Safety
SynoCell Side Effects: Stomach Upset and Drug Interactions
Most people who take SynoCell's ingredients report no problems or only mild stomach upset.
Quercetin and black pepper extract can change blood levels of some drugs, and Boswellia may add to bleeding risk. If you have a soy allergy or kidney problems, ask a doctor first.
Written by the SynoCell editorial teamUpdated
Does SynoCell have side effects?
It can, though the ingredients are generally mild. Reports mostly describe stomach upset; serious problems are rare in the studies. Interactions matter more.
Nobody has tested the five-ingredient formula in a trial, so its safety profile comes from studies of each ingredient. The U.S. health agency for complementary medicine notes that little safety information exists for herbal products used for arthritis, including ASU and Boswellia (NCCIH, Osteoarthritis In Depth).
SynoCell is sold as a dietary supplement and is not a drug. Ask your doctor or pharmacist first if you take blood thinners (such as warfarin), cyclosporine, seizure medicines, heart or blood pressure drugs, or any daily prescription, if you have kidney disease or a soy allergy, or if you are pregnant or nursing: quercetin and black pepper extract can change how some drugs work. See side effects and interactions.
No warning statement, other ingredients or capsule type is published, so read your own bottle. Amounts are on the full SynoCell label.
What side effects can each SynoCell ingredient cause?
| Ingredient (per serving) | Reported side effects | Main caution |
|---|---|---|
| ASU, 310 mg | Usually well tolerated; used daily for up to 3 years (WebMD, Avocado soy unsaponifiables) | Made partly from soy, a common allergen (MedlinePlus, Food allergy); avoid in pregnancy and breastfeeding (WebMD, Avocado soy unsaponifiables) |
| Quercetin, 310 mg | Rare and mild in human studies (Andres et al., 2018) | Very high doses may harm kidneys (RxList, Quercetin); several drug interactions (MSKCC, Quercetin) |
| Boswellia extract, 200 mg | Mild stomach upset, nausea, diarrhea (Sengupta et al., 2008); rare skin rash, mild constipation (MSKCC, Boswellia) | May add to bleeding risk with blood thinners (MSKCC, Boswellia) |
| Hyaluronic acid, 180 mg | Not well described; the oral studies were small and short (Oe et al., 2016) | Not the same as joint injections; little long-term data (Guadagna et al., 2018) |
| Black pepper extract, 5 mg | None reported at 20 mg in the classic absorption study (Shoba et al., 1998) | Can raise blood levels of some medicines (Horn and Hansten, 2017) |
In the 75-person Boswellia trial, minor stomach complaints were about as common on placebo as on the extract (Sengupta et al., 2008). Taking the capsules mid-meal with water and stopping if upset lasts more than a few days are sensible habits. For deeper detail on each ingredient, see the SynoCell ingredients overview.
Which medicines interact with SynoCell?
Blood thinners, some seizure, heart and transplant drugs, quinolone antibiotics and medicines cleared by certain liver enzymes. Quercetin and piperine are the usual reasons (MSKCC, Quercetin) (RxList, Quercetin) (Horn and Hansten, 2017).
| If you take | Ingredient to ask about | Why |
|---|---|---|
| Blood thinners (warfarin and others) | Quercetin, Boswellia | A raised INR was reported with quercetin; Boswellia may add to bleeding risk. (MSKCC, Quercetin) (MSKCC, Boswellia) |
| Cyclosporine, some antibiotics (quinolones) | Quercetin | Listed moderate interactions. (RxList, Quercetin) |
| Seizure drugs (phenytoin, carbamazepine) | Black pepper extract | Piperine raised blood levels in small studies. (Horn and Hansten, 2017) (Ziegenhagen et al., 2021) |
| Heart and blood pressure drugs (propranolol, losartan) | Black pepper, quercetin | Piperine raised propranolol levels; quercetin may interact with losartan. (Ziegenhagen et al., 2021) (MSKCC, Quercetin) |
| Drugs cleared by liver CYP3A4 or CYP2C19 | Quercetin, black pepper | Both can slow how some drugs are broken down. (MSKCC, Quercetin) (Horn and Hansten, 2017) |
| NSAID pain relievers | None known | No listed interaction, but tell your doctor about every supplement you take. (NIH ODS, Dietary Supplements: What You Need to Know) |
The warfarin concern is not theoretical. A man on warfarin who took quercetin had a raised INR, the blood test that tracks clotting time (MSKCC, Quercetin). On a blood thinner, start only with your prescriber's agreement.
Is 5 mg of black pepper extract a safe amount?
Probably for most adults, but it is above one cautious guidance value. Germany's risk agency derived a guidance value of about 2.3 mg a day for isolated piperine, while Australia allows up to 10 mg and Health Canada up to 14 mg (Ziegenhagen et al., 2021).
Germany (guidance)
A cautious value, since human safety data are thin (Ziegenhagen et al., 2021).
The drug interaction studies used 15 to 20 mg a day (Horn and Hansten, 2017). Whether 5 mg changes your medicines is untested. Read more in piperine and your medicines.
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Order nowWho is most likely to have problems with SynoCell?
People who are pregnant, under 18, allergic to soy, living with kidney disease or on daily medicines.
Reasons for each group: who SynoCell is for.
What symptoms mean I should stop SynoCell and get help?
Stop at once and get emergency help for any sign of a severe allergic reaction. Those reactions can start within two hours and can be life threatening (MedlinePlus, Food allergy).
Swelling of the lips, tongue or throat; trouble breathing; hives over large areas; or fainting after a dose.
Stop and call your doctor the same day for:
- Unusual bruising, nosebleeds, bleeding gums or dark stools, especially on a blood thinner
- New drowsiness or unsteadiness on seizure medicines
- Less urine than usual or swelling in the legs if you have kidney problems
A joint that turns hot, red and swollen, or joint pain with fever, needs urgent care too. It may be an infection (MedlinePlus, Septic arthritis).
How do I report a bad reaction to SynoCell?
Stop the product, get care if you need it, then file a report with the FDA through its online Safety Reporting Portal. You can file as a guest, and the FDA asks for as much detail as possible (FDA, How to Report a Problem with Dietary Supplements).
Keep the bottle
Note the lot code and photograph the label.
Write it down
Dates, symptoms, other medicines and what care you received.
Report it
Use the FDA portal, then call the order desk at +1 (302) 200-3480.
FAQ
Questions about SynoCell safety
What are the side effects of SynoCell?
The most common complaint linked to its ingredients is mild stomach upset, such as nausea or loose stools, mainly from Boswellia (Sengupta et al., 2008). Rare skin rashes have been reported (MSKCC, Boswellia). The bigger issues are interactions with some medicines and cautions for soy allergy, kidney disease and pregnancy. No trial has tested the full formula.
Can I take SynoCell with blood thinners?
Only with your prescriber's approval. Quercetin was linked to a raised INR in a man on warfarin (MSKCC, Quercetin), and Boswellia may increase bleeding risk (MSKCC, Boswellia). If your doctor agrees, expect an extra blood test after you start, and watch for unusual bruising, nosebleeds or dark stools.
Can SynoCell hurt your kidneys?
There is no report of kidney harm from SynoCell itself. The concern comes from quercetin: very high doses may damage the kidneys (RxList, Quercetin), and animal data suggest it may worsen existing kidney disease (Andres et al., 2018). SynoCell has 310 mg per serving. If you have kidney disease, ask your doctor before taking it.
Can I take SynoCell with ibuprofen?
Ibuprofen was not studied, but piperine at 15-20 mg a day raised levels of diclofenac, another NSAID (Horn and Hansten, 2017). Tell your doctor about every supplement you take (NIH ODS, Dietary Supplements: What You Need to Know). Keep NSAID use to the lowest dose for the shortest time, since heart attack and stroke risk can start in the first weeks (FDA, 2015 NSAID safety communication).
Can SynoCell cause an allergic reaction?
It can in some people. ASU comes partly from soybean oil, and soy is a common food allergen (MedlinePlus, Food allergy). Boswellia has rare reports of allergic skin reactions (MSKCC, Boswellia). Swelling of the face or throat, or trouble breathing, needs emergency care right away. People with a soy allergy should ask an allergist first.
Where do I report a bad reaction to a supplement?
Report it to the FDA through the Safety Reporting Portal, which accepts reports from registered users or guests (FDA, How to Report a Problem with Dietary Supplements). Stop the product, get care if needed and keep the bottle. Then call the order desk at +1 (302) 200-3480 so the seller has a record too.
Who wrote this
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Plain-language pages built from the label, the brand store and linked medical sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by an authorized U.S. retailer, not by the manufacturer. We earn money when you buy through our order links.
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Who it's for
A quick fit check: who may suit SynoCell, who should skip it, and who should ask a doctor first.
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Black pepper extract
5 mg of piperine: why it is added, which medicines it can affect, and how it compares with safety limits.
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How to use
The 2-capsule routine, best time of day, missed doses, travel, storage and spacing from your medicines.
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