Major interaction on record — check this product against your medications before combining. Based on 5 of 7 ingredients. Check your meds →
Dietary supplement

Sleep Guard Capsules Ingredients & Drug Interactions

by Perque

Sleep Guard Capsules label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

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

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

The interaction bottom line Most serious interaction: Major

Sleep Guard Capsules is a dietary supplement by Perque with 7 active ingredients. Its ingredients are commonly taken for sleep problems, low mood and depression, anxiety.Based on those ingredients, 803 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are L-Tryptophan, Magnesium, Vitamin B-6. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Sleep Guard Capsules by Perque

Ask about any prescription or over-the-counter medication and we check it for interactions with Sleep Guard Capsules by Perque — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Sleep Guard Capsules by Perque

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

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Sep 10, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 7 of its 7 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

Sleep Guard contains 7 ingredients, of which the active ones are L-tryptophan, riboflavin (vitamin B2), vitamin B-6, silica, and magnesium. L-tryptophan is an amino acid your body uses to make serotonin and other brain chemicals.

Riboflavin and vitamin B-6 are B vitamins that support energy and nerve function. Silica is a mineral compound, and magnesium is a mineral that plays roles in muscle and nerve function.

The product also contains vegetable capsule material, croscarmellose (a tablet binder), and no other inactive ingredients.

Does it work?

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

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use.

Why this rating?
  • The label markets this product for: Supports healthy restorative sleep.
  • We looked for evidence on: Insomnia, Anxiety, Sleep quality, Sleep onset, Sleep maintenance.
  • The closest evidence on file: L-tryptophan is rated "Insufficient Reliable Evidence To Rate" for Anxiety (Natural Medicines).
  • Also on file: Vitamin B6 is rated "Insufficient Reliable Evidence To Rate" for Anxiety, Insomnia.
  • Also on file: Magnesium is rated "Insufficient Reliable Evidence To Rate" for Perioperative anxiety.

Evidence for L-tryptophan's use in depression is limited — it's rated possibly ineffective for that condition. For anxiety, bruxism (teeth grinding), and premenstrual dysphoric disorder, there isn't enough reliable evidence to rate L-tryptophan's effectiveness.

Vitamin B-6 is effective for treating sideroblastic anemia and B-6 deficiency, likely effective for lowering high homocysteine levels, and possibly effective for pregnancy-related nausea and vomiting. Silica is possibly effective for osteoporosis, but evidence for hair loss and dental conditions is insufficient.

We hold no effectiveness data for riboflavin or magnesium as they appear in this product.

The evidence, ingredient by ingredient L-tryptophan Riboflavin Vitamin B6 Silicon Magnesium

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

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

Why this rating?
  • We hold adverse-effect (side-effect) data for 5 of the 5 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 5 of 5.
  • General safety write-ups exist for 5 of 5.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

L-tryptophan is generally well tolerated, but it has a notable safety history: in 1989, a contaminated batch from a single Japanese manufacturer caused over 1,500 cases of a rare neurological disorder called eosinophilia-myalgia syndrome (EMS) in the US. While almost all cases were traced to that specific contaminated product, the safety notes advise caution.

L-tryptophan is not recommended during pregnancy (rated possibly unsafe) and should be avoided while breastfeeding. Common side effects of L-tryptophan include belching, diarrhea, drowsiness, dry mouth, flatulence, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, and vomiting.

Riboflavin is very safe; excess amounts are excreted in urine. It may cause dose-related nausea and bright yellow urine at high doses.

Vitamin B-6 is safe at normal supplement doses but can cause nerve damage (sensory neuropathy) at very high doses sustained over time; common side effects include headache, heartburn, nausea, and vomiting. Magnesium is generally well tolerated but commonly causes diarrhea, nausea, vomiting, and gastrointestinal irritation.

Silica from food and standard supplements is not associated with adverse effects, though there is limited data on long-term, high-dose use. For silica, there is not enough safety data to support use during pregnancy or breastfeeding.

Side effects, ingredient by ingredient L-tryptophan Riboflavin Vitamin B6 Silicon Magnesium

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 4 of the 5 matched ingredients can interact with medications — L-tryptophan, Vitamin B6, Riboflavin, Magnesium.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications; heart-rhythm medications; Parkinson's medications.
  • For scale: 803 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking Sleep Guard, check with your doctor or pharmacist if you take any CNS depressants (sedatives, sleep aids, alcohol), serotonergic drugs (antidepressants, anxiety medications), or levodopa/carbidopa for Parkinson's disease — these carry Major or Moderate risks. Also confirm if you take blood pressure drugs, seizure medications, heart rhythm drugs, muscle relaxants, diuretics, calcium channel blockers, acid-reducing drugs, diabetes medications, antibiotics (quinolones or tetracyclines), or bone medications (bisphosphonates), as the B vitamins and magnesium in this product may affect them.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Major medication interactions have been identified, and safety information is well characterized.

Sleep Guard is centered on L-tryptophan, an amino acid that promotes sleep through serotonin production, plus supporting B vitamins and minerals. It's not recommended if you take CNS depressants, serotonergic drugs (like antidepressants), or Parkinson's medication, and several other medication types need careful timing or dosing review.

Avoid it if you're pregnant or breastfeeding, given the safety data for L-tryptophan and silica. Before you start, talk with your doctor or pharmacist about whether it's right for you and your medications.

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

Assessment coverage: 5 of 7 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Dec 26, 2020.

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

At a glance

General information

Key facts about Sleep Guard Capsules, straight from the product label.

Brand Perque
Net contents 90 Vegetable Capsule(s)
Market status On market
Date entered into DSLD Dec 26, 2020
DSLD ID 241000
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Sleep Guard Capsules by Perque, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Vegetable Capsule(s)
Maximum serving Sizes:
1 Vegetable Capsule(s)
Servings per container
90
IngredientAmount% DV
Vegetable Capsule120 mg--
L-Tryptophan500 mg--
Croscarmellose3 mg--
Riboflavin3 mg130%
Vitamin B-63 mg170%
Silica4 mg--
Magnesium5 mg--

Other ingredients: None

Tap any ingredient to jump to its full detail below.

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

Keep out of reach of children.

Do not use product if the tamper-resistant shrink band around the cap or the inner seal beneath the cap appears to have been tampered with or is missing.

Warning: Pregnant and nursing mothers need to check with their health professional before taking supplements.

Storage

Must be stored with cap on tightly in a cool, dry place.

General Statements

Uniquely Perque 100% active 100% natural 100% verified

Formulation

Does not contain: Citrus, MSG, wheat, gluten, corn, starch, sugar, soy, yeast, zein, sulfates, phosphates (other than coenzymes), preservatives, casein or other milk derivatives. No GMO's; No toxic minerals or metals

Supports healthy restorative sleep

Full disclosure label (no hidden or inactive ingredients)

V (Vegetarian)

FDA Disclaimer Statement

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

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Directions: One capsule daily about 30 min before bedtime, or as recommended by a health care professional.

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

See for yourself

Sleep Guard Capsules by Perque label

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

Sleep Guard Capsules label

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

View the full label (PDF)
What’s inside

The Ingredients in Sleep Guard Capsules by Perque

These are the 7 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Vegetable Capsule(s) Dosage formCapsule Servings per container90 Amounts shown are per serving.

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

Vegetable Capsule

120 mg per serving

L-Tryptophan

Interacts with
394 drugs
500 mg per serving

L-tryptophan is an essential amino acid the body uses to make serotonin and melatonin, and people take it to support sleep and mood. The evidence for...

L-Tryptophan monograph & interactions

Croscarmellose

3 mg per serving

Riboflavin

Interacts with
20 drugs
3 mg per serving Form: Riboflavin 5-Phosphate

Riboflavin (vitamin B2) is an essential nutrient your body needs to turn food into energy and to keep skin, eyes, and nerves healthy. It is generally...

Riboflavin monograph & interactions

Vitamin B-6

Interacts with
210 drugs
3 mg per serving Form: Pyridoxal 5-Phosphate

Vitamin B6 (pyridoxine) is an essential water-soluble vitamin that your body needs for metabolism, brain function, and making red blood cells. It is b...

Vitamin B-6 monograph & interactions

Silica

No known
interactions
4 mg per serving Form: Equisetum

Silicon is a trace mineral found in the body and in foods like oats, barley, and certain fruits and vegetables, and it is popular in supplements for h...

Silica monograph & interactions

Magnesium

Interacts with
295 drugs
5 mg per serving Form: C16 Alkyls, C18 Alkyls

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preven...

Magnesium monograph & interactions

Other (inactive) ingredients: None. These complete the product’s ingredient list but are not active constituents.

Interaction report

Sleep Guard Capsules by Perque Drug Interactions

Want to check YOUR meds against Sleep Guard Capsules?

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

 Go to the checker
803Drugs
254 Major 460 Moderate 89 Minor

Ingredients driving the most interactions

L-Tryptophan 394
Magnesium 295
Vitamin B-6 210
Riboflavin 20

Individual Drug Interactions

The ingredients in Sleep Guard Capsules interact with 803 drugs. Click any drug to see the details.

4 of the 7 ingredients in Sleep Guard Capsules interact with drugs. Each result below shows which ingredient is responsible. L-Tryptophan Magnesium Vitamin B-6 Riboflavin

Each ingredient & the kinds of drugs it affects

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

L-Tryptophan2 drug types · 394 drugs

Cns Depressants

Theoretically, concomitant use of L-tryptophan with CNS depressants might cause additive sedative effects.
Clinical research shows that L-tryptophan can cause fatigue and drowsiness.

Likelihood Probable Evidence B
Serotonergic Drugs

Theoretically, combining L-tryptophan with serotonergic drugs might cause additive serotonergic effects.
L-tryptophan is a precursor to serotonin. Theoretically, combining serotonergic drugs with L-tryptophan might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders.

Likelihood Possible Evidence D
L-Tryptophan full monograph & interactions

Magnesium15 drug types · 295 drugs

Levodopa/Carbidopa (Sinemet)

Magnesium can reduce the bioavailability of levodopa/carbidopa.
Clinical research in healthy volunteers shows that taking magnesium oxide 1000 mg with levodopa 100 mg/carbidopa 10 mg reduces the area under the curve (AUC) of levodopa by 35% and of carbidopa by 81%. In vitro and animal research shows that magnesium produces an alkaline environment in the digestive tract, which might lead to degradation and reduced bioavailability of levodopa/carbidopa.

Likelihood Probable Evidence B
Aminoglycoside Antibiotics

Concomitant use of aminoglycoside antibiotics and magnesium can increase the risk for neuromuscular weakness.
Both aminoglycosides and magnesium reduce presynaptic acetylcholine release, which can lead to neuromuscular blockade and possible paralysis. This is most likely to occur with high doses of magnesium given intravenously.

Likelihood Possible Evidence D
Antacids

Use of acid reducers may reduce the laxative effect of magnesium oxide.
A retrospective analysis shows that, in the presence of H2 receptor antagonists (H2RAs) or proton pump inhibitors (PPIs), a higher dose of magnesium oxide is needed for a laxative effect. This may also occur with antacids. Under acidic conditions, magnesium oxide is converted to magnesium chloride and then to magnesium bicarbonate, which has an osmotic laxative effect. By reducing acidity, antacids may reduce the conversion of magnesium oxide to the active bicarbonate salt.

Likelihood Possible Evidence D
Bictegravir/Emtricitabine/Tenofovir Alafenamide (Biktarvy)

Magnesium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide should be taken at least 2 hours before or 6 hours after magnesium containing products.

Likelihood Probable Evidence D
Bisphosphonates

Magnesium can decrease absorption of bisphosphonates.
Cations, including magnesium, can decrease bisphosphonate absorption. Advise patients to separate doses of magnesium and these drugs by at least 2 hours.

Likelihood Probable Evidence B
Calcium Channel Blockers

Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.
Magnesium inhibits calcium entry into smooth muscle cells and may therefore have additive effects with calcium channel blockers. Severe hypotension and neuromuscular blockades may occur when nifedipine is used with intravenous magnesium, although some contradictory evidence suggests that concurrent use of magnesium with nifedipine does not increase the risk of neuromuscular weakness. High doses of magnesium could theoretically have additive effects with other calcium channel blockers.

Likelihood Possible Evidence D
Digoxin

Magnesium salts may reduce absorption of digoxin.
Clinical evidence suggests that treatment with oral magnesium hydroxide or magnesium trisilicate reduces absorption of digoxin from the intestines. This may reduce the blood levels of digoxin and decrease its therapeutic effects.

Likelihood Possible Evidence B
Potassium-Sparing Diuretics

Potassium-sparing diuretics decrease excretion of magnesium, possibly increasing magnesium levels.
Potassium-sparing diuretics also have magnesium-sparing properties, which can counteract the magnesium losses associated with loop and thiazide diuretics. Theoretically, increased magnesium levels could result from concomitant use of potassium-sparing diuretics and magnesium supplements.

Likelihood Probable Evidence D
Quinolone Antibiotics

Magnesium decreases absorption of quinolones.
Magnesium can form insoluble complexes with quinolones and decrease their absorption. Advise patients to take these drugs at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Probable Evidence D
Skeletal Muscle Relaxants

Parenteral magnesium alters the pharmacokinetics of skeletal muscle relaxants, increasing their effects and accelerating the onset of effect.
Parenteral magnesium shortens the time to onset of skeletal muscle relaxants by about 1 minute and prolongs the duration of action by about 2 minutes. Magnesium potentiates the effects of skeletal muscle relaxants by decreasing calcium-mediated release of acetylcholine from presynaptic nerve terminals, reducing postsynaptic sensitivity to acetylcholine, and having a direct effect on the membrane potential of myocytes. Magnesium also has vasodilatory actions and increases cardiac output, allowing a greater amount of muscle relaxant to reach the motor end plate. A clinical study found that low-dose rocuronium (0.45 mg/kg), when given after administration of magnesium 30 mg/kg over 10 minutes, has an accelerated onset of effect, which matches the onset of effect seen with a full-dose rocuronium regimen (0.6 mg/kg). In another clinical study, onset times for rocuronium doses of 0.3, 0.6, and 1.2 mg/kg were 86, 76, and 50 seconds, respectively, when given alone, but were reduced to 66, 44, and 38 seconds, respectively, when the doses were given after a 15-minute infusion of magnesium sulfate 60 mg/kg. Giving intraoperative intravenous magnesium sulfate, 50 mg/kg loading dose followed by 15 mg/kg/hour, reduces the onset time of rocuronium, enhances its clinical effects, reduces the dose of intraoperative opiates, and prolongs the spontaneous recovery time. It does not affect the activity of subsequently administered neostigmine.

Likelihood Probable Evidence A
Sulfonylureas

Magnesium increases the systemic absorption of sulfonylureas, increasing their effects and side effects.
Clinical research shows that administration of magnesium hydroxide with glyburide increases glyburide absorption, increases maximal insulin response by 35-fold, and increases the risk of hypoglycemia, when compared with glyburide alone. A similar interaction occurs between magnesium hydroxide and glipizide. The mechanism of this effect appears to be related to the elevation of gastrointestinal pH by magnesium-based antacids, increasing solubility and enhancing absorption of sulfonylureas.

Likelihood Probable Evidence B
Tetracycline Antibiotics

Magnesium decreases absorption of tetracyclines.
Magnesium can form insoluble complexes with tetracyclines in the gut and decrease their absorption and antibacterial activity. Advise patients to take these drugs 1 hour before or 2 hours after magnesium supplements.

Likelihood Probable Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, magnesium may have antiplatelet effects, but the evidence is conflicting.
In vitro evidence shows that magnesium sulfate inhibits platelet aggregation, even at low concentrations. Some preliminary clinical evidence shows that infusion of magnesium sulfate increases bleeding time by 48% and reduces platelet activity. However, other clinical research shows that magnesium does not affect platelet aggregation, although inhibition of platelet-dependent thrombosis can occur.

Likelihood Unlikely Evidence B
Gabapentin (Neurontin)

Gabapentin absorption can be decreased by magnesium.
Clinical research shows that giving magnesium oxide orally along with gabapentin decreases the maximum plasma concentration of gabapentin by 33%, time to maximum concentration by 36%, and area under the curve by 43%. Advise patients to take gabapentin at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Unlikely Evidence B
Sevelamer (Renagel, Renvela)

Sevelamer may increase serum magnesium levels.
In patients on hemodialysis, sevelamer use was associated with a 0.28 mg/dL increase in serum magnesium. The mechanism of this interaction remains unclear.

Likelihood Possible Evidence B
Magnesium full monograph & interactions

Vitamin B-65 drug types · 210 drugs

Amiodarone (Cordarone)

Theoretically, vitamin B6 might increase the photosensitivity caused by amiodarone.
Despite initial case reports suggesting that pyridoxine may have a protective effect against amiodarone-induced photosensitivity, preliminary clinical research suggests that pyridoxine may actually exacerbate this adverse effect.

Likelihood Possible Evidence B
Antihypertensive Drugs

Theoretically, vitamin B6 may have additive effects when used with antihypertensive drugs.
Research in hypertensive rats shows that vitamin B6 can decrease systolic blood pressure. Similarly, clinical research in patients with hypertension shows that taking high doses of vitamin B6 may reduce systolic and diastolic blood pressure, possibly by reducing plasma levels of epinephrine and norepinephrine.

Likelihood Possible Evidence B
Phenobarbital (Luminal)

High doses of vitamin B6 may reduce the levels and clinical effects of phenobarbital.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenobarbital, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenobarbital to avoid high doses of vitamin B6.

Likelihood Possible Evidence D
Phenytoin (Dilantin)

High doses of vitamin B6 may reduce the levels and clinical effects of phenytoin.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenytoin, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenytoin to avoid high doses of vitamin B6.

Likelihood Possible Evidence D
Levodopa

Vitamin B6 may increase the metabolism of levodopa when taken alone, but not when taken in conjunction with carbidopa.
Vitamin B6 (pyridoxine) enhances the metabolism of levodopa, reducing its clinical effects. However, this interaction does not occur when carbidopa is used concurrently with levodopa (Sinemet). Therefore, it is not likely to be a problem in most people.

Likelihood Unlikely Evidence D
Vitamin B-6 full monograph & interactions

Riboflavin1 drug type · 20 drugs

Tetracycline Antibiotics

Theoretically, taking riboflavin with tetracycline antibiotics may decrease the potency of these antibiotics.
In vitro research suggests that riboflavin may inhibit the potency of tetracycline antibiotics. It is not clear if this effect is clinically significant, as this interaction has not been reported in humans.

Likelihood Possible Evidence D
Riboflavin full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Sleep Guard Capsules, from the product label.

Perque

See all Perque products
Name
Perque Integrative Health
City
Ashburn
State
VA
ZipCode
20147
Phone Number
800-525-7372
Pharmacist Counseling Corner

Sleep Guard Capsules by Perque: Common Questions

Does Sleep Guard Capsules by Perque interact with any medications?
Yes. Based on its ingredients, Sleep Guard Capsules has a known interaction with 803 medications, including 254 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Sleep Guard Capsules contains 7 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is L-tryptophan safe? I've heard about a contamination scare.
You're right to ask. In 1989, a contaminated batch of L-tryptophan from one Japanese manufacturer caused a rare neurological disorder in over 1,500 people in the US. While almost all cases were traced to that specific product, it's a real safety history to know about. Modern L-tryptophan is produced under stricter controls, but the safety data advises caution.
Can I take this while pregnant or breastfeeding?
Not without talking to your doctor first. L-tryptophan is rated possibly unsafe in pregnancy and is not safe while breastfeeding. Silica also lacks enough safety data for pregnancy and breastfeeding. Riboflavin and magnesium are considered likely safe at normal amounts during pregnancy and breastfeeding, and vitamin B-6 is likely safe in pregnancy at recommended doses.
Will this help me sleep?
L-tryptophan is used for sleep because it's a precursor to serotonin, which supports sleep regulation. However, the evidence for L-tryptophan's effectiveness in depression and anxiety is limited or insufficient. The data we hold doesn't establish how well it works as a sleep aid.
What are the most common side effects?
L-tryptophan most commonly causes drowsiness (which can be intended), but also belching, diarrhea, dry mouth, flatulence, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, and vomiting. Magnesium in the product often causes diarrhea, nausea, and gastrointestinal irritation. Vitamin B-6 may cause headache and nausea.
Can I take this with my blood pressure or seizure medication?
Not without checking first. Vitamin B-6 at high doses can interfere with blood pressure medications and seizure drugs like phenobarbital and phenytoin. Magnesium can also lower blood pressure. Talk with your doctor or pharmacist before combining Sleep Guard with those medications.
Why does the label list magnesium but not its dose?
The product facts provided don't include the specific dose of magnesium or the other ingredients in each capsule. Check the product label or contact the manufacturer for exact amounts, which will help you and your pharmacist assess any interactions with your medications.

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

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

Sleep Guard Capsules label
Go deeper

The Full Monographs Behind Sleep Guard Capsules’s Ingredients

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

Herb & supplement monograph

L-tryptophan

Interacts with 394 drugs

L-tryptophan is an essential amino acid the body uses to make serotonin and melatonin, and people take it to support sleep and mood. The evidence for supplement use is limited and mixed, and...

Read the full L-tryptophan monograph → Herb & supplement monograph

Riboflavin

Interacts with 20 drugs

Riboflavin (vitamin B2) is an essential nutrient your body needs to turn food into energy and to keep skin, eyes, and nerves healthy. It is generally very safe at typical doses, and the stro...

Read the full Riboflavin monograph → Herb & supplement monograph

Vitamin B6

Interacts with 210 drugs

Vitamin B6 (pyridoxine) is an essential water-soluble vitamin that your body needs for metabolism, brain function, and making red blood cells. It is best known for helping with pregnancy-rel...

Read the full Vitamin B6 monograph → Herb & supplement monograph

Silicon

Silicon is a trace mineral found in the body and in foods like oats, barley, and certain fruits and vegetables, and it is popular in supplements for hair, skin, nail, and bone health. Some s...

Read the full Silicon monograph → Herb & supplement monograph

Magnesium

Interacts with 295 drugs

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preventing or correcting deficiency. Some othe...

Read the full Magnesium monograph →
Sources

Sources & How We Checked

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

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

The 156 references behind this product’s interaction data

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

L-tryptophan 18 references
  1. Messiha FS. Fluoxetine: adverse effects and drug-drug interactions. J Toxicol Clin Toxicol 1993;31:603-30. PubMed
  2. Devoe LD, Castillo RA, Searle NS. Maternal dietary substrates and human fetal biophysical activity. The effects of tryptophan and glucose on fetal breathing movements. Am J Obstet Gynecol 1986;155:135-9. DOI
  3. Lieberman HR, Corkin S, Spring BJ. The effects of dietary neurotransmitter precursors on human behavior. Am J Clin Nutr 1985;42:366-70. PubMed
  4. U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements. Information Paper on L-Tryptophan and 5-hydroxy-L-tryptophan, February 2001.
  5. Sullivan EA, Kamb ML, Jones JL, et al. The natural history of eosinophilia-myalgia syndrome in a tryptophan-exposed cohort in South Carolina. Arch Intern Med 1996;156:973-9. DOI
  6. Philen RM, Hill RH, Flanders WD, et al. Tryptophan contaminants associated with eosinophilia-myalgia syndrome. Am J Epidemiol 1993;138:154-9. PubMed
  7. Bohme A, Wolter M, Hoelzer D. L-tryptophan-related eosinophilia-myalgia syndrome possibly associated with a chronic B-lymphocytic leukemia. Ann Hematol 1998;77:235-8. PubMed
  8. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
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Vitamin B6 32 references
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Silicon 19 references
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See these in context on the Magnesium monograph →

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

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

© 2021 Therapeutic Research Center, LLC

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