Juna Nightcap Sleep Gummies Review 2026: Worth the Price?
Read before you buy. — Mostly Legit
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"Microdose melatonin avoids hangover and crash"
MIT study: 0.3mg melatonin improved sleep efficiency better than higher doses or placebo. Standard dose, not novel.
PubMed: Melatonin dosage research (MIT study cited in product marketing) -
"Magnesium supports sleep and relaxation"
Clinical trials show 250-360mg elemental magnesium daily improves sleep; Juna's dose not disclosed.
PubMed: Magnesium sleep studies (knowledge base) -
"Plant-derived melatonin is superior to synthetic"
Phytomelatonin and synthetic melatonin are chemically identical; no clinical difference in efficacy or safety.
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"Price is $42 for 30 gummies (30-day supply)"
Estimated ingredient cost $0.20-0.40 per gummy; retail price $1.40 = 3.5-7x markup. Alternatives cost $23-37/month.
Internal: wholesale cost analysis vs. retail pricing
Consumer advice
If you like gummies and prefer convenience over cost, Nightcap is a legitimate option. But before buying, test whether you respond to 0.3mg melatonin alone (buy a cheap bottle first). If you do, save money by buying melatonin, magnesium, and passionflower separately—or try a basic melatonin gummy at 1/4 the price. The subscription discount (15% off) only makes sense if you commit to nightly use for 60+ days; otherwise, one-time purchase is fine. Avoid if you're pregnant, on SSRIs, or have bipolar disorder without doctor approval.
Claims vs Evidence
MODEST5 claims assessed. These grades assess the marketing claims, not the whole product. See each explanation for the evidence and its limits.
"Supports a restful night's sleep"
Supported
Melatonin 0.3mg improves sleep efficiency; magnesium, passionflower, and chamomile have moderate evidence for sleep support.
Based on: Phytomelatonin, Magnesium, Passionflower, Chamomile
"Helps you wake up refreshed without grogginess"
Partial
Low-dose melatonin (0.3mg) avoids hangover better than high doses; individual response varies.
Based on: Phytomelatonin
"Non-habit forming"
Supported
Melatonin and magnesium are not addictive; no physical dependence documented in clinical trials.
Based on: Phytomelatonin, Magnesium
"Supports evening relaxation and calm"
Partial
Passionflower and chamomile have weak-to-moderate evidence; GABA and L-tryptophan have poor oral bioavailability.
Based on: Passionflower, Chamomile, GABA, L-tryptophan
"Waking up refreshed"
Stretch
Sleep quality depends on sleep duration and circadian rhythm, not just melatonin dose.
Based on: Phytomelatonin
2 supported · 2 partial · 1 stretch
Signals
- Shows actual ingredient doses
Ingredients
Based on peer-reviewed research from PubMed and Examine.com
Why the chain breaks for this product
Most ingredients below have real research behind them. The problem isn't the ingredients — it's the doses. 22 of 47 are underdosed compared to the clinical studies, or not disclosed at all, so the product can claim the benefits without delivering the chain that gets you there.
Phytomelatonin (from St. John's Wort)
Natural sleep hormone. Clinically shown to improve sleep quality and reduce some inflammation-related symptoms.
Research-backed dose: 0.3–10 mg daily depending on use case
In this product: not specified (described as 'microdose')
Magnesium Blend
Essential minerals that regulate hydration, nerve function, and muscle contraction. Critical for recovery after heavy exercise.
Research-backed dose: 250-360 mg elemental magnesium daily for sleep/mood support
In this product: 100 mg
Underdosed: even at the label's max 1 serving/day, it falls short of the research-backed dose.
Traditional herb with early evidence for mild sleep improvement and anxiety relief. Most studies are small or use combinations.
Traditional fruit with early clinical evidence for blood sugar, cholesterol, and skin brightening benefits.
Antioxidant-rich fruit extract. May reduce exercise-related muscle damage and inflammation.
Research-backed dose: 500 mg daily based on available study data
In this product: Dose not disclosed
Herbal flower extract with clinical evidence for menopause symptoms, pain relief, and anxiety reduction.
Research-backed dose: 100-400 mg daily (oral); topical oil also studied
In this product: Dose not disclosed
Plant from beer brewing. Early research shows anti-inflammatory effects; human evidence is still very limited.
Brain's main calming neurotransmitter. Supplement form has limited evidence for direct brain effects.
Essential amino acid that may help regulate appetite and blood sugar when combined with other nutrients.
Rare low-calorie sugar that may help manage blood sugar and reduce calorie intake.
FiberSMART® Tapioca Syrup
Starchy root vegetable used as a food staple; biofortified forms may help address vitamin A deficiency.
Soluble plant fiber with prebiotic effects; early research suggests gut, metabolic, and immune benefits.
Cherry Powder
Powdered cherry used for color and flavor; dose too low for sleep benefits.
Organic acid found in fruit. Limited evidence for dry mouth relief; most supplement claims lack clinical backing.
In this product: 5 mg
Natural Colors (from Beets and Carrots)
Beetroot juice may improve exercise capacity and lower blood pressure, especially in COPD patients.
Pecmate®
South American herbal tea with antioxidant compounds. Human evidence is very limited and mostly pre-clinical.
Vitamin A (as beta-carotene)
Essential fat-soluble vitamin. Evidence from these studies is mixed and mostly indirect or context-specific.
In this product: 900 mcg
Vitamin C (as ascorbic acid)
Essential vitamin with well-known immune and antioxidant roles; topical form supports collagen and skin tone.
Research-backed dose: 65-2000 mg/day oral (RDA: 75-90 mg/day adults); 10-20% concentration topical serums
In this product: 90 mg
Effective at 1 serving/day, as the label directs.
Vitamin D (as cholecalciferol)
Essential fat-soluble vitamin. Supports bone health, immune function, and may improve exercise tolerance in deficient individuals.
Research-backed dose: 400–80,000 IU daily depending on condition and deficiency status
In this product: 20 mcg
Vitamin E (as d-alpha tocopheryl succinate)
Gentle skin acid that reduces redness, fights acne, and moisturizes with less irritation than glycolic acid.
In this product: 15 mg
Fat-soluble vitamin essential for blood clotting and bone health. Well-established nutritional role.
Research-backed dose: 90-120 mcg/day (Adequate Intake); higher doses used clinically for specific conditions
In this product: 120 mcg
Effective at 1 serving/day, as the label directs.
Thiamin (as thiamin mononitrate)
B1 vitamin form used in supplements. Corrects deficiency but high-dose supplementation shows limited clinical benefit.
In this product: 1.2 mg
B vitamin essential for energy metabolism. Most evidence in provided studies is for eye procedures, not oral supplements.
In this product: 1.3 mg
Niacin (as niacinamide)
Essential B vitamin that supports metabolism and immunity. Deficiency causes pellagra. Evidence for broader benefits is mixed.
In this product: 16 mg NE
Vitamin B6 (as pyridoxine HCl)
Essential B vitamin that supports metabolism, brain function, and immune health. Deficiency causes real harm.
Research-backed dose: 1.3–2.0 mg/day (dietary reference intake); therapeutic doses up to 100 mg/day studied for specific conditions
In this product: 1.7 mg
Underdosed: even at the label's max 1 serving/day, it falls short of the research-backed dose.
Folate (as folic acid)
B-complex effects depend on the exact formula. Specific B1/B6/B12 combinations have evidence as an NSAID adjunct for chronic low-back pain, but that does not establish the same effect for every oral B-complex product.
In this product: 400 mcg DFE
Vitamin B12 (as cyanocobalamin)
Essential B vitamin that treats deficiency-related anemia and supports nerve and metabolic health.
In this product: 2.4 mcg
B vitamin essential for metabolism. Little clinical proof it grows hair or nails in healthy people.
In this product: 30 mcg
Calcium (as calcium carbonate)
Essential mineral for bones and teeth. Widely under-consumed, especially in athletes and dancers.
In this product: 200 mg
Iron (as ferrous fumarate)
Essential dietary fats found in vegetable oils. Balance with omega-3s matters more than omega-6 intake alone.
In this product: 18 mg
Iodine (as potassium iodide)
Essential mineral. Prevents deficiency, but supplement overuse risks exceeding safe upper limits.
In this product: 150 mcg
Zinc (as zinc oxide)
Essential mineral with clinical support for gut health, diarrhea treatment, and immune function.
Research-backed dose: 10-20 mg/day based on study doses
In this product: 11 mg
Effective at 1 serving/day, as the label directs.
Selenium (as sodium selenate)
Essential minerals that regulate hydration, nerve function, and muscle contraction. Critical for recovery after heavy exercise.
In this product: 55 mcg
Essential trace mineral. Supports energy, iron metabolism, and connective tissue. Most people get enough from food.
Research-backed dose: 0.9 mg daily (RDA for adults); upper tolerable limit is 10 mg/day
In this product: 0.9 mg
Effective at 1 serving/day, as the label directs.
Manganese (as manganese sulfate)
Essential trace mineral that supports bone health, metabolism, and antioxidant defense.
Research-backed dose: 1.8–2.3 mg daily (Adequate Intake per age/sex; upper tolerable limit 11 mg/day for adults)
In this product: 2.3 mg
Effective at 1 serving/day, as the label directs.
Essential trace mineral. May support blood sugar regulation, but evidence is limited and inconsistent.
Research-backed dose: 200-1000 mcg daily (general knowledge; no study data provided)
In this product: 35 mcg
Underdosed: even at the label's max 1 serving/day, it falls short of the research-backed dose.
Molybdenum (as sodium molybdate)
Essential trace mineral. Limited human evidence for supplementation benefits beyond basic nutritional needs.
In this product: 45 mcg
Chloride (as potassium chloride)
Essential mineral. Limited direct supplement trial data; one RCT suggests modest blood pressure support.
Research-backed dose: 300 mg/day (supplement form); 3,500–4,700 mg/day total dietary intake per general guidelines
In this product: 72 mg
Underdosed: even at the label's max 1 serving/day, it falls short of the research-backed dose.
Potassium (as potassium chloride)
Essential mineral. Limited direct supplement trial data; one RCT suggests modest blood pressure support.
Research-backed dose: 300 mg/day (supplement form); 3,500–4,700 mg/day total dietary intake per general guidelines
In this product: 80 mg
Underdosed: even at the label's max 1 serving/day, it falls short of the research-backed dose.
Boron (as boron citrate)
Common food acid used in supplements as an excipient. Limited evidence for standalone health benefits.
In this product: 1 mg
Nickel (as nickel sulfate)
A heavy metal with no proven supplement benefit. Primarily known as a common allergen and environmental toxin.
In this product: 5 mcg
Silicon (as silicon dioxide)
Trace mineral found in plants and foods. Early research suggests bone and connective tissue support.
In this product: 2 mg
Vanadium (as vanadyl sulfate)
Cellular energy coenzyme. Limited human evidence; one trial showed fitness gains in a rare disease.
In this product: 10 mcg
Phytomelatonin
Natural sleep hormone. Clinically shown to improve sleep quality and reduce some inflammation-related symptoms.
Research-backed dose: 0.3–10 mg daily depending on use case
In this product: Dose not disclosed
Essential mineral with roles in mood, nerve function, and heart health. Evidence is mixed depending on the condition.
Research-backed dose: 250-350 mg/day based on study doses
In this product: Dose not disclosed
Traditional herb with early evidence for mild sleep improvement and anxiety relief. Most studies are small or use combinations.
Herbal flower extract with clinical evidence for menopause symptoms, pain relief, and anxiety reduction.
Research-backed dose: 100-400 mg daily (oral); topical oil also studied
In this product: Dose not disclosed
Safety & side effects
What NIH says about the ingredients in this product. This describes the ingredients, not tests of this product, and it is not medical advice. Ask a doctor or pharmacist first if you take medication, are pregnant or nursing, or have a health condition.
Melatonin
Short-term use of melatonin supplements appears to be safe for most people, but there isn't enough information on side effects at higher doses, and long-term safety information is lacking. The source flags extra concerns for children, including accidental ingestion and overdose.
Possible side effects
- Side effects reported in short-term adult studies included headache, dizziness, nausea, and sleepiness.
- In children, reported side effects have included drowsiness, more bedwetting or evening urination, headache, dizziness, and agitation.
- Melatonin may stay active longer in older people and cause daytime drowsiness.
Serious risks
- Over-the-counter melatonin might put children and teenagers at risk for accidental or intentional overdose.
- In poison control data on people 19 and younger, five people needed mechanical ventilation and two children under 2 died. The data did not show whether melatonin overdose or another cause led to the deaths.
- Melatonin supplements could affect hormonal development in children, including puberty, menstrual cycles, and prolactin overproduction. The source says this isn't known for sure.
- There may be a risk of allergic reactions to melatonin supplements.
- Some melatonin products may not contain what the label says. In one study, 26 percent of supplements contained serotonin.
Avoid or ask a doctor first if
- The 2015 American Academy of Sleep Medicine guidelines recommend against melatonin use by people with dementia.
- Parents should speak with a health care provider before giving children melatonin.
- Research on melatonin safety in pregnant or breastfeeding women has been lacking.
Medication interactions
- People who take medicine should consult their health care providers before using melatonin.
- People with epilepsy and those taking blood thinner medications need medical supervision when taking melatonin supplements.
Magnesium
Magnesium from food poses no health risk in healthy people, because the kidneys clear the excess. High doses from supplements or medications can cause diarrhea, nausea and abdominal cramping, and very high doses can lead to toxicity.
Possible side effects
- High doses from supplements or medications can cause diarrhea, nausea, and abdominal cramping.
- Magnesium carbonate, chloride, gluconate, and oxide are the forms most commonly reported to cause diarrhea.
Serious risks
- Very high doses can lead to magnesium toxicity, with low blood pressure, vomiting, difficulty breathing, irregular heartbeat, cardiac arrest and other signs.
- A few cases of fatal hypermagnesemia have been reported.
- Very large doses of magnesium-containing laxatives and antacids have been associated with magnesium toxicity.
- The risk of toxicity increases with impaired kidney function or kidney failure.
Avoid or ask a doctor first if
- People with impaired kidney function or kidney failure face higher risk of magnesium toxicity.
- People taking medications regularly should discuss their magnesium intake with their health care providers.
Medication interactions
- Magnesium may interact with oral bisphosphonates, tetracyclines, and quinolone antibiotics.
- Some medications, including diuretics and proton pump inhibitors, can affect magnesium status.
Upper limit: 350 mg a day for adults 19+. This label lists 100 mg.
Source: NIH Office of Dietary Supplements, Magnesium: Fact Sheet for Health Professionals
Passionflower
NCCIH says passionflower is likely safe as a food flavoring and may be safe as a tea for up to 7 nights or as a daily extract for up to 8 weeks. It may interact with anesthesia drugs and should not be used during pregnancy.
Possible side effects
- Possible side effects include drowsiness, dizziness, and confusion.
Serious risks
- Taken with anesthesia or other medicines used before and after surgery, passionflower might slow down the nervous system too much.
- Use in pregnancy may induce uterine contractions and possibly lead to other problems.
Avoid or ask a doctor first if
- Pregnant people should not use passionflower.
- People taking passionflower within 2 weeks of a scheduled surgery should talk to their health care provider.
- Little is known about whether passionflower is safe while breastfeeding.
Medication interactions
- Passionflower might interact with some anesthesia drugs.
- People who take any medicine should talk with their provider before using passionflower, since some herbs and medicines interact in harmful ways.
Chamomile
NCCIH says chamomile is likely safe orally in amounts found in teas and other foods, and possibly safe short term for medicinal use. Side effects are uncommon, but allergic reactions, estrogen-like effects, and drug interactions are noted.
Possible side effects
- Side effects are uncommon and may include nausea, dizziness, and allergic reactions in some people.
- Chamomile used near the eyes might cause eye irritation.
Serious risks
- Allergic reactions can include severe hypersensitivity reactions and anaphylaxis.
- Chamomile might worsen conditions sensitive to estrogen, such as breast or uterine cancer.
Avoid or ask a doctor first if
- People allergic to related plants are more likely to react to chamomile.
- Little is known about safety during pregnancy or breastfeeding.
- Chamomile might have some of the same effects as estrogen.
Medication interactions
- Taking chamomile with birth control pills might decrease the pills' effects, according to preliminary studies.
- Interactions have been reported with warfarin and some drugs metabolized by the liver; sedatives are a theoretical concern.
- People taking any medicine should talk with a health care provider before using chamomile.
Vitamin C
The source describes vitamin C as having low toxicity, with high doses mainly causing digestive upset. It names a few specific concerns, including kidney stones, iron overload in people with hereditary hemochromatosis, and a possible pro-oxidant effect.
Possible side effects
- The most common complaints are diarrhea, nausea, abdominal cramps, and other digestive upset.
Serious risks
- High intakes may raise urinary oxalate and uric acid, which could contribute to kidney stones, especially in people with renal disorders.
- The best evidence that vitamin C contributes to kidney stones is in patients who already have hyperoxaluria.
- In people with hereditary hemochromatosis, long-term high doses could worsen iron overload and cause tissue damage.
- A few in vitro studies suggested that supplemental oral vitamin C, acting as a pro-oxidant, could cause chromosomal or DNA damage and possibly contribute to cancer.
- In postmenopausal women with diabetes in the Iowa Women's Health Study, supplemental vitamin C of at least 300 mg/day was significantly associated with a higher risk of dying from CVD.
Avoid or ask a doctor first if
- People with hereditary hemochromatosis face a concern about iron overload with chronic high doses.
- The upper limits do not apply to people receiving vitamin C as medical treatment, who should be under a physician's care.
- Infants should get vitamin C only from formula and food.
Medication interactions
- Vitamin C supplements may interact with radiation therapy and with medications, including chemotherapy drugs and statins.
- People taking these medications regularly should talk with their health care providers about vitamin C intake.
Upper limit: 2000 mg a day for adults 19+. This label lists 90 mg.
Source: NIH Office of Dietary Supplements, Vitamin C: Fact Sheet for Health Professionals
Vitamin D
Vitamin D toxicity is almost always caused by excessive supplement intake. It can raise blood calcium and, in extreme cases, lead to kidney failure and death. The adult upper limit is 100 mcg (4,000 IU) a day.
Possible side effects
- High blood calcium from vitamin D toxicity can lead to nausea, vomiting, muscle weakness, and other symptoms.
Serious risks
- Toxicity can cause high blood and urine calcium. In extreme cases it may lead to kidney failure, soft tissue calcification, heart rhythm problems, and death.
- Toxicity is almost always caused by taking too much vitamin D through supplements.
Avoid or ask a doctor first if
- The source says people on regular medications should talk with their health care providers about vitamin D intake and status.
Medication interactions
- Vitamin D supplements may interact with orlistat, statins, steroids, and thiazide diuretics.
- Taking calcium supplements with vitamin D supplements may raise the risk of certain adverse effects.
Upper limit: 100 mcg a day for adults 19+. This label lists 20 mcg.
Source: NIH Office of Dietary Supplements, Vitamin D: Fact Sheet for Health Professionals
Vitamin K
Vitamin K has no Tolerable Upper Intake Level because the Food and Nutrition Board found a low potential for toxicity. It can interact with warfarin and other anticoagulants, and some other medications can lower vitamin K levels.
Serious risks
- The Food and Nutrition Board reported no adverse effects from vitamin K in food or supplements in humans or animals.
Avoid or ask a doctor first if
- People taking medications regularly should talk with their health care providers about their vitamin K status.
Medication interactions
- Vitamin K can interact with warfarin and other anticoagulants.
- Antibiotics, bile acid sequestrants, and orlistat can have adverse effects on vitamin K levels.
Source: NIH Office of Dietary Supplements, Vitamin K: Fact Sheet for Health Professionals
Thiamin
The body excretes excess thiamin in the urine. The FNB set no upper limit because adverse effects from high intakes (50 mg/day or more) haven't been reported, though it noted that excessive intakes could still have adverse effects.
Serious risks
- No adverse effects have been reported from high thiamin intakes, but the FNB noted that excessive intakes could still have adverse effects.
Avoid or ask a doctor first if
- People who take certain medications regularly should talk with their health care providers about their thiamin status.
Medication interactions
- Thiamin isn't known to interact with any medications, but certain medications can have an adverse effect on thiamin levels.
Source: NIH Office of Dietary Supplements, Thiamin: Fact Sheet for Health Professionals
Riboflavin
High riboflavin intakes from food have no observable toxicity, and the FNB set no upper limit because adverse effects from high intakes haven't been reported. The FNB still urges caution about excessive amounts, since limited data don't rule out adverse effects.
Serious risks
- Food intakes many times the RDA show no observable toxicity; the source suggests limited solubility and absorption may explain this.
- Limited data on adverse effects don't mean high intakes are harmless, and the FNB urges caution with excessive amounts.
Medication interactions
- Riboflavin is not known to have clinically relevant interactions with medications.
Source: NIH Office of Dietary Supplements, Riboflavin: Fact Sheet for Health Professionals
Vitamin B12
The source says vitamin B12 has no tolerable upper intake level because of its low potential for toxicity, and it is generally considered safe even at large doses. Some medications can affect B12 levels, and supplements may interact with certain medications.
Serious risks
- The Food and Nutrition Board set no upper limit for B12 because its potential for toxicity is low.
Avoid or ask a doctor first if
- People who regularly take certain medications are told to talk with their health care providers about their B12 status.
Medication interactions
- B12 supplements may interact with some medications. Gastric acid inhibitors and metformin may affect B12 levels.
- Several types of medications might adversely affect B12 levels.
Source: NIH Office of Dietary Supplements, Vitamin B12: Fact Sheet for Health Professionals
Biotin
The FNB set no upper limit for biotin because it found no evidence of toxicity in humans at high intakes. The source says high intakes, possibly even ones above the AI, may pose another type of health risk: falsely high or low lab test results.
Serious risks
- High biotin intakes, possibly even intakes above the AI, may pose a health risk tied to lab testing.
- Biotin beyond recommended intakes can cause clinically significant falsely high or falsely low lab results, depending on the test.
- In a small study of six healthy adults taking 10 mg/day for 1 week, biotin falsely lowered N-terminal pro-brain natriuretic peptide, which could result in a failure to identify congestive heart failure. Thyroid stimulating hormone was also falsely lowered.
- Case reports describe findings falsely indicating Graves' disease and severe hyperthyroidism in patients taking 10–300 mg biotin per day.
- A single 10 mg dose of biotin has interfered with thyroid function tests given within 24 hours.
- Per FDA, a patient with a high intake of supplemental biotin died after a troponin test gave a falsely low result because of biotin interference.
Medication interactions
- Biotin can interact with certain medications, and some medications can have an adverse effect on biotin levels.
Source: NIH Office of Dietary Supplements, Biotin: Fact Sheet for Health Professionals
Iron
Iron from food carries little overload risk for adults with normal intestinal function, but high-dose supplements can cause gastrointestinal effects. Extremely high doses can be severe, and iron overdose is a leading cause of fatal poisoning in young children.
Possible side effects
- High-dose iron supplements can cause stomach upset, constipation, nausea, abdominal pain, vomiting, and diarrhea.
- Supplements with 25 mg iron or more can reduce zinc absorption and plasma zinc concentrations.
Serious risks
- Large acute intakes from supplements or medicines can lead to corrosive necrosis of the intestine, which might lead to fluid and blood loss, shock, tissue damage, and organ failure.
- In severe cases, iron overdoses can lead to multisystem organ failure, coma, convulsions, and even death.
- Case reports suggest some people develop more serious gastrointestinal effects, including gastritis and gastric lesions.
- At least 43 U.S. children died between 1983 and 2000 from ingesting high-dose iron supplements.
- Without treatment, people with hereditary hemochromatosis typically develop signs of iron toxicity by their 30s.
- Iron toxicity effects in hemochromatosis can include liver cirrhosis, hepatocellular carcinoma, heart disease, and impaired pancreatic function.
Avoid or ask a doctor first if
- People with hemochromatosis: treatment guidance includes avoiding iron and vitamin C supplements.
- The required FDA label on solid iron supplements says accidental overdose is a leading cause of fatal poisoning in children under 6, and to keep the product out of children's reach.
Medication interactions
- Iron supplements may interact with levodopa and levothyroxine.
- Proton pump inhibitors can potentially reduce iron absorption.
Upper limit: 45 mg a day for adults 19+. This label lists 18 mg.
Source: NIH Office of Dietary Supplements, Iron: Fact Sheet for Health Professionals
Iodine
High iodine intake can cause goiter, elevated TSH, hypothyroidism, hyperthyroidism, thyroiditis and thyroid papillary cancer. Some people, such as those with autoimmune thyroid disease or iodine deficiency, may react to intakes considered safe for the general population.
Possible side effects
- High iodine intakes can cause goiter, elevated TSH levels, and hypothyroidism, some of the same symptoms as iodine deficiency.
Serious risks
- Iodine-induced hyperthyroidism can result from high iodine intakes, including when iodine is given to treat iodine deficiency.
- Studies have shown that excessive iodine intakes cause thyroiditis and thyroid papillary cancer.
- Acute iodine poisoning is rare and is usually caused by doses of many grams. Symptoms include burning of the mouth, throat, and stomach, fever, abdominal pain, nausea, vomiting, diarrhea, weak pulse, and coma.
- Long-term intakes above the UL increase the risk of adverse health effects.
Avoid or ask a doctor first if
- People with autoimmune thyroid disease or iodine deficiency may have adverse effects at iodine intakes considered safe for the general population.
- The ULs do not apply to people receiving iodine for medical treatment, who should be under a physician's care.
Medication interactions
- Iodine supplements have the potential to interact with several types of medications. People taking these medications on a regular basis should discuss their iodine intakes with their health care providers.
Upper limit: 1100 mcg a day for adults 19+. This label lists 150 mcg.
Source: NIH Office of Dietary Supplements, Iodine: Fact Sheet for Health Professionals
Zinc
Zinc from food is unlikely to cause toxicity. High intakes, mostly from supplements, can cause stomach and other symptoms, and doses of 50 mg or more over weeks can interfere with copper absorption. The adult upper limit is 40 mg.
Possible side effects
- High zinc intakes can cause nausea, dizziness, headaches, gastric distress, vomiting, and loss of appetite.
Serious risks
- Doses of 50 mg or more taken for weeks can interfere with copper absorption, reduce immune function, and lower HDL cholesterol.
- Very high supplemental doses (142 mg/day) might interfere with magnesium absorption and disrupt magnesium balance.
- According to a few reports, overuse of zinc-containing denture adhesive creams can lead to neurological symptoms and anemia.
Avoid or ask a doctor first if
- The upper limits don't apply to people receiving zinc for medical treatment, who should be under a physician's care.
- Zinc-free denture adhesive formulations are available to prevent the effects linked to zinc-containing creams.
Medication interactions
- Zinc may interact with quinolone antibiotics, tetracycline antibiotics, and penicillamine.
- Some diuretics can lower serum zinc by increasing zinc excretion in urine.
- People taking medications regularly should discuss their zinc status with their health care providers.
Upper limit: 40 mg a day for adults 19+. This label lists 11 mg.
Source: NIH Office of Dietary Supplements, Zinc: Fact Sheet for Health Professionals
Selenium
Selenium toxicity (selenosis) comes from chronically high intakes. The adult Tolerable Upper Intake Level is 400 mcg, set from the amounts linked to hair and nail brittleness and loss. Acute toxicity has followed misformulated supplements.
Possible side effects
- Early signs of too much selenium are a garlic odor on the breath and a metallic taste in the mouth.
- Hair loss and nail brittleness or loss are the most common clinical signs of chronically high selenium intake.
- Other signs of chronically high intake include skin rash, nausea, diarrhea, fatigue, irritability, and nervous system abnormalities.
Serious risks
- Acute selenium toxicity can cause severe gastrointestinal and neurological symptoms, respiratory distress syndrome, heart attack, kidney failure, cardiac failure, and, in rare cases, death.
- Acute toxicity has resulted from misformulated over-the-counter products containing very large amounts of selenium. In 2008, 201 people had severe adverse reactions to a liquid supplement with 200 times the labeled amount.
- Brazil nuts contain very high amounts of selenium and could cause selenium toxicity if eaten regularly.
Avoid or ask a doctor first if
- The upper limits do not apply to people taking selenium under a physician's care.
- People who take medications regularly should discuss their selenium status with their health care providers.
Medication interactions
- Selenium supplements may interact with medications, and some medications, such as cisplatin, can affect selenium levels in the body.
Upper limit: 400 mcg a day for adults 19+. This label lists 55 mcg.
Source: NIH Office of Dietary Supplements, Selenium: Fact Sheet for Health Professionals
Copper
The source says chronic exposure to high levels of copper can cause liver damage and gastrointestinal symptoms. Copper toxicity is rare in healthy people without a hereditary copper homeostasis defect. The adult UL is 10,000 mcg a day from food and supplements.
Possible side effects
- High copper exposure over time can cause gastrointestinal symptoms.
Serious risks
- Chronic exposure to high levels of copper can result in liver damage.
- Copper toxicity has been reported in people who drink water with high copper levels, for example from stagnant water in copper-containing pipes and fixtures.
- People with Wilson's disease can develop neurologic and liver damage that can result in cirrhosis.
Avoid or ask a doctor first if
- People with Wilson's disease have a high risk of copper toxicity.
Medication interactions
- Copper is not known to have any clinically relevant interactions with medications.
Upper limit: 10000 mcg a day for adults 19+. This label lists 0.9 mg.
Source: NIH Office of Dietary Supplements, Copper: Fact Sheet for Health Professionals
Manganese
The source says no evidence shows manganese toxicity from high dietary intakes. Toxicity has occurred with chronic inhalation of manganese dust at work and in people drinking water with high manganese levels. It mainly affects the central nervous system.
Serious risks
- Manganese toxicity mainly affects the central nervous system and can cause tremors, muscle spasms, tinnitus, hearing loss, and unsteadiness on one's feet.
- People who drink water with high manganese levels have also developed manganese toxicity.
- Workers such as welders and miners who chronically inhaled manganese dust have developed manganese toxicity.
- Toxicity signs and symptoms can progress to Parkinson's-like neuromotor impairments, including changes in gait and balance, tremor, and rigidity.
Avoid or ask a doctor first if
- People with chronic liver disease eliminate manganese less well in bile and are more susceptible to its neurotoxicity and other adverse effects of excess intake.
- Iron deficiency increases manganese absorption and can worsen symptoms of manganese toxicity.
Medication interactions
- Manganese is not known to have any clinically relevant interactions with medications.
Upper limit: 11 mg a day for adults 19+. This label lists 2.3 mg.
Source: NIH Office of Dietary Supplements, Manganese: Fact Sheet for Health Professionals
Chromium
The FNB found no adverse effects linked to high chromium intakes from food or supplements, so it set no UL. It still said caution may be warranted because the data are limited.
Serious risks
- Isolated case reports link chromium supplements to several problems, including liver dysfunction and renal failure.
- The FNB said caution may be warranted because data are limited, and high intakes could have adverse effects.
Avoid or ask a doctor first if
- People with renal or liver disease might be susceptible to adverse effects from high chromium intakes.
Medication interactions
- Several types of medications have the potential to interact with chromium supplements.
- People taking medications regularly should talk with their health care providers about their chromium intakes.
Source: NIH Office of Dietary Supplements, Chromium: Fact Sheet for Health Professionals
Molybdenum
The source says acute molybdenum toxicity is rare but can occur with industrial mining and metalworking exposure. In healthy people, a diet high in molybdenum usually does not pose a health risk because it is rapidly excreted in urine, though one study of high dietary intake in Armenia found joint and uric acid problems.
Serious risks
- Acute molybdenum toxicity is rare but can occur with industrial mining and metalworking exposure.
- In one study of high dietary molybdenum intake in an area of Armenia, affected people had achy joints, gout-like symptoms, and abnormally high blood uric acid.
Avoid or ask a doctor first if
- Infants up to 12 months should get molybdenum only from breast milk, formula, and food.
Medication interactions
- The source says molybdenum has no known, clinically relevant, interactions with medications.
Upper limit: 2000 mcg a day for adults 19+. This label lists 45 mcg.
Source: NIH Office of Dietary Supplements, Molybdenum: Fact Sheet for Health Professionals
Potassium
This page says little about potassium safety. The section on risks from excessive potassium is empty, and no upper limit is given. It does warn that some medications can affect potassium status in dangerous ways.
Avoid or ask a doctor first if
- The recommended intakes don't apply to people whose bodies clear potassium poorly, for example because of kidney disease or certain medications.
- People taking medications that affect potassium should talk with their health care providers about their potassium intake and status.
Medication interactions
- Several types of medications can affect potassium status in ways that could be dangerous.
Source: NIH Office of Dietary Supplements, Potassium: Fact Sheet for Health Professionals
Boron
No data are available on harm from high boron intake from food or water. Accidentally swallowing boric acid or borax products has caused symptoms, and very high doses can be fatal. The FNB set upper limits based on reproductive and developmental effects in animals.
Possible side effects
- Accidental swallowing of boric acid or borax, found in some household cleaners and pesticides, is linked to digestive, skin and nervous system symptoms.
- Boron toxicity can also cause headache, hypothermia, restlessness, and other symptoms.
Serious risks
- Extremely high doses of boron can be fatal in adults.
- In infants, high boron intakes have caused anemia, seizures, erythema, and thin hair.
- The upper limits are based on reproductive and developmental effects seen in animals.
Avoid or ask a doctor first if
- Infants should get boron only from breast milk, formula, and food.
Medication interactions
- Boron is not known to have any clinically relevant interactions with medications.
Upper limit: 20 mg a day for adults 19+. This label lists 1 mg.
Source: NIH Office of Dietary Supplements, Boron: Fact Sheet for Health Professionals
Price & Value
Extreme MarkupJuna Nightcap Sleep Gummies
$42.00
Melatonin 0.3mg gummies (Nature Made, Vitafusion) + Magnesium glycinate (NOW Foods, Pure Encapsulations) + Passionflower tea or extract
Melatonin gummies $8-12/30 servings + Magnesium $10-15/30 servings + Passionflower $5-10/month = ~$23-37/month total (vs. $35.70 subscription)
What you're actually paying for
This is a multi-ingredient blend at $1.40 per gummy a serving. Comparable options: Melatonin 0.3mg tablets ($5-10), magnesium glycinate ($10-15), or individual herbal teas (chamomile, passionflower).
Worth paying for
- Supports a restful night's sleep
- Non-habit forming
- Supports evening relaxation and calm
What's marketing
- Waking up refreshed
- Price is $42 for 30 gummies (30-day supply)
Research sources: PubMed · Examine.com
Analyzed product: https://juna-world.com/products/nightcap-sleep-gummies
Analysis generated: 2026-06-02 · Engine v1.0.0
Frequently Asked Questions
Is Juna Nightcap Sleep Gummies worth the money?
Juna Nightcap Sleep Gummies at $42.00 appears to offer reasonable value based on its ingredient quality and dosing. Nightcap is a reasonably formulated sleep gummy with modest, evidence-backed ingredients at therapeutic doses—but it's significantly overpriced for what you get. The product makes appropriate hedged claims ('supports sleep,' 'helps establish routine') rather than promising cures, and the microdose melatonin approach is scientifically sound. However, you can buy the same ingredients
Is Juna Nightcap Sleep Gummies a scam?
Juna Nightcap Sleep Gummies does not appear to be a scam. Our analysis found the claims are generally supported by the ingredients.
What are the ingredients in Juna Nightcap Sleep Gummies?
Juna Nightcap Sleep Gummies contains 47 ingredients including Phytomelatonin (from St. John's Wort), Magnesium Blend, Passionflower Extract, Wild Jujube (GABA), Tart Cherry Extract.
Does Juna Nightcap Sleep Gummies actually work?
Yes, Juna Nightcap Sleep Gummies can work for its intended purpose. 2 of 5 claims are fully supported. 2 are partially supported.
Are there cheaper alternatives to Juna Nightcap Sleep Gummies?
Yes, Melatonin 0.3mg gummies (Nature Made, Vitafusion) + Magnesium glycinate (NOW Foods, Pure Encapsulations) + Passionflower tea or extract at Melatonin gummies $8-12/30 servings + Magnesium $10-15/30 servings + Passionflower $5-10/month = ~$23-37/month total (vs. $35.70 subscription) offers similar benefits at a better price point. Many key ingredients in Juna Nightcap Sleep Gummies are available separately for less.
Does Juna Nightcap Sleep Gummies have side effects?
NIH summaries of the ingredients in Juna Nightcap Sleep Gummies note these possible effects. Melatonin: Side effects reported in short-term adult studies included headache, dizziness, nausea, and sleepiness. Magnesium: High doses from supplements or medications can cause diarrhea, nausea, and abdominal cramping. Passionflower: Possible side effects include drowsiness, dizziness, and confusion. This describes the ingredients, not tests of this product; ask a doctor or pharmacist.