What Is a Phospholipid?
A phospholipid is a type of lipid molecule with a phosphate-containing head group and two fatty acid tails. Phospholipids are the primary structural component of cell membranes in every living organism, forming the bilayer that separates the inside of a cell from the outside. If you have encountered this term on a supplement label, it is usually in the context of omega-3 absorption.
The relevance to your supplement choices is this: EPA and DHA can be bound to different carrier molecules. In fish oil, they are mostly bound to triglycerides. In krill oil, they are largely bound to phospholipids. In whole-cell marine phytoplankton, the omega-3 is partially bound to polar lipids including phospholipids within the cell membrane. We compared these formats in our phytoplankton vs krill oil article.
Some research suggests phospholipid-bound omega-3 may have modestly better bioavailability than triglyceride-bound forms. The evidence is real but not as dramatic as krill oil marketing implies. We think this is a genuine quality variable worth understanding, not a reason to pay three times the price for a product delivering less total omega-3 per capsule. You can check your product's omega-3 form using the guidance in our label reading guide.
Phospholipids in Supplements at a Glance
- What they are: Lipid molecules that form cell membranes, consisting of a phosphate-containing head and two fatty acid tails attached to a glycerol backbone
- Where they appear in supplements: Krill oil delivers EPA and DHA bound to phospholipids, while whole-cell phytoplankton contains omega-3 within a polar lipid matrix that includes phospholipids and glycolipids
- Absorption claim: Some published studies suggest modestly better bioavailability compared to the triglyceride form, though the magnitude of the effect remains debated and is smaller than krill oil marketing implies
- Not the same as: Triglycerides, which are the form found in standard fish oil, or ethyl esters, which are the form used in concentrated fish oil products
What our research found
Nannochloropsis naturally carries about 37 per cent of its lipids as polar lipids, including phospholipids. Under nitrogen stress, the cell diverts lipid production toward triglyceride storage and this proportion falls. Schizochytrium, the microalga used for most algal DHA oils, is over 90 per cent triglyceride. The species determines the lipid form you get.
Phospholipid-bound omega-3 is water-dispersible, which changes how your gut handles it. Unlike triglyceride oils, phospholipid forms mix in the aqueous digestive environment without requiring as much bile for emulsification. This may explain the absorption advantages seen in crossover studies, but the data on whether phospholipid-bound DHA crosses the blood-brain barrier more efficiently remains preliminary.
Sources
- Schuchardt JP et al. Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acid formulations — a comparative bioavailability study of fish oil vs. krill oil. Lipids in Health and Disease. 2011;10:145. PubMed
- West AL et al. Pharmacokinetics of Supplemental Omega-3 Fatty Acids Esterified in Monoglycerides, Ethyl Esters, or Triglycerides in Adults in a Randomized Crossover Trial. Journal of Nutrition. 2021;151(5):1111–1118. PubMed
Cara Hayes, MSc Nutrition and Dietetics (University of Sydney), writes all content in the Phytality Knowledge Centre. Read our editorial policy.
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Consult your healthcare provider before starting any supplement.
Methodology and Disclosure
Phytality manufactures whole-cell phytoplankton supplements containing polar-lipid-bound EPA. We have a commercial interest in lipid form being understood. Phospholipid biochemistry reflects standard cell biology. Bioavailability comparisons reflect published absorption studies. No EFSA-authorised health claims are cited for omega-3 lipid form.
Last reviewed: March 2026
