NutriDex

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Chlorella

Chlorella vulgaris

Green freshwater algae with small, consistent effects on cholesterol and blood pressure.

Moderate evidence 🛡️Gut & Immune⏳Longevity

✚ Updated · How we grade evidence

Evidence tier
Moderate
Research weight
Citations
8 verified / 8
Classification
Gut & Immune
❝
What the evidence says. Graded moderate: several meta-analyses show real but small reductions in total cholesterol (~9 mg/dL), LDL (~8 mg/dL) and systolic BP (~4 mmHg), yet most trials are short, small and concentrated in a single country (Iran), and the largest dedicated type-2-diabetes RCT found no benefit on glucose or lipids. (Moderate evidence: Several controlled trials; effects real but modest or context-dependent.)

What is Chlorella?

Chlorella (Chlorella vulgaris) is a gut and immune supplement used for modestly lower ldl & total cholesterol. NutriDex grades the human evidence as Moderate. Chlorella is a protein-rich freshwater green alga sold as tablets or powder. Pooled across roughly 19 randomized trials (~800 people), supplementation produced small but statistically significant drops in total cholesterol (about 9 mg/dL), LDL (about 8 mg/dL), systolic blood pressure (about 4.5 mmHg) and fasting glucose (about 4 mg/dL), with no clear change in triglycerides, HDL or body weight. In non-alcoholic fatty liver disease, small Iranian RCTs and a meta-analysis show modest improvements in AST and glycemic markers, mostly as an add-on to standard care. An 8-week trial reported increased natural-killer-cell activity, hinting at immune effects. Limits are real: most studies are short (8–12 weeks), small, single-country and of low-to-moderate quality, and a well-conducted 1,500 mg/day diabetes RCT found no benefit. Effects are best seen as a minor metabolic nudge, not a treatment.

Purported Benefits

✓Modestly lower LDL & total cholesterol
✓Small blood-pressure reduction
✓Support liver enzymes in fatty-liver disease
✓Boost NK-cell immune activity (early)

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Lower total and LDL cholesterolMeta-analyses (~19 RCTs) show small but significant drops (~9 mg/dL TC, ~8 mg/dL LDL); studies short and low-quality. Moderate ↑ benefit · small 2
Reduce blood pressurePooled 19-RCT meta-analysis found ~4.5 mmHg systolic and ~1.6 mmHg diastolic reduction. Moderate ↑ benefit · small 1
Improve liver enzymes/glycemia in fatty-liver diseaseSmall Iranian RCTs and a meta-analysis lowered AST and improved glucose/HOMA-IR, mostly as add-on to standard care. Preliminary ↑ benefit · small 3
Glycemic control in type 2 diabetesWell-conducted RCT (n=84) of 1,500 mg/day for 8 weeks found no improvement in glucose, HbA1c or lipids. Preliminary — no effect · negligible 1
Boost NK-cell immune activitySingle 8-week RCT (n=51) raised NK-cell activity and cytokines; isolated finding, not replicated. Preliminary ↑ benefit 1

Dosing & Compounds

Typical Dose
Most trials used 1,200–5,000 mg/day of dried whole-cell Chlorella (tablets/powder), often split with meals over 8–12 weeks.
Active Compounds
ChlorophyllCarotenoids (lutein, beta-carotene)Protein & cell-wall polysaccharidesVitamin K, B12-analogues, iron

Safety & Cautions

Generally well tolerated short-term; common effects are nausea, bloating, diarrhea and green-tinged stool, with occasional photosensitivity reactions. Chlorella is rich in vitamin K and can blunt warfarin/anticoagulants (a documented case raised INR control issues), so avoid or monitor closely. Its iodine content and possible additive glucose- and blood-pressure-lowering mean caution with thyroid medication, antidiabetics and antihypertensives. Safety in pregnancy and breastfeeding is not established, and products can be contaminated with heavy metals if poorly sourced. Educational only — always check with your doctor or pharmacist before combining Chlorella with any medicine.

Key Studies

Meta-analysis Sherafati 2022 ✓ PubMed
Dose-response meta-analysis (10 RCTs, 539 adults): C. vulgaris lowered total cholesterol and LDL; no effect on triglycerides or HDL; LDL benefit only ≤1500 mg/day.
Meta-analysis Sherafati 2021 ✓ PubMed
Meta-analysis (7 RCTs): C. vulgaris reduced AST -9.15 U/L; no overall effect on ALT or ALP, though ALT fell vs placebo (not vs metformin).
Meta-analysis Fallah 2018 ✓ PubMed
Meta-analysis (19 RCTs, 797 adults): Chlorella cut total cholesterol -9.09 mg/dL, LDL -8.32, SBP -4.51 mmHg, DBP -1.64, fasting glucose -4.23.
RCT Sherafati 2021 ✓ PubMed
Double-blind RCT (n=84, T2DM): 1,500 mg/day for 8 weeks did NOT improve glucose, HbA1c, lipids or anthropometrics vs placebo.
Safety LactMed 2023 ✓ Full text
NIH safety review: Chlorella poorly studied in pregnancy/lactation; vitamin K and iodine content noted as practical concerns.
RCT Ebrahimi-Mameghani 2017 ✓ PubMed
RCT (n=70, NAFLD): 1,200 mg/day Chlorella for 8 weeks improved fasting glucose, insulin resistance (HOMA-IR) and hs-CRP vs placebo.
RCT Ebrahimi-Mameghani 2014 ✓ PubMed
Double-blind RCT (n=60, NAFLD): 1,200 mg/day Chlorella + vitamin E for 8 weeks improved weight, ALP and fasting glucose vs vitamin E alone.
RCT Kwak 2012 ✓ PubMed
Double-blind RCT (n=51): 5 g/day Chlorella for 8 weeks raised NK-cell activity and serum IFN-γ and IL-1β vs placebo in healthy adults.
8 sources cited · 8 verified Search all studies on PubMed ↗

Common questions about Chlorella

What is Chlorella used for?

Chlorella is most often taken for Modestly lower LDL & total cholesterol, Small blood-pressure reduction, Support liver enzymes in fatty-liver disease, Boost NK-cell immune activity (early). Green freshwater algae with small, consistent effects on cholesterol and blood pressure.

Does Chlorella work — what does the evidence say?

Moderate evidence. Several controlled trials; effects real but modest or context-dependent. Chlorella is a protein-rich freshwater green alga sold as tablets or powder. Pooled across roughly 19 randomized trials (~800 people), supplementation produced small but statistically significant drops in total cholesterol (about 9 mg/dL), LDL (about 8 mg/dL), systolic blood pressure (about 4.5 mmHg) and fasting glucose (about 4 mg/dL), with no clear change in triglycerides, HDL or body weight. In non-alcoholic fatty liver disease, small Iranian RCTs and a meta-analysis show modest improvements in AST and glycemic markers, mostly as an add-on to standard care. An 8-week trial reported increased natural-killer-cell activity, hinting at immune effects. Limits are real: most studies are short (8–12 weeks), small, single-country and of low-to-moderate quality, and a well-conducted 1,500 mg/day diabetes RCT found no benefit. Effects are best seen as a minor metabolic nudge, not a treatment.

What is the typical dose of Chlorella?

Most trials used 1,200–5,000 mg/day of dried whole-cell Chlorella (tablets/powder), often split with meals over 8–12 weeks.

Is Chlorella safe? Any cautions or side effects?

Generally well tolerated short-term; common effects are nausea, bloating, diarrhea and green-tinged stool, with occasional photosensitivity reactions. Chlorella is rich in vitamin K and can blunt warfarin/anticoagulants (a documented case raised INR control issues), so avoid or monitor closely. Its iodine content and possible additive glucose- and blood-pressure-lowering mean caution with thyroid medication, antidiabetics and antihypertensives. Safety in pregnancy and breastfeeding is not established, and products can be contaminated with heavy metals if poorly sourced.

How many studies support Chlorella?

NutriDex cites 8 sources for Chlorella, graded "Moderate".

Cite this page
APA

Peh, D. (2026). Chlorella (Chlorella vulgaris): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/chlorella

BibTeX
@misc{nutridex_chlorella,
  author       = {Peh, Daryl},
  title        = {Chlorella (Chlorella vulgaris): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/chlorella},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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