Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Spirulina & Chlorella Ingredients & Drug Interactions

by Swanson GreenFoods Formulas

Capsule Category: Other Combinations
Most serious interaction: Moderate
The interaction bottom line Most serious interaction: Moderate

Spirulina & Chlorella is a dietary supplement by Swanson GreenFoods Formulas with 2 active ingredients. Its ingredients are commonly taken for general nutrition and energy, antioxidant support, cholesterol and metabolic health.Based on those ingredients, 626 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are certified organic Chlorella powder, Parry's Vegetarian certified organic Spirulina. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of Spirulina & Chlorella by Swanson GreenFoods Formulas

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 2 of its 2 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains two active ingredients: Spirulina and Chlorella, both certified organic. Spirulina is a blue-green algae that has been studied for potential effects on blood pressure and other conditions.

Chlorella is a green algae sometimes used for general wellness. The product also contains inactive ingredients — rice powder, rice bran extract, and the capsule material itself — which are fillers and binders.

Does it work?

Moderate evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed

This product doesn't appear to be marketed for a specific use, so we graded its ingredients' overall clinical evidence instead.

Moderate

Some clinical evidence supports its ingredients for:

Why this rating?
  • The label markets general wellness (“antioxidant support and natural detoxification”), not a specific health condition, so there is no single claim to grade against clinical-evidence data.
  • Since the label doesn't commit to one use, we graded the ingredients' overall clinical evidence instead.
  • On file: Pregnancy-related iron deficiency — rated "Possibly Effective" (Chlorella) (Natural Medicines).
  • On file: Hypertension — rated "Possibly Effective" (Blue-green Algae) (Natural Medicines).

Spirulina has possibly effective evidence for high blood pressure (hypertension). For other conditions it's studied for — acne, hay fever, iron-deficiency anemia, and arsenic poisoning — the evidence we have isn't strong enough to rate it either way.

Chlorella shows possibly effective evidence for pregnancy-related iron deficiency. For brain tumors, fatty liver disease, depression, and fatigue, the evidence remains insufficient to establish whether it works.

The evidence, ingredient by ingredient Blue-green Algae Chlorella

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Spirulina is generally well tolerated when taken by mouth. The most common side effects reported are stomach cramping, bloating, diarrhea, dizziness, fatigue, gas, headache, nausea, and vomiting.

Rare allergic reactions including rash, itching, and in one case anaphylaxis (a severe allergic reaction) have been documented. A few cases of mild gum bleeding and bruising were reported in people taking spirulina at standard doses.

Chlorella is also generally well tolerated short-term, with common side effects including allergic reactions, stomach cramping, constipation, diarrhea, fatigue, gas, nausea, photosensitivity (sun sensitivity), and stool discoloration. Rare but serious allergic reactions including anaphylaxis have occurred.

An important caution for both: product quality and purity vary widely, and contamination with toxins or heavy metals is a documented concern.

Side effects, ingredient by ingredient Blue-green Algae Chlorella

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Chlorella, Blue-green Algae.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications.
  • For scale: 626 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before you start, check with your pharmacist if you take blood thinners or antiplatelet drugs (Moderate risk from spirulina), warfarin specifically (Moderate risk from chlorella's vitamin K content), diabetes medications (Moderate risk from spirulina), immunosuppressants (Moderate risk from spirulina), or photosensitizing drugs (Moderate risk from chlorella).

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

This product might appeal to someone looking for general wellness support, particularly if spirulina's blood pressure effects interest them. However, if you take blood thinners, diabetes medications, immunosuppressants, photosensitizing drugs, or warfarin, you'll want to check with your pharmacist first.

The quality and purity concerns are real — talk to your pharmacist about whether this brand is reputable.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Oct 23, 2019.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Spirulina & Chlorella, straight from the product label.

Brand Swanson GreenFoods Formulas
Barcode (UPC) 087614060866
Net contents 90 Veggie Capsule(s)
Market status On market
Date entered into DSLD Oct 23, 2019
DSLD ID 206860
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Spirulina & Chlorella by Swanson GreenFoods Formulas, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
2 Veggie Capsule(s)
Maximum serving Sizes:
2 Veggie Capsule(s)
Servings per container
45
UPC/BARCODE
087614060866
IngredientAmount% DV
Parry's Vegetarian certified organic Spirulina400 mg--
certified organic Chlorella powder400 mg--

Other ingredients: Hydroxypropyl Methylcellulose, organic Brown Rice powder, organic Rice Bran extract, organic Rice concentrate

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
General Statements

Two superfoods combined as one powerful supplement Boosts antioxidant activity Supports the body's natural detoxification Science-backed quality since 1969

Antioxidant support

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement, take two capsules one to three times per day with food and water.

Brand IP Statement(s)

Parry's Vegetarian Certified Organic Spirulina is a trademark of Parry Nutraceuticals, Ltd.

Precautions

Warning: For adults only.

Consult your physician before using this or any product if you are pregnant or nursing, taking medication or have a medical condition.

Keep out of reach of children.

Do not use if seal is broken.

Storage

Store in a cool, dry place.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease

FDA Statement of Identity

Dietary Supplement

See for yourself

Spirulina & Chlorella by Swanson GreenFoods Formulas label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

What’s inside

The Ingredients in Spirulina & Chlorella by Swanson GreenFoods Formulas

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Veggie Capsule(s) Dosage formCapsule Servings per container45 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

400 mg per serving

Blue-green algae are nutrient-rich aquatic microorganisms (such as spirulina and Klamath Lake algae) taken as a supplement for energy, nutrition, and...

Parry's Vegetarian certified organic Spirulina monograph & interactions

Certified organic Chlorella powder

Interacts with
337 drugs
400 mg per serving

Chlorella is a nutrient-rich freshwater green algae taken as a supplement for general wellness, immune support, and 'detox.' Some small studies sugges...

Certified organic Chlorella powder monograph & interactions

Other (inactive) ingredients: Hydroxypropyl Methylcellulose, Organic Brown Rice powder, Organic Rice Bran extract, Organic Rice concentrate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Spirulina & Chlorella by Swanson GreenFoods Formulas Drug Interactions

Want to check YOUR meds against Spirulina & Chlorella?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

Go to the checker
626Drugs
626 Moderate

Each ingredient & the kinds of drugs it affects

For each ingredient in Spirulina & Chlorella with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

certified organic Chlorella powder2 drug types · 337 drugs

Photosensitizing Drugs

Theoretically, chlorella might have additive effects with photosensitizing drugs.
Chlorella has been reported to cause photosensitization. In five case reports, patients who had ingested chlorella exhibited swelling followed by erythematopurpuric lesions on sun-exposed areas of the body. Theoretically, concomitant use with photosensitizing drugs may exacerbate effects.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Theoretically, chlorella might reduce the clinical effects of warfarin.
Chlorella contains significant amounts of vitamin K. There is at least one case report of warfarin therapy becoming sub-therapeutic after initiation of chlorella supplements.

Likelihood Possible Evidence D

Parry's Vegetarian certified organic Spirulina3 drug types · 327 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, spirulina blue-green algae might increase the risk of bleeding if used with other anticoagulant or antiplatelet drugs. However, this is unlikely.
Spirulina blue-green algae have shown antiplatelet and anticoagulant effects in vitro. However, one preliminary study in 24 patients receiving spirulina blue-green algae 2.3 grams daily for 2 weeks showed no effect on platelet activation or measures of clotting time.

Likelihood Unlikely Evidence D
Antidiabetes Drugs

Theoretically, taking blue-green algae with antidiabetes drugs might increase the risk of hypoglycemia.
Human research shows that spirulina blue-green algae can have hypoglycemic effects in patients with diabetes, at least some of whom were using antidiabetes drugs. However, blue-green algae does not seem to improve glycated hemoglobin (HbA1c) levels in patients with diabetes. A meta-analysis of animal studies also suggests that spirulina blue-green algae have hypoglycemic effects.

Likelihood Possible Evidence B
Immunosuppressants

Theoretically, concurrent use of blue-green algae might interfere with immunosuppressive therapy.
Blue-green algae have been shown to stimulate the immune system.

Likelihood Possible Evidence D
The maker

Brand information

Manufacturer and brand details for Spirulina & Chlorella, from the product label.

Swanson GreenFoods Formulas

See all Swanson GreenFoods Formulas products
Name
Swanson Health Products
City
Fargo
State
ND
ZipCode
58104
Phone Number
1-800-437-4148
Web Address
swanson.com
Pharmacist Counseling Corner

Spirulina & Chlorella by Swanson GreenFoods Formulas: Common Questions

Does Spirulina & Chlorella by Swanson GreenFoods Formulas interact with any medications?
Yes. Based on its ingredients, Spirulina & Chlorella has a known interaction with 626 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Spirulina & Chlorella contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Will this affect my blood thinner medication?
Possibly. Spirulina in this product carries a Moderate interaction with blood thinners and antiplatelet drugs — theoretically it could increase your bleeding risk, though this is considered unlikely. Chlorella can also be a concern if you're specifically on warfarin, because chlorella contains vitamin K, which reduces warfarin's effectiveness. Check with your pharmacist about your exact medication before starting.
What are the most common side effects?
For spirulina: stomach cramping, bloating, diarrhea, dizziness, fatigue, gas, headache, nausea, and vomiting. For chlorella: allergic reactions, stomach cramping, constipation, diarrhea, fatigue, gas, nausea, and sun sensitivity. Both are generally well tolerated, but these are the ones reported most often.
Can I take this if I'm pregnant or breastfeeding?
The data on file doesn't include pregnancy or breastfeeding safety information for spirulina. For chlorella, we don't have safety data either way. You'll want to talk with your doctor or pharmacist for personalized advice before taking this during pregnancy or while breastfeeding.
Does this actually work for anything?
Spirulina has possibly effective evidence for high blood pressure. Chlorella shows possibly effective evidence for pregnancy-related iron deficiency. For other conditions either is marketed for — like acne, hay fever, liver disease, or fatigue — the evidence we have isn't strong enough to say whether it works.
Is this product quality controlled?
Product quality and purity vary widely across spirulina and chlorella supplements, and contamination with toxins or heavy metals is a documented concern. Ask your pharmacist whether this Swanson brand has a good reputation for safety and testing.
Can I take this if I have a sun sensitivity?
Chlorella in this product can cause photosensitivity — making your skin more sensitive to sunlight — and theoretically could add to that effect if you're already on a photosensitizing medication. If you're prone to sun sensitivity or take drugs that cause it, check with your pharmacist first.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if Spirulina & Chlorella is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Spirulina & Chlorella label
Sources

Sources & How We Checked

Spirulina & Chlorella's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 35 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Blue-green Algae 22 references
  1. Jensen GS, Ginsberg DJ, Huerta P, et al. Consumption of Aphanizomenon flos-aquae has rapid effects on the circulation and function of immune cells in humans. A novel approach to nutritional mobilization of the immune system. JANA 2000;2:50-6.
  2. Iwasa M, Yamamoto M, Tanaka Y, et al. Spirulina-associated hepatotoxicity. Am J Gastroenterol 2002;97:3212-13. PubMed
  3. Hayashi O, Katoh T, Okuwaki Y. Enhancement of antibody production in mice by dietary Spirulina platensis. J Nutr Sci Vitaminol (Tokyo) 1994;40:431-41.. PubMed
  4. Vitale S, Miller NR, Mejico LJ, et al. A randomized, placebo-controlled, crossover clinical trial of super blue-green algae in patients with essential blepharospasm or Meige syndrome. Am J Ophthalmol 2004;138:18-32. PubMed
  5. Mani UV, Desai S, Iyer U. Studies on the long-term effect of spirulina supplementation on serum lipid profile and glycated proteins in NIDDM patients. J Nutraceut 2000;2(3):25-32. DOI
  6. Chiu HF, Yang SP, Kuo YL, et al. Mechanisms involved in the antiplatelet effect of C-phycocyanin. Br J Nutr 2006;95:435-40. PubMed
  7. Hsiao G, Chou PH, Shen MY, et al. C-phycocyanin, a very potent and novel platelet aggregation inhibitor from Spirulina platensis. J Agric Food Chem 2005;53:7734-40.
  8. Katz M, Levine AA, Kol-Degani H, Kav-Venaki L. A compound herbal preparation (CHP) in the treatment of children with ADHD: a randomized controlled trial. J Atten Disord 2010;14:281-91. PubMed
  9. Madhyastha, H. K., Radha, K. S., Sugiki, M., Omura, S., and Maruyama, M. Purification of c-phycocyanin from Spirulina fusiformis and its effect on the induction of urokinase-type plasminogen activator from calf pulmonary endothelial cells. Phytomedicine PubMed
  10. Mazokopakis, E. E., Karefilakis, C. M., Tsartsalis, A. N., Milkas, A. N., and Ganotakis, E. S. Acute rhabdomyolysis caused by Spirulina (Arthrospira platensis). Phytomedicine. 2008;15(6-7):525-527. PubMed
  11. Halidou, Doudou M., Degbey, H., Daouda, H., Leveque, A., Donnen, P., Hennart, P., and Dramaix-Wilmet, M. [The effect of spiruline during nutritional rehabilitation: systematic review]. Rev.Epidemiol.Sante Publique 2008;56(6):425-431.
  12. Konno, T., Umeda, Y., Umeda, M., Kawachi, I., Oyake, M., and Fujita, N. [A case of inflammatory myopathy with widely skin rash following use of supplements containing Spirulina]. Rinsho Shinkeigaku 2011;51(5):330-333. PubMed
  13. Le TM, Knulst AC, Röckmann H. Anaphylaxis to Spirulina confirmed by skin prick test with ingredients of Spirulina tablets. Food Chem Toxicol 2014;74:309-10. PubMed
  14. Rzymski P, Niedzielski P, Kaczmarek N, Jurczak T, Klimaszyk P. The multidisciplinary approach to safety and toxicity assessment of microalgae-based food supplements following clinical cases of poisoning. Harmful Algae 2015;46:34-42. DOI
  15. Petrus M, Culerrier R, Campistron M, et al. First case report of anaphylaxis to spirulin: identification of phycocyanin as responsible allergen. Allergy 2010;65(7):924-5. PubMed
  16. Marles RJ, Barrett ML, Barnes J, et al. United States Pharmacopeia safety evaluation of spirulina. Crit Rev Food Sci Nutr 2011;51(7):593-604. PubMed
  17. Majdoub H, Ben Mansour M, Chaubet F, et al. Anticoagulant activity of a sulfated polysaccharide from the green alga Arthrospira platensis. Biochim Biophys Acta 2009;1790(10):1377-81. PubMed
  18. Cha BG, Kwak HW, Park AR, et al. Structural characteristics and biological performance of silk fibroin nanofiber containing microalgae spirulina extract. Biopolymers 2014;101(4):307-18. PubMed
  19. Jensen GS, Drapeau C, Lenninger M, Benson KF. Clinical safety of a high dose of phycocyanin-enriched aqueous extract from Arthrospira (Spirulina) platensis: results from a randomized, double-Blind, placebo-controlled study with a focus on anticoagulant ac
  20. Hamedifard Z, Milajerdi A, Reiner Z, Taghizadeh M, Kolahdooz F, Asemi Z. The effects of spirulina on glycemic control and serum lipoproteins in patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized con
  21. Moradi S, Zobeiri M, Feizi A, Clark CCT, Entezari MH. The effects of spirulina (Arthrospira platensis) supplementation on anthropometric indices, blood pressure, sleep quality, mental health, fatigue status and quality of life in patients with ulcerative
  22. Ghanbari F, Amerizadeh A, Behshood P, Moradi S, Asgary S. Effect of microalgae arthrospira on biomarkers of glycemic control and glucose metabolism: a systematic Review and meta-analysis. Curr Probl Cardiol 2022;47(10):100942. PubMed

See these in context on the Blue-green Algae monograph →

Chlorella 13 references
  1. Peirce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York, NY: William Morrow and Co., 1999.
  2. Ng TP, Tan WC, Lee YK. Occupational asthma in a pharmacist induced by chlorella, a unicellular algae preparation. Resp Med 1994;88:555-7. PubMed
  3. Jitsukawa K, Suizu R, Hidano A. Chlorella photosensitization. New phytophotodermatosis. Int J Dermatol 1984;23:263-8. PubMed
  4. Merchant RE, Carmack CA, Wise CM. Nutritional supplementation with Chlorella pyrenoidosa for patients with fibromyalgia syndrome: a pilot study. Phytother Res 2000;14:167-73.
  5. Merchant RE, Rice CD, Young HF. Dietary Chlorella pyrenoidosa for patients with malignant glioma: effects on immunocompetence, quality of life, and survival. Phytother Res 1990;4:220-31.
  6. Halperin SA, Smith B, Nolan C, et al. Safety and immunoenhancing effect of a Chlorella-derived dietary supplement in healthy adults undergoing influenza vaccination: randomized, double-blind, placebo-controlled trial. CMAJ 2003;169:111-7..
  7. Ohtake, T., Negishi, K., Okamoto, K., Oka, M., Maesato, K., Moriya, H., and Kobayashi, S. Manganese-induced Parkinsonism in a patient undergoing maintenance hemodialysis. Am J Kidney Dis 2005;46(4):749-753. PubMed
  8. Ng, T. P., Tan, W. C., and Lee, Y. K. Occupational asthma in a pharmacist induced by Chlorella, a unicellular algae preparation. Respir.Med. 1994;88(7):555-557. PubMed
  9. Ohkawa, S., Yoneda, Y., Ohsumi, Y., and Tabuchi, M. [Warfarin therapy and chlorella]. Rinsho Shinkeigaku 1995;35(7):806-807.
  10. Azocar J, Diaz A. Efficacy and safety of chlorella supplementation in adults with chronic hepatitis C virus infection. World J Gastroenterol 2013;19(7):1085-90. PubMed
  11. Panahi Y, Badeli R, Karami GR, Badeli Z, Sahebkar A. A randomized controlled trial of 6-week Chlorella vulgaris supplementation in patients with major depressive disorder. Complement Ther Med 2015;23(4):598-602. PubMed
  12. Nakano S, Takekoshi H, Nakano M. Chlorella pyrenoidosa supplementation reduces the risk of anemia, proteinuria and edema in pregnant women. Plant Foods Hum Nutr 2010;65(1):25-30. PubMed
  13. Yavasoglu I, Turgutkaya A, Bolaman Z. Chlorella-induced thrombocytopenia. Sao Paulo Med J 2018;136(6):602-3. PubMed

See these in context on the Chlorella monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring