Spirulina
Other supplementAlso called · 7 names▾▴
blue-green algae, blue green algae, spirulina algae, Spirulina sp., Aphanizomenon sp., Arthrospira platensis, Arthrospira maxima
Blue-green algae dietary supplement
Herbs and supplements are not FDA-approved before sale. About these sources
- Other
Research strength: 1 / 5
MotherToBaby says many herbal supplements have not been evaluated in pregnancy, and its general fact sheet does not assess Spirulina specifically. A 2026 systematic review found four studies of 1,070 pregnant women with anemia, generally in the second or third trimester. Those studies measured maternal hemoglobin, so their results do not establish Spirulina's effects in early pregnancy. Guy's and St Thomas' NHS Trust advises against herbal products and dietary supplements during pregnancy because reliable information is limited. The available sources leave first-trimester effects unclear. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Herbal Products (general information)Teratology service
- Guy's and St Thomas' NHS Trust: Herbal remedies and dietary supplementsUK government
- Gunawan et al. 2026: Systematic review and meta-analysis
- Niang et al. 2017: Pregnancy study in Dakar
Research strength: 3 / 5
MotherToBaby says many herbal supplements have not been evaluated in pregnancy, and its general fact sheet does not assess Spirulina specifically. A 2026 systematic review found four studies of 1,070 pregnant women with anemia, generally in the second or third trimester. The pooled before-and-after hemoglobin result increased, but the comparison with standard iron was not statistically significant and results varied widely between studies. Guy's and St Thomas' NHS Trust advises against herbal products and dietary supplements during pregnancy because reliable information is limited. The review's results address anemia treatment, not an overall assessment of pregnancy effects in the second trimester. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Herbal Products (general information)Teratology service
- Guy's and St Thomas' NHS Trust: Herbal remedies and dietary supplementsUK government
- Gunawan et al. 2026: Systematic review and meta-analysis
- Niang et al. 2017: Pregnancy study in Dakar
- Marlina and Nurhayati 2020: Spirulina compared with iron
Research strength: 3 / 5
MotherToBaby says many herbal supplements have not been evaluated in pregnancy, and its general fact sheet does not assess Spirulina specifically. A 2026 systematic review found four studies of 1,070 pregnant women with anemia, mainly in the second or third trimester. The pooled findings describe maternal hemoglobin changes and varied widely between studies; they do not establish overall effects of Spirulina later in pregnancy. Guy's and St Thomas' NHS Trust advises against herbal products and dietary supplements during pregnancy because reliable information is limited. The available studies leave third-trimester effects uncertain. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Herbal Products (general information)Teratology service
- Guy's and St Thomas' NHS Trust: Herbal remedies and dietary supplementsUK government
- Gunawan et al. 2026: Systematic review and meta-analysis
- Niang et al. 2017: Pregnancy study in Dakar
Spirulina — Breastfeeding
Research strength: 2 / 5
LactMed reports no data on how Spirulina components enter breast milk or on effects in nursing mothers or infants. A 2019 case report described green milk after maternal use of mixed blue-green algae pills immediately before and after delivery; the milk returned to normal 3 days after she stopped. The primary report describes the milk-color change and provides no infant outcome in its abstract. Guy's and St Thomas' NHS Trust advises against herbal products and dietary supplements while breastfeeding because reliable information is limited. LactMed warns that Spirulina products grown in uncontrolled conditions may contain heavy metals or other contaminants, and MotherToBaby gives a similar general caution for herbal products. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- LactMed: SpirulinaUS government
- Naor et al. 2019: Green breast milk case reportUS government
- Guy's and St Thomas' NHS Trust: Herbal remedies and dietary supplementsUK government
- MotherToBaby: Herbal Products (general information)Teratology service
Pregnancy
The 2026 review included four studies of 1,070 pregnant women with anemia, generally in the second or third trimester. Its single-arm analysis found a mean hemoglobin increase of 1.81 g/dL (95% CI 0.24 to 3.39; p=0.0243; I-squared 94.7%). The comparative analysis versus standard iron was not statistically significant (MD 1.45 g/dL; 95% CI -0.22 to 3.13; p=0.0881; I-squared 95.0%). The results concern hemoglobin and show substantial between-study variation.
Breastfeeding
LactMed's June 2021 record reports no published data on Spirulina components in milk or on effects in nursing mothers or infants. A 2019 case report describes green milk after maternal use of mixed blue-green algae pills immediately before and after delivery; the milk returned to normal appearance 3 days after stopping. The primary abstract reports no infant outcome.
LactMed describes Spirulina as a freshwater blue-green algae containing protein, B vitamins, vitamin E, chlorophyll, beta-carotene, and iron. LactMed notes that supplement composition can vary and that products grown in uncontrolled conditions can contain contaminants. MotherToBaby also notes that herbal products can contain metals or ingredients not listed on the label.
What was tested
The pregnancy studies primarily measured maternal hemoglobin in pregnant women with anemia. A 2025 product study tested 52 Spirulina and Chlorella supplements, and a 2026 analysis tested eight Spirulina products and modeled exposure estimates for pregnant and breastfeeding women. These were product analyses and a modeled exposure screen, not clinical pregnancy outcomes.
We found no disagreement between the sources checked.
- Guy's and St Thomas' NHS Trust advises avoiding herbal products and dietary supplements during pregnancy and breastfeeding because reliable information is limited. (Guy's and St Thomas' NHS Trust)
Not enough research found yet.
- MotherToBaby: Herbal Products (general information)Teratology serviceSecondary
- LactMed: SpirulinaUS governmentSecondaryPage dated 2021-06-21
- Guy's and St Thomas' NHS Trust: Herbal remedies and dietary supplementsUK governmentSecondaryIndependent check
- Gunawan et al. 2026: Clinical effects of Spirulina supplementation on hemoglobin levels in anemic pregnant womenPrimaryPage dated 2026-01-12Independent check
- Niang et al. 2017: Spirulina supplementation in pregnant women in the Dakar regionPrimaryPage dated 2017-01-20Independent check
- Marlina and Nurhayati 2020: The effectiveness of Spirulina compared with iron supplement on anemia among pregnant women in IndonesiaPrimaryIndependent check
- Naor et al. 2019: Green breast milk following ingestion of blue-green algaeUS governmentPrimaryIndependent check
- Sochacka et al. 2025: Spirulina and Chlorella dietary supplement product analysisUS governmentPrimaryPage dated 2025-10-28Independent check
- Kuru et al. 2026: Spirulina heavy-metal product analysis and modeled exposure assessmentPrimaryPage dated 2026-05-23Independent check
Last reviewed 2026-10-16
Independent check 2026-10-16
Not yet clinician-reviewed
Ask your provider about your situation.
Related
- Chlorella