Safety
Synaptril Side Effects: What Each Ingredient Can Do
Synaptril side effects have not been studied, because no trial has tested the capsule. Its ingredients are linked to mild stomach upset, loose stools and trouble sleeping. The bigger flags are blood sugar changes with alpha lipoic acid and butcher's broom, a warfarin interaction with CoQ10, and a rare liver injury with turmeric.
Written by the Synaptril label deskUpdated
The list01
What are the side effects of Synaptril?
Synaptril side effects are not known from any study of the capsule. What we have are the reported effects of its six ingredients, mostly at doses far higher than one capsule can hold.
Most are mild and digestive: nausea, cramps, loose stools. A few are rare but serious, and those are the ones worth reading twice.
The magnesium glycinate likely fills most of the 575 mg blend, so the other five sit at small amounts. Small amounts lower the odds of dose-related effects. They do not remove allergy, interaction or rare liver risks.
| Ingredient | Common or mild | Rare or serious |
|---|---|---|
| Magnesium (glycinate) | Diarrhea, nausea, cramps at high doses (NIH ODS, Magnesium) | Build-up risk with poor kidney function (NIH ODS, Magnesium) |
| Alpha lipoic acid | Rash, itching, nausea, stomach pain, vertigo (Linus Pauling Institute, Lipoic acid) | Low blood sugar; autoimmune low blood sugar in some people (MSKCC, Alpha-lipoic acid) |
| Butcher's broom | Diarrhea (MSKCC, Butcher's broom) | One case of diabetic ketoacidosis (MSKCC, Butcher's broom) |
| L-carnitine | Nausea, cramps, fishy odor at about 3 g a day (NIH ODS, Carnitine) | None listed at small doses |
| Turmeric | Nausea, reflux, diarrhea or constipation (NCCIH, Turmeric) | Liver injury, about 1 in 10,000-100,000 users (LiverTox, Turmeric) |
| Coenzyme Q10 | Insomnia, digestive upset (NCCIH, Coenzyme Q10) | May counteract warfarin (MSKCC, Coenzyme Q10) |
The label02
Is Synaptril safe to take?
For most healthy adults, one capsule a day is a small dose of mild ingredients. It is not risk-free, and the label itself names people who should not take it.
The caution panel reads: "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." It also says to keep the bottle away from children and not to use it if the seal is damaged or missing.
No stimulant is listed, so jitters from caffeine are not a concern. The FDA does not check supplements for safety before they go on sale (FDA, Dietary supplements Q and A), and no lab report for Synaptril is published.
Digestion03
Can Synaptril cause stomach upset or loose stools?
It can, though the label dose makes it less likely. Magnesium is the usual cause of loose stools in supplements, and Synaptril holds 80 mg of it (NIH ODS, Magnesium).
The adult upper limit for magnesium from supplements is 350 mg a day. One capsule gives 80 mg, about 23% of that limit (NIH ODS, Magnesium). If you also take an antacid, laxative or another magnesium product, add those amounts together.
Turmeric, alpha lipoic acid, butcher's broom and CoQ10 can each upset the stomach too (NCCIH, Turmeric) (Linus Pauling Institute, Lipoic acid) (MSKCC, Butcher's broom) (NCCIH, Coenzyme Q10). The label sets no food rule; see how to take Synaptril.
Weak kidneys clear magnesium more slowly, which raises the risk of too much building up (NIH ODS, Magnesium). Ask your doctor before any magnesium product.
Blood sugar04
Can Synaptril affect blood sugar?
Possibly. Two of its six ingredients carry blood sugar warnings, so people with diabetes should ask a doctor before taking Synaptril.
Alpha lipoic acid may improve how cells take up glucose. People on insulin or diabetes pills are told to watch their blood sugar closely (Linus Pauling Institute, Lipoic acid). In people with certain genes, it has triggered a rare autoimmune form of low blood sugar. One reported case followed 600 mg a day (Okuroglu 2020, ALA and IAS) (MSKCC, Alpha-lipoic acid).
MSKCC advises people with diabetes not to use butcher's broom. It cites a woman who developed diabetic ketoacidosis five days after using it (MSKCC, Butcher's broom). CoQ10 may also interact with insulin (NCCIH, Coenzyme Q10).
Ask your doctor first, check your glucose more often in the first weeks, and report any low readings.
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See packsLiver05
Is there a liver risk with Synaptril?
A small one, from the turmeric. Turmeric is now the most common cause of herbal liver injury in the U.S., though it is rare: about 1 in 10,000 to 100,000 people exposed (LiverTox, Turmeric).
Cases usually appear 1 to 4 months after starting. Most were linked to high-absorption curcumin products (NCCIH, Turmeric); Synaptril lists a standard extract at a small amount. Warning signs are tiredness, nausea, poor appetite, dark urine and yellow skin or eyes (NCCIH, Turmeric). Stop at once and call a provider if they appear.
Self-check06
Is Synaptril a safe fit for you? Five quick questions
Answer five yes-or-no questions to see whether to talk to a doctor before your first capsule. A "yes" does not mean you can never take it; it means ask first.
The questions cover blood thinners, diabetes medicine, pregnancy and age, two drug types that magnesium can block, and memory changes. Drug details are on supplements and medicines.
Never stop or change a prescription because of a supplement. New or worsening memory problems need a doctor, since many causes can be treated (MedlinePlus, Memory loss). Sudden confusion, trouble speaking or weakness on one side: call 911.
If it happens07
What should you do if you react to Synaptril?
Stop taking it, and get help that matches how bad the reaction is. Mild stomach upset can wait for a call to your doctor; trouble breathing or signs of liver injury cannot.
Keep the bottle. The label, the edge code ENB_452_01_062526 and your order ID help a doctor and the order desk. Refunds go through +1 (323) 348-1373 under the 60-day guarantee.
Stop the capsule
Do not take another until you have spoken to a doctor or pharmacist.
Get the right help
Severe symptoms, such as swelling, trouble breathing or sudden confusion: call 911. Otherwise call your doctor.
Report it
You or your doctor can report a supplement reaction to the FDA through its MedWatch program.
Tell the seller
Call +1 (323) 348-1373 or email [email protected] with your order ID. Keep every bottle for a return.
FAQ08
Side effect questions, answered
Can Synaptril cause headaches?
Headache is not among the effects listed for its ingredients in the sources we use. Alpha lipoic acid lists vertigo, and CoQ10 can disturb sleep, which may leave you feeling off (Linus Pauling Institute, Lipoic acid) (NCCIH, Coenzyme Q10). If headaches start after the capsule, stop and ask your doctor.
Can Synaptril cause digestive upset?
Yes, mild digestive upset is the most likely effect. Magnesium can loosen stools, and turmeric, alpha lipoic acid and CoQ10 can cause nausea or stomach upset (NIH ODS, Magnesium) (NCCIH, Turmeric). One capsule a day keeps magnesium at 80 mg, well under the 350 mg supplement limit.
Can Synaptril affect blood sugar?
It might. Alpha lipoic acid may lower blood sugar, and MSKCC advises people with diabetes against butcher's broom (Linus Pauling Institute, Lipoic acid) (MSKCC, Butcher's broom). If you use insulin or diabetes pills, ask your doctor first and check your glucose more often when you start.
What should I do if I have a reaction to Synaptril?
Stop the capsule and contact your doctor. Call 911 for trouble breathing, swelling, sudden confusion or one-sided weakness. Keep the bottle and your order ID, then call the order desk at +1 (323) 348-1373 about a refund.
How do I report a supplement side effect to the FDA?
Use the FDA's MedWatch program, which takes reports from consumers as well as doctors. Have the product name, the edge code from the bottle, the dates you took it and what happened. Your doctor can also file the report for you.
Can Synaptril keep me awake at night?
It contains no listed caffeine or other stimulant. CoQ10 can cause insomnia in some people (NCCIH, Coenzyme Q10), but the amount in one capsule is small. If your sleep changes after starting, note it and talk to your doctor.
Is it safe to take two Synaptril capsules a day?
No. The label says to take one capsule daily and "Do not exceed recommended dose." Doubling up raises the magnesium to 160 mg and doubles every other ingredient, with no evidence of extra benefit. If you miss a day, simply carry on the next.
Who wrote this09
Written and reviewed by
Pages built from the label, the sales page and linked NIH, FDA, CDC, FTC and peer-reviewed sources.
Last updated . See our editorial standards and how we check reviews. This website is run by Getsynaptril, a stocked U.S. Synaptril counter, not by the manufacturer or the distributor. We are paid when you buy through our order links.
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