LDL Cholesterol 37 mg/dL: Is That Low?

LDL cholesterol of 37 mg/dL (1.0 mmol/L) is very low on standard clinical reference ranges. Optimal LDL is under 100 mg/dL (2.6 mmol/L). Source: NHLBI, American Heart Association.

Is LDL Cholesterol 37 mg/dL Low, Normal, or High?

LDL cholesterol 37 mg/dL is considered very low. While lower LDL cholesterol is generally associated with reduced cardiovascular risk, values below 50 mg/dL are uncommon and may warrant a closer look. The American Heart Association considers optimal LDL to be below 100 mg/dL, but readings this far below the range can sometimes be linked to medications, genetic factors, or underlying health conditions. Your doctor can help determine whether this result is a positive sign or something to investigate further.

An LDL cholesterol level of 37 mg/dL is notably low, falling significantly below the typical reference range of 50-99 mg/dL and signaling a condition known as hypobetalipoproteinemia, which warrants careful investigation rather than celebration. While low LDL is generally considered beneficial for cardiovascular health, such extremely reduced levels can indicate an underlying issue with the body's cholesterol production, absorption, or metabolism. Common causes for a value this low include primary genetic conditions, such as familial hypobetalipoproteinemia, which impacts the liver's ability to produce apoB-containing lipoproteins, or secondary factors like severe malabsorption disorders (e.g., celiac disease or inflammatory bowel disease), advanced liver disease, or an overactive thyroid. Following this finding, your healthcare provider will typically recommend repeat testing to confirm the level, along with additional blood work to assess liver function, thyroid hormone levels, and potentially fat-soluble vitamin levels, as very low LDL can impair their transport. A key detail patients should understand is that while high cholesterol is widely publicized as a health risk, cholesterol is a vital component for cell membranes, hormone synthesis, and nutrient absorption; a severe deficit, like 37 mg/dL, suggests a potential disruption to these fundamental biological processes, even in the absence of obvious symptoms. Further diagnostic steps may include a gastrointestinal workup or genetic testing to pinpoint the exact cause.

Hidden Risk of LDL Cholesterol 37 mg/dL

A very low LDL cholesterol of 37 mg/dL is unusual enough that it should prompt a conversation with your doctor, even though conventional wisdom says lower is better when it comes to LDL. For most people, low LDL is indeed protective. But at very low levels, the picture becomes more nuanced.

An LDL cholesterol level of 37 mg/dL places an individual at a significantly increased risk for developing malnutrition and vitamin deficiencies. Essential fat-soluble vitamins (A, D, E, K) and certain fatty acids require dietary fats for absorption, and persistently low LDL can impair this process. This deficiency can manifest as neurological issues, weakened immune function, and vision problems. Furthermore, extremely low LDL is associated with increased mortality from other causes, potentially due to underlying conditions that also suppress LDL, rather than the low LDL itself being directly causative of all observed issues. The body's structural integrity, particularly cell membranes, relies on cholesterol, and critically low levels can theoretically impact cellular function over time, though this is less well-established than malabsorption risks.

• Very low LDL is most commonly caused by lipid-lowering medications like high-dose statins, PCSK9 inhibitors, or ezetimibe. If your medication has driven LDL this low, your doctor may want to reassess the dosage
• Some research suggests that very low LDL may be associated with a slightly increased risk of hemorrhagic stroke, though the data is not conclusive and the overall benefit of LDL reduction still outweighs this risk for most people
• Genetic conditions like hypobetalipoproteinemia can cause naturally very low LDL. These are usually harmless but should be identified
• Underlying conditions such as hyperthyroidism, liver disease, malabsorption disorders, or certain cancers can lower LDL as a secondary effect
• Malnutrition or rapid weight loss can temporarily drive LDL below normal levels

What Does a LDL Cholesterol Level of 37 mg/dL Mean?

LDL stands for low-density lipoprotein. It is a type of particle in your blood that carries cholesterol from your liver to cells throughout your body. Your cells need cholesterol to build membranes, produce hormones, and carry out essential functions. LDL gets its reputation as the "bad" cholesterol because when there is too much of it, excess particles can embed themselves in artery walls and form plaques.

A very low LDL cholesterol reading such as 37 mg/dL is most likely attributable to a combination of factors, with severe caloric restriction or a very low-fat diet being primary dietary culprits. Individuals experiencing significant, unintended weight loss or those rigorously adhering to extremely low-fat eating patterns may see their LDL plummet. Certain medications, particularly statins taken at high doses or in combination with other lipid-lowering agents, can aggressively reduce LDL beyond the target range. Less commonly, but importantly, underlying conditions such as hyperthyroidism or malabsorption syndromes (like celiac disease or inflammatory bowel disease) can lead to decreased cholesterol synthesis and absorption, resulting in such profound LDL reduction.

At 37 mg/dL, your LDL is well below the optimal threshold of under 100 mg/dL that most health organizations recommend. In fact, it is lower than what most people achieve even with aggressive treatment. For context, the average American adult has an LDL around 110 to 130 mg/dL.

Such a low level can happen for a few reasons. The most common is medication. Statins, especially at high doses, combined with drugs like ezetimibe or PCSK9 inhibitors, can bring LDL down dramatically. Some people also have genetic variations that naturally keep their LDL very low throughout life. These individuals tend to have exceptionally low rates of heart disease.

Less commonly, very low LDL can be a marker of an underlying health issue. Hyperthyroidism speeds up the clearance of LDL from the blood. Liver disease can reduce the production of lipoproteins. Malabsorption conditions can limit the cholesterol your body absorbs from food. If your LDL is unexpectedly low and you are not taking cholesterol medication, your doctor should look into the cause.

Seeing LDL Cholesterol come back at 37 mg/dL outside the usual range is unsettling, so take a slow breath. One lipid number rarely tells the whole story by itself. What tracks with heart risk is how your LDL, HDL, and triglycerides sit together, since the same value can mean very different things depending on the rest. A general page cannot know your full picture, but you can see it read together.

Lifestyle Changes for LDL Cholesterol 37 mg/dL

Foods that actually help

If your LDL cholesterol of 37 mg/dL is the result of medication, lifestyle changes are still important for your overall cardiovascular health, even if your LDL number itself does not need to come down further. Heart health depends on more than just one number.

If your LDL cholesterol is 37 mg/dL, the immediate next step is a comprehensive clinical evaluation to pinpoint the underlying cause. Discuss your current diet in detail, focusing on fat intake and overall caloric consumption, and report any recent unintentional weight loss. A review of all current medications, especially those affecting lipid levels, is crucial. Consider retesting lipid panel in 4-6 weeks after making targeted dietary adjustments, such as moderately increasing intake of healthy fats (e.g., olive oil, avocados, nuts), ensuring adequate caloric intake. Depending on the clinical picture and initial investigations, a referral to a registered dietitian or an endocrinologist may be warranted to address nutritional status and potential metabolic derangements.

Regular exercise remains beneficial regardless of your LDL level. The American Heart Association recommends 150 minutes of moderate aerobic activity per week. Exercise supports healthy HDL cholesterol levels, lowers blood pressure, reduces inflammation, and improves insulin sensitivity, all of which complement a low LDL reading.

Maintaining a healthy weight supports your overall lipid profile and reduces strain on your cardiovascular system. Even with excellent LDL numbers, excess body weight can raise triglycerides and lower HDL, offsetting some of the protection.

If you smoke, quitting is the single most impactful change for cardiovascular health. Smoking damages the lining of blood vessels and promotes plaque formation regardless of LDL levels.

Stress management and quality sleep support cardiovascular health through multiple pathways, including blood pressure regulation and inflammation reduction. Aim for seven to nine hours of sleep per night and find stress management practices that fit your lifestyle.

Written by

Ethan Keller

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