Normal vs optimal: What your biomarkers are really telling you

Our bodies constantly send signals through subtle shifts—like fatigue, poor sleep, skin changes, and low energy. These meaningful clues reveal what’s happening beneath the surface. One powerful way to understand these signals is through blood work.

At Coral, we go beyond sex hormone testing. While measuring estrogen, progesterone, and testosterone helps establish a baseline, these values alone don’t paint the full picture. Many other systems in the body—like the thyroid, liver, and adrenals—play a crucial role in how you feel. When they’re out of balance, they can create symptoms that mimic perimenopause or menopause, such as hot flashes, sleep troubles, and mood changes. That’s why we look at a full panel to understand how your organs are functioning and where deeper imbalances may lie.

Fixing sex hormones alone, even with menopausal hormone therapy (MHT), won’t resolve issues that originate elsewhere. True relief and lasting health come from understanding the whole system and supporting it as a connected network.

We’re often reassured when our lab results fall “within the normal range,” but to truly make sense of those numbers, it’s important to ask: What does normal really mean? Traditional reference ranges are based on averages from large populations and are designed to detect disease—they don’t necessarily reflect what’s optimal for your unique health. That’s why Coral focuses on identifying optimal ranges: values linked to feeling your best, lowering disease risk, and supporting long-term vitality for your unique body.

Rethinking lab results this way is key to a more personalized, proactive approach to health—especially when you don’t feel well despite “normal” labs. Let’s take a closer look at what’s measured in your blood, how ranges are determined, and explore a well-studied example to bring this concept to life.

What are biomarkers?

Biomarkers are measurable indicators found in blood, urine, and other tissues that offer a powerful glimpse into our inner health landscape. These biological clues play a central role across the full spectrum of care: preventing disease, making a diagnosis, guiding treatment decisions, tracking progress, and even predicting future health risks. They represent everything from blood pressure and body temperature to hormone and cholesterol levels.

Since many chronic conditions develop silently over time, tracking biomarkers offers a kind of early warning system. They help us tune in to what our bodies are saying, before symptoms are even felt.

What are optimal vs reference (or “normal”) ranges?

When you get a lab test, you receive a measurement of a specific biomarker, like blood sugar or cholesterol. This number is then compared to a reference range, a window of values considered typical for a “healthy” population. If your result falls outside this range, it may suggest a potential health concern. But even results that fall within the normal range may not reflect your body’s optimal state, especially if you’re experiencing symptoms or have specific risk factors.

How are reference ranges determined?

Ideally, reference ranges are created by testing at least 120 healthy people using the same method. The results are then sorted, and the middle 95% is considered the “normal range.” This means that even among healthy individuals, about 5% will naturally fall outside that range. That’s why it’s so important to interpret lab results in the full context of your health: your symptoms, history, and how you feel. An “abnormal” result doesn’t always mean something is wrong.

These ranges should ideally be tailored to age, sex, and ethnicity. But in reality, few reference ranges are established this way. Due to time, cost, and logistical barriers, many labs rely on textbooks, historical standards, and information from laboratory equipment and reagent manufacturers.

Why reference ranges may fall short?

Many early reference groups were mainly men, so results may not fully reflect women’s biology and health needs. It wasn’t until 1993 that including women and minorities in clinical trials became a requirement, and only in 2015 did the NIH establish a policy on Sex as a Biological Variable, requiring researchers to incorporate sex as a factor in research design and analysis. Inclusive representation by sex, age, ethnicity, and lifestyle leads to better, more personalized care. Thankfully, research today is committed to exploring these differences.

In addition, even “healthy” reference groups may include individuals with undiagnosed disease, poor lifestyle habits, or early-stage health issues, skewing the reference range toward suboptimal health rather than optimal function.

Enter optimal ranges

Personalized medicine is evolving, with optimal ranges at the forefront. These narrower windows within traditional reference ranges better reflect what supports energy, resilience, symptom relief, and long-term health. Because “normal” varies by age, sex, life stage, lifestyle, and health goals. Especially through phases like puberty, pregnancy, and menopause, optimal ranges provide a more precise guide.

Grounded in research and clinical experience, optimal ranges bridge the gap between raw lab data and real-life health. They require interpreting results in context: considering symptoms, trends, and multiple biomarkers together. Ultimately, this approach empowers people to act early, preventing disease and striving for true well-being.

We can now look at many of our biomarker levels from a new perspective, and categorize them using this scale:

• High – Above the reference range; may indicate excess

• Low – Below the reference range; may indicate deficiency

• Below Optimal – In range but lower than ideal for health

• Optimal – Ideal range for health

• Above Optimal – In range but higher than ideal for health

Let’s take fasting insulin for example

What it is:

Fasting insulin is the amount of insulin circulating in your blood after several hours without eating, typically measured in the morning before breakfast. Insulin is a vital hormone that acts like a “key” to allow glucose (from food) to enter your cells for energy or storage, thus reducing your blood sugar levels. Insulin can also influence fat storage, protein metabolism, and overall energy balance.

Why it matters:

Fasting insulin is a powerful early indicator of insulin resistance, even before blood sugar levels become abnormal. Insulin resistance happens when your cells become less responsive to insulin, so your body has to produce more of it to keep blood sugar levels in check. This elevated insulin worsens insulin resistance, perpetuating a brutal cycle. 

People who are more insulin sensitive need less insulin to keep blood glucose in a health range. This contributes to a reduced risk of insulin resistance, a positive stride toward avoiding type 2 diabetes, heart disease, and other chronic conditions.

What’s considered normal vs optimal:

Medscape, a respected clinical resource, lists the fasting insulin reference range as = 150 pmol/L. This is a wide range, and many metabolic health experts believe this range is too high. 

In current research and clinical practice, there is not yet a concrete consensus on what optimal fasting insulin levels are, but studies suggest that keeping levels close to 50 pmol/L align best with feeling truly healthy. 

Taken together, these findings suggest that while lab-defined “normal” ranges for fasting insulin may extend up to 25 µIU/mL, truly optimal levels for long-term metabolic health appear to be much lower.  For most people, maintaining fasting insulin levels 15 to 50 pmol/L may offer the greatest protection against chronic disease.

Coral’s approach

At Coral, we prioritize going beyond “normal” ranges for biomarkers with robust research support. We help you understand your results in context: considering your symptoms, life stage, goals, and trends over time. This shift from reactive to proactive care empowers you to take action before disease develops and move toward a higher standard of well-being.

Disclaimer: The information provided here is for informational purposes only. It is not intended as medical advice. Always consult with your doctor or healthcare provider to determine what is best for your individual health needs.

References:

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