AumniVIDA

Apolipoprotein B (ApoB)

Updated October 31, 2026 · 39 sources · Written by the AumniVIDA team

Units

What is ApoB?

ApoB (apolipoprotein B) is the protein on every LDL, VLDL, IDL and Lp(a) particle, one per particle, so a blood ApoB test counts the particles that drive atherosclerosis. The US median is 90 mg/dL (0.90 g/L)0.90 g/L (90 mg/dL); European goals are under 100, 80 or 65 mg/dL depending on risk.

Cutaway illustration of an LDL particle: a ribbon-like ApoB-100 protein belt wraps a sphere of phospholipids around a core of cholesterol esters and triglycerides.
Every LDL particle is held together by a single ApoB-100 protein, so counting ApoB counts the particles.

Questions people ask about ApoB

  1. 01ApoB test: how to measure it, what it costs and how to prepareAn ApoB test is a standard blood draw that counts atherogenic particles. You do not need to fast. Guidelines suggest it most when triglycerides are high, with diabetes or obesity, or when LDL-C is very low on treatment. Results come in mg/dL or g/L, and experts suggest retesting 4 to 12 weeks after a treatment change.Read the answer
  2. 02How to lower ApoBMedications lower ApoB the most: PCSK9 inhibitors by 43 to 50 percent, statins by about 33 percent, and bempedoic acid or added ezetimibe by about 14 to 15 percent. Diet changes each lower it by a few mg/dL: psyllium by 5, walnuts by 4, oat beta-glucan by 3. Cutting saturated fat helps too.Read the answer
  3. 03What does a high ApoB mean?A high ApoB means more cholesterol-carrying particles are circulating, and more can lodge in the artery wall.Read the answer
  4. 04What is a normal ApoB level?The median ApoB in US adults not on lipid drugs is 90 mg/dL (0.90 g/L)0.90 g/L (90 mg/dL), and labs flag 100 mg/dL (1.0 g/L)1.0 g/L (100 mg/dL) or higher.Read the answer
  5. 05ApoB vs LDL cholesterol: which matters more?ApoB counts all atherogenic particles; LDL cholesterol measures the cholesterol inside LDL particles.Read the answer
  6. 06ApoB vs Lp(a): what is the difference?ApoB counts every atherogenic particle, Lp(a) included.Read the answer

Key takeaways

  1. 1

    ApoB counts atherogenic particles directly, because each LDL, VLDL, IDL and Lp(a) particle carries exactly one ApoB [1].

  2. 2

    Genetic studies show heart disease risk falls by the same amount per 10 mg/dL of ApoB lowered, whether triglycerides or LDL-C fall [2].

  3. 3

    European goals are under 100, 80 and 65 mg/dL (1.0, 0.8 and 0.65 g/L) for moderate, high and very high risk [3]; the US AHA/ACC calls 130 mg/dL a risk enhancer [4].

  4. 4

    ApoB adds the most when triglycerides are high, with diabetes or obesity, or when LDL-C is very low on treatment [3].

  5. 5

    You do not need to fast for an ApoB test [5].

  6. 6

    No trial has yet compared ApoB-guided treatment with LDL-C-guided treatment [6].

What is ApoB?

ApoB, short for apolipoprotein B, is the structural protein of every particle that can carry cholesterol into the artery wall. Each of those particles carries exactly one ApoB molecule, so the ApoB blood test is a direct count of them.

Cholesterol and triglycerides do not dissolve in blood. They travel inside lipoproteins: small spheres with a fatty core and a protein-studded shell. The particles that cause atherosclerosis (LDL, VLDL, IDL, Lp(a) and chylomicron remnants) all carry one copy of ApoB, which holds the particle together and lets the liver clear it [1].

Because the ratio is one to one, the ApoB concentration in your blood equals the concentration of these particles [1]. That is the core idea behind the test. A standard lipid panel tells you how much cholesterol the particles carry. ApoB tells you how many particles there are.

Labs report ApoB in mg/dL in the US or g/L in Europe and Canada. To convert, divide mg/dL by 100: 90 mg/dL is 0.90 g/L. The median for US adults not taking lipid drugs is 90 mg/dL [1]. See what a normal ApoB level is for the full distribution.

Two side-by-side panels: one shows a few large particles, the other many small particles, each panel holding the same total amount of cargo.
Two people can carry the same amount of LDL cholesterol in very different numbers of particles. ApoB counts the particles; LDL-C weighs the cargo.

What does ApoB do in the body?

ApoB builds and labels the particles that deliver fat and cholesterol around the body. The liver makes the full-length ApoB-100 for VLDL, IDL, LDL and Lp(a); the gut makes a shorter ApoB-48 for chylomicrons that carry dietary fat.

ApoB-100 is one of the largest proteins in the blood: its precursor is 4,563 amino acids long [7]. The liver wraps each new VLDL particle in one ApoB-100. As VLDL gives up triglyceride to muscle and fat tissue, it shrinks into IDL and then LDL, keeping the same ApoB the whole way. A region of ApoB-100 rich in basic amino acids binds the LDL receptor, which is how the liver pulls LDL back out of the blood [7].

The intestine uses the same gene but edits the RNA: a single C to T change creates a stop signal at codon 2153, producing ApoB-48, about half the length [8]. ApoB-48 lacks the receptor-binding region and rides on chylomicrons, which carry fat from a meal [1].

Some people inherit a faulty ApoB. In familial defective ApoB-100, LDL particles bind the receptor at about a third of normal strength, so they stay in the blood longer and LDL rises [9]. This is one of the genetic causes of familial hypercholesterolemia, alongside LDL receptor and PCSK9 variants.

Not all ApoB particles are equally common. In one large cohort, LDL made up about 91 percent of ApoB particles and VLDL about 9 percent [10]. Chylomicrons carrying ApoB-48 are typically under 1 percent, even after a meal [3]. Lp(a) is a small share: in UK Biobank, mean ApoB was about 1,870 nmol/L and mean Lp(a) about 45 nmol/L [11], so Lp(a) is roughly 2 percent of particles on average, with wide variation between people.

The ApoB particle family. Each particle carries one ApoB; HDL carries none. [10]
ParticleApoB formMade inMain cargoShare of ApoB particles
LDLApoB-100Formed from VLDL in bloodCholesterol esterAbout 91%
VLDL and IDLApoB-100LiverTriglyceride, then cholesterolAbout 9%
Lp(a)ApoB-100 plus apo(a)LiverCholesterol ester, oxidized phospholipidsAbout 2% on average, varies widely
Chylomicrons and remnantsApoB-48IntestineDietary triglycerideUnder 1%, even after meals
HDLNoneLiver and intestineCholesterol returning to the liverNot counted
Cutaway illustration of an LDL particle: a ribbon-like ApoB-100 protein belt wraps a sphere of phospholipids around a core of cholesterol esters and triglycerides.
Every LDL particle is held together by a single ApoB-100 protein, so counting ApoB counts the particles.

Why does ApoB matter for heart disease?

Atherosclerosis starts when ApoB particles slip into the artery wall and get stuck. The more particles in the blood, the more get trapped. Genetic studies and drug trials agree that the benefit of lowering blood lipids tracks the drop in ApoB.

Cholesterol only enters the artery wall inside ApoB particles, and the number of particles that become trapped depends mainly on how many are in the bloodstream [12]. That makes particle number, not just cholesterol content, the natural measure of exposure.

The causal evidence comes from three directions.

  • Consensus on LDL. The European Atherosclerosis Society reviewed over 200 studies with more than 2 million people and concluded that LDL causes atherosclerotic disease, with risk rising with both the level and the years of exposure [13].
  • Mendelian randomization. Genes that lower triglycerides and genes that lower LDL-C reduced coronary risk by the same amount, an odds ratio of 0.77, for every 10 mg/dL lower ApoB, in 654,783 people. Once ApoB was accounted for, triglycerides and LDL-C added nothing [2]. A separate multivariable analysis found ApoB was the lipid trait that explained the link with coronary disease [14].
  • Observational head-to-head studies. Across 12 studies with 233,455 people, the relative risk per standard deviation was 1.43 for ApoB, 1.34 for non-HDL-C and 1.25 for LDL-C [15]. In UK Biobank, when ApoB, non-HDL-C and triglycerides were tested together, only ApoB stayed linked to heart attack [16]. Total particle count captured lipid risk regardless of whether the particles were LDL or VLDL, large or small [10].

Earlier cohort work pointed the same way. In the Swedish AMORIS study, ApoB predicted fatal heart attack better than LDL-C in both sexes [17]. In INTERHEART, across 52 countries, the ApoB/ApoA1 ratio carried the largest population attributable risk of any factor, 49 percent [18].

For what a high result means for you, see what a high ApoB means.

How ApoB became a guideline marker

  1. 1986

    Full ApoB-100 sequence published

  2. 1987

    Gut RNA editing explains ApoB-48

  3. 1987

    Familial defective ApoB-100 described

  4. 2001

    AMORIS: ApoB beats LDL-C for fatal heart attack

  5. 2004

    INTERHEART: ApoB/ApoA1 ratio tops risk factors

  6. 2011

    Meta-analysis ranks ApoB above non-HDL-C and LDL-C

  7. 2016

    EAS/EFLM: no fasting needed

  8. 2017

    EAS consensus: LDL causes atherosclerosis

  9. 2018

    AHA/ACC: ApoB 130 mg/dL is a risk enhancer

  10. 2019

    ESC/EAS ApoB goals; genetics tie benefit to ApoB

  11. 2020

    Multivariable MR: ApoB is the driving trait

  12. 2021

    Canada adds ApoB treatment thresholds

  13. 2024

    NLA ApoB consensus; Lp(a) 6 times LDL per particle

  14. 2025

    Particle count beats particle type

  15. 2026

    ACC/AHA guideline adds selective ApoB testing

ApoB went from a protein sequence in 1986 to a goal or threshold in European, Canadian and US guidance within about 35 years.

How is ApoB measured?

ApoB is measured from a normal blood sample with an automated antibody test that most clinical labs already run. You do not need to fast. The test is accurate, cheap for labs to perform, and often ordered alongside a standard lipid panel.

Commercial ApoB assays use antibodies (immunoturbidimetric or immunonephelometric methods) on the same analyzers that run routine lipid panels. Bias for most assays is below 4 mg/dL, and the coefficient of variation is usually 5 to 6 percent [1]. Unlike calculated LDL-C, ApoB does not depend on a formula that breaks down when triglycerides are high or LDL-C is very low [1].

Fasting does not change ApoB [5]. Even after a meal, more than 95 percent of circulating ApoB is ApoB-100 in people without severe hypertriglyceridemia [1]. The test counts ApoB-100 and ApoB-48 together.

The National Lipid Association describes the cost of running the test as low, but notes that some insurers still deny or restrict coverage [1]. Prices to patients vary by country, lab and plan.

For who should test, how results are reported and when to retest, see the ApoB test.

When an ApoB test adds the most

Standard lipid panel done. When does adding ApoB help most?

  • Triglycerides above 133 mg/dL (1.5 mmol/L)1.5 mmol/L (133 mg/dL), or 200 mg/dL or moreAdd ApoB: Canada (CCS 2021) uses the first cut point, the 2018 AHA/ACC guideline the second
  • Diabetes, obesity or metabolic syndromeAdd ApoB: LDL-C may understate particle number (ESC/EAS 2019)
  • Very low LDL-C on treatmentAdd ApoB: LDL-C may understate particle number (ESC/EAS 2019)
  • LDL-C and non-HDL-C at goal, residual risk suspectedUse ApoB selectively (ACC/AHA 2026)
  • Suspected inherited lipid disorder or family screeningAdd ApoB to clarify a possible genetic disorder (NLA 2024)
  • Starting or changing lipid-lowering therapyRepeat ApoB 4 to 12 weeks later (NLA 2024)

No fasting needed (EAS/EFLM 2016). Discuss any result, and whether to test at all, with your clinician.

ApoB adds most when LDL-C is likely to understate the particle count: high triglycerides, diabetes, obesity, very low LDL-C on treatment, or a suspected inherited lipid disorder.

What is a good ApoB level?

It depends on your cardiovascular risk. European guidelines set ApoB goals of under 100 mg/dL (1.0 g/L)1.0 g/L (100 mg/dL) at moderate risk, under 80 mg/dL (0.8 g/L)0.8 g/L (80 mg/dL) at high risk and under 65 mg/dL (0.65 g/L)0.65 g/L (65 mg/dL) at very high risk. The US flags 130 mg/dL (1.3 g/L)1.3 g/L (130 mg/dL) as a risk enhancer.

No guideline uses a single normal range for ApoB. Each one ties the number to your overall risk, which a clinician estimates from age, blood pressure, diabetes, smoking, family history and existing heart disease. The table below puts every major guideline's ApoB numbers in one place.

  • ESC/EAS (Europe). ApoB goals of under 65, 80 and 100 mg/dL for very high, high and moderate risk, alongside LDL-C goals of under 55, 70 and 100 mg/dL [3]. The 2025 focused update kept ApoB as a secondary target [6].
  • NLA (US lipid specialists). Suggested ApoB thresholds of 60, 70 and 90 mg/dL for very high, high and borderline to intermediate risk, chosen to match LDL-C thresholds of 55, 70 and 100 mg/dL [1].
  • CCS (Canada). ApoB of 1.05 g/L or higher supports starting a statin at intermediate risk; 0.7 g/L or higher on a maximal statin supports adding ezetimibe or a PCSK9 inhibitor in people with heart disease [19].
  • AHA/ACC (US). The 2018 guideline lists ApoB of 130 mg/dL or more as a risk-enhancing factor [4]. The 2026 guideline reintroduced goals for LDL-C, non-HDL-C and, in select cases, ApoB [20], and uses ApoB selectively to judge residual risk once LDL-C and non-HDL-C goals are met [6]. Check its recommendation tables for exact ApoB values [21].

For the full population distribution and what optimal means, see normal ApoB levels.

ApoB numbers in major guidelines and consensus statements, side by side. Goals are levels to stay below; thresholds are levels at which treatment is started or intensified. [1]
SourceWho it applies toApoB (mg/dL)ApoB (g/L)TypeLDL-C counterpart
ESC/EAS 2019, kept in 2025 updateVery high riskunder 65under 0.65Goalunder 55 mg/dL (1.4 mmol/L)1.4 mmol/L (55 mg/dL)
ESC/EAS 2019High riskunder 80under 0.80Goalunder 70 mg/dL (1.8 mmol/L)1.8 mmol/L (70 mg/dL)
ESC/EAS 2019Moderate riskunder 100under 1.00Goalunder 100 mg/dL (2.6 mmol/L)2.6 mmol/L (100 mg/dL)
NLA 2024Very high risk600.60Consider intensifying55 mg/dL
NLA 2024High risk700.70Consider intensifying70 mg/dL
NLA 2024Borderline to intermediate risk900.90Consider intensifying100 mg/dL
CCS 2021 (Canada)Heart disease, on maximal statin70 or higher0.70 or higherAdd ezetimibe or PCSK9 inhibitor1.8 mmol/L or higher
CCS 2021 (Canada)Intermediate risk, primary prevention105 or higher1.05 or higherStart a statin3.5 mmol/L or higher
CCS 2021 (Canada)Low risk with a statin-indicated condition145 or higher1.45 or higherStart a statin5.0 mmol/L or higher
AHA/ACC 2018Primary prevention130 or higher1.30 or higherRisk-enhancing factorabout 160 mg/dL
EAS/EFLM 2016Lab reports100 or higher1.00 or higherFlag as abnormal115 mg/dL (3 mmol/L)3 mmol/L (115 mg/dL) flag

ApoB goals and cut points by guideline (mg/dL)

Very high risk goal metModerate risk goal metLab flagRisk enhancerVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLVery high risk goal met: 30 to 65 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLModerate risk goal met: 65 to 100 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLLab flag: 100 to 130 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dLRisk enhancer: 130 to 160 mg/dL300.3650.65ESC very high: 65 mg/dL800.8ESC high: 80 mg/dL1001ESC moderate: 100 mg/dL1301.3AHA/ACC: 130 mg/dL160 mg/dL1.6 g/L
Very high risk goal met
300.3 to 650.65
Moderate risk goal met
650.65 to 1001
Lab flag
1001 to 1301.3
Risk enhancer
1301.3 to 1601.6
  • 65 mg/dL0.65 g/L: ESC very high
  • 80 mg/dL0.8 g/L: ESC high
  • 100 mg/dL1 g/L: ESC moderate
  • 130 mg/dL1.3 g/L: AHA/ACC
Guideline numbers cluster between 65 and 130 mg/dL (0.65 to 1.30 g/L). Lower goals apply to higher-risk people; 130 mg/dL is where the AHA/ACC calls ApoB a risk enhancer.

How is ApoB different from LDL cholesterol?

LDL-C measures how much cholesterol LDL particles carry; ApoB counts the particles themselves, including VLDL, IDL and Lp(a). Usually the two move together, but when they disagree, risk follows ApoB more closely.

In populations, ApoB, LDL-C and non-HDL-C are tightly correlated, above 0.90 in UK Biobank [22]. In individuals they can split apart. High triglycerides, obesity and insulin resistance tend to produce smaller, cholesterol-depleted LDL particles, which lowers LDL-C while ApoB stays high [1].

When the markers disagree, the extra particles matter. In statin-treated patients, ApoB above the median with LDL-C below it carried a hazard ratio of 1.49 for heart attack, while high LDL-C with low ApoB carried no extra risk [23]. Statins also lower ApoB less than LDL-C, 33 percent versus 42 percent on average, so LDL-C can look on target while particle count does not [24].

Non-HDL-C sits in between: it is the cholesterol in all ApoB particles and needs no extra test. The full comparison is on ApoB vs LDL cholesterol, and the Lp(a) comparison is on ApoB vs Lp(a). The LDL cholesterol and triglycerides hubs explain those markers on their own.

How ApoB, LDL-C and non-HDL-C relate

Particle down, What each test counts across

Chylomicron remnant (ApoB-48)

  • LDL-CNot counted
  • Non-HDL-CIts cholesterol
  • ApoBOne particle

VLDL (ApoB-100)

  • LDL-CNot counted
  • Non-HDL-CIts cholesterol
  • ApoBOne particle

IDL (ApoB-100)

  • LDL-CIts cholesterol, in standard methods
  • Non-HDL-CIts cholesterol
  • ApoBOne particle

LDL (ApoB-100)

  • LDL-CIts cholesterol
  • Non-HDL-CIts cholesterol
  • ApoBOne particle

Lp(a) (ApoB-100)

  • LDL-CIts cholesterol, in standard methods
  • Non-HDL-CIts cholesterol
  • ApoBOne particle

HDL (no ApoB, not atherogenic)

  • LDL-CNot counted
  • Non-HDL-CNot counted
  • ApoBNot counted

LDL makes up about 91% of ApoB particles and VLDL about 9% (Morze 2025); chylomicrons are typically under 1% (ESC/EAS 2019).

ApoB counts every atherogenic particle, non-HDL-C weighs the cholesterol in all of them, and LDL-C weighs only the cholesterol in LDL.

What raises and lowers ApoB?

Genes, diet, body weight, insulin resistance, some medications and some illnesses raise ApoB. Diet changes lower it by a few mg/dL each; medications lower it by roughly 14 to 50 percent.

What raises it. Inherited disorders such as familial hypercholesterolemia and familial combined hyperlipidemia; diets high in saturated fat [25]; obesity and insulin resistance [1]; new kidney, liver or thyroid disease; and some medications, including sex hormone therapy, thiazide diuretics, antiretroviral therapy and immunosuppressants [1]. Ketogenic diets raised ApoB by 35 mg/dL (0.35 g/L)0.35 g/L (35 mg/dL) in a small pooled analysis of normal-weight adults [26].

What lowers it. Food changes each lower ApoB by a few mg/dL: about 10 g a day of psyllium by 5 mg/dL [27], 3.5 g a day of oat beta-glucan by 3 mg/dL [28], walnuts by about 4 mg/dL [29]. Combined patterns such as the Portfolio diet go further [30]. Medications go further still: statins lower ApoB by about 33 percent [24], PCSK9 inhibitors by 43 to 50 percent [31] [32], and bempedoic acid by about 14 percent [33].

The full ranking, with every lever in one table, is on how to lower ApoB. In AumniVIDA, the longevity focus and Mediterranean pattern protocols track the saturated fat and fiber targets that move ApoB, and the keto and low-carb protocol keeps your lipid trend in view. Decisions about medication belong with your clinician.

Overhead view of a table with a bowl of oat porridge, a small dish of psyllium husk, walnuts, a bowl of lentils and a small jug of olive oil.
Psyllium, oats, walnuts and virgin olive oil each have trial evidence for small ApoB reductions; their effects add up rather than standing alone.

What does the evidence not show yet?

ApoB is the best-supported measure of atherogenic particles, but no outcome trial has yet tested ApoB-guided treatment against LDL-C-guided treatment, and adding ApoB to standard risk scores barely changes who is classed as high risk.

  • Little gain in population risk scores. In 165,544 people without heart disease, adding ApoB and ApoA-I to standard risk factors changed the C-index by only 0.0006 [34]. In UK Biobank the gain from adding ApoB to total and HDL cholesterol was 0.0004 [22]. ApoB earns its place mostly in individuals whose LDL-C understates their particle count, not as a universal screening upgrade.
  • No ApoB-guided outcome trial. ApoB thresholds are derived from LDL-C trials and regression, because no completed trial used ApoB entry criteria [1]. ApoB-guided treatment has not been tested against conventional LDL-C-guided management in outcome trials [6].
  • No agreed lifelong optimum. Guidelines set goals by short-term risk. Whether very low ApoB from early adulthood prevents more disease is inferred from genetics, where lifelong lower LDL tracks lower risk [13], not from trials that started in young adults.
  • Contested special cases. A 2025 study of lean people on ketogenic diets that reported no link between ApoB and plaque growth was retracted in 2026 over methodological errors [35]. That leaves the question of whether diet-driven ApoB rises carry the same risk unanswered, not settled in either direction.
  • One number cannot separate particle types. The routine test counts ApoB-100 and ApoB-48 together and cannot tell Lp(a) from LDL, so an Lp(a) test is still needed once [36].

The research

Foundational studies

The work that established what this marker means.

Guidelines and reviews

Where expert bodies and systematic reviews have landed.

Recent research

Notable work from the last three years.

What well-known voices say about ApoB

Their positions, summarized in our words. Follow each link for the full context.

  • Peter AttiaPhysician, host of The Drive podcast and author of Outlive

    Argues for lowering ApoB early in life and well below guideline goals. He has said he sees no reason for ApoB above about 60 mg/dL, would like people below the 5th percentile, and uses medication, including a statin with a PCSK9 inhibitor in his own case, to get there.

    The Drive #202 clip: early and aggressive lowering of ApoB

  • Allan SnidermanCardiologist and ApoB researcher at McGill University

    Has spent decades arguing that ApoB is a better marker of vascular risk than LDL cholesterol, because the number of particles decides how many get trapped in the artery wall. He favors causal, 30-year risk models over 10-year scores so prevention can start earlier.

    The Drive #185: Cardiovascular disease and why we should change the way we assess risk

  • G. Michael AllanFamily physician and co-author of the CFPC Tools for Practice evidence summaries

    Takes the skeptical primary-care view: in people without heart disease, adding ApoB to standard risk factors barely changes risk prediction, so clinicians should use risk calculators and proven therapies. The summary notes Canada's guideline still prefers ApoB or non-HDL-C when triglycerides are high.

    Tools for Practice #343: non-traditional lipoproteins for cardiovascular risk

Watch

Talks and explainers worth your time. Nothing loads from YouTube until you press play.

  • ApoB, LDL-C, Lp(a), and insulin as risk factors for cardiovascular disease [AMA 43 sneak peek]

    Peter Attia MDOpen on YouTube

    Attia compares ApoB with LDL-C, Lp(a) and insulin as risk markers on his own channel.

  • What Should Your ApoB Levels Be for Optimal Heart Health? | Thomas Dayspring | The Proof EP #315

    The Proof with Simon HillOpen on YouTube

    Lipidologist Thomas Dayspring discusses ApoB targets in a long-form interview.

  • Peter Attia on the INSANE Longevity Benefits of Low ApoB (how to lower ApoB with diet)

    FoundMyFitness ClipsOpen on YouTube

    A clip from Rhonda Patrick's podcast on why Attia targets low ApoB and the role of diet.

  • How to Lower Your ApoB (Lifestyle, Diet, & Medication)

    Jeremy London, MDOpen on YouTube

    A physician walks through lifestyle, diet and medication options for lowering ApoB.

  • #240 Dr. Spencer Nadolsky on Repatha, ApoB Targets, and What Actually Matters in Lipidology

    Dr. Mike HartOpen on YouTube

    Physician Spencer Nadolsky covers ApoB targets and PCSK9 therapy from a clinical view.

Protocols that act on ApoB

Common questions

What does ApoB stand for?

ApoB stands for apolipoprotein B. The two main forms are ApoB-100, made in the liver, and ApoB-48, made in the gut [8]. A standard ApoB blood test counts both together [1].

Is ApoB included in a standard lipid panel?

Usually not. A standard panel measures total cholesterol, HDL-C and triglycerides and calculates LDL-C and non-HDL-C. ApoB is a separate test your clinician adds, which is why the National Lipid Association calls for wider access and coverage [1].

Is ApoB genetic?

Partly. Inherited conditions such as familial hypercholesterolemia, including familial defective ApoB-100 [9], and familial combined hyperlipidemia cause high ApoB. The NLA suggests using ApoB to help screen family members when a genetic lipid disorder is suspected [1]. Diet, weight and other conditions still move it.

Can ApoB be too low?

Very low ApoB from medication appears safe in trials: patients on evolocumab in FOURIER reached a median ApoB of 38 mg/dL [1]. Very low ApoB without treatment can signal a rare inherited disorder, and lipid experts advise referral to a specialist clinic in that case [5].

What is the ApoB/ApoA1 ratio?

It divides the atherogenic particle protein (ApoB) by the main HDL protein (ApoA1). In INTERHEART, the top fifth of the ratio carried 3.25 times the heart attack odds of the bottom fifth [18]. Current guidelines focus on ApoB itself rather than the ratio.

Does ApoB include Lp(a)?

Yes. Each Lp(a) particle carries one ApoB-100, so it is counted in your ApoB result [5]. Lp(a) is usually a small share of the total, so a normal ApoB does not rule out high Lp(a). See ApoB vs Lp(a).

Can ApoB be higher than LDL cholesterol?

The numbers are not directly comparable because one counts particles and the other weighs cholesterol, but ApoB can be high relative to LDL-C. That pattern is common with high triglycerides, obesity and insulin resistance [1]. See ApoB vs LDL.

How do I convert ApoB from g/L to mg/dL?

Multiply g/L by 100. An ApoB of 0.8 g/L is 80 mg/dL, and 1.2 g/L is 120 mg/dL. Research papers sometimes use nmol/L; in UK Biobank a mean of 1.03 g/L corresponded to about 1,870 nmol/L [11].

Sources

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