Walk into a maternity store or browse e-commerce platforms, and you will see shelves lined with bottles of DHA algal oil. Some are labelled "500 mg algal oil per capsule", some "100 mg DHA", others "Low EPA" or "Derived from Schizochytrium", alongside a host of English certifications. Average consumers can easily feel overwhelmed. Which figures truly matter? Do not be misled by fancy packaging. Focus on four critical indicators: pure DHA content, EPA ratio, cleanliness of the ingredient list, and raw material credentials. We break down each point below, together with relevant national standards and authoritative references.

1. Check DHA Content: Focus on Net DHA per Capsule, Avoid Being Misled by Total Algal Oil Weight

This is the most common pitfall. Many products prominently display "500 mg algal oil per capsule" in large font, while fine print states "100 mg DHA contained within". Algal oil is a blended lipid; only a fraction consists of DHA. The remainder comprises other fatty acids, glycerides, trace moisture and impurities. DHA purity = Net DHA content ÷ Total algal oil weight

General industry benchmarks:

• ≥35%: Minimum acceptable standard (Announcement No. 3 of the former Ministry of Health (2010) designated DHA algal oil as a novel food, specifying a minimum DHA content of 35 g/100 g, i.e. 35%)
• 40%–50%: Mainstream good purity range on the market
• ≥50%: High-purity premium grade

The Chinese Nutrition Society recommends an adequate daily DHA intake of 100 mg for infants aged 0–1, and 200 mg for pregnant and breastfeeding women. If you choose algal oil delivering 100 mg DHA per capsule, one capsule daily suffices for infants. If each capsule only supplies 60 mg DHA, nearly two capsules are required, which effectively raises the unit cost.

Practical tip: Locate the nutrition facts panel or the line stating contents per capsule. Only pay attention to the milligram value listed after "DHA" and disregard the total algal oil weight. Calculate purity by dividing DHA mass by total algal oil mass. Avoid any product below 35% purity.

2. Check EPA Ratio: Low EPA Required for Infants & Expectant Mothers; More Flexible for Adults

EPA and DHA are omega-3 "siblings" with distinct physiological roles, covered in our previous article. For children aged 0–3, pregnant and lactating women, EPA is non-essential and competes with DHA for metabolic resources. Low-EPA algal oil is therefore the logical choice.

What do national standards specify? National Food Safety Standard: Infant Formula (GB 10765-2021) does not set an independent EPA upper limit for supplements, yet it inherits the guiding principle from GB 10765-2010: where DHA is added to infant formula, the quantity of EPA among long-chain fatty acids shall not exceed the quantity of DHA. In industry practice aligned with the novel food announcement issued by the former Ministry of Health, infant-grade algal oil generally requires EPA <1%, with high-quality mainstream products achieving <0.3%. A 2025 popular science document published by the China Health Food Association offers clearer guidance: for infants aged 0–3, the EPA:DHA ratio shall not exceed 1:3, and EPA shall account for ≤0.1% of total fatty acids in infant formula.

Conversely, EPA delivers tangible benefits for adults aged 35 and above and individuals with dyslipidaemia (triglyceride reduction and anti-inflammatory effects). They may opt for EPA-containing algal oil or fish oil, with an EPA:DHA ratio of approximately 2:1, as outlined in the prior article and not elaborated further here.

Practical tip: For infants and pregnant women, look for labels stating "Low EPA", "EPA <0.3%", or specific EPA mg values on test reports. Eliminate infant algal oil where EPA exceeds DHA, or EPA accounts for more than 1% of total fatty acids. This criterion is less critical for adult consumption.

3. Check the Ingredient List: Shorter Is Better – Watch for Unnecessary Excess Additives

The ideal ingredient list for algal oil soft capsules is concise: DHA algal oil, gelatin (or plant-based gel), glycerin, purified water. These four components constitute the capsule shell and carrier, representing a clean formulation.

Exercise caution if the following ingredients appear in algal oil targeted at infants or pregnant women:

• Sucrose, glucose syrup, fruit powder: Elevate risks of dental caries and blood glucose fluctuations, unnecessary for infants.
• Artificial flavourings (vanillin, ethyl vanillin), synthetic colourants (tartrazine, allura red): Permitted for ordinary food under GB 2760, yet best avoided in infant formulations and supplements for vulnerable groups. A 2025 TGA sampling survey in Australia indicated products containing redundant additives resulted in a 3.2-fold higher incidence of intestinal discomfort in infants.
• Preservatives (sodium benzoate, potassium sorbate): Properly sealed algal oil stabilised with antioxidants such as vitamin E requires no extra preservatives. Added preservatives raise concerns over manufacturing processes or formulation stability.
• Diluent oils (sunflower oil, flaxseed oil) disguised as pure algal oil: Listed second or third in ingredients, these dilute purity and reduce cost-effectiveness.

Also verify molecular form. Natural algal oil exists as triglyceride (TG) form, matching the fatty acid structure in breast milk, readily recognised by pancreatic lipase and efficiently absorbed. Ethyl ester (EE) form is chemically synthesised and requires secondary hepatic metabolism; infants and pregnant women should avoid it where possible. Prioritise products labelled "natural triglyceride (TG) form" on packaging or product pages.

Practical tip: Photograph the ingredient list. For vulnerable groups, avoid products containing more than four auxiliary ingredients alongside sugar, flavourings, colourants or preservatives.

4. Check Raw Materials & Qualifications: Identified Algal Species, Novel Food Approval and Third-Party Testing

This criterion verifies the origin and reliability of the oil inside the bottle.

Full scientific name of algal strain required – vague descriptions such as "premium deep-sea microalgae" are insufficient Under Announcement No.3 (2010) issued by the former Ministry of Health, legally compliant domestic DHA algal oil can only be sourced from three microalgae strains:

• Schizochytrium sp.: The dominant industrial strain, delivering 35%–53% DHA in oil with EPA <0.3%. Produced via fully enclosed fermentation, with no ocean contact.
• Crypthecodinium cohnii: High DHA content with extremely low EPA, though subject to minor batch-to-batch variation.
• Ulkenia amoeboida: Less widely utilised.
• Transparent labelling should state "DHA algal oil derived from Schizochytrium sp.". Labels merely reading "algal oil" or "extracted from deep-sea algae" break the traceability chain.

Novel Food qualification and international GRAS status DHA algal oil was approved as a novel food in Announcement No.3 (2010) by the former Ministry of Health – the baseline compliance requirement for domestic products. Export-grade or premium lines often hold U.S. FDA GRAS notifications (GRN No. 000732 for Schizochytrium algal oil receiving a "no questions" letter) and EU Novel Food certification. Domestic health foods claiming "aids memory improvement" must feature a blue cap approval number formatted "G/J followed by eight digits", verifiable via the official National Medical Products Administration website.

Batch-specific third-party test reports Reputable brands provide downloadable test reports accredited by CMA or CNAS via official websites. Focus on four key metrics:

• Measured DHA level vs labelled value (a deviation within ±10% is satisfactory)
• Measured EPA level (<0.3% of total fatty acids for infant formulations)
• Peroxide value (algal oil oxidises easily; ≤1.5 meq/kg preferred, statutory upper limit generally ≤5 meq/kg)
• Heavy metals (lead ≤0.01 mg/kg, total mercury ≤0.005 mg/kg), aflatoxins and solvent residues: Not detected.
• Practical tip: Request batch-specific CMA test reports from e-commerce customer service. Treat brands refusing to provide documentation with suspicion. Prioritise products listing the Latin algal species name, referencing the 2010 Novel Food Announcement, and optionally bearing Blue Cap certification, GRAS notice or batch test reports.

Quick Self-Check Checklist (30-second screening before purchase)

Net DHA per capsule? Is purity ≥35% after excluding carrier algal oil? Approximately 100 mg DHA per capsule is optimal for infants and pregnant women.

Stated EPA content? For infant/prenatal formulations: EPA <0.3%, and absolute EPA quantity far lower than DHA. More flexible for adults.

Ingredient list: Maximum four core components, free of sugar, flavourings, colourants and preservatives; marked TG form?

Raw material: Scientific name of Schizochytrium or Crypthecodinium stated? Supported by the 2010 Novel Food Announcement? Available Blue Cap certification / GRAS notice / batch test reports?

Products satisfying all four criteria are reliable algal oil options. If any requirement fails, do not risk offering the product to infants or pregnant women regardless of low pricing.

One final reminder: DHA algal oil is not medicine. It fills dietary gaps, as residents in China generally have insufficient intake of deep-sea fish. Selecting the correct supplement is only the first step. Consistent intake at recommended doses combined with eating fish 2–3 times weekly delivers better outcomes than stockpiling multiple misaligned high-priced products.

Key References

1. Announcement No. 3 of the former Ministry of Health: Approval of seven substances including DHA algal oil and cottonseed oligosaccharides as novel foods (2010)
2. GB 10765-2021 National Food Safety Standard: Infant Formula; the clause stipulating EPA ≤ DHA inherited from GB 10765-2010
3. Adequate DHA intake recommendations published by the Chinese Nutrition Society (100 mg/day for infants; 200 mg/day for pregnant and lactating women)
4. Scientific Selection of DHA Supplements, China Health Food Association, March 2025
5. U.S. FDA GRAS Notice Inventory GRN No. 000732 (Schizochytrium algal oil)
6. Industry quality control thresholds (purity ≥35%, peroxide value ≤1.5 meq/kg, EPA <0.3%) compiled from testing specifications and market sampling reports