Most clinical trials testing celery seed have used daily doses ranging from about 150 mg to 1,500 mg of extract, with the specific amount depending on the health outcome being studied and how concentrated the product was. No regulatory body has established an official recommended dose, and the concentration of active compounds varies so much between products that “1,000 mg of celery seed” can mean very different things on two different labels. The research base is genuinely small, but it offers enough data to give you a reasonable starting framework.
Doses That Have Been Tested in Humans
A 2025 systematic review and meta-analysis of randomized controlled trials found that celery was administered as capsules or decoctions, with capsule doses ranging from roughly 10 mg to 2,250 mg per day, and treatment durations varying from 12 to 84 days.1PubMed Central. Effects of celery (Apium graveolens) on blood pressure, glycemic and lipid profile in adults: a systematic review and meta-analysis of randomized controlled trials That is a wide range, but the two most commonly cited human doses in the literature sit at opposite ends of it.
The higher dose is 1,340 mg per day (about 1.34 g) of celery seed extract, split into four capsules, tested in 51 hypertensive patients over four weeks.2PubMed. Safety evaluation and biochemical efficacy of celery seed extract (Apium Graveolens) capsules in hypertensive patients: a randomized, triple-blind, placebo-controlled, cross-over, clinical trial The lower dose is 150 mg per day (75 mg twice daily, taken before breakfast and before dinner) of a standardized celery seed extract containing 85% of a compound called 3-n-butylphthalide (NBP), tested over 12 weeks for metabolic syndrome markers.3PubMed Central. Effect of Celery Seed (Apium graveolens L.) Administration on the Components of Metabolic Syndrome, Insulin Sensitivity, and Insulin Secretion: A Clinical Trial
That is a nearly tenfold difference, which tells you how much the standardization of the extract matters. The 150 mg product was concentrated to deliver a high percentage of a specific phthalide compound thought to drive the therapeutic effects, while the 1,340 mg product was a broader extract. Subgroup analysis in the 2025 meta-analysis found that celery seeds or celery preparations exceeding 1,000 mg per day were more effective than lower doses for blood pressure and lipid outcomes, and that celery seeds outperformed other parts of the plant like stalks or leaves.1PubMed Central. Effects of celery (Apium graveolens) on blood pressure, glycemic and lipid profile in adults: a systematic review and meta-analysis of randomized controlled trials
Blood Pressure Is the Most-Studied Use
If you are taking celery seed for any single purpose, blood pressure reduction has the most human data behind it. In the trial of 51 hypertensive patients, 1.34 g of celery seed extract daily led to a drop of about 11 mmHg in systolic blood pressure and 8 mmHg in diastolic blood pressure.4PubMed Central. Antihypertensive Property of Celery: A Narrative Review on Current Knowledge The extract was given alongside patients’ usual blood pressure medications, not as a replacement, and showed no harmful effects on kidney function, liver function, or blood cell counts.2PubMed. Safety evaluation and biochemical efficacy of celery seed extract (Apium Graveolens) capsules in hypertensive patients: a randomized, triple-blind, placebo-controlled, cross-over, clinical trial
Animal research helps explain why this effect occurs. Celery seed extracts appear to relax blood vessels through calcium channel blocking activity, interfering with the mechanism that tightens arterial walls.4PubMed Central. Antihypertensive Property of Celery: A Narrative Review on Current Knowledge In both normal and hypertensive rats, hexanic celery seed extract also slowed heart rate alongside the blood pressure drop, suggesting a dual effect: wider blood vessels and a calmer heartbeat.5Revista Brasileira de Farmacognosia. Evaluation of mechanism for antihypertensive and vasorelaxant effects of hexanic and hydroalcoholic extracts of celery seed in normotensive and hypertensive rats
One finding from the rat studies is particularly relevant to the dosing question. When researchers compared extraction methods, a hexane-based extract caused the largest blood pressure drop (about 38 mmHg) compared to methanol or water-ethanol extracts (roughly 23–24 mmHg), partly because the hexane extract contained several times more NBP.6PubMed Central. Antihypertensive effect of celery seed on rat blood pressure in chronic administration This reinforces the point that the extraction method shapes how much active compound you actually get per milligram, which in turn determines how much you need to take.
Uric Acid and Gout
Celery seed has a longstanding folk reputation for helping with gout, and laboratory and animal evidence offers some support for that tradition. Several flavonoid compounds in celery seeds, including luteolin, apigenin, and chrysoeriol, inhibit xanthine oxidase, the enzyme responsible for producing uric acid.7PubMed Central. Identification of Xanthine Oxidase Inhibitors from Celery Seeds Using Affinity Ultrafiltration–Liquid Chromatography–Mass Spectrometry In mice with artificially elevated uric acid levels, oral administration of celery extract over two weeks brought serum uric acid down from about 4.6 mg/dL to 2.7 mg/dL and significantly reduced the activity of the enzyme in the liver.8PubMed Central. Inhibitory Effects of Apium graveolens on Xanthine Oxidase Activity and Serum Uric Acid Levels in Hyperuricemic Mice A separate rodent study confirmed that both aqueous and oily fractions of celery seed extract reduced serum uric acid and xanthine oxidase activity in a hyperuricemia model.9PubMed Central. Anti‑gouty arthritis and anti‑hyperuricemia properties of celery seed extracts in rodent models
The problem is that none of these studies were conducted in humans. There is no tested human dose for celery seed as a uric acid intervention. The animal doses, often in the range of hundreds of milligrams per kilogram of body weight, cannot be directly translated to a human capsule dose without bridging studies that have not been done. If you take celery seed for gout, you are essentially borrowing the dosing range from the blood pressure trials and hoping the gout-relevant compounds are present in sufficient quantity. That is a reasonable bet given the overlapping active compounds, but it is a bet, not evidence-based dosing.
Joint Inflammation and Stomach Protection
Beyond uric acid, a standardized celery seed extract was tested in a rat model of polyarthritis and found to suppress inflammation at least as effectively as aspirin, ibuprofen, and naproxen. The same preparation also reduced existing inflammation and provided pain relief in two different test systems.10PubMed. Celery Seed and Related Extracts with Antiarthritic, Antiulcer, and Antimicrobial Activities No human arthritis trial has been published for celery seed, so there is no clinically validated dose for this application.
Celery seed also shows gastroprotective properties in animal models. Pretreatment with celery extract reduced gastric ulcers in a dose-dependent manner, likely through antioxidant activity that shields the stomach lining from oxidative damage.11PubMed. Gastric antiulcer, antisecretory and cytoprotective properties of celery (Apium graveolens) in rats In a separate study, celery seed extract counteracted the stomach damage caused by indomethacin (a common anti-inflammatory drug) by restoring a growth factor important for tissue repair and reducing inflammatory signaling.12PubMed Central. Apium extract alleviates indomethacin-induced gastric ulcers in rats via modulating the VEGF and IK-κB/NF-κB p65 signaling pathway A compound isolated from celery seed also showed potent activity against Helicobacter pylori, the bacterium linked to stomach ulcers, at very low concentrations and was specifically active against H. pylori without affecting other common gut bacteria tested.13PubMed. A novel compound from celery seed with a bactericidal effect against Helicobacter pylori
These findings help explain why celery seed has been used as a digestive remedy in traditional medicine systems, but they remain animal and laboratory results. Translating a rat stomach dose to a human supplement dose is speculative without dedicated clinical trials.
Why the Label Can Be Misleading
One of the most practically important things to understand about celery seed supplements is that “celery seed extract” is not one standardized product. The active compounds, phthalides like NBP and sedanenolide plus flavonoids like apigenin and luteolin, make up a variable fraction of any given product depending on how it was extracted and processed.
Celery seed oil, for instance, is dominated by limonene, a terpene that is not the therapeutically interesting part. Analysis of celery seed oil found that out of about 13.7 grams of oil, roughly 7.6 grams was limonene while only about 2.9 grams consisted of phthalides.14Journal of Pharmacy and Nutrition Sciences. Enrichment of Bio-Active Phthalides in Celery Seed Oil That means crude celery seed oil is only about 20% phthalides by weight, while a standardized extract can be engineered to contain 85% or more NBP.3PubMed Central. Effect of Celery Seed (Apium graveolens L.) Administration on the Components of Metabolic Syndrome, Insulin Sensitivity, and Insulin Secretion: A Clinical Trial
This is why the 150 mg/day dose in one trial and the 1,340 mg/day dose in another are not as far apart as they initially appear. The 150 mg product was highly concentrated in the specific compound thought to matter most for cardiovascular outcomes, while the 1,340 mg product was a broader-spectrum extract delivering its active compounds at a lower percentage. When you pick up a bottle at a health food store, the label might say “celery seed” or “celery seed extract” without specifying the extraction method or the phthalide content. Two products labeled “500 mg celery seed” could deliver wildly different amounts of the bioactive compounds. If possible, look for products that state what they are standardized to, usually a percentage of NBP or total phthalides.
A Pharmaceutical-Grade Compound From Celery Seed
NBP, the same phthalide that drives celery seed’s blood pressure effects, has attracted serious pharmaceutical attention for brain health. It has been approved in China as a clinical drug for treating ischemic stroke, and research in animal models suggests it protects nerve cells by activating a survival signaling pathway in brain tissue. Studies have demonstrated both preventive and therapeutic effects against vascular dementia in rats.15PubMed Central. L-3-n-butylphthalide protects against vascular dementia via activation of the Akt kinase pathway
The doses used in pharmaceutical NBP formulations for stroke are distinct from what you would find in a dietary supplement, and the clinical context is completely different. But this is worth knowing because it illustrates that celery seed’s active compounds have real pharmacological potency, not the vague “may support wellness” potency that supplement marketing often implies. Compounds that are powerful enough to treat stroke are powerful enough to deserve careful attention to dose and drug interactions.
Safety and Side Effects
At the doses tested so far, celery seed extract appears to be well tolerated in the short term. In the 12-week trial using 150 mg per day, the most common side effects in the celery seed group were mild diarrhea and abdominal bloating, each reported by about 7% of participants. All adverse events were mild, transient, and resolved on their own without anyone needing to stop the supplement.3PubMed Central. Effect of Celery Seed (Apium graveolens L.) Administration on the Components of Metabolic Syndrome, Insulin Sensitivity, and Insulin Secretion: A Clinical Trial In the four-week blood pressure trial at 1.34 g per day, no serious adverse events occurred, and the researchers described the extract as safe for hypertensive patients.2PubMed. Safety evaluation and biochemical efficacy of celery seed extract (Apium Graveolens) capsules in hypertensive patients: a randomized, triple-blind, placebo-controlled, cross-over, clinical trial
Both trials were small, though, with 28 and 51 participants respectively, and neither lasted longer than 12 weeks. Long-term safety data does not exist for celery seed supplements. If you plan to take celery seed daily for months, you are operating outside the boundaries of what has been formally tested.
Who Should Be Cautious
Several groups should think carefully before adding celery seed supplements to their routine:
- People on blood pressure medication: Celery seed can lower blood pressure on its own. Combined with antihypertensive drugs, the additive effect could push blood pressure too low, causing dizziness or fainting. The clinical trial that tested this combination found it to be safe, but participants were being monitored, and the sample was small.
- People on blood thinners: Some celery compounds may have antiplatelet activity. If you take warfarin or similar medications, the interaction risk is worth discussing with your prescriber.
- People with birch pollen allergy: Celery contains a profilin allergen that cross-reacts with birch pollen proteins.16Clinical & Experimental Allergy. Cloning of the minor allergen Api g 4 profilin from celery (Apium graveolens) and its cross-reactivity with birch pollen profilin Bet v 2 If you are allergic to birch pollen, you may react to concentrated celery products even if raw celery stalks do not bother you much, because the allergen concentration is higher in extract form.
- Pregnant women: Celery seed has traditionally been considered a uterine stimulant in herbal medicine. Clinical safety data during pregnancy does not exist, so most practitioners advise avoiding it.
Celery seed supplements also deserve attention from a contaminant perspective. Because they are concentrated forms of the plant, any heavy metals present in the raw celery, cadmium in particular, can be present at higher levels per serving than you would get from eating celery stalks. This is not unique to celery seed; it is a general concern with botanical supplements made from plants that accumulate certain metals from soil. Choosing products from manufacturers that test for heavy metals and publish certificates of analysis is a reasonable precaution.
Timing and Practical Tips
The limited clinical data offers some practical guidance on when to take celery seed. The 150 mg/day trial split the dose into two capsules, one before breakfast and one before dinner.3PubMed Central. Effect of Celery Seed (Apium graveolens L.) Administration on the Components of Metabolic Syndrome, Insulin Sensitivity, and Insulin Secretion: A Clinical Trial The 1.34 g/day trial divided it into four capsules taken daily.2PubMed. Safety evaluation and biochemical efficacy of celery seed extract (Apium Graveolens) capsules in hypertensive patients: a randomized, triple-blind, placebo-controlled, cross-over, clinical trial Splitting the dose makes pharmacological sense: it maintains steadier levels of the active compounds rather than delivering one large spike that drops off. Taking celery seed with meals may reduce the mild gastrointestinal side effects that a small percentage of users experience, though no trial has directly compared fed versus fasted dosing.
If you are starting celery seed for the first time, beginning at the lower end of the tested range and working up is sensible. Something in the ballpark of 500 mg of a general extract, or 75–150 mg of a product standardized to a high percentage of phthalides, reflects the doses that have at least some human data behind them. Expecting results overnight is unrealistic. The trials that showed benefits ran for four to twelve weeks before measuring outcomes, so you would want to give any regimen at least a month before deciding whether it is doing anything for you.