What omega-3 does in your body
EPA and DHA, two of the omega-3 fatty acids, are building blocks of cell membranes. DHA is especially concentrated in the eyes and brain, where it is involved in vision and cognitive function; omega-3s also help regulate inflammation and lower blood triglycerides. That said, recent research suggests the heart-disease prevention benefit is less clear than hoped, so taking it is not automatically beneficial for everyone.
What can happen if you don't get enough
Omega-3s are essential fatty acids: your body cannot make enough on its own, so you need them from food or supplements. Severe deficiency is rare, but studies have linked eating little fish over a long period with dry eyes, dry skin, and poorer concentration. These symptoms have many possible causes, though, so a lack of omega-3 cannot be assumed from them alone.
The risks of taking too much
Omega-3 keeps platelets from clumping and thins the blood slightly. According to the NIH, the US FDA advises keeping omega-3 from supplements to no more than 5 g of EPA + DHA combined per day; more than that can lead to frequent minor bleeding such as nosebleeds or bleeding gums. If you take an anticoagulant such as warfarin, an antiplatelet drug, or blood pressure medication, decide on the dose with your doctor or pharmacist. Nausea and fishy burps are also common side effects at high doses.
How much after 65?
In the Dietary Reference Intakes for Koreans (2020), the adequate intake of EPA + DHA after 65 is 310 mg for men aged 65–74 and 280 mg for men 75 and older, and 150 mg for women aged 65–74 and 140 mg for women 75 and older. An adequate intake is based on what healthy people typically eat; one piece of mackerel (about 70–80 g) can exceed a day's worth. Check the 2025 revision's tables for the latest values.
Separately, Korea's Ministry of Food and Drug Safety (MFDS) sets daily ranges for each recognized function of omega-3 supplements. A product can only claim a function if the "EPA + DHA combined" amount on the label falls in the range below.
| MFDS-recognized function | Daily amount (EPA + DHA combined) |
|---|---|
| Improving blood triglycerides and blood circulation | 500–2,000 mg |
| Relieving dry eyes | 600–2,240 mg |
| Improving memory | 900–2,000 mg |
Daiso omega-3 lineup by manufacturer
Unlike magnesium, omega-3 at Daiso is a competitive category with several drugmakers. Daewoong Pharmaceutical sells two omega-3 lines under its "Dr. Bear" brand, and Chong Kun Dang Health offers its own. Even among omega-3 products, the source (plant-based algal oil or fish oil), the form (standard triglyceride or re-esterified triglyceride, rTG), and the added vitamins differ, so they are worth comparing.
Amount per product
We list only values we could confirm from Daiso Mall listings and expert analyses. Values that the maker has not disclosed, or where sources disagree, are marked "not confirmed."
| Product | Price and pack | Source and form | EPA + DHA per daily serving |
|---|---|---|---|
| Daewoong rTG Omega-3 | KRW 5,000 · 30 capsules (30 days), 1 a day | Fish oil (described as Norwegian), rTG form | 500 mg (per an expert comparison column) |
| Daewoong Plant-Based Nutiji Omega-3 | KRW 5,000 · 850 mg × 30 capsules (30 days), 1 a day | Microalgae (algal) source; "Nutiji" in the name refers to natural triglyceride (nTG) form | Not confirmed (ingredient listed as "oil containing EPA and DHA") |
| Chong Kun Dang Health rTG Omega-3 Vitamin ADE | KRW 5,000 · 30 capsules (30 days), 1 a day | rTG form + vitamins A, D, E; claims: circulation and blood triglycerides | Not confirmed |
| Chong Kun Dang Dailywise Supercritical rTG Omega-3 | KRW 2,000 · 12 capsules (12 days) | rTG form (described as supercritical extraction) | Not confirmed |
- What 500 mg means: The 500 mg of EPA + DHA in Daewoong's rTG Omega-3 exactly meets the minimum for the "blood triglycerides and circulation" claim (500 mg). It falls short of the thresholds for dry eyes (600 mg or more) and memory (900 mg or more), which is why pharmacists and experts have called the dose modest.
- Plant-based (algal) omega-3: Microalgae oils are often much richer in DHA than EPA. If the label only gives "EPA + DHA combined," there may be very little EPA, so check whether EPA and DHA are listed separately.
- Vitamin ADE combinations: If you also take a multivitamin, vitamins A and D will overlap. Vitamin A in particular is fat-soluble, so watch for excess.
- Working out purity: Divide the EPA + DHA amount by the capsule weight. For example, 500 mg of EPA + DHA in a 1,000 mg capsule is about 50% purity.
Is the rTG form better absorbed?
Some studies found rTG absorbed better than the ethyl ester (EE) form, but most were small, short-term comparisons of blood levels, and there are reports that the difference shrinks when taken with a fatty meal. The daily EPA + DHA amount and rancidity control (expiry date, storage) matter more than whether the label says rTG.
What to check before buying
If you rarely eat fish or are vegetarian, consider the plant-based product; if absorption is your priority, consider the rTG products. If you already take a multivitamin, make sure a combination product won't double up on vitamins A, D, and E. If you take anticoagulants or antiplatelet drugs, talk to your care team before starting any new omega-3.
Please keep in mind
- This article is based on information checked as of the date shown at the top. New research or changes in official guidelines may change the details, so please use it as a reference rather than taking it as definitive.
- For an accurate diagnosis and advice about your health, please see a doctor in person.