Minimum, Not a Magic Number
The study analyzed more than 17,000 adults in the UK Biobank who wore wrist activity monitors and completed a fitness test. Over nearly eight years of follow-up, researchers tracked heart attacks, strokes, heart failure and atrial fibrillation.
They found that meeting the current guideline was linked to a modest 8 to 9 percent reduction in cardiovascular risk across fitness levels. A reduction greater than 30 percent was associated with about three to four times as much weekly exercise.
The findings do not mean that 150 minutes a week is useless — quite the opposite. The study suggests it works as a simple public health floor, one that benefits people regardless of whether they start out fit or deconditioned.
But the results also challenge the way many people understand the guideline. The number is often treated as a target to reach and stop at.
The researchers studied moderate-to-vigorous physical activity, a category that includes exercise intense enough to raise the heart rate, such as brisk walking, running and cycling. They also measured cardiorespiratory fitness using estimated VO₂ max, a measure of how efficiently the heart, lungs and muscles deliver and use oxygen during exertion.
This is a pretty important distinction. Fitness and physical activity are of course related, but they are not the same thing. Two people may report similar exercise habits and still differ in cardiovascular fitness because of genetics, age, health history, training response or earlier-life conditioning.
“Future guidelines may need to differentiate between the minimal moderate to vigorous exercise volume required for a basic safety margin and the substantially higher volumes necessary for optimal cardiovascular risk reduction,” they conclude.
Less Fit People Faced a Steeper Climb


Participants wore an accelerometer for seven consecutive days between 2013 and 2015. They also completed a submaximal cycling test used to estimate VO₂ max. The researchers then linked these data to hospital and death records through October 2022.
During a median follow-up of 7.85 years, 1,233 cardiovascular events occurred. These included 874 cases of atrial fibrillation, 156 heart attacks, 111 cases of heart failure and 92 strokes.
The pattern was not simply “more exercise is better” in a straight line. Instead, the researchers found a non-linear relationship between activity, fitness and risk. Higher fitness appeared to provide its own protective margin. At the same time, increasing weekly activity lowered risk across the fitness spectrum.
For a 20 percent reduction in cardiovascular risk, people with the lowest fitness needed about 370 minutes of moderate-to-vigorous activity per week. People with the highest fitness needed about 340 minutes. For a 30 percent reduction, the estimates rose to about 610 minutes per week for the least fit and 560 minutes for the most fit.
You might not like to hear this, but if you’re already unfit, you need to invest much more time and effort than someone who is fitter to reach the same cardiovascular protection. If that sounds like common sense, it is. But the new study is helpful because the figures it offers help frame things more clearly and offer a measurable goal.
Set Achievable Goals
The study was observational, so it cannot prove that exercising 600 minutes a week caused the lower risk. People who exercise more may differ in other ways, such as diet, income, sleep, access to care, smoking history or underlying health.
Also, not everyone can afford to exercise for 10 hours a week. In fact, most don’t. For older adults, people with heart disease, or those who have been inactive for years, that could be unrealistic or unsafe without medical guidance.
For broad public health, 150 minutes a week remains a useful and achievable goal. But if you can safely do more, the heart may keep benefiting well beyond that threshold.
The findings appeared in the British Journal of Sports Medicine.
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