Answer

Does LDL particle size matter, or just the number?

LDL particle size apob cholesterol heart-health ldl

Verdict

Conflicting

LDL particle number, not particle size, drives heart disease risk.

+6 22 sources: 11 positive, 4 partly, 7 negative

22 sources: 11 positive, 4 partly, 7 negative

By Arun AgrahriLast reviewed 1 timecoded source

Based on what researchers say in public interviews on YouTube. Educational only, not medical advice. Ask a qualified clinician before changing a supplement, medication, treatment, or testing plan.

Short answer

The number matters more than the size. Jim Otvos, who built the NMR test that made particle size measurable, says small dense LDL looks riskier mainly because those people carry more particles. He calls the idea that large fluffy LDL is benign flatly wrong, pointing to people with inherited high cholesterol who die at 30 or 35 with large particles.

Not enough evidence

Lowering ApoB lowers the risk of heart disease.

The verdict on LDL particle size overall. 2 sources: 2 positive

What the evidence says

positive partly neutral negative Each researcher and each study counts once per claim, however often they come up.

  1. Conflicting

    LDL particle number, not particle size, drives heart disease risk.

    22 sources: 11 positive, 4 partly, 7 negative.

    Researchers say

    2 positive, 1 negative

    Studies show

    9 positive, 4 partly, 6 negative

    16 papers we read · 3 cited on tape, not yet checked against the paper

    60 more not counted · see why
    We could not tell what position it takes on this claim. 26
    We could not confirm who is speaking. 17
    We could not tell where the evidence comes from. 8
    A host's remark inside an interview. 4
    The study is not yet read in full. 3
    The same study is already counted once. 1
    The study cited could not be identified. 1
    Show the receipts from 22 sources

    1. Alan Sniderman, on The Drive, at 52:40 Video · positive · Opinion

      “how can you pretend you've evaluated the system when you haven't counted the number of anthrogenic particles”

    2. Peter Attia Video · positive · 2 mentions

      on The Drive, at 10:27 · positive · Opinion

      “the apob concentration to me is the most important number you want to understand to predict”

      on Huberman Lab, at 48:24 · neutral · Opinion

      “it is a direct measurement of the concentration of LDL and vldl particles”

    3. REVEAL, Merck, cited on The Drive, at 1:16:57 Study · positive

      “it was the reduction in the number of apob lipoproteins that actually mattered”

    4. MESA and Framingham Offspring Study, cited on The Dr. Hyman Show, at 26:26 Study · positive

      “knowing the number of particles always beats the cholesterol concentration in terms of predicting risk”

    5. Sniderman, cited on The Drive, at 1:19:28 Study · positive

      “where there is discordance even with non-hdl cholesterol in apob risk follows april b”

    6. Other primary study, Am J Cardiol, 2006, PMID 16563891 Study · positive

      Although apo-A-I added significantly to the predictive power of apo-B, categorical and continuous multivariate analyses showed that this is not the case for LDL size.

    7. Other primary study, J Am Coll Cardiol, 2007, PMID 17276177 Study · positive

      Whereas LDL size was inversely related to CAD (OR 0.60, 95% CI 0.47 to 0.76), this relation was abolished upon adjustment for LDL-P.

    8. Trial or observed group, Circulation, 2009, PMID 19204302 Study · positive

      After adjusting for LDLNMR particle concentration, there was no additional contribution of LDLNMR size to CVD risk (P for trend=0.25), while HDLNMR and VLDLNMR particle size remained significantly associated with CVD after adjustment for the respective concentrations.

    9. Trial or observed group, JAMA, 2017, PMID 28846118 Study · positive

      The clinical benefit of lowering LDL-C levels may therefore depend on the corresponding reduction in apoB-containing lipoprotein particles.

    10. Other primary study, Int J Epidemiol, 2021, PMID 33130851 Study · positive

      Our agnostic genetic investigation prioritizes ApoB across all datasets considered, suggesting that ApoB, representing the total number of hepatic-derived lipoprotein particles, is the primary lipid determinant of CAD.

    11. Other primary study, Eur Heart J, 2025, PMID 40289348 Study · positive

      Particle diameter or size subclasses were not associated with CAD after apoB-P adjustment.

    12. Trial or observed group, Circulation, 2002, PMID 12370215 Study · partly

      Of these 2 factors, LDL particle concentration (NMR) was the stronger predictor (relative risk for the highest compared with the lowest quartile=4.17, 95% CI 1.96-8.87).

    13. Other primary study, J Clin Lipidol, 2011, PMID 21981843 Study · partly

      The independent effects of small LDL-P remained significant after adjustment for LDL-cholesterol, high-density lipoprotein (HDL), triglycerides, non-HDL, and large LDL-P.

    14. Systematic review, BMC Cardiovasc Disord, 2023, PMID 37914996 Study · partly

      The results of this systematic review suggest that higher concentrations of small dense LDL particles are associated with increased risk for cardiovascular disease.

    15. Other primary study, JAMA, 1998, PMID 9643858 Study · partly

      Results from this prospective study suggest that the measurement of fasting plasma insulin level, apolipoprotein B level, and LDL particle size may provide further information on the risk of IHD compared with the information provided by conventional lipid variables.

    16. Mark Hyman, on The Dr. Hyman Show, at 03:31 Video · negative · Opinion

      “he had a lot of these small dense cholesterol particles that cause heart disease”

    17. Other primary study, Am Heart J, 2002, PMID 12486427 Study · negative

      Multiple logistic regression analysis revealed that small dense LDL was independently associated with the incidence of CHD in both sexes (odds ratio [OR] 3.5, 95% CI 2.1-5.7, and OR 2.9, 95% CI 1.5-5.6, P <.005).

    18. Other primary study, Arterioscler Thromb Vasc Biol, 2005, PMID 15618542 Study · negative

      These results indicated that estimated cholesterol levels in the large LDL subfraction were not associated with an increased risk of IHD in men and that the cardiovascular risk attributable to variations in the LDL size phenotype was largely related to markers of a preferential accumulation of small dense LDL particles.

    19. Other primary study, J Cardiol, 2008, PMID 18922385 Study · negative

      Multivariate logistic regression analysis found apoB (OR 2.96; 95% CI 1.02-8.54), apoB/HDL-c (OR 4.14; 95% CI 1.33-12.83), nonHDL-c (OR 5.41; 95% CI 2.08-14.10), apoB/apoAI (OR 6.64; 95% CI 2.37-18.57), and LDL particle size (9.59; 95% CI 2.92-31.54) were independently associated with CHD.

    20. Other primary study, Int J Cardiol, 2018, PMID 29628276 Study · negative

      LDL particles showed the strongest association with cardiovascular events when the particle composition, rather than the total concentration, was investigated.

    21. Other primary study, Arterioscler Thromb Vasc Biol, 2025, PMID 40808652 Study · negative

      After further adjustment for ApoB, the association between LDL-C with all-cause ASCVD were completely reversed with a HR of 0.84 (95%CI: 0.81-0.86), but E-sdLDL-C continued to have a significant positive association with an HR of 1.11 (95%CI: 1.08-1.13).

    22. Other primary study, Circulation, 1997, PMID 8994419 Study · negative

      Statistical adjustment for concomitant variations in LDL cholesterol, triglycerides, HDL cholesterol, and apolipoprotein B concentrations had virtually no impact on the relationship between small LDL particles and the risk of IHD.

Where the sources disagree

Conflicting

LDL particle number, not particle size, drives heart disease risk.

Supports it 11 sources

Researchers

Studies

Partly 4 sources
Against it 7 sources

Researchers

Studies

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Detailed Answer

The short version

LDL particle number, not particle size, drives heart disease risk. Size mostly rides along with the count.

A standard cholesterol panel reports LDL-C, the amount of cholesterol carried inside your LDL particles. It does not tell you how many particles are doing the carrying. Two people can sit at the same LDL-C with very different particle counts, and it is the count that lines up with heart disease.

Why "small dense LDL is worse" got started

At a given LDL-C, people with small dense particles do show higher cardiovascular risk. Jim Otvos, a guest on Peter Attia's show, says his own NMR studies reproduced that finding.

The catch is arithmetic. An LDL particle is always full, so a smaller particle carries less cholesterol than a large one. If your LDL-C is 130 and your particles are small, you need more of them to hold that same 130. Small dense LDL is therefore a marker of a high particle count, not a separate hazard.

Why "large fluffy LDL is safe" does not follow

Otvos points to familial hypercholesterolemia, an inherited condition that drives lifelong high cholesterol. Those patients carry very high LDL particle counts, and their particles are large, not small. The severe form kills people in their thirties. Large particles in large numbers are still dangerous, and size was never the protection.

What to measure instead

ApoB counts every plaque-building particle directly, one protein per particle, and the test reads consistently between labs. That is why Tom Dayspring, a guest on Attia's show, says he no longer orders the commercial panels built around sub-fractions and size. He calls them a way to generate revenue rather than a way to make a decision.

Layne Norton, a guest on Rhonda Patrick's show, went through the same shift. He held the ratio-and-particle-size view in grad school, then changed his mind when Mendelian randomization studies showed lifetime LDL exposure tracking with mortality. Regardless of size, he says, LDL can get into the artery wall and cause damage.

Where the evidence disagrees

Mark Hyman, on his own show, calls small dense particles "the biggest factor that drives heart attacks". He treats saturated fat raising the large buoyant kind as no cause for worry. Elsewhere he ranks ApoB above particle size, so his position is not uniform.

Robert Lustig, a guest on Andrew Huberman's show, takes the same side on size: he calls large buoyant LDL cardiovascularly neutral and small dense LDL the particle that drives plaque.

Related Questions

Is large fluffy LDL harmless?
No. Otvos calls that idea flatly wrong. People with the inherited form of very high cholesterol carry large LDL particles in very high numbers, and the severe form kills them in their thirties. Size was never the protective part.
Why does small dense LDL show higher risk in studies then?
An LDL particle is always full of lipid. A smaller particle carries less cholesterol, so at the same LDL-C you need more of them. Small dense LDL flags a high particle count rather than causing extra risk on its own.
Should I pay for an LDL particle size test?
Tom Dayspring says he no longer orders the commercial panels built around particle size and HDL sub-fractions. ApoB counts the particles directly, costs less and reads consistently across labs.
What is the difference between LDL-C, LDL-P and ApoB?
LDL-C is the cholesterol carried inside the particles. LDL-P is how many LDL particles there are. ApoB counts every artery-damaging particle, one protein per particle, which makes it the widest of the three.
Does everyone agree on this?
No. Otvos, Dayspring and Norton land on particle number. Hyman calls small dense particles the biggest driver of heart attacks, and Robert Lustig calls large buoyant LDL neutral.

More Questions About LDL particle size

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