Total Cholesterol 133 mg/dL: Is That Low?

Is Total Cholesterol 133 mg/dL Low, Normal, or High?

Total cholesterol 133 mg/dL is considered low based on standard clinical reference ranges. Most health organizations, including the American Heart Association and the National Heart, Lung, and Blood Institute, define desirable total cholesterol as under 200 mg/dL. While being well below that threshold might sound like great news, a reading of 133 mg/dL is unusually low and may warrant a closer look. Your doctor will want to understand why your cholesterol is this low, especially if it has dropped significantly from previous readings. Low total cholesterol is not automatically a problem, but it is worth exploring the full picture behind the number.

A total cholesterol reading of 133 mg/dL sits noticeably below the healthy reference range of 150-199 mg/dL, clinically indicating a low cholesterol level that warrants attention. While cholesterol is often viewed solely as a risk factor when high, a value like 133 mg/dL, which is 11% below the lower normal limit, can signal an underlying health condition rather than simply excellent lifestyle choices. At this specific level, common considerations include malabsorption issues, where the body struggles to absorb fats and nutrients, potentially linked to gastrointestinal disorders, or an overactive thyroid gland (hyperthyroidism) accelerating the body's metabolism and cholesterol breakdown. Impaired liver function, affecting the organ responsible for cholesterol production, is also a key area of investigation. To thoroughly understand this result, your doctor will typically recommend a more comprehensive lipid panel, assessing HDL and LDL fractions, along with blood tests for liver enzymes and thyroid stimulating hormone. A detail often overlooked by patients is the critical role cholesterol plays in the body beyond heart disease; it's vital for cell membrane structure, hormone production, and vitamin D synthesis. Experiencing a low cholesterol concern can be surprising given the pervasive focus on high cholesterol, but this finding underscores the importance of a finely tuned bodily balance for overall health.

Hidden Risk of Total Cholesterol 133 mg/dL

A total cholesterol of 133 mg/dL often gets overlooked because most conversations about cholesterol focus on high readings. But very low cholesterol carries its own set of concerns that are less commonly discussed. Research from the National Institutes of Health has explored links between very low cholesterol and certain health outcomes that deserve attention.

A total cholesterol level of 133 mg/dL, while seemingly beneficial, can signal underlying issues. Significantly low cholesterol in this range, 11% below the lower limit of normal, might be associated with increased risk of hemorrhagic stroke, particularly in older adults, due to compromised blood vessel integrity. It can also be linked to malnutrition, severe liver or kidney disease, and an overactive thyroid (hyperthyroidism), where the body breaks down substances too rapidly. In some cases, critically low cholesterol can impact hormone production and nutrient absorption, potentially leading to fatigue, mood disturbances, and difficulties with vitamin D synthesis.

• Some studies have found associations between very low total cholesterol and increased risk of hemorrhagic stroke, though the connection is still being researched
• Cholesterol plays a critical role in hormone production, cell membrane structure, and vitamin D synthesis. Very low levels may affect these processes
• Low cholesterol can sometimes be a sign of an underlying condition such as hyperthyroidism, liver disease, malnutrition, or malabsorption issues
• Certain medications, chronic infections, or severe illness can push total cholesterol unusually low as a secondary effect
• Mental health research has explored potential links between very low cholesterol and mood changes, though findings remain mixed and no firm conclusions have been drawn

What Does a Total Cholesterol Level of 133 mg/dL Mean?

Total cholesterol is a combined measurement of several types of cholesterol and fats in your blood. The basic formula is: total cholesterol equals LDL cholesterol plus HDL cholesterol plus 20 percent of your triglycerides. So when you see a total cholesterol number, it reflects multiple components working together rather than a single type of fat.

For a total cholesterol reading of 133 mg/dL, the most probable causes often involve significant dietary changes or underlying medical conditions. A very low-fat diet, especially one that severely restricts essential fatty acids, could contribute to this level. Malabsorption issues, such as those seen in celiac disease or inflammatory bowel disease, impairing the body's ability to absorb fats and cholesterol, are also strong contenders. Certain medications, particularly those used for hyperlipidemia or hormone replacement therapy, when combined with other factors, can drive cholesterol down this far. Less commonly, severe infections or chronic inflammatory states can temporarily lower cholesterol.

Your body needs cholesterol. It is not simply a harmful substance. Cholesterol is essential for building and maintaining cell walls, producing hormones like estrogen and testosterone, creating bile acids that help you digest food, and synthesizing vitamin D. Every cell in your body uses cholesterol as part of its structure.

At 133 mg/dL, your total cholesterol is significantly below the desirable range of 150 to 199 mg/dL. For some people, this is simply their natural baseline driven by genetics, diet, and lifestyle. For others, it could signal that something else is going on. Your doctor will want to look at each component of the lipid panel individually. For example, if your HDL (the protective cholesterol) is very low, even a low total number might not be as reassuring as it first appears.

It is also important to understand that cholesterol levels are just one factor in overall health. A reading of 133 mg/dL does not tell the full story on its own. Your doctor will interpret it alongside your other lab results, medical history, and lifestyle factors to form a complete assessment.

Lifestyle Changes for Total Cholesterol 133 mg/dL

If your total cholesterol is 133 mg/dL and your doctor has ruled out underlying conditions, the focus shifts to making sure your body is functioning well overall. Regular physical activity supports healthy cholesterol balance. The American Heart Association recommends at least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking, swimming, or cycling. Exercise tends to raise HDL cholesterol, which is especially important when total cholesterol is on the low side.

If your total cholesterol is 133 mg/dL, immediate steps should focus on understanding the 'why'. Schedule a follow-up with your primary care provider to discuss your recent diet, any new medications, and your overall health history; they may order further tests to assess liver function, thyroid status, and nutrient levels. Consider a detailed dietary review with a registered dietitian, focusing on adequate intake of healthy fats and caloric density. Track any new symptoms like fatigue, weight loss, or mood changes, and be prepared to discuss these at your next appointment. A repeat lipid panel in 1-3 months may be recommended.

Maintaining a healthy weight is another key factor. Being significantly underweight can contribute to low cholesterol levels. If weight loss has been unintentional, it is worth mentioning to your healthcare provider. Sustainable body weight management supports stable cholesterol production.

Sleep quality also plays a role in cholesterol regulation. Research suggests that chronic sleep deprivation can alter lipid metabolism. Aiming for seven to nine hours of quality sleep per night supports your body's natural processes, including cholesterol production and balance.

Stress management matters as well. Chronic stress affects your hormonal balance, and since cholesterol is a building block for hormones, prolonged stress may influence your lipid profile in subtle ways. Finding consistent ways to manage stress, whether through exercise, spending time in nature, or simply resting, contributes to overall cardiovascular and metabolic health.

Written by

Ernestas K.

Clinical research writer specializing in human health, biology, and preventive medicine.

Reviewed against AHA, NIH, ACC, Mayo Clinic, PubMed guidelines · Last reviewed March 20, 2026