The two omega-3s in the capsule do different things to LDL. A 2011 meta-analysis by Wei and Jacobson in Current Atherosclerosis Reports pooled randomized placebo-controlled trials that gave EPA alone (10 trials), DHA alone (17), or compared the two head to head (6). Against placebo, DHA raised LDL by 7.23 mg/dL, while EPA produced a small, non-significant fall. In the head-to-head trials, DHA raised LDL 4.63 mg/dL more than EPA. Both lowered triglycerides, with DHA lowering them further. DHA also raised HDL by 4.49 mg/dL; EPA did not.
The biggest LDL rises show up when triglycerides start very high. The American Heart Association's 2019 science advisory on omega-3s for high triglycerides reviewed prescription doses of 4 g a day. In people with very high triglycerides (500 mg/dL or more), EPA+DHA products cut triglycerides by 30% or more alongside increases in LDL, while EPA-only did not raise LDL. In people with triglycerides of 200 to 499 mg/dL, the AHA found both forms lowered triglycerides by roughly the same amount and did not raise LDL, whether taken alone or with a statin. Those figures apply to prescription doses above 3 g a day of EPA+DHA. Check how much EPA and DHA your own daily dose provides before assuming the same size of effect.
A higher LDL number here does not automatically mean more risk. The same AHA advisory reports that in the largest trials of 4 g a day, non-HDL cholesterol and apolipoprotein B (ApoB) fell modestly, which the authors read as a reduction in total atherogenic lipoproteins. LDL-C measures the cholesterol carried inside LDL particles. ApoB counts the particles themselves, one per particle. When triglycerides fall sharply, the two can move in opposite directions, and ApoB is the closer measure of how many of those particles you have.
REDUCE-IT tested EPA only, in a specific group. The AHA advisory cites a 25% reduction in major cardiovascular events in REDUCE-IT, a randomized trial of 4 g a day of prescription EPA-only in high-risk patients already on a statin. That result belongs to that drug and that population. It does not show that an over-the-counter EPA+DHA capsule reduces heart attacks, and the advisory does not claim it does.
How to read your own panel. Start with the label: it lists EPA and DHA per serving, and a DHA-heavy product fits the LDL pattern above better than an EPA-heavy one. Then put your before and after results side by side. Non-HDL cholesterol needs no extra test: subtract HDL from total cholesterol, both of which are on a standard lipid panel. If triglycerides fell, LDL rose, and non-HDL or ApoB held steady or fell, that matches what the AHA describes. If LDL, non-HDL and ApoB all rose, that is not the pattern the AHA describes, and it is worth raising with your doctor. Either way, do not stop or swap a prescribed omega-3 or statin without talking to the prescriber.
Our lipid panel guide covers where ApoB fits and when it is worth adding to a standard panel. For triglyceride targets and what moves them, see high triglycerides.