Oleoylethanolamide Side Effects: Is OEA Safe and What Trials Logged

Oleoylethanolamide (OEA) side effects are rarely reported, and most people tolerate it well. In human trials that gave 125 to 250 mg a day for 8 to 12 weeks, researchers who checked for side effects reported none in one trial and no major adverse events in another. OEA is also not a foreign compound: it is a lipid messenger your body already makes from oleic acid, a common dietary fat.

Key Takeaways

• Most people tolerate OEA well. It is a lipid messenger the body makes on its own from oleic acid (Bowen et al., 2017).
• In an 8-week trial, 46 adults took 125 mg of OEA or a placebo once a day with their main meal, and no side effects were reported in either group (Pouryousefi et al., 2022).
• In a 12-week trial, 76 adults took 125 mg twice a day before their main meals. Participants were checked every two weeks, no major adverse events were found, and 74 finished (Tutunchi et al., 2020).
• Trials used 125 to 250 mg a day. Our OEA Supplement gives 200 mg per serving, inside that range.
• Check with a clinician first if you are pregnant or breastfeeding, have a liver condition or take prescription medicine.

Is Oleoylethanolamide Safe?

For most people, yes. OEA is an endogenous lipid mediator, meaning your body makes it from its own building blocks. It is formed from oleic acid, a monounsaturated fat, and a 2017 review notes that eating oleic acid raises blood levels of OEA. OEA binds strongly to a receptor called PPAR-alpha, and the review links it to food intake control (Bowen et al., 2017). A supplement adds to a compound your body already produces, rather than introducing something unfamiliar.

The human trials of OEA as a supplement are small and recent, and they back up that picture. Where researchers tracked side effects, they found none or no major ones over 8 to 12 weeks of daily use. For a broader look at what OEA does, see OEA benefits, dosage and safety and our OEA ingredient page.

What OEA Trials Logged

These trials were run in adults with metabolic conditions, and each one is named plainly below. What matters for this guide is what the researchers saw in terms of safety, not the outcomes they set out to measure.

Trial	Who and how long	Dose and timing	What was logged
Pouryousefi et al., 2022	46 adults with prediabetes, 8 weeks	125 mg once a day with the main meal	No side effects reported from OEA or placebo; daily phone check-ins
Tutunchi et al., 2020	76 adults with obesity and fatty liver, 12 weeks	125 mg twice a day, 30 minutes before main meals	No major adverse events; checked every two weeks; 74 of 76 finished
Ostadrahimi et al., 2024	60 adults with obesity, 8 weeks	125 mg before lunch and before dinner	56 of 60 finished; weekly check-ins on supplement use

In the 12-week trial, the two people who left the study gave personal reasons, and routine blood count measures showed no differences between the OEA and placebo groups apart from a slightly lower value in one red blood cell measure with OEA (Tutunchi et al., 2020). In the 8-week trial with daily phone check-ins, the authors wrote that no side effects from the supplement or the placebo were reported (Pouryousefi et al., 2022). The third trial kept weekly track of supplement use, and 56 of the 60 people who started completed it (Ostadrahimi et al., 2024). These are small trials lasting up to 12 weeks, and across them OEA was taken daily without safety problems being recorded.

OEA Supplement Side Effects: The Other Ingredients

Many OEA products, ours included, pair OEA with other ingredients. Ours combines OEA with palmitoylethanolamide (PEA), L-theanine, acetyl-L-carnitine and green tea extract, so it is worth knowing the safety notes for each:

Ingredient	Where to read more
Palmitoylethanolamide (PEA)	See PEA benefits, dosage and side effects
L-theanine	An amino acid found in tea; see L-theanine side effects
Acetyl-L-carnitine	See acetyl-L-carnitine benefits and side effects
Green tea extract	See green tea extract, caffeine and safety

Green tea extract carries the one note worth knowing. NCCIH reports no safety concerns for green tea as a drink, and says liver problems are uncommon but have occurred in some people, mainly with concentrated extracts in tablet or capsule form. Green tea also naturally contains caffeine (NCCIH). That is why anyone with a liver condition, or anyone sensitive to caffeine, should check with a clinician before starting a product that includes it.

OEA Dose and Timing: What Trials Used

The trials above used 125 mg once a day or 125 mg twice a day, so 125 to 250 mg daily. Every one of them tied the dose to food: once a day with the main meal, or 30 minutes before the main meals, or before lunch and dinner. If you are new to OEA, taking it around a meal follows how it was studied. Always follow the directions on your product label and do not take more than the label says.

Our guide to OEA benefits covers what the research measured beyond safety.

Who Should Check With a Clinician First

OEA is a good fit for most healthy adults. As with any new supplement, talk with your clinician before starting if you:

• Are pregnant or breastfeeding
• Have a liver condition, mainly because of the green tea extract in many OEA products
• Are sensitive to caffeine
• Take any prescription medicine

Where Our OEA Supplement Fits

Our OEA Supplement gives 200 mg of oleoylethanolamide per serving, within the 125 to 250 mg a day range used in the trials above. It combines OEA with PEA, L-theanine, acetyl-L-carnitine and green tea extract in vegan capsules, made with third-party tested ingredients, designed to support fullness, focus and healthy metabolism as part of your daily routine. Benefits build with consistent daily use: months 1 to 2 can bring early changes, and 3 months and beyond is where the full benefit builds. For the bigger picture, see our metabolic health and energy guide.

If you like L-theanine on its own, our Theanine Nasal Spray gives 36 mg of L-theanine per 2-spray serving, with alkaline water the only other ingredient. It is caffeine-free and absorbed through the lining of the nose, so some of each dose skips digestion.

Frequently Asked Questions

What are the side effects of oleoylethanolamide?

Side effects are rarely reported. One 8-week trial reported none from OEA or placebo, and a 12-week trial found no major adverse events.

Is oleoylethanolamide safe?

Most people tolerate it well. Your body makes OEA naturally from oleic acid, and trials lasting up to 12 weeks recorded no safety problems with daily use.

What are OEA supplement side effects?

OEA itself has a clean record in trials, so check the other ingredients too. Green tea extract, found in many OEA products, contains caffeine and has been linked to uncommon liver problems in some people.

How much OEA is safe to take?

Trials used 125 to 250 mg a day without safety problems being recorded. Follow your product label; ours gives 200 mg per serving.

Can I take OEA every day?

Yes. The trials gave it every day for 8 to 12 weeks.

Should OEA be taken with food?

The trials tied it to meals: with the main meal, or 30 minutes before the main meals.

Is OEA bad for the liver?

The 12-week trial was run in adults with fatty liver and found no major adverse events. If you have a liver condition, check with your clinician first, mainly because many OEA products include green tea extract.

Can I take OEA while pregnant or breastfeeding?

Talk with your clinician first, as you would before starting any new supplement during pregnancy or breastfeeding.

Sources

• Bowen KJ, Kris-Etherton PM, Shearer GC, West SG, Reddivari L, Jones PJH. Oleic acid-derived oleoylethanolamide: A nutritional science perspective. Progress in Lipid Research, 2017. https://pubmed.ncbi.nlm.nih.gov/28389247/
• Pouryousefi E, Javadi M, Hashemipour S, Nooshabadi MR, Haghighian HK. Improved glycemic status, insulin resistance and inflammation after receiving oral oleoylethanolamide supplement in people with prediabetes: a randomized controlled trial. Diabetology and Metabolic Syndrome, 2022. https://pubmed.ncbi.nlm.nih.gov/35659064/
• Tutunchi H, Naeini F, Saghafi-Asl M, Farrin N, Monshikarimi A, Ostadrahimi A. Effects of oleoylethanolamide supplementation on atherogenic indices and hematological parameters in patients with nonalcoholic fatty liver disease: A clinical trial. Health Promotion Perspectives, 2020. https://pubmed.ncbi.nlm.nih.gov/33312933/
• Ostadrahimi A, Khajebishak Y, Moradi F, Payahoo L. The effect of Oleoylethanolamide supplementation on lipid profile, fasting blood sugar and dietary habits in obese people: a randomized double-blind placebo-control trial. BMC Endocrine Disorders, 2024. https://pubmed.ncbi.nlm.nih.gov/39379951/
• National Center for Complementary and Integrative Health. Green Tea: Usefulness and Safety. Updated February 2025. https://www.nccih.nih.gov/health/green-tea

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.