Side effects
Synaptril Side Effects and Drug Interactions
Synaptril side effects have not been studied in the capsule itself, so the likely ones come from its ingredients: mild stomach upset or loose stools from magnesium, nausea from alpha lipoic acid, and poor sleep from CoQ10. Interactions matter more: warfarin, diabetes medicines, some antibiotics and osteoporosis drugs. Turmeric has rare links to liver injury.
Written by the Synaptril label deskUpdated
By ingredient01
What are the Synaptril side effects?
Synaptril side effects are not documented for the capsule, because no study has tested it. The known side effects belong to its six ingredients, mostly at doses far above what one capsule holds.
The table lists each ingredient, the most a capsule can hold by the blend math, and what the sources report. Most effects are mild and stomach-related. The serious ones are rare.
| Ingredient | Most per capsule | Reported side effects |
|---|---|---|
| Magnesium | 80 mg (printed) | Diarrhea, nausea and cramps at high supplement doses (NIH ODS, Magnesium) |
| Alpha lipoic acid | About 175 mg | Nausea, vomiting, indigestion, low blood sugar; rare autoimmune low blood sugar (MSKCC About Herbs, Alpha-Lipoic Acid) |
| Butcher's broom | About 88 mg | Traditional use only; adults only (EMA, Rusci rhizoma (butcher's broom)) |
| L-carnitine | About 58 mg | Nausea, cramps, fishy body odor at about 3 g a day (NIH ODS, Carnitine) |
| Turmeric extract | About 44 mg | Nausea, reflux, diarrhea; rare liver injury (NCCIH, Turmeric) |
| Coenzyme Q10 | About 35 mg | Trouble sleeping, stomach upset (NCCIH, Coenzyme Q10) |
Ceilings come from label order and the magnesium math, not a lab test. See alpha lipoic acid and turmeric for detail.
How likely02
Are Synaptril side effects likely at one capsule a day?
Side effects from one Synaptril capsule a day are likely to be uncommon and mild, because the amounts are small.
The numbers show the margin. The supplement limit for magnesium is 350 mg a day (NIH ODS, Magnesium), and a capsule gives 80 mg. The fishy odor from L-carnitine shows up near 3 g a day (NIH ODS, Carnitine), about 50 times the most a capsule can hold.
Small does not mean zero. Interactions with medicines and rare reactions do not need a large dose, so the next sections matter more than the table.
Interactions03
Which medicines interact with Synaptril?
Synaptril can interact with blood thinners, diabetes medicines, some antibiotics, osteoporosis drugs and seizure medicines. Each link runs through one ingredient.
Coenzyme Q10 may weaken warfarin, and the INR may need a check (Linus Pauling Institute, Coenzyme Q10). Magnesium binds tetracycline and quinolone antibiotics and bisphosphonates, so doses are spaced apart (NIH ODS, Magnesium).
Pick a type of medicine to see which ingredient matters and why.
Blood thinners (warfarin)
- Coenzyme Q10Reported to reduce warfarin's effect; your INR may need checking. (Linus Pauling Institute, Coenzyme Q10)
Diabetes medicines
- Alpha lipoic acidMay lower blood sugar further; check your glucose more often. (Linus Pauling Institute, Lipoic Acid)
Antibiotics (tetracyclines, quinolones)
- MagnesiumBinds these antibiotics; take them at least 2 hours before or 4-6 hours after. (NIH ODS, Magnesium)
Osteoporosis drugs (bisphosphonates)
- MagnesiumCan reduce absorption; separate by at least 2 hours. (NIH ODS, Magnesium)
Water pills and acid reducers (PPIs)
- MagnesiumThese drugs change magnesium levels; your doctor may check them. (NIH ODS, Magnesium)
Seizure medicines
- L-carnitineValproic acid and some other seizure drugs lower carnitine levels; ask your neurologist. (NIH ODS, Carnitine)
Liver problems or many medicines
- TurmericRare liver injury, mostly with high-absorption curcumin; stop and call a doctor for dark urine or yellow skin. (NIH LiverTox, Turmeric)
A starting list for a talk with your pharmacist, not a full interaction check. Keep taking prescribed medicine; never stop or change a dose because of a supplement.
More detail in the guide to supplements and medicines.
Stomach04
Can Synaptril cause stomach upset or diarrhea?
Yes, Synaptril can cause mild stomach upset in some people, though one capsule makes it less likely. Three of its ingredients list stomach effects.
Magnesium causes diarrhea, nausea and cramps mainly at high supplement doses (NIH ODS, Magnesium). Alpha lipoic acid can cause nausea and indigestion (MSKCC About Herbs, Alpha-Lipoic Acid). Turmeric can cause nausea, reflux and diarrhea (NCCIH, Turmeric).
- Take the capsule in the middle of a meal.
- Add up magnesium from other supplements and antacids.
- Stop and call your doctor if symptoms last or are severe.
Blood sugar05
Can Synaptril lower blood sugar?
Synaptril may lower blood sugar slightly in people on diabetes medicines, because of its alpha lipoic acid.
People on insulin or diabetes pills are advised to watch their glucose when taking lipoic acid (Linus Pauling Institute, Lipoic Acid). In rare cases it has triggered insulin autoimmune syndrome, a form of low blood sugar; about 27 cases are reported, mostly in Japan (MSKCC About Herbs, Alpha-Lipoic Acid).
If you feel unwell after starting the capsule, check your glucose and call your doctor. Keep your diabetes medicine as prescribed.
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See packsLiver06
Is there a liver risk with the turmeric in Synaptril?
The liver risk from the turmeric in Synaptril is rare, but it is real enough to know the warning signs.
NIH's LiverTox describes several dozen cases of liver injury from turmeric products, many tied to high-absorption curcumin (NIH LiverTox, Turmeric). The label lists a 95% curcuminoid extract and does not say it is a high-absorption form. The capsule likely holds a small amount.
Dark urine, yellow skin or eyes, or unusual tiredness can signal liver trouble. Stop the capsule and call your doctor promptly.
Label cautions07
What does the Synaptril label warn about?
The Synaptril label warns against going over one capsule a day and rules out anyone under 18 and pregnant or nursing mothers.
It also asks anyone who takes a medication or has a medical condition to consult a physician first. Keep taking prescribed medicine; never stop or change a dose because you started a supplement.
The caution, word for word
"Do not exceed recommended dose. Not for use for those under the age of 18 or pregnant or nursing mothers. Consult with a physician prior to use especially if you are taking a medication or have a medical condition."
KEEP OUT OF REACH OF CHILDREN. DO NOT USE IF SAFETY SEAL IS DAMAGED OR MISSING. STORE IN A COOL, DRY PLACE.
See who Synaptril is for before you order.
If it happens08
What should you do if you have a side effect from Synaptril?
Stop taking Synaptril, call your doctor, and report the reaction. Serious symptoms need urgent care.
NCCIH advises telling every provider which supplements you take and stopping one that causes side effects (NCCIH, Using Dietary Supplements Wisely).
Stop the capsule
Keep the bottle so your doctor can read the label.
Get help
Call your doctor. Sudden confusion, slurred speech, a drooping face or weakness on one side means call 911.
Report it to FDA
Use the online Safety Reporting Portal, or call 1-888-463-6332 (FDA, How to Report a Problem).
Ask about a refund
Call +1 (323) 348-1373 with your order ID within 60 days of purchase.
FAQ09
Questions about Synaptril side effects
Can Synaptril keep you awake at night?
It can in some people. Coenzyme Q10, one of the six ingredients, may cause trouble sleeping (NCCIH, Coenzyme Q10). If you sleep worse after starting Synaptril, move the capsule to the morning, and stop it if the problem continues.
Can Synaptril cause headaches?
Headache is not among the side effects our sources list for Synaptril's six ingredients. A new headache can still happen with any change in routine. If it is severe, sudden or comes with other symptoms, stop the capsule and seek care.
Can Synaptril cause a fishy body odor?
Unlikely. The fishy odor linked to L-carnitine appears at about 3 g a day (NIH ODS, Carnitine), and a Synaptril capsule can hold at most about 58 mg. If you notice an odor anyway, stop and tell your doctor.
Should I stop Synaptril before surgery?
Tell your surgeon about Synaptril well before the date. NCCIH notes some supplements can be risky before surgery (NCCIH, Using Dietary Supplements Wisely), and CoQ10 may affect warfarin. Your surgical team will say when to stop it.
Is Synaptril safe to take with a statin?
No interaction between statins and Synaptril appears in our sources, but ask your pharmacist. NCCIH notes CoQ10 does not appear to relieve statin muscle pain (NCCIH, Coenzyme Q10). Keep taking your statin exactly as prescribed.
Where do I report a bad reaction to Synaptril?
Report a reaction to Synaptril through FDA's online Safety Reporting Portal, or call 1-888-INFO-FDA (1-888-463-6332) (FDA, How to Report a Problem). Also tell your doctor and the order desk at +1 (323) 348-1373.
Is Synaptril safe to take for many months?
No long-term study of Synaptril exists. NCCIH says ordinary turmeric is likely safe for 2 to 3 months (NCCIH, Turmeric); data beyond that is thin for most ingredients. Review the capsule with your doctor every few months.
Who wrote this10
Written and reviewed by
Pages built from the label, the sales page and linked NIH, FDA, CDC, FTC and peer-reviewed sources.
Last updated . Learn about our editorial standards and how we check reviews. This website is run by a U.S. retail partner of Synaptril, not by the manufacturer or the distributor. We make money when you buy through our order links.
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