Cholesterol Levels By Age: What's Normal and What's Actually Happening

Right then. You've had your cholesterol tested, you've been handed a piece of paper with numbers on it, and now you're sitting at home wondering if you're fine or if you should be panic-eating oats. Welcome to the club.

Here's the thing nobody tells you: your cholesterol at 25 should look nothing like your cholesterol at 55. And yet, we're often given the same target ranges regardless of whether we're fresh out of university or collecting our bus pass. Bit odd, that.

So let's talk about what's actually normal at different ages, why your numbers shift over time, and when you should pay attention versus when you can just carry on with your Tuesday.

First Things First: What Are We Even Measuring?

Before we dive into ages, let's get clear on what your cholesterol results actually include. According to HEART UK (the UK's cholesterol charity, and frankly, they know their stuff), a proper cholesterol test should give you five key numbers:

• Total cholesterol (TC): The headline figure everyone fixates on
• HDL cholesterol: The "good" stuff that clears cholesterol from your arteries
• Non-HDL cholesterol: All the "bad" types lumped together (mainly LDL)
• LDL cholesterol: The one that can clog your arteries if levels get too high
• TC:HDL ratio: The relationship between your total and HDL cholesterol

You should also get your triglycerides tested. They're blood fats linked to heart disease, and they matter just as much as cholesterol. If your GP only gave you your total cholesterol, you're entitled to ask for the full breakdown. It's a bit like being given a football score without knowing which team won.

The "Healthy Adult" Ranges (AKA The Baseline)

HEART UK provides these general guidelines for healthy UK adults. These are the targets if you don't have cardiovascular disease and aren't at particularly high risk:

Notice that women have a higher HDL target? That's not arbitrary. Women naturally have higher HDL levels than men due to genetic differences. Oestrogen gives women a cardiovascular advantage, at least until menopause arrives and changes the game entirely (more on that shortly).

Your Cholesterol Journey Through The Decades

In Your 20s: The Baseline Years

If you're in your twenties and getting your cholesterol tested, you're either unusually health-conscious or there's a family history that's prompted your GP to have a look. Either way, well done for being here.

In your twenties, your cholesterol should generally be at its lowest and most stable. Most people sit comfortably within the healthy ranges without much effort. Your liver is efficient, your hormones are doing their thing, and unless you're living entirely on meal deals, your body tends to regulate cholesterol quite well.

What's typical: Total cholesterol around 3.5 to 4.5 mmol/L, with good HDL levels and low LDL. If your numbers are significantly higher than the healthy ranges at this age, it's worth investigating. Familial hypercholesterolaemia (FH) is a genetic condition that causes high cholesterol from birth, and it affects about 1 in 250 people in the UK.

What to watch: Establishing good habits now matters more than your actual numbers. The lifestyle patterns you set in your twenties tend to stick around, for better or worse.

In Your 30s: The First Creep Upwards

Welcome to the decade where your cholesterol starts quietly rising, even if you're doing everything "right." It's not personal. It's biology.

As you age, your liver becomes slightly less efficient at clearing LDL cholesterol from your bloodstream. Meanwhile, lifestyle factors start accumulating: maybe you're more sedentary than you were at 22, stress levels are higher, sleep is worse (especially if small humans have entered your life), and your metabolism isn't quite as forgiving as it once was.

What's typical: Total cholesterol creeping from the low 4s into the mid-to-high 4s (mmol/L). This is normal. If you're still below 5.0 mmol/L and your HDL is healthy, you're doing fine.

What to watch: The rate of change matters more than the absolute numbers. A sudden jump warrants attention. A gradual rise? That's just being thirty-something.

In Your 40s: Where Things Get Interesting

The forties are when cholesterol patterns start diverging sharply between men and women, and when "normal" becomes a more complicated concept.

For women: If you're approaching perimenopause (which can start in your early-to-mid forties), your cholesterol may start shifting upwards. Oestrogen helps keep LDL low and HDL high. As oestrogen levels begin fluctuating and eventually declining, those protective effects fade. It's common to see total cholesterol rise by 10-20% during this transition.

For men: Your cholesterol has likely been gradually rising since your thirties, and by your forties, it's not unusual to see total cholesterol in the 5.0 to 5.5 mmol/L range. Testosterone levels start declining (about 1% per year after age 30), which can affect how your body handles cholesterol.

What's typical: Total cholesterol between 4.8 and 5.5 mmol/L. Many perfectly healthy people in their forties sit just above the "below 5.0" guideline. This doesn't automatically mean you need treatment, especially if your HDL is good and your non-HDL cholesterol is reasonable.

What to watch: Your TC:HDL ratio becomes more important than total cholesterol alone. HEART UK notes this ratio is used for risk assessment calculators like QRISK3. A ratio below 4.5 is generally considered lower risk, even if your total cholesterol is slightly elevated.

In Your 50s: The Menopause Effect and Beyond

For women, the fifties often bring the most dramatic cholesterol changes. Post-menopause, it's entirely normal (and common) to see LDL cholesterol rise by 10-20 mg/dL (roughly 0.25-0.5 mmol/L) and HDL cholesterol dip slightly.

This is why many women who sailed through their thirties and forties with perfect cholesterol suddenly find themselves with elevated levels in their fifties. You haven't done anything wrong. Your hormones have just changed the rules of the game.

For men, cholesterol tends to plateau or even decline slightly after age 55-60. Why? Not entirely clear, but it's a recognised pattern.

What's typical: Total cholesterol between 5.0 and 6.0 mmol/L is increasingly common and not necessarily cause for alarm if other factors (blood pressure, weight, family history, smoking status) are favourable.

What to watch: This is the decade where your GP will likely calculate your 10-year cardiovascular risk using QRISK3. This tool looks at multiple factors (age, cholesterol, blood pressure, smoking, family history, ethnicity) to estimate your actual risk of heart disease or stroke. Two people with identical cholesterol levels can have very different risk scores based on these other factors.

60s and Beyond: Population Averages vs Individual Health

Here's something that might surprise you: among people over 60, the relationship between cholesterol levels and cardiovascular risk becomes less straightforward. Some research suggests that very low cholesterol in older adults may actually be associated with worse health outcomes, possibly because chronic illness and frailty can lower cholesterol.

This doesn't mean high cholesterol is suddenly good for you. It means context matters enormously, and comparing your numbers to population-wide guidelines becomes less useful.

What's typical: Total cholesterol often ranges from 5.0 to 6.5 mmol/L. Many healthy older adults sit above the "below 5.0" target.

What matters more: Your overall cardiovascular health, whether you already have heart disease (which changes treatment targets significantly), and whether your cholesterol is stable or rising rapidly. Your GP should be taking a holistic view rather than focusing solely on cholesterol numbers.

Why "Normal" Doesn't Always Mean "Optimal"

Here's the tricky bit: the "healthy adult" ranges provided by HEART UK are based on what's ideal for reducing cardiovascular risk in the general population. But if you already have cardiovascular disease (you've had a heart attack, stroke, or have peripheral arterial disease), your targets are much stricter.

For people with existing cardiovascular disease (what's called "secondary prevention"), HEART UK and national guidelines recommend:

• Non-HDL cholesterol: 2.6 mmol/L or below
• LDL cholesterol: 2.0 mmol/L or below

Notice how much lower those targets are? That's because if you've already had a cardiovascular event, preventing another one becomes the priority, and evidence shows that lower is genuinely better in this context.

For primary prevention (you don't have cardiovascular disease but may be at higher risk), guidelines recommend reducing non-HDL cholesterol by more than 40%. This is where your GP will use risk calculators to work out whether treatment is warranted.

The TC:HDL Ratio: Why It Matters More Than You'd Think

Your TC:HDL ratio divides your total cholesterol by your HDL cholesterol. It's used in risk assessment tools because it captures the balance between "good" and "bad" cholesterol more effectively than total cholesterol alone.

Here's why it's useful: you could have a total cholesterol of 6.0 mmol/L (which sounds concerning) but if your HDL is 2.0 mmol/L (which is excellent), your ratio would be 3.0 (which is very good). Conversely, you could have a total cholesterol of 4.5 mmol/L (which sounds fine) but if your HDL is only 0.9 mmol/L (which is low), your ratio would be 5.0 (which suggests higher risk).

That said, HEART UK cautions that this ratio should be interpreted carefully. A reassuringly normal ratio might mask high non-HDL and LDL cholesterol if your HDL happens to be very high. This is why you need to look at all the numbers together, not fixate on any single one.

When Age-Related Changes Warrant Action

So your cholesterol has crept up with age. When should you actually do something about it?

Act sooner if:

• Your LDL or non-HDL cholesterol is significantly above target ranges
• You have other cardiovascular risk factors (high blood pressure, smoking, diabetes, strong family history)
• Your cholesterol has risen sharply rather than gradually
• Your HDL cholesterol is low (below 1.0 mmol/L for men, below 1.2 mmol/L for women)
• Your triglycerides are elevated alongside low HDL (this combination is particularly concerning)

Less urgent if:

• Your rise is gradual and consistent with your age
• Your HDL cholesterol is healthy
• You have no other cardiovascular risk factors
• Your TC:HDL ratio is favourable
• Your QRISK3 score (if calculated) is low

Your GP should be calculating your cardiovascular risk, not just handing you a cholesterol number and leaving you to worry about it. If they haven't discussed your overall risk with you, ask them to. It makes a significant difference to whether treatment is recommended.

What You Can Actually Do About It

Right. So your cholesterol is higher than it was a decade ago, or it's crept above the ideal range. What now?

The good news is that for most people, especially in the context of age-related rises, dietary and lifestyle approaches can make a meaningful difference. We're firm believers in a food-first approach at Oat of Allegiance (we're currently developing products that support heart health through nutrition), and the evidence backs this up.

Evidence-based dietary approaches:

• Oat beta-glucan: The GB Nutrition and Health Claims (NHC) Register recognises that beta-glucan contributes to the maintenance of normal blood cholesterol levels. The beneficial effect is obtained with a daily intake of 3g of oat beta-glucan. It's a soluble fibre that binds to cholesterol in your digestive system, reducing absorption.
• Plant sterols and plant stanol esters: Another authorised health claim on the GB NHC Register. Plant sterols and plant stanol esters have been shown to lower blood cholesterol. Blood cholesterol lowering may reduce the risk of coronary heart disease. The beneficial effect is obtained with a daily intake of 1.5-2.4g of plant sterols/plant stanol esters. Plant sterols block cholesterol absorption in your gut by competing for the same uptake pathway.
• Replacing saturated fats: Swapping saturated fats for unsaturated fats (think olive oil instead of butter, nuts instead of crisps) has consistent evidence for lowering LDL cholesterol. The GB NHC Register confirms that replacing saturated fats with unsaturated fats in the diet has been shown to lower blood cholesterol, and high cholesterol is a risk factor in the development of coronary heart disease.

These aren't magic bullets. They work best as part of an overall healthy eating pattern, alongside staying active, managing stress, sleeping adequately, and not smoking. But they're backed by proper clinical evidence, which is why they're approved for health claims on food labels in Great Britain.

For some people, particularly those at higher cardiovascular risk or with existing heart disease, medication may be appropriate alongside dietary changes. That's a conversation to have with your GP, and there's no shame in it. The goal is reducing your risk, not achieving the perfect numbers through sheer force of will.

The Bottom Line

Your cholesterol at 55 should not be judged by the same standards as your cholesterol at 25. Age-related changes are normal, expected, and don't automatically mean you're heading for trouble.

What matters is context: your other risk factors, your family history, your overall health, and the trajectory of change. A total cholesterol of 5.5 mmol/L might be perfectly fine for one person and a cause for intervention in another. This is why those risk calculators exist and why your GP should be taking a holistic view.

If your numbers are rising with age, it's worth paying attention and making dietary improvements where you can. But it's not worth losing sleep over if everything else is favourable. Work with your GP, get your full lipid profile tested (not just total cholesterol), and understand your actual cardiovascular risk rather than fixating on a single number.

And if you're sat there comparing your cholesterol to your friend's or your partner's or some general guideline you found online, stop. Their age, hormones, genetics, and risk factors are different from yours. Your cholesterol is your cholesterol. Judge it in context, not in comparison.