This week we chatted with our co-founder, Steve, to talk about how molecular changes in your mid-40s and early 60s may be why you feel like you're getting older—and how to combat it. Since Steve has made it to the other side of 60, he’s the right person on our team to chat with about this.

If you’ve ever felt like your body is ageing in sudden, dramatic bursts, which Steve says he definitely experienced, you’re not alone. There’s actual science proving this is the case! New research from Stanford University suggests that ageing may not be the slow, steady process we often assume. Instead, it seems to come in "waves," with some of the most significant changes happening in two key age ranges. Any guesses? Yep, the mid-40s and early 60s.

This might explain why your metabolism suddenly feels sluggish, your skin starts to wrinkle faster, and you just don’t have the energy you used to. And at some points in life, this seems to happen overnight. Steve told us it’s like feeling the same for 10 years and then waking up one day feeling 5 years older somehow. But don’t worry—understanding the science behind these changes can help you take control and grow older with real vitality from the inside out. Here's what the research found and how Team Yeu believes you can make the most of it.

And if you’re reading this and still in your 30s, this is the perfect time to absorb this information! Equip yourself with a toolkit of tips to help you feel your best as you head into the next two decades.

Ageing in waves just means you need to learn how to surf

According to the study, researchers discovered that the body undergoes rapid shifts in the levels of key molecules and microbes in two major intervals: around age 44 and again around age 60. Michael Snyder, PhD, a professor of genetics at Stanford University and one of the researchers, explained, “We’re not just changing gradually over time; there are some really dramatic changes.”

In fact, when researchers studied over 135,000 molecules and microbes from participants’ blood samples, 81% of them didn’t follow a gradual, linear ageing pattern. Instead, most of these molecules changed drastically at two key points in life: mid-40s and early 60s. This suggests that many of the ageing processes we experience are more like sudden shifts than a steady progression.

What happens in your 40s

If you’re in your mid-40s, you might notice changes in how you metabolise food, handle stress, or recover from exercise. According to the research, these changes are largely driven by molecular shifts affecting your heart, skin, and muscles. For instance:

Metabolism slows down, meaning your body burns fewer calories at rest. This makes it easier to gain weight and harder to lose it.
Muscle mass decreases, which affects not only your strength and endurance but also your overall energy levels.
Your ability to process caffeine and alcohol declines, so you may notice that you’re more sensitive to that extra cup of coffee or glass of wine and a big night out with friends probably means you’re hanging on for dear life for 4 days afterwards. (If you were actually wondering who to thank for letting you party in your 20s and still get to work in a functioning state the next day, it’s your mitochondria!)

While some of these changes may seem frustrating, they’re also an opportunity to make adjustments. Prioritising regular exercise—especially strength training—can help counter muscle loss, while a balanced diet rich in whole foods can support your metabolism.

What happens in your 60s

Once you hit your early 60s, the body goes through another rapid phase of change, particularly in areas like immune health, oxidative stress, and organ function. According to the study, these changes affect:

Caffeine metabolism and how your body processes carbohydrates can make it harder to manage your weight or blood sugar levels.
Kidney and cardiovascular health increases your risk for conditions like high blood pressure or kidney disease.
Muscle and skin ageing leads to more visible signs of ageing like wrinkles and muscle weakness.

At this stage, maintaining a healthy lifestyle becomes even more critical. Focusing on regular movement—like walking, cycling, or swimming—can keep your heart strong and muscles engaged. Reducing alcohol consumption and incorporating more antioxidants into your diet can also help your body handle oxidative stress better.

We are so interested in the constant mention of caffeine throughout this study with part of our product promise for the future being that Yeu will deliver caffeine-free energy. This study gives a big nod to our hunch that excessive caffeine ain’t doin’ us much good as a crutch to feel energised as we grow older.

So what’s behind the waves of change?

One of the most interesting findings of the study is that these shifts are happening across the board, in both men and women. This suggests that while menopause and hormonal changes may play a role for women, there are broader molecular processes at play for everyone. That’s also why Yeu will be perfect for both the ladies and gents out there looking to maintain a true sense of vitality through these decades and beyond.

At the cellular level, many of these changes are tied to key mechanisms of ageing, such as:

Mitochondrial decline affects how your cells produce energy, leading to fatigue and slower recovery.
Telomere shortening accelerates cellular ageing and reduces the body’s ability to repair itself.
Increased oxidative stress damages cells and contributes to inflammation, one of the hallmarks of ageing.

These molecular changes also impact how your body responds to stress, alcohol, and even your diet. For example, if you’ve noticed that your tolerance for alcohol has decreased, it’s not just in your head—your body’s ability to metabolise it is actually changing on a molecular level.

Some gentle things we can all do

While you can’t stop the clock, you can slow it down by taking charge of your health. Here are some science-backed strategies to help you both prepare and get through these middle-life decades without losing your lust for life:

Strength training is one of the most effective ways to combat muscle loss and boost your metabolism. Aim for at least two sessions a week that target all major muscle groups.
Daily movement helps keep your heart healthy and combats the risk of chronic disease. Whether it’s walking, swimming, or simply stretching, staying active can help counter the effects of ageing.
As your metabolism slows, your body needs more protein to maintain muscle mass. Incorporate lean proteins like fish, chicken, and plant-based options into your meals to support muscle repair.
To fight oxidative stress and keep your metabolism humming, focus on whole foods rich in antioxidants—like berries, leafy greens, and nuts. Reducing processed foods and sugar can also help keep inflammation at bay.
As your body becomes less efficient at processing alcohol and caffeine, reducing your intake can help you feel better and protect your organs. Try swapping that extra cup of coffee for herbal tea, or enjoy alcohol-free alternatives during social gatherings.
Skincare isn’t just about aesthetics; it’s a reflection of your internal health. While we by no means encourage or even use fancy products, some antioxidants like vitamins C and E can help protect your skin from oxidative stress, while hydration and sunscreen keep it strong and supple. Even a good layer of standard face cream can do the job every evening.

Make the most of it!

Ageing doesn’t have to be something to fear. We stopped doing that a while ago, and that’s why Yeu is on team healthspan, not necessarily team lifespan. Armed with the knowledge of what’s happening on a molecular level, you can make informed choices to support your health and energy and take it all in your stride. The rapid changes that occur in your 40s and 60s are an opportunity to reassess and prioritise your well-being.

By staying active, eating well, and paying attention to your body’s needs, you can not only slow the effects of ageing but also feel empowered as you move into the next chapter of life. Time has a way of moving on whether we’re ready or not, and if Steve has a few wrinkles from laughing a lot and some stiffness in the morning as he gets ready to take our dogs out on a walk, it means he’s still here, has another day, and his cells are still kickin’ it for him after 40, 50, or 60 years, and he’ll opt for being grateful and making the most of it.

Your 40s and 60s are game changers