Benefits
Blood sugar and HbA1c markers
In a 90-day randomized trial in 60 adults with type 2 diabetes in India, adding 50 or 100 mg a day of isolated thymoquinone to metformin lowered HbA1c from 7.2% to 6.7% and 6.8%, versus 7.3% to 7.1% on metformin alone, with larger drops in fasting and after-meal glucose. There was no placebo, the abstract gives no p-values, the higher dose did no better, and several authors worked for two drug companies.
Sleep and stress scores with a thymoquinone-rich black seed oil
These trials used BlaQmax, a black seed oil standardized to 5% thymoquinone (200 mg a day, about 10 mg of thymoquinone), not isolated thymoquinone. In 72 adults with unrefreshing sleep, 90 days improved sleep and perceived stress scores versus placebo; in 70 adults, 7 days improved wrist-monitor sleep measures. Staff of the maker co-authored both trials.
Liver, kidney and blood count markers over 90 days
In a 90-day placebo-controlled safety trial in 70 healthy adults taking 200 mg a day of a black seed oil standardized to 5% thymoquinone, there were no serious adverse effects and no significant changes in liver (ALT, AST, ALP) or kidney (creatinine, urea) markers or blood counts. Cholesterol and triglycerides fell but stayed in the normal range. Staff of the maker co-authored it.
Absorption and blood levels in people
In two volunteers who took 1 or 3 g of a high-thymoquinone black seed oil, neither thymoquinone nor its derivatives could be detected in blood 30 and 60 minutes later, possibly because it is unstable and binds tightly to proteins. In a 20-day study of 4 adults it or its reduced form was found in urine. In rabbits, about 58% of an oral dose was absorbed.
Most research is still in cells and animals
Most thymoquinone research is laboratory and animal work. Reviews describe effects on antioxidant enzymes and on the Nrf2 and NF-κB signaling pathways, but these have not been shown at supplement doses in people. The few human trials are small and short, and most were run or funded by companies that make the product being tested.
Mechanism of action
Antioxidant and inflammation signaling
In cell and animal studies, thymoquinone raised antioxidant enzyme activity, scavenged free radicals, and acted on the Nrf2 and NF-κB pathways that control responses to oxidative stress and inflammation. These effects have not been confirmed at supplement doses in people.
Cell energy sensing through AMPK
Laboratory work reviewed in the literature suggests thymoquinone acts on AMPK, an enzyme that senses a cell's energy status and adjusts its metabolism. Whether this has anything to do with the blood sugar changes seen in the single human trial is unknown.
Unstable in body fluids and tightly bound to protein
Thymoquinone added to human serum can be measured, yet after people swallowed black seed oil it was not found in their blood, which researchers attribute to its instability and strong protein binding. In rabbits, more than 99% of it in plasma was protein bound, with an elimination half-life of about 4.6 hours after oral dosing.
Blocks the drug-processing enzyme CYP2C9 in lab tests
In human liver microsomes, thymoquinone inhibited several cytochrome P450 enzymes and was most potent against CYP2C9 (IC50 about 0.5 µM), which breaks down warfarin, phenytoin and other drugs. This is test-tube data, not a measured interaction in people.
Clinical trials
Three-arm randomized multicenter study in India of metformin SR 1,000 mg/day alone or with 50 or 100 mg/day of thymoquinone tablets for 90 days; authors were affiliated with Jina Pharmaceuticals and Intas Pharmaceuticals; the paper also includes a mouse experiment. (Ali et al. 2021, Drug Res (Stuttg))
60 adults with type 2 diabetes in India.
Among those who completed the study, HbA1c fell from 7.2% to 6.7% (50 mg) and from 7.2% to 6.8% (100 mg), versus 7.3% to 7.1% with metformin alone; fasting and after-meal glucose also fell more with thymoquinone. The abstract reports no p-values or dropout numbers, the control arm had no placebo, and the 100 mg arm's HbA1c drop (0.4 points) was no larger than the 50 mg arm's (0.5 points).
Double-blind, placebo-controlled crossover pilot of thymoquinone 1 mg/kg (frequency not stated in the abstract) or placebo for 4 weeks each, separated by a 2-week washout, added to existing anti-seizure drugs. (Akhondian et al. 2011, Epilepsy Res)
22 children with seizures that did not respond to medicines, in Mashhad, Iran.
Seizure frequency fell more with thymoquinone than with placebo in the first period (P = 0.04) and again after the crossover, comparing the end of the second period with the end of the first (P = 0.02), and parent satisfaction was higher (P = 0.03). The abstract does not report how many children finished. A very small, short study; seizure disorders need specialist care, and it is not a basis for self-treatment.
Randomized, double-blind, placebo-controlled safety trial of 200 mg/day of a black seed oil standardized to 5% thymoquinone (5.12% in the batch tested) for 90 days; several authors work at Akay Natural Ingredients, the maker. (Thomas et al. 2022, Toxicol Rep)
70 healthy adults in India.
No serious adverse effects and no significant changes in blood counts, liver enzymes (ALT, AST, ALP) or kidney markers (creatinine, urea). Total cholesterol, LDL, VLDL and triglycerides fell significantly but stayed within the normal range. This is black seed oil delivering about 10 mg of thymoquinone a day, not isolated thymoquinone.
Randomized, double-blind, placebo-controlled trial of 200 mg/day BlaQmax (black seed oil standardized to 5% thymoquinone) for 90 days; two authors were employed by the maker, Akay Natural Ingredients. (Mohan et al. 2023, Front Nutr)
72 healthy adults with self-reported unrefreshing sleep in India.
Pittsburgh sleep quality scores and perceived stress scores (PSS-14) improved more than with placebo at days 45 and 90 (stress effect size 1.19 at the end, P < 0.001), with reported changes in melatonin, cortisol and orexin. No side effects were reported. A single maker-linked trial of a black seed oil, not isolated thymoquinone.
Randomized, double-blind, placebo-controlled trial of 200 mg/day BlaQmax (also sold as ThymoDream) for 7 days, measured by wrist actigraphy and a sleep questionnaire; the maker, Akay Natural Ingredients, conceived the study, prepared the capsules and approved the protocol. (Mohan et al. 2023, Front Nutr)
70 healthy adults aged 18 to 65 with self-reported non-restorative sleep (35 per group).
Versus placebo, sleep efficiency improved 7.8%, total sleep time 19.1%, time to fall asleep 35.4% and wake time after sleep onset 22.5% (all P < 0.001), and questionnaire scores improved. No side effects were reported. Only one week long, and the product is a black seed oil, not isolated thymoquinone.
Randomized, double-blind, placebo-controlled phase 2 trial at three US sites of TQ Formula, an enteric-coated black seed oil capsule standardized to 1.7% thymoquinone, 3 g/day for 14 days; funded by Novatek Pharmaceuticals, in which several authors hold shares. (Bencheqroun et al. 2022, Pathogens)
55 non-hospitalized adults with symptomatic SARS-CoV-2 infection.
The efficacy primary endpoint was not met: median time to sustained clinical response was 6 days with TQ Formula and 8 days with placebo (P = 0.77). Adverse event rates did not differ (P = 0.16). Total symptom burden fell faster (P < 0.001) and some T-cell counts rose, but these were secondary measures. COVID-19 needs medical care; this is not a treatment.
Single-center, randomized, open-label pilot of high-thymoquinone black seed oil capsules (2 capsules 3 times a day for 20 days; about 12.2 mg of thymoquinone per capsule) versus no supplement, with no placebo. (El-Banna et al. 2026, Sci Rep)
8 healthy adults in Germany (4 per group).
Overall gut bacterial diversity did not differ between groups, though a few individual taxa rose or fell. Thymoquinone and/or its reduced form were detected in urine of the supplemented group, which the authors say confirms detectability but allows no pharmacokinetic conclusions. No adverse events were reported. Very small and exploratory.