Hemp seeds top all 132 foods in our data for protein: hulled seeds, sold as hemp hearts, hold 31.6 g per 100 g, or 9.5 g in 3 tbsp (30 g), which supply 166 calories. About three quarters of those calories come from fat, mostly polyunsaturated, including 2.61 g of the plant omega-3 ALA in the same serving. Lysine is the limiting amino acid, and in a rat test dehulled hemp seed protein scored 63 to 66% on the PDCAAS quality scale.
Hemp comes from Cannabis sativa, the same species as marijuana, but the seeds do not naturally contain THC, the psychoactive compound. The FDA says hemp seed ingredients carry only trace amounts of THC and CBD, picked up during harvest and processing when the seeds touch other parts of the plant, and that eating them cannot make a person high. Those traces are the reason for the drug test questions covered below.
Few human trials have used the seeds themselves. Most research used hemp seed oil or protein powder. The results so far show shifts in blood fats and little change in cholesterol, so the seeds are better judged as a nutritious food than as a proven remedy.
Health benefits of hemp seeds
The top findings from 18 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★No change in cholesterol from hemp oilIn 86 healthy adults, two 1 g capsules of hempseed oil a day for 12 weeks did not change cholesterol, triglycerides or inflammation markers. This was oil, not seeds.
- ★Lower blood pressure from hemp protein powderIn 35 adults with mild high blood pressure, a hemp protein and peptide powder lowered the 24-hour top number from 135.1 to 128.1 mm Hg. Hemp protein alone gave 133.5; this was a seed powder, not whole seeds.
- ★No positive drug test from eating hemp seedsIn a Korean study, all 64 urine samples after 1 week of eating 30 g of hemp seeds a day were under the screening cutoff. Over 12 weeks, 3 samples from 2 people were above the cutoff level but screened negative, the authors say.
- ★Lower blood sugar after a hemp protein mealIn two small trials, 20 to 40 g of hemp protein lowered blood sugar over the next hour, compared with a carbohydrate control. It worked about like soy protein in single-meal tests of a powder.
- ★Raised blood omega-3 and omega-6 levelsIn 30 adults, eating hulled hemp seeds and hemp oil for 4 weeks raised blood levels of ALA (an omega-3) and GLA (an omega-6). Cholesterol and blood pressure did not change.
All 18 studies, strongest evidence first
Two capsules a day of hempseed oil for 12 weeks did not change any blood fatty acid or cholesterol level in healthy adults
Double-blind, placebo-controlled trial in 86 healthy people split into four groups taking placebo, fish oil, flaxseed oil or hempseed oil, two 1 g capsules a day. Fish oil raised EPA and DHA and flaxseed oil raised ALA for a while. None of the oils changed total, HDL or LDL cholesterol, triglycerides, platelet clumping or inflammation markers. This was oil, not seeds.
Eating hulled hemp seeds and hemp oil for 4 weeks raised blood levels of omega-3 ALA and omega-6 GLA but did not change cholesterol or blood pressure
Double-blind crossover trial in 30 adults with a BMI of 25 to 35, who ate hemp products and a control for 4 weeks each. Blood fats, glucose, insulin, blood pressure and body composition did not differ between treatments. The abstract reports higher EPA too, in the second set of measurements. It does not name the foods; the trial registry lists hulled hemp seeds plus hemp oil against sesame seeds plus soybean oil.
Eating 30 g of hemp seeds a day for 12 weeks did not cause a positive urine drug screen
Korean study of 64 urine samples after 1 week and 480 samples over 12 weeks. Two hemp seed products carried 53.1 and 124.81 µg of THC per 30 g, and two hemp seed oil capsules 11.1 µg. All 64 short-term samples were under the 25 ng/mL cutoff, and 3 long-term samples from 2 people were above the cutoff level but screened negative, the authors say. The abstract does not give the number of participants.
Hemp seed capsules raised HDL cholesterol compared with the start of the study in sedentary young men
Double-blind, placebo-controlled trial in 48 sedentary young men in Iran, in four groups: hemp seed, hemp seed plus aerobic exercise, exercise plus placebo, or placebo. Hemp seed was two 1 g capsules a day. Exercise alone also changed weight, fat mass and triglycerides, so the seed’s own part is hard to separate.
2 g of hemp seed powder a day for 8 weeks did not change antioxidant markers in sedentary young men
Double-blind trial in 48 young men in four groups of 12: interval exercise plus hemp seed, exercise plus placebo, hemp seed alone, or control. Testosterone rose significantly in the two exercise groups, and the abstract lists no significant rise for hemp seed alone. Exercise also improved BMI, body fat and muscle mass.
A hemp protein and peptide powder taken daily for 6 weeks lowered 24-hour systolic blood pressure from 135.1 to 128.1 mmHg
Double-blind crossover trial in 35 adults with mild hypertension. Each person took three 6-week treatments, 50 g of casein, 50 g of hemp seed protein, or 45 g of hemp seed protein plus 5 g of hemp peptides a day, with a 2-week break. Hemp seed protein alone gave 133.5 over 78.9 mmHg. This was a protein powder made from the seed, not whole seeds. The authors report no conflicts of interest.
60 g a day of hemp thickened women’s arm muscle from 2.6 to 3.1 cm during 8 weeks of weight training, while soy did the same in men
Double-blind trial in 22 men and 12 women who lifted weights, given 60 g a day of hemp (with 40 g of protein and 9 g of oil) or soy matched for protein and calories. Soy raised arm muscle thickness in men from 3.7 to 4.0 cm. Twitch torque held up after a fatigue test in men on hemp. The trial registry lists the hemp as a powder.
20 to 40 g of hemp protein lowered blood sugar over the next hour compared with a carbohydrate control, about like soy protein
Two crossover trials, in 27 and 16 people, compared 20 and 40 g of hemp protein concentrate with soy protein and a carbohydrate control before a pizza meal. The effect grew with the dose, and 40 g of either protein also lowered insulin before the meal. These were single-meal tests of a protein powder, not whole seeds.
20 g a day of hemp hull powder for 2 weeks did not change gut leakiness after hard cycling
Randomized crossover trial in 23 cyclists, using bars with 20, 5 or 0 g a day of hemp hull powder, the outer shell, which is a different product from hulled hemp seeds. Muscle damage markers, cortisol and blood counts did not differ either, though blood metabolite patterns did. The study received funding from Brightseed, Inc., which the paper says was not involved in its design, analysis or the decision to publish.
30 mL a day of hempseed oil for 4 weeks changed blood fatty acids but left fasting cholesterol unchanged compared with flaxseed oil
Double-blind crossover trial in 14 healthy volunteers, 4 weeks per oil with a 4-week washout. Hemp oil raised linoleic and gamma-linolenic acid in blood fats and flaxseed oil raised ALA. Glucose, insulin and clotting factors did not differ. The total-to-HDL cholesterol ratio was lower after hemp oil, but the P value was 0.065, which is not significant. This was oil, not seeds.
In a 20-week crossover trial, hempseed oil eased skin dryness and itch and cut the use of skin medicines in atopic dermatitis compared with olive oil
Randomized, single-blind trial in people with atopic dermatitis, who took each oil in turn. Plasma fatty acids rose after hemp oil. The skin’s water loss fell by an amount that was not significant (p = 0.074), while dryness and itch (p = 0.027) and medicine use (p = 0.024) improved. The abstract does not give the number of people, and single blinding with symptom questionnaires leaves room for bias. This was oil, not seeds.
3 g a day of hempseed oil for 8 weeks raised the omega-3 index by 1.18% but did not change cholesterol in children with high blood fats
Pilot trial in 36 children and teenagers aged 6 to 16 with primary hyperlipidemia, randomized to the oil or a control group, with both on diet therapy. The oil supplied 1.4 g of linoleic acid and 0.7 g of ALA a day. Red blood cells held less saturated fat (down 5.02%), but the serum lipid profile did not differ from control. This was a small pilot of an oil, not seeds.
Hemp oil with up to 0.6 mg of THC a day for 10 days gave no confirmed positive drug test in 15 adults
Volunteers who had not used cannabis took four daily THC doses from 0.09 to 0.6 mg, in blends of hemp and canola oil, for 10 days each. At 0.6 mg one urine specimen screened positive at the 50 ng/mL cutoff, but the highest confirmed metabolite level was 5.2 ng/mL, below the 15 ng/mL federal confirmation cutoff. The authors equate 0.6 mg with about 300 g of hulled seeds at 2 µg/g, a level they call typical of Canadian products at the time. This was oil, and the seed THC level is from 2001.
One volunteer who drank 135 mL of hemp seed oil over 4½ days tested positive on a workplace urine drug test for days
Case report of a single volunteer taking commercial cold-pressed hemp seed oil twice a day. Confirmed metabolite levels reached 68 ng/mL, and the first negative sample came 53 hours after the last dose. Oils vary in THC, and this was one person.
Protein from dehulled hemp seed scored 63 to 66% on the protein quality score PDCAAS in a rat test, with lysine the limiting amino acid
Analysis of 30 commercial hemp products from Western Canada, with digestibility measured in rats. Whole seed scored 49 to 53%, so removing the hull improved both digestibility and score. Dehulled seed averaged 35.9% protein and 46.7% fat. The authors say hemp protein scores equal to or higher than certain grains, nuts and some pulses.
Rats fed 5 or 10% hempseed in their chow for 12 weeks recovered better after blood flow to the heart was cut off and restored
Forty rats were split into four groups on chow with 5% or 10% hempseed, 1% palm oil, or 10% partly defatted hempseed as the control. Hearts from hempseed-fed rats recovered more contractile function and moved faster during reperfusion, but were not protected from extra heartbeats. The authors credit the high polyunsaturated fat content.
In rabbits on a high-cholesterol diet, 10% hempseed brought platelet clumping back to normal without lowering cholesterol
Rabbits ate one of 6 diets for 8 weeks. Platelets clumped more in rabbits fed 0.5% cholesterol, and adding 10% hempseed normalized this while blood cholesterol stayed high. Adding gamma-linolenic acid (GLA), a fat found in hempseed, directly to platelet samples blocked the effect too.
Ground hemp seeds in the diet of obese rats lowered total cholesterol and improved blood vessel relaxation, but also lowered HDL
Obese Zucker rats (6 per group) ate ground hemp seeds (12% of the diet) or hemp seed oil (4%) for 4 weeks from age 8 weeks. Seeds lowered total cholesterol to 0.81 of the control level and HDL to 0.71, and improved the response of vessels to acetylcholine, which the oil did not. The authors conclude the seeds were more beneficial than the oil.
Who should be careful with hemp seeds
Most people can eat hemp seeds freely. Take a little care if one of these applies:
- Trace THC. The FDA says seeds can pick up traces during harvest, and measured levels vary by brand: 0.06 to 5.91 µg per gram in Korea and 0.11 to 2.08 µg per gram in Türkiye. EFSA set a short-term safe dose of 1 µg per kilogram of body weight in 2015, and its 2020 estimates found heavy adult eaters of hemp seeds could pass it, though EFSA expects those estimates to overstate real intake.
- Drug testing. A Korean trial found 30 g of seeds a day did not cause positive urine tests, but hemp oil did in one volunteer. If your job or sport has zero tolerance for THC, ask the testing body before making hemp a daily food.
- Allergy. Hemp seed allergy is rare but real: a 2024 case series described three people with anaphylaxis, linked to hemp food or to exposure to the plant. Lab work also found hemp seed proteins that may cross-react with hazelnut, though what that means in practice is not yet known, so people with nut or seed allergies should ask their allergist.
How to choose, store and eat hemp seeds
- Hulled seeds (hemp hearts): the form behind this page’s numbers, with 166 calories, 9.5 g of protein and 1.2 g of fiber in 3 tbsp (30 g). In a Canadian analysis, dehulled seed averaged 35.9% protein and 46.7% fat, against 24.0% and 30.4% for whole seed.
- Whole seeds with the shell: they keep more fiber, with 27.5% dietary fiber in the seed used in one rat study. The shell cost protein quality, though: whole seed scored 49 to 53% on PDCAAS in a rat test, against 63 to 66% for dehulled seed.
- Oil and protein powder: these are different foods, and most trials above used them. Doses ran from 3 g to 30 mL of oil a day, and 20 to 50 g of protein powder a day.
Hemp fats spoil easily: in a lab test of heated hemp seed oil, the omega-6 and omega-3 fats had predicted half-lives of about 3 and 5 days at 25 °C (77 °F). We found no official storage guidance, so a sealed, cool, dark place and a sniff before use are sensible, as with other seeds high in polyunsaturated fat. We also found no official pesticide residue data for hemp seeds, so none is quoted here.
Sources
- FDA responds to three GRAS notices for hemp seed-derived ingredients for use in human food. US Food and Drug Administration. 2018.
- EFSA CONTAM Panel. Scientific opinion on the risks for human health related to the presence of tetrahydrocannabinol (THC) in milk and other food of animal origin. EFSA Journal. 2015.
- EFSA. Acute human exposure assessment to tetrahydrocannabinol (Δ9-THC). EFSA Journal. 2020.
- Jang E, Kim H, Jang S, et al. Concentrations of THC, CBD, and CBN in commercial hemp seeds and hempseed oil sold in Korea. Forensic Sci Int. 2020.
- Kacargil CU, Soyturk H, Aydin AA, et al. Determination of cannabinoids in commercial hemp seeds and hemp seed oil products in Türkiye by LC-MS/MS. Forensic Sci Int. 2026.
- Bennici A, Grixti Soler D, Marcassa G, et al. Cannabis sativa as a clinically relevant nsLTP allergen in the Mediterranean region: a case series exemplifying different possible routes of sensitization. Eur Ann Allergy Clin Immunol. 2024.
- Beriziky P, Cherkaoui M, Linxe L, et al. Hemp seed: an allergen source with potential cross-reactivity to hazelnut. Food Res Int. 2023.
- House JD, Neufeld J, Leson G. Evaluating the quality of protein from hemp seed (Cannabis sativa L.) products through the use of the protein digestibility-corrected amino acid score method. J Agric Food Chem. 2010.
- Majewski M, Jurgoński A. The effect of hemp (Cannabis sativa L.) seeds and hemp seed oil on vascular dysfunction in obese male Zucker rats. Nutrients. 2021.
- Pratap Singh A, Fathordoobady F, Guo Y, Singh A, Kitts DD. Antioxidants help favorably regulate the kinetics of lipid peroxidation, polyunsaturated fatty acids degradation and acidic cannabinoids decarboxylation in hempseed oil. Sci Rep. 2020.
History of hemp seeds
Hemp is one of the oldest crops. A 2021 genome study of 110 plants from around the world found that Cannabis sativa was first domesticated in early Neolithic times in East Asia. All current hemp and drug cultivars descend from a gene pool still found in feral plants and landraces in China.
People may have used the seeds very early. A site in the Oki Islands of Japan held cannabis achenes, the small dry fruits we call seeds, from about 8000 BC, which probably signals use of the plant.
In ancient China, hemp was counted as a grain. The Classic of Rites lists hemp with soybeans, wheat, proso millet and foxtail millet as the five grains, although a later commentator put rice in its place, and the debate over hemp or rice ran on for centuries.
In late medieval Germany and Italy, hemp went into cooked dishes, as filling for pies and tortes or boiled in soup. In later Europe it was grown mostly for its fibers, including the ropes of Christopher Columbus’s ships.
The modern food market began in Canada. Commercial production was permitted from 1998 under Health Canada licenses, after a committee at the University of Manitoba worked with the provincial government, and Canadian hemp is grown mostly for its food value as hulled seeds and oil. Several of the trials on this page came from that same university.
In the United States, the 2018 Farm Bill removed hemp from Schedule I and made it an agricultural commodity. That December the FDA said it had no questions about the safety conclusions for hulled hemp seed, hemp seed protein powder and hemp seed oil, and noted that foods with hemp seed were already on sale.
Sources
- Ren G, Zhang X, Li Y, et al. Large-scale whole-genome resequencing unravels the domestication history of Cannabis sativa. Sci Adv. 2021.
- Hemp. Wikipedia.
- Five Grains. Wikipedia.
- FDA responds to three GRAS notices for hemp seed-derived ingredients for use in human food. US Food and Drug Administration. 2018.
Frequently asked questions about hemp seeds
Are hemp seeds good for you?
They are nutritious, but the evidence for health effects is thin. Three tablespoons (30 g) of hulled seeds give 9.5 g of protein, 1.2 g of fiber and 2.61 g of the omega-3 ALA for 166 calories, plus about half of the US Daily Value of magnesium (50%) and all of the manganese (99%). In trials, hemp products changed blood fats but not cholesterol, and no study here reaches strong evidence.
How much protein is in hemp seeds?
Hulled hemp seeds have 31.6 g of protein per 100 g, or 9.5 g in 3 tbsp (30 g), the most of the 132 foods compared on this site. Protein supplies 21% of the calories. Lysine is the limiting amino acid, giving a protein completeness score of 79 out of 100 here, and in a rat test dehulled seed scored 63 to 66% on the PDCAAS scale.
Do hemp seeds have omega-3?
Yes, as ALA, the plant omega-3: 2.61 g in 3 tbsp (30 g) and 8.68 g per 100 g, fourth among the 110 foods with omega-3 data on this site. This site lists no EPA or DHA, the fish-oil omega-3s, for hemp seeds. Results on blood levels are mixed: 4 weeks of hulled seeds plus oil raised ALA and GLA in a 30-person trial, but 12 weeks of hemp oil capsules changed no blood fatty acid in 86 people.
Do hemp seeds lower cholesterol?
Not in the trials that tested it. Hemp seeds plus oil (30 adults, 4 weeks), oil capsules (86 adults, 12 weeks), a hemp oil crossover (14 adults, 4 weeks) and hemp oil in children with high blood fats (36 children, 8 weeks) all found no change in cholesterol against control. One small trial of seed capsules in 48 young men saw HDL rise from baseline, but exercise was part of that result. Rat studies are mixed.
Can hemp seeds get you high?
No. The FDA says hemp seeds do not naturally contain THC, that hemp seed ingredients carry only traces picked up in harvest and processing, and that eating them cannot make a person high. Measured THC in commercial seeds ran from 0.06 to 5.91 µg per gram in Korea and from 0.11 to 2.08 µg per gram in Türkiye, so levels vary by brand.
Will hemp seeds make you fail a drug test?
Probably not at normal food amounts, but it is not impossible, and oil has caused a positive. In a Korean trial, 30 g of hemp seeds a day for 12 weeks gave no positive screen. One volunteer who drank 135 mL of hemp oil over 4½ days tested positive, and a 2026 trial in Türkiye found trace urinary THC metabolites after hemp oil, up to 4.52 ng/mL, and lower-level findings after seeds. If a test has zero tolerance, ask the testing body first.
Are hemp seeds the same as CBD?
No. Hemp seeds are a food, while CBD products are cannabinoid extracts, and a 2026 review describes CBD oil as derived from the cannabis plant and hemp oil as derived from hemp seeds. The FDA says hemp seed ingredients hold only trace CBD from contact with other plant parts. Studies of CBD products tell you nothing about eating hemp seeds.
How many hemp seeds should you eat a day?
No study here sets an ideal amount. This page’s serving is 3 tbsp (30 g), which has 166 calories, and the Korean trial gave 30 g a day for 12 weeks, the longest seed intake in this review. The other trials used oil (3 g to 30 mL a day) or protein powder (20 to 50 g a day), which are different products.