Algae
Sea Moss (Irish Moss)
Sea Moss (Irish Moss) is an algae-based supplement. It is mainly associated with use related to iodine deficiency, although the available evidence is not sufficient to establish that it reliably addresses this indication.
Curious about Sea Moss (Irish Moss) beyond its wellness reputation? See which areas of interest are discussed and how cautiously to read them.
Overview
Sea Moss (Irish Moss) is an algae-based supplement. It is mainly associated with use related to iodine deficiency, although the available evidence is not sufficient to establish that it reliably addresses this indication.
The overall research picture is very limited and should be interpreted cautiously. The published evidence is built around a small research base, with the strongest available design being a case report rather than controlled clinical research. This means reported experiences cannot be used to determine how consistently Sea Moss works, what effects are caused by the supplement, or whether findings apply broadly to different people.
Claims involving wellness, cognitive, mood, sleep, sexual, or hair-related outcomes remain preliminary and should not be treated as established benefits. There is also not enough evidence to identify which people are most likely to benefit or to define how results may differ across health conditions. Sea Moss is therefore best viewed as a supplement with an insufficient overall evidence base, rather than as a proven treatment.
Barely researched: 9 studies. Last checked Oct 8, 2026.
- 0
- human evidence
- 0
- eligible
- 4
- unclassified
- 2
- animal / null result
Best-evidenced uses
- Thyroid Health SupportLow · Reference knowledge
- Nutrient Deficiency ReplenishmentLow · Reference knowledge
- Gut-Brain Axis SupportVery low · Reference knowledge
- 9
- Studies
Evidence checked Oct 8, 2026 · newest study 2023
The text on this page was written before the latest evidence check. The tables and numbers are up to date.
- D
- 9
310 community reports across 3 platforms
Coverage
- Effects
- 6
- Side effects
- 5
- Interactions
- 20
How to read the evidence
Evidence tier — overall strength of the evidence for the whole compound
- StrongWell established — backed by strong, consistent human research.
- ModerateSome genuine support, but mostly from small or lower-quality studies. Promising, not proven.
- PreliminaryEarly-stage evidence — a promising hypothesis, not an established effect yet.
- LimitedVery limited evidence — treat this as a hypothesis, not proof.
- InsufficientNot enough good evidence to draw conclusions yet.
Certainty — how sure we can be that the effect is real
- Very highVery sure — strong, consistent evidence
- HighFairly sure — consistent evidence from good studies
- MediumModerately sure — new studies could change this
- LowNot sure — little or mixed evidence
- Very lowVery unsure — almost no usable evidence
Source — where the data comes from
- Meta-analysisPooled analysis of many trials — the strongest evidence
- RCTRandomized controlled trial — a strong human study design
- ClinicalA human clinical study
- Reference knowledgeFrom general health-science or pharmacology references, not a study of this exact claim
- Animal researchStudied in animals, not humans
- Community reportsAggregated user reports — anecdotal signal, not evidence
- TheoreticalMechanism-based reasoning, not yet tested
Study grade — quality of each underlying study (A best, D weakest)
- AHigh-quality — strong, consistent human trials
- BGood — solid evidence with some limitations
- CModerate — limited, small, or mixed-quality studies
- DWeak — preliminary, indirect, or animal-only
Confidence — how strongly the sources back a finding
A 0–100 score from study quality and agreement
Most supplement evidence is graded C–D. Read it as preliminary signal, not proof.
These are research findings, not promises. A supplement does not replace medical treatment, and taking more does not work better.
What does research say?
None of these claims has good evidence yet. Best evidence first.
6 claims:3 not enough evidence3 not tested in people
Thyroid Health SupportNot enough evidence
Too few or too small studies to know if it works.
The one study found a benefit. Strongest study: a single case report. Amount studied: 1-2 g/day.
Sea moss provides iodine needed for thyroid hormone synthesis when iodine intake is inadequate. Its iodine content is highly variable, so it is not a reliable standardized iodine therapy, and excess intake can impair thyroid function.
Open the Thyroid Health Support pageNutrient Deficiency ReplenishmentNot enough evidence
Too few or too small studies to know if it works.
The one study found a benefit. Amount studied: 1-4 g/day, for chronic.
Nutrient deficiency replenishment was mentioned in 5 of 299 community reports, including 3 Reddit reports and 2 YouTube reports.
Open the Nutrient Deficiency Replenishment pageGut-Brain Axis SupportNot enough evidence
Too few or too small studies to know if it works.
The one study found a benefit. Amount studied: typical intake, for chronic.
Open the Gut-Brain Axis Support pageAntioxidant Protection EnhancementNot tested in people
Only tested in animals, cells or theory. Results like these often do not carry over to people.
All 2 studies with a clear result found a benefit. Strongest study: an animal study. Amount studied: typical dietary intake, for 48 days.
Open the Antioxidant Protection Enhancement pageMale Fertility ImprovementNot tested in people
Only tested in animals, cells or theory. Results like these often do not carry over to people.
The one study found a benefit. Strongest study: an animal study. Studied for 48 days.
Open the Male Fertility Improvement pageTestosterone Level IncreaseNot tested in people
Only tested in animals, cells or theory. Results like these often do not carry over to people.
The one study found a benefit. Strongest study: an animal study. Studied for 48 days.
Testosterone increased by 22.6% in a study in animals; this finding does not establish the same effect in people.
Open the Testosterone Level Increase page
Only reported by users, not studied: Physical Energy Increase, Immune System Support, Mood Improvement, Chronic Pain Reduction, Sleep Quality Improvement, Constipation Relief, and 1 more.
Before you try it
What studies and reports say about side effects and who it may not suit.
- Side effects
With weak evidence: Heavy Metal Accumulation, Thyroid Function Decrease, Thyroid Function Increase, Acne Worsening, and Intestinal Permeability Increase (Leaky Gut).
- May not suit you if you have
- Chronic Kidney Disease
- Pregnancy, breastfeeding, children
- Avoid in pregnancy and breastfeeding. Not enough data for children.
- Reported by users
- Bloating (10 posts), Headache (8 posts), and Nausea (5 posts)
General wellness information, not medical advice. Ask a doctor before you start, especially if you take medicines or have a health condition.
How people take it
Amounts from studies and from official limits.
- Typical dose
- 500 mg a day, as Sea Moss Extract (Standardized)
- Forms
- Sea Moss Extract (Standardized), Sea Moss (Irish Moss), Raw Sea Moss (Chondrus crispus), and Sea Moss Topical Gel
The expert view shows every study, dose protocol and source.
How it works
The clearest proposed mechanism for Sea Moss (Irish Moss) centers on iodine and thyroid hormone production. Iodine from sea moss provides the substrate for thyroid hormone synthesis, while Zinc supports thyroid peroxidase, an enzyme required in that process. Iron also supports iodine utilization because iron deficiency can impair thyroid peroxidase activity.
Selenium complements this pathway at the next stage: it is an essential cofactor for iodothyronine deiodinases, which convert T4 to active T3. Together, iodine, Zinc, Iron, and Selenium are described as supporting thyroid hormone synthesis and metabolism through related steps rather than through separate, unrelated actions.
This thyroid-focused pathway does not establish a single mechanism for the reported experiences involving mood, sleep, memory, alertness, motivation, sexual function, hair strength, or dream recall. Those experiences are reported at an anecdotal level, and the mechanism descriptions do not show that they result from changes in thyroid hormone production or metabolism.
Effects
6 listedStart here
The best we have, but the evidence is still weak
- →Thyroid Health SupportCertaintyLowSourceReference knowledgenot used for recommendations2 other sources
Sea moss provides iodine needed for thyroid hormone synthesis when iodine intake is inadequate. Its iodine content is highly variable, so it is not a reliable standardized iodine therapy, and excess intake can impair thyroid function.
What the sources found
2 positive · 0 neutral · 0 negativeconfidence 53/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Why this rating
Rests on: reports and reference sources, no studies
- No studies: low at most
- Not eligible as a recommendation: low at most
Where the evidence comes from
- Community reports1
- Reference knowledge1
Dose & course
1-2 g/day
Who it applies to
- Adults
- Unspecified
Why it isn't used for recommendations
No oral-route evidence in adults
Open Thyroid Health SupportShow studies (2)
Reference knowledgepositive75% confidenceSea moss is a natural source of iodine, a critical substrate for thyroid hormone synthesis. Adequate iodine intake is essential for maintaining euthyroid status, particularly in iodine-deficient individuals.
1-2 g/dayweeks to monthsEstablished pharmacologyCommunity reportsmoderate effectpositive30% confidenceThis effect was mentioned in 4 of 299 community reports discussing it (Reddit 2, YouTube 2).
4 mentionsReddit 2 · Youtube 2 - →Nutrient Deficiency ReplenishmentCertaintyLowSourceReference knowledgelong-termnot used for recommendations2 other sources
Nutrient deficiency replenishment was mentioned in 5 of 299 community reports, including 3 Reddit reports and 2 YouTube reports.
What the sources found
2 positive · 0 neutral · 0 negativeconfidence 53/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Why this rating
Rests on: reports and reference sources, no studies
- No studies: low at most
- Not eligible as a recommendation: low at most
Where the evidence comes from
- Community reports1
- Reference knowledge1
Dose & course
1-4 g/day · chronic
Timing
felt within days · sustained
Who it applies to
- Adults
Why it isn't used for recommendations
No oral-route evidence in adults
Open Nutrient Deficiency ReplenishmentShow studies (2)
Reference knowledgepositive70% confidenceSea moss provides bioavailable forms of iodine, potassium, magnesium, calcium, and trace minerals, supporting electrolyte and micronutrient balance, especially in deficient states.
1-4 g/dayChronicEstablished pharmacologyCommunity reportsmoderate effectpositive36% confidenceThis effect was mentioned in 5 of 299 community reports discussing it (Reddit 3, YouTube 2).
5 mentionsReddit 3 · Youtube 2felt within dayssustained
Very low probability(4)
- →Gut-Brain Axis SupportCertaintyVery lowSourceReference knowledgenot used for recommendations1 other source
What the sources found
1 positive · 0 neutral · 0 negativeconfidence 60/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Why this rating
Rests on: reports and reference sources, no studies
- No studies: low at most
- Not eligible as a recommendation: low at most
Where the evidence comes from
- Reference knowledge1
Dose & course
typical intake · chronic
Who it applies to
- Adults
Why it isn't used for recommendations
Very little evidence on file
Open Gut-Brain Axis SupportShow studies (1)
Reference knowledgepositive60% confidenceCarrageenan in sea moss may modulate gut microbiota composition and intestinal barrier function, indirectly influencing neuroinflammation and mood regulation via the gut-brain axis.
typical intakeChronicEstablished pharmacology - →Antioxidant Protection EnhancementCertaintyVery lowSourceAnimal researchnot used for recommendations1 cited study · 1 other source
What the sources found
2 positive · 0 neutral · 0 negativeconfidence 41/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Why this rating
Rests on: animal or lab studies only
- Animal or lab studies only: low at most
- Not eligible as a recommendation: low at most
Where the evidence comes from
- Article1
- Reference knowledge1
Dose & course
typical dietary intake · 48 days
Who it applies to
- Adults
- Animal
- Parenteral
- Unspecified
Why it isn't used for recommendations
Very little evidence on file
Open Antioxidant Protection EnhancementShow studies (2)
Animal studyDAnimalpositive12% confidence2021The effect of Red Seaweed (Chondrus crispus) on the fertility of male albino rats.
Decreased by 18.2% vs pre-treated group; significant
-18.2%Moderate effectHigh risk of biasReference knowledgepositive70% confidenceSea moss contains polyphenols and sulfated polysaccharides (e.g., carrageenan) with demonstrated in vitro antioxidant activity, contributing to systemic free radical scavenging.
typical dietary intakeacute and chronicEstablished pharmacology - →Male Fertility ImprovementCertaintyVery lowSourceAnimal researchanimal / in-vitro onlynot adult-relevantnot used for recommendations1 cited study
What the sources found
1 positive · 0 neutral · 0 negativeconfidence 12/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Why this rating
Rests on: animal or lab studies only
- Animal or lab studies only: low at most
- Not eligible as a recommendation: low at most
Where the evidence comes from
- Article1
Dose & course
48 days
Who it applies to
- Animal
- Parenteral
Why it isn't used for recommendations
Very little evidence on file
Open Male Fertility ImprovementShow studies (1)
Animal studyDAnimalpositive12% confidence2021The effect of Red Seaweed (Chondrus crispus) on the fertility of male albino rats.
Increased by 35% vs pre-treated (control) group; significant
35%Large effectHigh risk of bias - →Testosterone Level IncreaseCertaintyVery lowSourceAnimal researchanimal / in-vitro onlynot adult-relevantnot used for recommendations1 cited study
Testosterone increased by 22.6% (p<0.05) in a study in animals; this finding does not establish the same effect in people.
What the sources found
1 positive · 0 neutral · 0 negativeconfidence 10/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Why this rating
Rests on: animal or lab studies only
- Animal or lab studies only: low at most
- Not eligible as a recommendation: low at most
Where the evidence comes from
- Article1
Dose & course
48 days
Who it applies to
- Animal
- Parenteral
Why it isn't used for recommendations
Very little evidence on file
Open Testosterone Level IncreaseShow studies (1)
Animal studyDAnimalpositive10% confidence2021The effect of Red Seaweed (Chondrus crispus) on the fertility of male albino rats.
Increased by 22.6% vs pre-treated group; reported as significant in text, though the abstract calls it insignificant
22.6%Moderate effectHigh risk of biasStudies disagree
Side effects
5 listedHighest probability
- →Heavy Metal AccumulationCertaintyLowSourceReference knowledge1 other source
Seaweeds including sea moss can accumulate heavy metals such as arsenic, lead, and mercury from contaminated waters, and product quality varies significantly.
What the sources found
0 not observed · 0 unclear · 1 reportedconfidence 70/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Where the evidence comes from
- Reference knowledge1
Open Heavy Metal AccumulationShow studies (1)
Reference knowledgenegative70% confidenceSea moss can bioaccumulate arsenic, lead, cadmium, and mercury from seawater; chronic consumption may lead to toxic metal accumulation, especially in contaminated harvest regions.
- →Thyroid Function DecreaseCertaintyLowSourceReference knowledge1 other source
Excess iodine can produce a sustained Wolff-Chaikoff effect and cause or worsen hypothyroidism, especially in people with preexisting thyroid disease.
What the sources found
0 not observed · 0 unclear · 1 reportedconfidence 60/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Where the evidence comes from
- Reference knowledge1
Open Thyroid Function DecreaseShow studies (1)
Reference knowledgenegative60% confidenceHigh iodine intake can paradoxically suppress thyroid function (Wolff-Chaikoff effect), particularly in individuals with autoimmune thyroiditis or prior thyroid damage.
- →Thyroid Function IncreaseCertaintyLowSourceReference knowledge1 other source
Thyrotoxicosis (Jod-Basedow phenomenon) has been reported.
What the sources found
0 not observed · 0 unclear · 1 reportedconfidence 60/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Where the evidence comes from
- Reference knowledge1
Open Thyroid Function IncreaseShow studies (1)
Reference knowledgenegative60% confidenceExcessive iodine can induce hyperthyroidism, especially in those with pre-existing thyroid conditions.
- →Acne WorseningCertaintyLowSourceReference knowledge1 other source
High iodide exposure can rarely provoke or worsen acneiform eruptions.
What the sources found
0 not observed · 0 unclear · 1 reportedconfidence 55/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Where the evidence comes from
- Reference knowledge1
Open Acne WorseningShow studies (1)
Reference knowledgenegative55% confidenceHigh iodine intake can exacerbate acne in susceptible individuals.
- →Intestinal Permeability Increase (Leaky Gut)CertaintyLowSourceReference knowledge1 other source
What the sources found
0 not observed · 0 unclear · 1 reportedconfidence 50/100
How big is the effect
No study gave a number we could compare, so the size is not known.
Where the evidence comes from
- Reference knowledge1
Open Intestinal Permeability Increase (Leaky Gut)Show studies (1)
Reference knowledgenegative50% confidenceCarrageenan, a component of sea moss, has been shown in some studies to increase intestinal permeability and promote gut inflammation, though human relevance is debated.
Don't take it if
Conditions and states that rule it out7 listedHighest probability
- →Chronic Kidney DiseaseCertaintyMediumSourceReference knowledgeTheoretical
Where the evidence comes from
- Reference knowledge
Confidence
confidence 70/100
Open Chronic Kidney DiseaseRationale
Impaired renal excretion of potassium combined with sea moss's high potassium content increases the risk of life-threatening hyperkalemia.
Low probability(6)
- →HyperthyroidismCertaintyLowSourceReference knowledgeTheoretical
Excess iodine from sea moss can provide additional substrate for thyroid hormone overproduction, potentially worsening hyperthyroidism.
Where the evidence comes from
- Reference knowledge
Confidence
confidence 80/100
Open HyperthyroidismRationale
High iodine content can exacerbate hyperthyroidism or trigger thyrotoxicosis in susceptible individuals.
- →PregnancyCertaintyLowSourceReference knowledgeTheoretical
Excess iodine can cause fetal thyroid dysfunction, including both hypothyroidism and hyperthyroidism, because the fetal thyroid is highly sensitive to iodine fluctuations.
Where the evidence comes from
- Reference knowledge
Confidence
confidence 80/100
Open PregnancyRationale
Excessive iodine intake from sea moss may disrupt fetal thyroid development; risk of neonatal hypothyroidism or goiter due to transplacental passage of excess iodine.
- →BreastfeedingCertaintyLowSourceReference knowledgeTheoretical
Iodine transfers into breast milk, and excess iodine can cause thyroid dysfunction in infants because their thyroid is sensitive to iodine levels.
Where the evidence comes from
- Reference knowledge
Confidence
confidence 75/100
Open BreastfeedingRationale
High iodine levels in sea moss can concentrate in breast milk, potentially causing infant thyroid dysfunction including transient hypothyroidism.
- →Graves' DiseaseCertaintyLowSourceReference knowledgeTheoretical
Iodine supplementation can exacerbate Graves' disease and interfere with its treatment. Sea moss should be avoided in this autoimmune thyroid condition.
Where the evidence comes from
- Reference knowledge
Confidence
confidence 75/100
Open Graves' DiseaseRationale
Sea moss provides high amounts of iodine, which can exacerbate hyperthyroidism in Graves' disease by providing substrate for uncontrolled thyroid hormone synthesis.
- →Hashimoto's ThyroiditisCertaintyLowSourceReference knowledgeTheoretical
Excess iodine may worsen autoimmune thyroiditis and accelerate thyroid damage in people with Hashimoto's Thyroiditis.
Where the evidence comes from
- Reference knowledge
Confidence
confidence 75/100
Open Hashimoto's ThyroiditisRationale
Excess iodine can worsen autoimmune thyroiditis and accelerate thyroid damage.
- →Thyroid NodulesCertaintyLowSourceReference knowledgeTheoretical
High iodine intake may stimulate autonomous thyroid nodule function, potentially leading to hyperthyroidism.
Where the evidence comes from
- Reference knowledge
Confidence
confidence 70/100
Open Thyroid NodulesRationale
Iodine may stimulate growth or activity of autonomous thyroid nodules, potentially causing hyperthyroidism.
Pregnancy, breastfeeding and children
What is known for each group. Ask a doctor before using it in any of them.
- PregnancyAvoid
Studies or guidelines say to avoid it in this group.
Excessive iodine intake from sea moss may disrupt fetal thyroid development; risk of neonatal hypothyroidism or goiter due to transplacental passage of excess iodine.
- BreastfeedingAvoid
Studies or guidelines say to avoid it in this group.
High iodine levels in sea moss can concentrate in breast milk, potentially causing infant thyroid dysfunction including transient hypothyroidism.
- ChildrenNot enough data
Too little research to say anything. This is not a clearance.
Interactions
Combine with caution
Highest severity first
- →AmiodaroneTheoreticalCaution
Amiodarone already supplies a large iodine burden, so additional variable iodine from sea moss may increase the risk of iodine-induced hypothyroidism or hyperthyroidism.
- →Iodinated Contrast MediaTheoreticalCaution
Iodinated Contrast Media contains massive iodine loads, and combining it with sea moss supplementation could trigger thyroid dysfunction through Jod-Basedow or Wolff-Chaikoff effects.
Where the evidence comes from
- Reference knowledge
Open Iodinated Contrast MediaConfidence
confidence 75/100
- →Levothyroxine (T4)TheoreticalCaution
Sea moss’s high iodine content can interfere with thyroid hormone synthesis and destabilize levothyroxine dosing, potentially causing hypothyroidism or hyperthyroidism.
- →Methimazole (Antithyroid)TheoreticalCaution
Excess iodine from sea moss can override the antithyroid effect of Methimazole, potentially causing loss of thyroid control and thyrotoxicosis.
Where the evidence comes from
- Reference knowledge
Open Methimazole (Antithyroid)Confidence
confidence 70/100
- →Propylthiouracil (Antithyroid)TheoreticalCaution
High iodine intake from sea moss can antagonize the therapeutic action of Propylthiouracil, risking exacerbation of hyperthyroidism.
Where the evidence comes from
- Reference knowledge
Open Propylthiouracil (Antithyroid)Confidence
confidence 70/100
- →WarfarinTheoreticalCaution
Sea moss is not established to contain clinically significant amounts of vitamin K; any effect on warfarin is theoretical and product-dependent.
Unrated(6)
- →ACE InhibitorsTheoreticalCaution
ACE Inhibitors can increase potassium levels, and the potassium in sea moss may add to the risk of hyperkalemia.
- →Antiplatelet AgentsTheoreticalCaution
Clinically relevant antiplatelet activity from oral sea moss is not established; any additive effect with antiplatelet drugs is theoretical.
- →Angiotensin II Receptor Blockers (ARBs)TheoreticalCaution
Angiotensin II Receptor Blockers (ARBs) can increase potassium levels, while sea moss is high in potassium; combined use may increase hyperkalemia risk, especially in patients with reduced kidney function.
Where the evidence comes from
- Reference knowledge
Open Angiotensin II Receptor Blockers (ARBs)Confidence
confidence 60/100
- →LithiumTheoreticalCaution
Lithium and excess iodine can both suppress thyroid function, increasing the risk of hypothyroidism and goiter.
- →Potassium-Sparing DiureticsTheoreticalCaution
Sea moss contains significant potassium, so combining it with Potassium-Sparing Diuretics may increase the risk of hyperkalemia, especially in patients with reduced kidney function.
Where the evidence comes from
- Reference knowledge
Open Potassium-Sparing DiureticsConfidence
confidence 60/100
- →Digoxin (Cardiac Glycoside)TheoreticalCaution
Sea moss may affect serum potassium, and potassium abnormalities can influence digoxin toxicity; however, sea moss is not established to alter potassium enough to change digoxin effect.
Where the evidence comes from
- Reference knowledge
Open Digoxin (Cardiac Glycoside)Confidence
confidence 55/100
Okay to combine with
Highest probability of useful synergy
- →SupplementsSeleniumCertaintyMediumSourceReference knowledgeComplementary
Selenium is an essential cofactor for iodothyronine deiodinases, which convert T4 to active T3; with iodine from Sea Moss (Irish Moss), it supports thyroid hormone metabolism.
- →SupplementsZincCertaintyMediumSourceReference knowledgeComplementary
Zinc is required for thyroid peroxidase enzyme function and works complementarily with iodine from Sea Moss (Irish Moss) for thyroid hormone synthesis.
- →SupplementsProbioticsCertaintyMediumSourceReference knowledgeComplementary
Sea moss acts as a prebiotic due to its carrageenan and fiber content, providing a substrate for beneficial gut bacteria; co-administration with probiotics may enhance gut health synergistically.
- →SupplementsVitamin C (Ascorbic Acid)CertaintyMediumSourceReference knowledgePotentiating
Vitamin C enhances the absorption of non-heme iron present in sea moss, potentially improving its nutrient replenishment effects for iron status.
Where the evidence comes from
- Reference knowledge
Open Vitamin C (Ascorbic Acid)Confidence
confidence 55/100
Weakens or is weakened by
Highest probability
- →SupplementsCalciumCertaintyMediumSourceReference knowledgeCompetitive
Taking Calcium and Sea Moss simultaneously can cause Calcium to bind with minerals in Sea Moss, reducing absorption of iodine, potassium, and other trace minerals from both sources.
- →LithiumCertaintyMediumSourceReference knowledgeDepleting
Iodine in sea moss may reduce the efficacy of lithium in bipolar disorder by altering thyroid function, which can indirectly destabilize mood regulation and increase risk of lithium-induced goiter or hypothyroidism.
Where the evidence comes from
- Reference knowledge
Confidence
confidence 60/100
Also listed as dangerous interaction — do not combine. This antagonist entry explains the pharmacological mechanism.
Open Lithium
Forms & dosage
Raw Sea Moss (Chondrus crispus)
Oral4/10
Iodine and heavy-metal levels may vary depending on where the raw dried sea moss was harvested. Thorough washing and sourcing from a reputable supplier are recommended.
- Bioavailability
- Low
- Availability
- Health & supplement stores
- Rating
- 4/10 · Minimal
The most traditional and widely available form, but nutrient content is highly variable and bioavailability is uncharacterized. Lacks standardization.
May cause digestive upset in sensitive individuals due to high fiber and carrageenan content.
4 g · Daily
Pharmacology- Daily total
- 4 g
- Time of day
- Any time
- With meals
- Any time
Sea Moss (Irish Moss)
Oral5/10
This form is perishable, so it must be refrigerated and consumed within a few weeks. It is often combined with lime or other preservatives.
- Bioavailability
- Low
- Availability
- Health & supplement stores
- Rating
- 5/10 · Minimal
The most popular consumer form, but essentially identical to raw powder in nutrient profile. Gel formation may slightly improve digestibility.
Perishable and requires refrigeration. Tolerability is generally good, but the carrageenan content can be a gut irritant for some.
10 g · Daily
Pharmacology- Daily total
- 10 g
- Time of day
- Any time
- With meals
- Any time
Sea Moss Extract (Standardized)
Oral6/10
- Bioavailability
- Moderate
- Availability
- Health & supplement stores
- Rating
- 6/10 · Minimal
Offers a more concentrated and potentially more consistent dose than raw or gel forms, but still lacks robust clinical data on specific bioactive compounds.
May be better tolerated than raw sea moss as it contains less indigestible fiber.
500 mg · Daily
Pharmacology- Daily total
- 500 mg
- Time of day
- Any time
- With meals
- Any time
Sea Moss Topical Gel
Topical3/10
- Availability
- Health & supplement stores
- Rating
- 3/10 · Minimal
Purely a cosmetic form with no evidence of systemic absorption. Used for its mucilaginous and mineral content on the skin.
Generally well-tolerated topically, but can cause irritation in sensitive individuals.
Research & prescription forms (1)
Forms used in research or medicine — not everyday consumer products.
Chondrus crispus Extract (Research Grade)
OralDelivery researchResearch suppliers only · research only
A purified, non-commercial extract used in in-vitro and animal studies to investigate specific bioactives like carrageenans and peptides, not sold as a consumer supplement.
Used to isolate mechanisms of action, such as immunomodulatory or antiviral effects, distinct from whole-plant consumer products.
Community experience
Based on 310 public posts from Reddit, YouTube, and Bluesky.
What users report (not studied)
No study backs these. They come only from public posts and videos.
10 outcomes mentioned across 310 public reports. A report often mentions several, so these counts do not add up to the total.
Reported benefits7
- Physical Energy Increase40 mentionsReddit, Youtube
- Immune System Support15 mentionsReddit
- Mood Improvement13 mentionsReddit, Youtube
- Chronic Pain Reduction9 mentionsReddit, Youtube
- Sleep Quality Improvement8 mentionsReddit
- Constipation Relief8 mentionsReddit, Youtube
- Detoxification Support6 mentionsYoutube, Reddit
What people report taking
dose read from 11 of 310 reportsToo few reports gave a readable dose, so no typical dose is shown.
Forms taken
How often
Self-reported from public posts and videos. Not evidence of effect, and not a recommendation.
More
Write-up
For Sea Moss (Irish Moss), the listed marker is Immunoglobulin A, a lab-based biomarker rather than a number you can measure at home. The expected direction is an increase, reported in mg/dL. A result that does not increase is information about the observed change, but it should not be treated by itself as proof that Sea Moss (Irish Moss) is working or not working.
A practical way to check this marker is the Immune Standard panel, which includes Immunoglobulin A and does not require fasting. Recheck after 3.5 weeks rather than measuring again too early, since timing affects how the result is interpreted. This is self-tracking information, not a diagnosis; results that appear abnormal or raise concern belong with a clinician.
References
10 screened · 8 analysed · 10 listed below
Studies and sources cited on this page. Evidence quality varies — check the grade on each.
- Maine organic dairy producers' receptiveness to seaweed supplementation and effect of Chondrus crispus on enteric methane emissions in lactating cows.Front Vet Sci2023Animal studyD
- “Fueling the Fire” - Irish Sea-Moss Resulting in Jod-Basedow Phenomenon in a Patient With Grave’s DiseaseJ Endocr Soc2021Case StudyDn=1
- The effect of Red Seaweed (Chondrus crispus) on the fertility of male albino rats.Saudi J Biol Sci2021Animal studyD
- Effects of Dietary Inclusion of Seaweed, Heat Stress and Genetic Strain on Performance, Plasma Biochemical and Hematological Parameters in Laying Hens.Animals (Basel)2020Animal studyD
- Feed Supplementation with Red Seaweeds, Chondrus crispus and Sarcodiotheca gaudichaudii, Reduce Salmonella Enteritidis in Laying Hens.Front Microbiol2017Animal studyD
- Red Seaweeds Sarcodiotheca gaudichaudii and Chondrus crispus down Regulate Virulence Factors of Salmonella Enteritidis and Induce Immune Responses in Caenorhabditis elegans.Front Microbiol2016Animal studyD
- A Cultivated Form of a Red Seaweed (Chondrus crispus), Suppresses β-Amyloid-Induced Paralysis in Caenorhabditis elegans.Mar Drugs2015Animal studyD
- Prebiotic effects of diet supplemented with the cultivated red seaweed Chondrus crispus or with fructo-oligo-saccharide on host immunity, colonic microbiota and gut microbial metabolites.BMC Complement Altern Med2015Animal studyD
- Feed supplementation with red seaweeds, Chondrus crispus and Sarcodiotheca gaudichaudii, affects performance, egg quality, and gut microbiota of layer hens.Poult Sci2014Animal studyD
- Established pharmacology