MICROgenics Kelp 1000 [Discontinued] by Carlson Health

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Dental plaque. It is unclear if oral Ascophyllum nodosum is beneficial in patients with dental plaque. Details: A small crossover study in adults with moderate to heavy calculus formation shows that taking a specific brand of Ascophyllum nodosum capsules (ProDen PlaqueOff, SDC Swedencar eAB) 500 mg daily for 6 months reduces the buildup of supragingival calculus by 52% when compared with placebo. The buildup of plaque was reduced by 19% in males, but was not reduced in females, when compared with placebo (94996).
• Gastroesophageal reflux disease (GERD). Although there has been interest in using oral Ascophyllum nodosum for GERD, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose.
• Gingivitis. It is unclear if oral Ascophyllum nodosum is beneficial in patients with dental plaque. Details: A small crossover study in adults with moderate to heavy calculus formation shows that taking a specific brand of Ascophyllum nodosum capsules (ProDen PlaqueOff, SDC Swedencar eAB) 500 mg daily for 6 months does not reduce gingivitis when compared with placebo (94996).
• Impaired glucose tolerance (prediabetes). Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with prediabetes that are overweight or obese shows that taking a specific product (InSea2, InnoVactiv Inc.) containing 500 mg of Ascophyllum nodosum and Fucus vesiculosus extracts daily for 12 weeks reduces postprandial blood glucose but does not improve fasting blood glucose, glycated hemoglobin (HbA1c), body weight, lipids, or blood pressure when compared with placebo (110560).
• Inflammatory bowel disease (IBD). Although there has been interest in using oral Ascophyllum nodosum for IBD, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose.
• Iodine deficiency. It is unclear if oral Ascophyllum nodosum is beneficial in patients with iodine deficiency. Details: Ascophyllum nodosum contains iodine, and there is interest in its use for patients with iodine deficiency. A small clinical study in females with iodine insufficiency shows that taking a specific brand of Ascophyllum nodosum capsules (Napiers Hebridean Seagreens (NaHS), Seagreens Ltd) 500 mg daily for 14 days increases urinary iodine excretion by almost three-fold and increases thyroid stimulating hormone levels by 36% when compared with baseline (94997). The validity of these findings is limited by the lack of a control group.
• Metabolic syndrome. Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Observational research in adults with one or more components of metabolic syndrome has found that taking a specific combination product (Gdue, Aesculapius) containing extracts of Ascophyllum nodosum and Fucus vesiculosus in a 95:5 ratio along with chromium picolinate two to three times daily with meals for around 6 months is associated with reductions in body weight by 7.3 kg, waist circumference by 7.5 cm, fasting blood glucose by 16 mg/dL, glycated hemoglobin (HbA1c) by 0.55%, systolic blood pressure by 7 mmHg, diastolic blood pressure by 4 mmHg, low-density lipoprotein (LDL) cholesterol by 18 mg/dL, and 10-year cardiovascular risk scores by 1.8% when compared to baseline (110559). It is unclear if these effects are due to Ascophyllum nodosum, Fucus vesiculosus, or the combination. Further, the validity of these findings is limited by a lack of control group.
• Obesity. Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with prediabetes that are overweight or obese shows that taking a specific product (InSea2, InnoVactiv Inc.) containing 500 mg of Ascophyllum nodosum and Fucus vesiculosus extracts daily for 12 weeks does not reduce body weight, body mass index (BMI), body fat, lipids, blood pressure, or measures of glycemic control when compared with placebo (110560).
• Peptic ulcers. Although there has been interest in using oral Ascophyllum nodosum for peptic ulcers, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose. More evidence is needed to rate Ascophyllum nodosum for these uses.

(Read more about ASCOPHYLLUM NODOSUM)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging skin. Although there has been interest in using topical Fucus vesiculosus for aging skin, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose.
• Cardiovascular disease (CVD). Although there has been interest in using oral Fucus vesiculosus for CVD, including atherosclerosis and hypertension, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose.
• Constipation. Although there has been interest in using oral Fucus vesiculosus for constipation, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose.
• Diarrhea. Although there has been interest in using oral Fucus vesiculosus for diarrhea, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose.
• Dyspepsia. Although there has been interest in using oral Fucus vesiculosus for dyspepsia, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose.
• Hypercholesterolemia. It is unclear if oral Fucus vesiculosus is beneficial in hypercholesterolemia. Details: A small clinical study in patients with obesity or overweight and low-density lipoprotein (LDL) cholesterol levels exceeding 77 mg/dL shows that taking a polyphenol-rich extract of Fucus vesiculosus (Maritech Synergy, Marinova) 2000 mg, providing 560 mg of polyphenols, daily for 12 weeks increases levels of high-density lipoprotein (HDL) cholesterol by 10%, compared with 2% in those receiving placebo. No differences were observed for total cholesterol, LDL cholesterol, or triglycerides (106723).
• Hypothyroidism. Although there has been interest in using oral Fucus vesiculosus for hypothyroidism, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose.
• Impaired glucose tolerance (prediabetes). Oral Fucus vesiculosus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with prediabetes and dysglycemia shows that taking a specific product (Gdue, Aesculapius), containing extracts of Fucus vesiculosus and Ascophyllum nodosum in a 5:95 ratio along with chromium picolinate three times daily for 6 months reduces fasting and postprandial blood glucose, glycated hemoglobin (HbA1c), insulin, and insulin resistance when compared with placebo (100847). It is unclear if these effects are due to Fucus vesiculosus, other ingredients, or the combination. Another small clinical study in adults with prediabetes and also overweight or obese shows that taking a specific product (InSea2, InnoVactiv Inc.) containing 500 mg of Fucus vesiculosus and Ascophyllum nodosum extracts daily for 12 weeks reduces postprandial blood glucose but does not improve fasting blood glucose, HbA1c, body weight, lipids, or blood pressure when compared with placebo (110560).
• Iodine deficiency. Although there has been interest in using oral Fucus vesiculosus for iodine deficiency and goiter, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose.
• Metabolic syndrome. Oral Fucus vesiculosus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Observational research in adults with one or more components of metabolic syndrome has found that taking a specific combination product (Gdue, Aesculapius) containing extracts of Fucus vesiculosus and Ascophyllum nodosum in a 5:95 ratio along with chromium picolinate two to three times daily with meals for around 6 months is associated with reductions in body weight by 7.3 kg, waist circumference by 7.5 cm, fasting blood glucose by 16 mg/dL, glycated hemoglobin (HbA1c) by 0.55%, systolic blood pressure by 7 mmHg, diastolic blood pressure by 4 mmHg, low-density lipoprotein (LDL) cholesterol by 18 mg/dL, and 10-year cardiovascular risk scores by 1.8% when compared to baseline (110559). It is unclear if these effects are due to Fucus vesiculosus, other ingredients, or the combination. Further, the validity of these findings is limited by a lack of control group.
• Obesity. Oral Fucus vesiculosus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in moderately overweight females shows that seaweeds such as Fucus vesiculosus, taken in combination with lecithin and vitamins for up to 2 years, do not result in sustained weight loss when compared to baseline (13663). Another small clinical study in adults with prediabetes and also overweight or obese shows that taking a specific product (InSea2, InnoVactiv Inc.) containing 500 mg of Fucus vesiculosus and Ascophyllum nodosum extracts daily for 12 weeks does not reduce body weight, body mass index (BMI), body fat, lipids, blood pressure, or measures of glycemic control when compared with placebo (110560).
• Wound healing. Although there has been interest in using topical Fucus vesiculosus for wound healing, there is insufficient reliable information about the clinical effects of Fucus vesiculosus for this purpose. More evidence is needed to rate Fucus vesiculosus for these uses.

(Read more about FUCUS VESICULOSUS)

POSSIBLY INEFFECTIVE

• Abortion. Despite traditional use for the induction of second trimester abortion, most research shows that intravaginal laminaria does not significantly reduce time to delivery or improve abortion rates, and it may actually worsen some outcomes when compared with standard of care. Details: One clinical study shows that intravaginal administration of laminaria along with misoprostol does not improve second trimester abortion rates at 24 and 48 hours after treatment initiation when compared with using only misoprostol. Also, using laminaria along with misoprostol does not shorten delivery time when compared with misoprostol alone (95688). Another small clinical study shows that adding intravaginal laminaria to misoprostol therapy significantly increases induction time and the need for opioid analgesics when compared with misoprostol alone (109576). Also, a small clinical study in patients undergoing second trimester abortions shows that intravaginal laminaria increases pain with cervical ripening and induction-to-delivery time when compared with mifepristone (109577). A retrospective study in 126 patients undergoing second trimester abortions has found that intravaginal administration of laminaria (Dilateria, Cooper Surgical) one day before using misoprostol might actually prolong delivery time by about 6 hours and does not improve abortion rates at 24 hours after induction when compared with misoprostol alone (105806). Some research shows that intravaginal administration of laminaria (Dilateria, Milex Products Inc.) one day before using prostaglandin E2 (PGE2) suppositories to induce second trimester abortions shortens the delivery time by about 3 hours when compared with PGE2 suppositories alone; however, the incidence of febrile episodes is about 2.3-fold higher for patients treated with laminaria (94045). Also, one small clinical study shows that intravaginal administration of laminaria the night before a scheduled abortion reduces procedure time by around 4 minutes, increases cervical dilation at the time of abortion, and reduces the need for additional dilation when compared with misoprostol treatment on the day of abortion. However, more patients preferred misoprostol over laminaria (109575). Laminaria has also been compared with a mechanical cervical dilation device, called Dilapan-S. A small clinical study in patients undergoing second trimester surgical abortion shows that intravaginal administration of laminaria for cervical preparation has no effect on pain scores or analgesic use following dilator placement or dilation and evacuation (D&E) when compared with Dilapan-S. The validity of these findings may be limited by the single-blinded nature of the study, as well as significant baseline differences between the treatment groups with respect to vaginal parity (105805).
• Parturition. Intravaginal administration of laminaria does not seem to be beneficial for cervical ripening. Details: While some research suggests that intravaginal laminaria might reduce the duration of induction, results are conflicting. Additionally, studies suggest that intravaginal laminaria does not seem to reduce the incidence of birth by caesarean section (8945,95689,102765). Also, a small observational study has found that intravaginal laminaria is associated with a greater risk of endometritis and fetal infectious complications when compared with a control group not receiving laminaria (8945).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acute radiation syndrome. Although there has been interest in using oral laminaria for acute radiation syndrome, there is insufficient reliable information about the clinical effects of laminaria for this purpose.
• Cancer. Although there has been interest in using oral laminaria for cancer prevention, there is insufficient reliable information about the clinical effects of laminaria for this purpose.
• Hypertension. Although there has been interest in using oral laminaria for hypertension, there is insufficient reliable information about the clinical effects of laminaria for this purpose.
• Obesity. It is unclear if oral laminaria is beneficial in patients with obesity. Details: A small clinical study in overweight Japanese adults shows that taking iodine-reduced laminaria powder 2 grams, providing 1 gram of alginate, three times daily for 8 weeks reduces body fat percentage in males, but not females, when compared with placebo. Laminaria does not affect body weight or body mass index when compared with placebo (109572).
• Radiation exposure. Although there has been interest in using oral laminaria to minimize environmental radiation exposure, there is insufficient reliable information about the clinical effects of laminaria for this purpose. More evidence is needed to rate laminaria for these uses.

(Read more about LAMINARIA)

POSSIBLY SAFE ...when used orally, short-term. Ascophyllum nodosum dried powder has been used with apparent safety at a dose of up to 500 mg daily for up to 6 months (94996,94997,103900). However, marine products such as Ascophyllum nodosum are known to accumulate heavy metals such as arsenic (94997,94999). Some supplement products are prospectively analyzed to confirm a lack of contaminants and that heavy metal levels are below threshold (94997).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using amounts greater than those found in food.

(Read more about ASCOPHYLLUM NODOSUM)

POSSIBLY SAFE ...when applied topically to the skin. A gel containing 1% Fucus vesiculosus extract, applied to the skin twice daily, has been used in clinical research with apparent safety for up to 5 weeks (12799).

POSSIBLY UNSAFE ...when used orally due to its iodine content and possible heavy metal content. Fucus vesiculosus contains up to 0.05% iodine or 226 mcg/gram dry weight (12789,74217). Ingesting more than 150 mcg of iodine daily can cause hyperthyroidism or exacerbate existing hyperthyroidism (12788). Fucus vesiculosus can also contain heavy metals, including cadmium, arsenic, and lead, and can cause heavy metal nephropathy (12789,12800,74213).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally because it may contain iodine and heavy metals (12789,74213,74217); avoid using.

(Read more about FUCUS VESICULOSUS)

LIKELY SAFE ...when used in amounts found in foods. Laminaria has Generally Recognized as Safe (GRAS) status in the US (94048).

POSSIBLY SAFE ...when iodine-reduced laminaria supplements are used, short-term. Iodine-reduced laminaria powder has been safely used at doses up to 6 grams daily for up to 8 weeks (109572).

POSSIBLY UNSAFE ...when used orally in medicinal amounts. The average laminaria-based supplement might contain as much as 1000 mcg of iodine. Ingesting more than 1100 mcg iodine daily (the tolerable upper intake level) can cause hypothyroidism, hyperthyroidism, or exacerbate existing hyperthyroidism (9556,94046). In addition, some laminaria supplements may contain arsenic (645,10275,15588). There is insufficient reliable information available about the safety of laminaria for its other uses.

PREGNANCY: POSSIBLY UNSAFE
when used intravaginally for cervical ripening; there is an increased risk of parental and neonatal infection (8945).

PREGNANCY: LIKELY UNSAFE
when used intravaginally to induce labor; use has been associated with endometriosis, neonatal sepsis, fetal hypoxia, and intrauterine death (6).

PREGNANCY: UNSAFE
when used orally due to potential hormonal effects (19); avoid using.

LACTATION: LIKELY UNSAFE
when used orally because of potential toxicity (19).

(Read more about LAMINARIA)

AMIODARONE (Cordarone) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, combining Ascophyllum nodosum with amiodarone might cause excessively high iodine levels.  Details Ascophyllum nodosum contains iodine (94997,95000,95102), although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide (94997). Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use might increase the risk of having excessive iodine levels and adversely affecting thyroid function (7135,17574). Monitor thyroid function.

ANTITHYROID DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, Ascophyllum nodosum might alter the effects of antithyroid drugs.  Details Ascophyllum nodosum contains iodine (94997,95000,95102), although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide (94997). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Ascophyllum nodosum while using antithyroid drugs could alter the effects of the antithyroid drugs (17574).

THYROID HORMONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.  Details Ascophyllum nodosum contains iodine (94997,95000,95102), although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide (94997). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Ascophyllum nodosum while using thyroid hormone could alter the effects of thyroid hormone (17574).

(Read more about ASCOPHYLLUM NODOSUM)

AMIODARONE (Cordarone) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, combining Fucus vesiculosus with amiodarone might cause excessively high iodine levels.  Details Fucus vesiculosus contains high concentrations of iodine (7135). Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use might increase the risk of having excessive iodine levels and adversely affecting thyroid function (7135,17574). Monitor thyroid function.

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, taking Fucus vesiculosus with antiplatelet or anticoagulant drugs might increase the risk of bruising and bleeding.  Details In vitro evidence suggests that a constituent of Fucus vesiculosus, known as fucoidan, has anticoagulant effects (12797,74149,74183,74240). However, in clinical research, fucoidan does not seem to have significant anticoagulant activity when taken orally, possibly due to poor absorption (74183).

ANTITHYROID DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, Fucus vesiculosus might alter the effects of antithyroid drugs.  Details Fucus vesiculosus contains high concentrations of iodine (7135). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Fucus vesiculosus while using antithyroid drugs could alter the effects of the antithyroid drugs (2138,17574).

CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of Fucus vesiculosus with CYP2C8 substrates might increase the risk for adverse effects.  Details In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP2C8 (97791). This interaction has not been reported in humans.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of Fucus vesiculosus with CYP2C9 substrates might increase the risk for adverse effects.  Details In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP2C9 (97791). This interaction has not been reported in humans.

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of Fucus vesiculosus with CYP2D6 substrates might alter the effects of these substrates.  Details In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, both inhibits and induces CYP2D6 (97791). This interaction has not been reported in humans.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of Fucus vesiculosus with CYP3A4 substrates might increase the risk for adverse effects.  Details In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP3A4 (97791). This interaction has not been reported in humans.

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Concomitant use of Fucus vesiculosus and lithium has resulted in hyperthyroidism.  Details There is a case of hyperthyroidism occurring in a patient taking Fucus vesiculosus and lithium (74217). Monitor thyroid hormones closely in patients taking lithium and Fucus vesiculosus concomitantly.

THYROID HORMONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, Fucus vesiculosus might alter the effects of thyroid hormone.  Details Fucus vesiculosus contains high concentrations of iodine (7135). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Fucus vesiculosus while using thyroid hormone could alter the effects of thyroid hormone.

(Read more about FUCUS VESICULOSUS)

ACE INHIBITORS (ACEIs) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, laminaria might increase the risk of hyperkalemia when taken with ACEIs.  Details Laminaria contains potassium (19).

AMIODARONE (Cordarone) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, combining laminaria with amiodarone might cause excessively high iodine levels.  Details Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use with laminaria supplements, some of which may contain as much as 1000 mcg iodine, might increase the risk of adverse effects from iodine, including altered thyroid function (9556,94046).

ANTITHYROID DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, laminaria might alter the effects of antithyroid drugs.  Details Some laminaria supplements contain up to 1000 mcg of iodine (9556,94046). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking laminaria could theoretically alter the effects of antithyroid drugs.

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, laminaria might increase the risk of hyperkalemia, which could increase the effects and adverse effects of digoxin.  Details Laminaria contains potassium (19).

POTASSIUM-SPARING DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, laminaria might increase the risk of hyperkalemia when taken with potassium-sparing diuretics.  Details Laminaria contains potassium (19).

THYROID HORMONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, laminaria might alter the effects of thyroid hormone.  Details Some laminaria supplements contain up to 1000 mcg of iodine (9556,94046). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking laminaria could theoretically alter the effects of thyroid hormone.

(Read more about LAMINARIA)

General ...Orally, Ascophyllum nodosum seems to be generally well-tolerated.

Endocrine ...Orally, taking Ascophyllum nodosum powder 500 mg daily for 14 days has been reported to cause elevated levels of thyroid stimulating hormone (TSH) in 2 of 22 women in a clinical trial. The powder contained 356 mcg iodine per 500 mg. Levels of free thyroxine (T4) were unaffected (94997).

Gastrointestinal ...Orally, Ascophyllum nodosum has been reported to cause stomach discomfort in one clinical trial (94996).

(Read more about ASCOPHYLLUM NODOSUM)

General ...When used orally, Fucus vesiculosus may be unsafe due to its iodine content. Topically, Fucus vesiculosus appears to be well tolerated.
Most Common Adverse Effects:
Orally: Goiter, hyperthyroidism, hypothyroidism.
Serious Adverse Effects (Rare):
Orally: Thyroid cancer.

Cardiovascular ...In one report, a young adult with obesity developed palpitations and syncope after taking an oral weight loss supplement containing a combination of Fucus vesiculosus, dandelion, and boldo for 3 weeks. The patient was found to have a prolonged QT interval on ECG and frequent episodes of sustained polymorphic ventricular tachycardia (14321). It is not clear whether Fucus vesiculosus, another ingredient, or the combination of ingredients is responsible for this adverse effect. The product was not analyzed to determine the presence of any potential toxic contaminants.

Endocrine ...Orally, Fucus vesiculosus can cause or exacerbate hyperthyroidism due to its high iodine content (12789,13061,74217). One case of hyperthyroidism has been reported for a 60-year-old patient taking lithium for bipolar disorder and a combination product containing Fucus vesiculosus 0.125 grams, cascara 0.170 grams, and Frangula 0.222 grams per tablet for laxative purposes. The patient had been taking one tablet of the combination laxative product daily for several years. Following discontinuation of the supplement, thyroid levels normalized (74217). Similar cases of hyperthyroidism have been reported for patients taking other seaweed-containing herbal supplements (Dream Shape; Ever Youth). Analyses of these supplements shows that these products contain triiodothyronine 1 mcg and thyroxine 3-4 mcg. In addition to seaweed, Dream Shape also contains hydrangea vine, maltose, chrysanthemum, Chinese matrimony vine, and sucrose, while Ever Youth contains radish, lotus leaf, chrysanthemum, hawthorn, senna tea, and Chinese matrimony vine (13061).
Orally, prolonged use of Fucus vesiculosus has been associated with hypothyroidism (13664). The iodine in Fucus vesiculosus can cause idiosyncratic reactions.
According to the Institute of Medicine Food and Nutrition Board, prolonged, high dietary intake of iodine is associated with goiter and an increased risk of thyroid cancer (7135).

Genitourinary ...A case of hemorrhagic cystitis characterized by dysuria and polyuria has been reported in a young adult who took a specific product (Slim-Kombu, Balestra and Mech) containing Fucus vesiculosus and 19 other herbal extracts orally for weight loss. Upon discontinuation, symptoms improved (46959). It is unclear if this effect was due to Fucus vesiculosus or other ingredients in the supplement.

Renal ...A case of hemorrhagic cystitis characterized by dysuria and polyuria has been reported in a young adult who took a specific product (Slim-Kombu, Balestra and Mech) containing Fucus vesiculosus and 19 other herbal extracts orally for weight loss. Upon discontinuation, symptoms improved (46959). It is unclear if this effect was due to Fucus vesiculosus or other ingredients in the supplement. Nephrotoxicity has been associated with oral intake of Fucus vesiculosus that was contaminated with arsenic (12800).

(Read more about FUCUS VESICULOSUS)

General ...Orally, iodine-reduced laminaria seems to be well tolerated, while other laminaria formulations may contain excess amounts of iodine, as well as arsenic.
Most Common Adverse Effects:
Intravaginally: Cervical bleeding and pelvic cramps.
Serious Adverse Effects (Rare):
Orally: Arsenic poisoning.
Intravaginally: Rupture of cervical wall, fetal hypoxia, and fetal death. Anaphylaxis in sensitive individuals.

Dermatologic ...Orally, laminaria has been linked to a report of induced or exacerbated acne (9555).

Endocrine ...Orally, laminaria can affect levels of certain thyroid hormones, and might cause hypothyroidism or hyperthyroidism, or exacerbate existing hyperthyroidism (9556,94046).

Genitourinary ...Intravaginally, laminaria used for cervical ripening can cause pelvic cramps and cervical bleeding (8945). Uterine contractions associated with laminaria use have been implicated in fetal hypoxia and subsequent intrauterine death (6). Use of endocervical laminaria tents has been associated with possible rupture of the cervical wall and subsequent neonatal and parental infection (6,8945).

Immunologic ...There are case reports of anaphylactic reactions to laminaria when used intravaginally as a cervical dilator. In at least one case, ventilation was required (102766).

Other ...Laminaria concentrates arsenic from the ocean. In one case, use of an oral laminaria supplement for several months resulted in symptoms of arsenic poisoning including headache, weakness, fatigue, worsening memory loss, rash, nail damage, diarrhea, and vomiting. Urinary arsenic levels were elevated (15588). The concentration of arsenic in laminaria may vary between different batches, and also depends upon the part of the world where it was harvested (645,10275,15588). The concentration of arsenic has been reported to be higher in preparations from Australia than from Great Britain (645,10275).

(Read more about LAMINARIA)