Interactions on record — worth a quick check against your medications. Based on 1 of 2 ingredients. Check your meds →
Dietary supplement

Blue-Green Algae 500 mg Ingredients & Drug Interactions

by Source Naturals

Blue-Green Algae 500 mg label
See full label image
Tablet Or Pill Category: Other Combinations
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Blue-Green Algae 500 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Blue-Green Algae 500 mg is a dietary supplement by Source Naturals with 2 active ingredients. Its ingredients are commonly taken for general nutrition and energy, antioxidant support, cholesterol and metabolic health.Based on those ingredients, 327 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Aphanizomenon flos-aquae. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Blue-Green Algae 500 mg by Source Naturals

Ask about any prescription or over-the-counter medication and we check it for interactions with Blue-Green Algae 500 mg by Source Naturals — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Blue-Green Algae 500 mg by Source Naturals

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

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 16, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 2 active ingredients.
  • “Organic Blue-Green Algae Blend” is a proprietary blend — the label gives one combined amount (500 mg) without saying how much of each component you get.

This product has 2 active ingredients: Aphanizomenon flos-aquae and Arthrospira platensis, both species of blue-green algae (also called spirulina). The product also contains inactive ingredients — silica, modified cellulose gum, and stearic acid — which are standard tablet binders and flow agents.

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 Blue-green Algae's overall clinical evidence instead.

Moderate

Some clinical evidence supports Blue-green Algae for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: Hypertension — rated "Possibly Effective" (Natural Medicines).

The evidence for blue-green algae is mixed. The data we hold shows it's possibly effective for high blood pressure (hypertension).

For acne, allergic rhinitis (hay fever), iron deficiency anemia, and arsenic poisoning, the evidence isn't established — we don't have enough reliable data to rate whether it works for those uses.

The evidence, ingredient by ingredient Blue-green Algae

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 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Blue-green algae are generally well tolerated, but a few things matter. Some people report stomach upset — abdominal cramps, bloating, diarrhea, nausea, flatulence, headache, dizziness, fatigue, and vomiting — though these aren't common.

Allergic reactions are rare but serious; one case report described anaphylaxis (a severe allergic reaction) in a teenager 6 hours after taking the product. A small number of people taking spirulina have experienced mild gum bleeding or bruising.

The biggest safety flag is contamination risk — quality varies widely across products, and some contain toxins or heavy metals. The data advises caution with product selection and notes that safety information is limited.

Side effects, ingredient by ingredient Blue-green Algae

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?
  • 1 of the 1 matched ingredient can interact with medications — 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: 327 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.

Check before combining this with blood thinners or antiplatelet drugs (like warfarin, apixaban, clopidogrel, or aspirin). Also confirm it's okay if you take immunosuppressants or diabetes medications.

These are Moderate-severity interactions — not emergency-level, but worth your doctor's or pharmacist's attention.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with some supporting evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

If you take blood thinners, diabetes medications, or immunosuppressants, check with your doctor or pharmacist before starting this. Even if you don't, be aware that contamination is a real concern with blue-green algae supplements — research the specific brand.

It may help with high blood pressure, but evidence for other uses is thin. Talk it over with your own doctor or pharmacist to see if it fits your situation.

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 Jun 23, 2017.

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 Blue-Green Algae 500 mg, straight from the product label.

Brand Source Naturals
Barcode (UPC) 021078001720
Net contents 100 Tablet(s)
Market status On market
Date entered into DSLD Jun 23, 2017
DSLD ID 75389
Product type Other Combinations
Supplement form Tablet Or Pill
Dietary claims / uses All Other
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free
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 Blue-Green Algae 500 mg by Source Naturals, 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:
1 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
UPC/BARCODE
021078001720
IngredientAmount% DV
Organic Blue-Green Algae Blend500 mg--
Aphanizomenon flos-aquae0 NP--
Arthrospira platensis0 NP--

Other ingredients: Silica, modified Cellulose Gum, Stearic Acid

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.
FDA Statement of Identity

Dietary Supplement

General Statements

From Klamath Lake

Source Naturals Blue-Green Algae is wildcrafted and harvested in the prime upper regions of Upper Klamath Lake, Oregon, and is of the highest quality available.

Suggested/Recommended/Usage/Directions

Suggested Use: 1 tablet daily.

Precautions

Do not exceed suggested use.

Note: If you are pregnant, may become pregnant, or breastfeeding, consult your health care professional before using this product.

Do not use if either tamper-evident seal is broken or missing.

Keep out of the reach of children.

Formula

Its name comes from the two color pigments it contains, phycocyanin, which is blue, and chlorophyll, which is green.

Formulation

Suitable for Vegetarians and Vegans.

Contains no dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.

General

SN0172 REV G151

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Blue-Green Algae 500 mg by Source Naturals label

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

Blue-Green Algae 500 mg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Blue-Green Algae 500 mg by Source Naturals

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

Serving size1 Tablet(s) Dosage formTablet Or Pill 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.

Organic Blue-Green Algae Blend

500 mg per serving

Other (inactive) ingredients: Silica, Modified Cellulose Gum, Stearic Acid. These complete the product’s ingredient list but are not active constituents.

Interaction report

Blue-Green Algae 500 mg by Source Naturals Drug Interactions

Want to check YOUR meds against Blue-Green Algae 500 mg?

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
327Drugs
327 Moderate

Ingredients driving the most interactions

Aphanizomenon flos-aquae 327

Individual Drug Interactions

The ingredients in Blue-Green Algae 500 mg interact with 327 drugs. Click any drug to see the details.

1 of the 2 ingredients in Blue-Green Algae 500 mg interact with drugs. Each result below shows which ingredient is responsible. Aphanizomenon flos-aquae

Each ingredient & the kinds of drugs it affects

For each ingredient in Blue-Green Algae 500 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Aphanizomenon flos-aquae3 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
Aphanizomenon flos-aquae full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Blue-Green Algae 500 mg, from the product label.

Source Naturals

Name
Source Naturals, Inc.
Street Address
P. O. Box 2118
City
Santa Cruz
State
CA
ZipCode
95062
Web Address
www.sourcenaturals.com
Pharmacist Counseling Corner

Blue-Green Algae 500 mg by Source Naturals: Common Questions

Does Blue-Green Algae 500 mg by Source Naturals interact with any medications?
Yes. Based on its ingredients, Blue-Green Algae 500 mg has a known interaction with 327 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Blue-Green Algae 500 mg 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.
What are the most common side effects?
Most people tolerate it fine, but some report stomach trouble — bloating, diarrhea, nausea, cramping, or flatulence — along with headache, dizziness, or fatigue. Allergic reactions are rare but possible, and a couple of cases of mild bleeding have been reported.
Is this safe to take if I'm pregnant or breastfeeding?
The facts on file don't include safety data for pregnancy or breastfeeding. Talk with your doctor or pharmacist about whether it's right for you in that situation — they can weigh what you need.
Does this actually work for high blood pressure?
The data shows it's possibly effective for high blood pressure — so there's some evidence behind it, but it's not proven. Results aren't guaranteed, and it shouldn't replace prescribed blood pressure medication without talking to your doctor first.
What's the contamination risk I keep hearing about?
Quality varies a lot across blue-green algae products, and some can contain toxins or heavy metals. The data recommends being cautious about which brand you pick. It's worth researching the manufacturer's testing and quality standards.
Can this help with anemia or hay fever?
The evidence for anemia and allergic rhinitis (hay fever) isn't established in the data we hold — we don't have enough reliable research to say whether it works for those. If either is a concern, check with your doctor about proven options.

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

Not sure if Blue-Green Algae 500 mg is safe with your meds?

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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.

Blue-Green Algae 500 mg label
Go deeper

The Full Monographs Behind Blue-Green Algae 500 mg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Blue-green Algae

Interacts with 327 drugs

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

Read the full Blue-green Algae monograph →
Sources

Sources & How We Checked

Blue-Green Algae 500 mg'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 22 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 →

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

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