Hemp Oil (Cannabis sativa L. Seed Oil): A Comprehensive Reference
1. Identity, Botanical Source, and Common Preparations
1.1 Botanical and Chemical Identity
Hemp (Cannabis sativa L.) is an annual plant of the Cannabaceae family cultivated for a range of purposes, including the production of fiber, shives, secondary metabolites (including cannabinoids), and nutritionally valuable seeds. Non-drug varieties of Cannabis sativa L., collectively termed "hemp," have been a source of food, fiber, and medicine for thousands of years.
The term hemp oil encompasses more than one distinct product, and this distinction is scientifically and commercially important. Hemp oil is often used interchangeably with hempseed oil; however, hemp oil commonly refers to oil extracted from the flowers of the hemp plant and contains a range of cannabinoids, more frequently cannabidiol (CBD). In the vast majority of dietary supplement and food contexts, "hemp oil" refers to hempseed oil (HSO) — the fixed oil cold-pressed or solvent-extracted from the dehulled or whole seeds of Cannabis sativa L. This article focuses on hempseed oil (HSO) as the primary subject, while noting distinctions where relevant.
Unlike cannabis, hemp contains very low levels of delta-9-tetrahydrocannabinol (THC). The 2018 Farm Bill in the United States established the specific definition of hemp versus cannabis by limiting the THC content of hemp to no more than 0.3%.
1.2 Physical Characteristics
The oil extracted from dried hemp seeds is liquid at room temperature with a bold yellow colour, bland taste, and pleasant nutty odour. Hemp seed oil is a yellowish-green, translucent oily liquid at room temperature and becomes yellow-brown upon extended exposure.
1.3 Common Forms and Preparations
Hempseed oil is commercially available in several forms, each with distinct characteristics influenced by the method of manufacture:
- Cold-pressed unrefined oil: The cold-press process allows the preservation of minor compounds that are responsible for a richer sensory profile and higher antioxidant and pro-healthy activities compared to refined oils. However, cold pressing has low extraction efficiency and leads to oil with high chlorophyll levels, probably due to intensive mechanical destruction of hempseed cells during pressing; high amounts of chlorophyll negatively influence oil quality and shelf life, since it can lead to oil photooxidation due to chlorophyll's role as a sensitizer.
- Refined oil: Natural chlorophyll content present in samples is effectively removed by conventional refining and bleaching processes, in order to minimize the negative effects of high chlorophyll content in edible oils.
- Supercritical CO₂ extract: Supercritical carbon dioxide (SC-CO₂) extraction is employed at temperatures of 40, 60 and 80 °C and pressures of 300 and 400 bar.
- Emulsions and nanoemulsions: Formulated preparations of hemp seed oil in oil-in-water emulsions are the subject of pharmaceutical research for enhanced delivery.
- Dietary supplement capsules: Encapsulated hempseed oil is widely sold as a dietary supplement.
- Topical preparations: Hemp seed oil and cannabis seed extracts are incorporated into creams, lotions, and cosmetic formulations for dermatological application.
EU regulatory standards apply to cold-pressed forms: According to Commission Regulation (EU) 2022/1393, cold-pressed hemp seed oil (CP-HSO) is considered food derived from hemp seeds, which are the seeds from the industrial type of Cannabis sativa L. The regulation established the maximum level of delta-9-tetrahydrocannabinol (Δ9-THC) equivalents for CP-HSO at 7.5 mg/kg.
2. Traditional and Historical Use
2.1 Ancient China
Hemp was one of the main crops in ancient China, holding important status in China's long history of farming fiber crops for spinning yarn, weaving cloth, making paper, and formulating traditional medicines. All of the traditional uses of hemp were invented in China; the earliest hemp cordage and textile remains, the earliest records of hemp seed use for food, the first paper, and the first medicinal use of hemp can all be traced back to ancient China.
From the time of the earliest primitive societies (about 4,000–5,000 years ago) to the Qin and Han dynasties (221 BC to 220 AD), ancient Chinese techniques of hemp sowing, cultivation, and processing developed rapidly and became fairly advanced. The earliest Neolithic farming communities along the Wei and Yellow rivers cultivated hemp along with millet, wheat, beans, and rice.
The oldest Chinese pharmacopeia, the (c. 100 AD) Shennong Bencaojing ("Shennong's Materia Medica Classic"), describes cannabis. The seeds are considered to be tonic, demulcent, alternative [restorative], laxative, emmenagogue, diuretic, anthelmintic, and corrective.
Hemp seed was consumed as food mainly by poor people and applied externally to treat a variety of skin diseases, wounds, and even falling hair. In later years, hemp seed flowers are mentioned as an extract for frying foods. It was only around the 10th century that hemp seed ceased being a major grain crop in China, although it is still used to make kitchen oil in Nepal.
During the Ming dynasty, the scientist, doctor, and herbalist Li Shizhen wrote about cannabis' medical benefits in his Bencao Gangmu, the Compendium of Materia Medica, widely regarded as the most comprehensive text on traditional Chinese medicine.
2.2 Spread to Korea, Japan, and East Asia
Ancient China cultivated the hemp plant in order to weave its fiber into cloth, and used its seed for food and oil. Hemp spread beyond China in the third century B.C., with the seed stock going to Korea, from which it crossed the narrow channel to Japan's southern island, Kyushu. The very canvas on which Renaissance artists created their masterpieces took its name from the genus Cannabis (from which the fabric was originally made), and the oil in the paint was often derived from hemp seed.
2.3 Ancient Egypt and the Mediterranean
Ancient civilizations such as the Chinese and Egyptians extracted oil from hemp seeds. This oil was used for cooking, lighting lamps, and for medicinal purposes. Hemp's spread into Europe and the Mediterranean world further established the plant's oil as a utilitarian and nutritional commodity across multiple ancient cultures.
2.4 Traditional Purposes and Preparations
Across documented traditional systems, hemp seed oil was prepared by mechanical pressing or by infusion and was used:
- As a food and condiment: Added to porridge, used in cooking, and consumed raw for nutritional sustenance.
- Topically: Applied to skin conditions, wounds, and as a hair treatment in Chinese traditional medicine.
- As a lamp fuel and varnish: Including as a drying oil in paints and varnishes in European traditions.
- Medicinally (oral): As a laxative, tonic, and to address pain and inflammatory conditions, as documented in Chinese pharmacopeias.
3. Key Constituents and Active Compounds
3.1 Fatty Acid Profile
The dominant characteristic of hempseed oil is its exceptional polyunsaturated fatty acid (PUFA) content. The concentration of unsaturated fatty acids in hempseed oil exceeds 90%, higher than most conventional vegetable oils.
Polyunsaturated fatty acids (PUFA) make up around 75% of the total fatty acids, while linoleic acid represents more than 50% of the oil. In hemp seeds, α-linolenic acid and oleic acid constitute 12–19% of the total fatty acids, while γ-linolenic acid and stearidonic acid have reduced ratios.
Specific major fatty acid proportions from peer-reviewed characterization studies include:
- Linoleic acid (LA, 18:2 n-6; omega-6): approximately 55% of total fatty acids.
- α-Linolenic acid (ALA, 18:3 n-3; omega-3): approximately 16–18%.
- Oleic acid (18:1 n-9): approximately 11%.
- Polyunsaturated fatty acids overall range from 76.26% to 82.75% and are mainly composed of linoleic acid and α-linolenic acid, with a ratio close to 3:1.
A nutritionally important feature is the omega-6 to omega-3 ratio. Cold-pressed hempseed oil has an ω6:ω3 ratio of around 2.5–3:1, which is considered optimal from a nutritional point of view and recommended for healthy diets. The extracted hempseed oil contains linoleic acid (18:2 omega-6) and α-linolenic acid (18:3 omega-3) at a ratio of 2.5:1–3:1; its consumption is considered to provide a cardioprotective effect and improve the lipid profile.
3.2 Minor but Bioactive Fatty Acids
Two minor but biologically significant fatty acids distinguish hempseed oil from many other edible oils:
Gamma-linolenic acid (GLA, 18:3 n-6): Hempseed is a rich and unusual source of the polyunsaturated fatty acid gamma linolenic acid (GLA) (18:3n-6). GLA is relatively rare in the human diet. It is present in small amounts in oats and barley. According to the USDA Standard Release, it is present in hemp seeds (1.34% by mass). GLA is a biologically active omega-6 fatty acid with anti-inflammatory, immunomodulatory, and cardiovascular protective effects.
Stearidonic acid (SDA, 18:4 n-3): Another important biological metabolite of ALA and LA, stearidonic acid (18:4n-3; SDA) is also present in hempseed oil. Both GLA and SDA can inhibit inflammatory responses. Plant-derived SDA is a promising precursor regarding endogenous synthesis of n-3 long-chain PUFA in humans, because the rate-limiting Δ6-desaturation of ALA to SDA has already occurred effectively in the plant.
3.3 Tocopherols (Vitamin E)
The total tocopherol amount in hempseed oil has been shown to be higher than that found in sunflower, sesame, and amaranth oil. It can reach values higher than 90 mg/100 g of oil based on the type of extraction process used. The γ-tocopherol, α-tocopherol, δ-tocopherol, plastochromanol-8, and β-tocopherol contents of 51 hemp genotypes averaged 21.68 ± 3.19, 1.82 ± 0.49, 1.20 ± 0.40, 0.18 ± 0.07 and 0.16 ± 0.04 mg per 100 g of seeds, respectively. γ-Tocopherol is consistently reported as the dominant tocopherol form in hempseed oil, functioning as a lipid-soluble antioxidant.
3.4 Phytosterols
The most interesting compounds in the unsaponifiable fraction were β-sitosterol (1905.00 ± 59.27 mg/kg of oil), campesterol (505.69 ± 32.04 mg/kg of oil), phytol (167.59 ± 1.81 mg/kg of oil), cycloartenol (90.55 ± 3.44 mg/kg of oil), and γ-tocopherol (73.38 ± 2.86 mg/100 g of oil). In various studies on phytosterol determinations in hemp oil, total phytosterols ranged between 2.19 mg/g and 6.7 mg/g.
3.5 Chlorophylls, Carotenoids, and Other Minor Compounds
Total content of chlorophylls found in different types of commercial hemp seed oil samples presented a wide range, from 0.41 up to 4.81 mg/kg (blend 1), with a mean value of 1.46 mg/kg for all samples. The total carotenoids of hemp oil have been found to range from 7.8 to 8.2 mg/100 g for oil obtained by cold-pressing.
3.6 Trace Cannabinoids
Cannabinoid profiles of commercial hemp seed oils have been evaluated by liquid chromatography coupled to high-resolution mass spectrometry. Besides tetrahydrocannabinol and cannabidiol, 30 other cannabinoids were identified for the first time in hemp seed oil. Notably, the healthy properties of hemp seed oil are strictly related to its chemical composition, which varies depending not only on the manufacturing method but also on the hemp variety employed. Cannabinoid levels in well-produced hempseed oil remain at trace concentrations and are subject to regulatory maximum limits (e.g., 7.5 mg/kg Δ9-THC equivalents under EU Regulation 2022/1393).
4. Mechanisms of Action
4.1 Essential Fatty Acid Provision and Membrane Incorporation
Hemp seed oil contains linoleic acid (LA, 18:2 n-6) and α-linolenic acid (ALA, 18:3 n-3) as its major omega-6 and omega-3 polyunsaturated fatty acids (PUFA), respectively. Linolenic and linoleic fatty acids are known as essential fatty acids because humans cannot produce them themselves and must obtain them in their diet. PUFA are mostly distributed at the sn-2 position of triacylglycerols, making them highly bioaccessible.
4.2 GLA's Anti-Inflammatory Eicosanoid Pathway
Unlike LA, which requires several enzymatic conversion steps, GLA bypasses the rate-limiting delta-6-desaturase enzyme, enabling more direct conversion into dihomo-gamma-linolenic acid (DGLA) and subsequently into anti-inflammatory eicosanoids. DGLA competes with arachidonic acid (AA) for cyclooxygenase and lipoxygenase enzymes. While AA is metabolized into pro-inflammatory prostaglandins and leukotrienes, DGLA produces prostaglandin E1 (PGE1), which has anti-inflammatory properties. PGE1 suppresses tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta, cytokines that amplify inflammatory responses.
When acting on GLA, arachidonate 5-lipoxygenase produces no leukotrienes, and the conversion by the enzyme of arachidonic acid to leukotrienes is inhibited.
An important consideration is that due to inefficiencies in the conversion of linoleic acid (LA) to GLA in some individuals, it is necessary to obtain GLA from dietary sources. This is particularly relevant in atopic conditions, where there is evidence of reduced conversion of linoleic acid to gamma-linolenic acid (GLA).
4.3 Antithrombotic and Cardiovascular Mechanisms
Hempseed is a notable source of omega-3 and omega-6 fatty acids, particularly ALA and GLA, which have been shown to exert antithrombotic effects by modulating platelet aggregation and reducing blood viscosity. Dietary hempseed has been shown in preclinical studies to reduce platelet aggregation (Richard et al., J Thromb Haemost, 2007).
4.4 Phytosterol Mechanism
The high β-sitosterol content of hempseed oil provides a mechanism relevant to cholesterol metabolism: phytosterols competitively inhibit cholesterol absorption in the gastrointestinal tract by displacing cholesterol from intestinal micelles, thereby potentially reducing circulating LDL cholesterol concentrations.
4.5 Antioxidant Mechanism
The oil extracted from hemp seeds has significant nutritional and biological properties due to the unique composition of polyunsaturated fatty acids and various antioxidant compounds. The potential of this oil for the prevention of oxidative stress and for the treatment of oxidative-stress-induced ailments is of increasing interest. γ-Tocopherol and β-sitosterol are the primary antioxidant contributors within the oil's unsaponifiable fraction.
5. Scientific Evidence by Area of Use
5.1 Skin Health and Atopic Dermatitis
Human clinical evidence (strongest area):
The most rigorously examined clinical application of hempseed oil is dietary supplementation for atopic dermatitis (eczema). Hempseed oil is a rich and balanced source of omega-6 and omega-3 polyunsaturated fatty acids (PUFAs). Anecdotal evidence indicated that dietary hempseed oil might be useful in treating symptoms of atopic dermatitis. In the primary published clinical trial, dietary hempseed oil and olive oil were compared in a 20-week randomized, single-blind crossover study with atopic patients.
Levels of both essential fatty acids — linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3) — and gamma-linolenic acid (GLA; 18:3n-6) increased in all lipid fractions after hempseed oil, with no significant increases of arachidonic acid (20:4n-6) in any lipid fractions after either oil. Intra-group transepidermal water loss (TEWL) values decreased (p=0.074), qualities of both skin dryness and itchiness improved (p=0.027), and dermal medication usage decreased (p=0.024) after hempseed oil intervention. Dietary hempseed oil caused significant changes in plasma fatty acid profiles and improved clinical symptoms of atopic dermatitis.
A separate larger crossover study confirmed comparable findings: A 20-week controlled, single-blind, crossover study with 20 atopic patients reported significant changes in plasma fatty acid profiles, subjective clinical improvement in skin dryness and itchiness, and a reduction in dermal medication use with 2 tablespoons of HSO daily compared with olive oil for 8 weeks. However, a high risk of bias is introduced by the first author's financial interests in HSO.
The earlier study cited (2005) enrolled 10 participants with atopic dermatitis who took 30 mL of hempseed oil per day for 8 weeks. The results showed that the symptoms of atopic dermatitis were mitigated, and plasma fatty acid levels were increased.)
Topical application: In a single-blinded, randomized controlled trial, a cream containing 3% cannabis seed extract was applied for 12 weeks twice a day on the cheeks of 11 healthy participants. The research proved that the extract was safe, and its application led to a decrease in cheek sebum production as well as a lowering of the erythema index.
Evidence strength summary: There is a scarcity of data regarding the impact of applying hemp actives on humans, primarily because there are only a few clinical studies available. Only about 1,000 people have so far participated in studies examining the effect of hemp-based preparations on the skin with various dermatological problems. Having in mind that these people suffered from a variety of different dermatological conditions (atopic dermatitis, psoriasis, acne, etc.) and were not exposed to hemp-based products only by topical application but also by oral administration and inhalation, it can be concluded that the amount of clinical evidence is still limited. Further randomized, controlled studies need to be conducted. The overall evidence for dermatological benefit is preliminary but promising, with the atopic dermatitis data being the most consistent finding in human studies, though limited by small sample sizes and some conflicts of interest.
5.2 Cardiovascular Health and Lipid Profile
Human clinical evidence:
A well-designed randomized, double-blind crossover trial by Schwab et al. (2006) examined the cardiovascular effects of hempseed oil. Fourteen healthy volunteers participated in the study. A randomised, double-blind crossover design was used. The volunteers consumed hempseed oil (HO) and flaxseed oil (FO) at 30 mL/day for 4 weeks each. No significant differences were found between the periods in measured values of fasting serum total or lipoprotein lipids, plasma glucose, insulin, or hemostatic factors. The effects of HO and FO on the profile of serum lipids differed significantly, with only minor effects on concentrations of fasting serum total or lipoprotein lipids, and no significant changes in concentrations of plasma glucose or insulin or in haemostatic factors.
A 2018–2019 pilot study in children and adolescents with primary hyperlipidemia found partial effects: Eight weeks of supplementation with hempseed oil significantly (p < .01) reduced the RBC content of total saturated and monounsaturated fatty acids, increased the levels of total n-3 and n-6 PUFAs and the omega-3 index, but failed to affect the serum lipid profile compared to the control group. The findings support the contribution of HSO supplementation in improving the RBC phospholipid composition and omega-3 index, while no effect was observed regarding modulation of the lipid profile.
A 2025 systematic review synthesized the totality of cardiovascular evidence: Dietary hempseed intake has shown cardiovascular benefits in animal studies, improving post-ischemic heart performance. However, a 12-week human study found no significant changes in cardiovascular parameters following supplementation with hempseed, flaxseed, or fish oil. Preclinical studies suggest that hempseed can improve lipid profiles, reduce blood pressure, and reduce oxidative stress and inflammation, though clinical evidence remains limited and findings from animal models may not directly translate to human cardiovascular benefits due to physiological differences between species. Despite the promising findings, there is a need for long-term randomized controlled trials to establish the efficacy and safety of hempseed in diverse populations.
In obese rat models, hemp seeds and the oil decreased lipid peroxidation in the blood plasma and in the heart (reflected as malondialdehyde content), improved contraction to noradrenaline, and up-regulated the sensitivity of potassium channels dependent on ATP and Ca²⁺. Meanwhile, acetylcholine-induced vasodilation was improved by hemp seeds exclusively. Dietary supplementation with ground hemp seeds was much more beneficial than the oil, suggesting that lipid fractions are only partially responsible for this effect.
Evidence strength summary: Evidence for clinically meaningful cardiovascular benefit in humans is currently weak. Improvements to membrane fatty acid composition and the omega-3 index have been demonstrated, but effects on serum lipid profiles (LDL, HDL, total cholesterol, triglycerides) have been inconsistent or absent in human trials. Animal data are more promising but not directly translatable. No large-scale, long-term cardiovascular prevention RCTs have been conducted using hempseed oil.
5.3 Dermatology: Psoriasis, Acne, and Other Inflammatory Skin Conditions
Previous studies revealed that cannabis-based products are usually well tolerated and showed promising results for example in the treatment of atopic dermatitis, psoriasis, and contact dermatitis. However, further controlled human clinical trials are needed to fully unravel the potential of these compounds.
For acne, an in-vitro study (Jin & Lee, 2018, PLoS One) examined hemp seed hexane extracts on Propionibacterium acnes-induced inflammation and lipogenesis in sebocytes, finding an ameliorative effect. This was an in-vitro result, and its clinical significance in humans remains unestablished. A clinical trial using a topical cream containing 3% cannabis seed extract applied twice daily for 12 weeks in 11 healthy participants demonstrated safety and a reduction in sebum production and the erythema index.
Evidence strength summary: Evidence for acne and psoriasis is predominantly in-vitro and from very small clinical trials. It is preliminary and insufficient for clinical recommendations.
5.4 Gastrointestinal Function
Hemp seed (not specifically the oil) has a documented role in traditional Chinese medicine as a laxative, formalized in the classic preparation Hemp Seed Pill (Mazirenwan). A 2011 RCT by Cheng et al. (Am J Gastroenterol, 2011;106(1):120–9) evaluated this traditional preparation for functional constipation and found efficacy versus placebo. This preparation combines hemp seed with other herbal components and should not be conflated with isolated hempseed oil.
5.5 Antioxidant Activity
Most studies of hemp seed oil were conducted in vitro, meaning there is a lack of information about effects and activity in vivo. An in-vivo study using Drosophila melanogaster larvae as a model organism examined antioxidant effects, but the extrapolation of such results to human physiology requires caution. Human clinical evidence specifically documenting antioxidant outcomes from hempseed oil supplementation is lacking.
5.6 Gut Microbiota (Emerging, Preclinical)
An in-vitro molecular docking study found that γ-linolenic and linoleic acids showed strong binding affinities with key metabolic enzymes involved in probiotic metabolism. These results indicate that both major fatty acids and minor bioactive constituents contribute to the nutritional and antioxidant value of hemp seed oils and reveal a potential to promote probiotic growth under in vitro conditions. This is preliminary in-vitro evidence only.
6. Body Systems and Health Areas of Association
- Integumentary system (skin): The best-supported area of clinical association, particularly via dietary supplementation in atopic dermatitis, mediated by GLA/LA/ALA-dependent modulation of skin barrier function, transepidermal water loss, and cutaneous inflammation.
- Cardiovascular system: Preclinical and partial human evidence supports improvement in erythrocyte membrane fatty acid composition and antithrombotic activity; clinically significant lipid-lowering effects not yet demonstrated in human trials.
- Immune and inflammatory system: GLA and SDA in hempseed oil are associated with modulation of eicosanoid synthesis, prostaglandin balance, and inhibition of pro-inflammatory cytokines. Mechanism is plausible and supported by in-vitro data; clinical anti-inflammatory effects remain under investigation.
- Gastrointestinal system: Hempseed products have traditional and clinical support for constipation (via preparations such as Hemp Seed Pill); isolated hempseed oil's direct GI effects are less well characterized.
- Metabolic/Lipid system: Fatty acid incorporation into membrane phospholipids and the omega-3 index are measurably improved in several RCTs, but fasting serum lipid concentrations have not been consistently affected.
7. Dosage Forms and Dosages Reported in Clinical Studies
The following dosages are drawn directly from published clinical studies and should not be interpreted as recommendations:
- 30 mL per day for 8 weeks (oral), used in the 2005 study of 10 participants with atopic dermatitis.
- 2 tablespoons per day for 8 weeks (oral), used in the 20-week crossover study with 20 atopic patients (olive oil comparator).
- 30 mL per day for 4 weeks (oral), used in the Schwab et al. double-blind crossover study in 14 healthy volunteers assessing serum lipid profiles.
- Topical 3% cannabis seed extract cream, applied twice daily for 12 weeks, used in the single-blinded topical RCT in 11 healthy participants.
Study design limitations and discrepancies in levels of hempseed oil bioactive compounds make direct comparisons between studies challenging. Further controlled studies are required to achieve a complete understanding of the effects of HSO in the modulation of medical conditions.
8. Safety Considerations and Interactions
8.1 General Tolerability
When taken by mouth, hemp seed, seed oil, and seed protein are commonly consumed as food. In clinical studies at doses of 30 mL per day over 8–20 weeks, hempseed oil has been well tolerated without serious adverse events being reported.
An acute and subchronic safety study in rats found that no changes in body or organ weights were observed following acute and sub-chronic hemp leaf oil administration in sex-matched groups. Moreover, blood pressure and heart rate remained comparable across groups after acute and sub-chronic treatment. While this is preclinical, it supports the general tolerance profile of hemp-derived oils.
8.2 Anticoagulant and Antiplatelet Interactions
Hempseed is a notable source of omega-3 and omega-6 fatty acids, particularly ALA and GLA, which have been shown to exert antithrombotic effects by modulating platelet aggregation and reducing blood viscosity. Although beneficial for CVD prevention, these properties pose a potential risk to patients receiving anticoagulant therapy.
Patients with bleeding disorders or those scheduled for surgery should discontinue hempseed consumption at least 2 weeks prior to procedures due to potential anticoagulant effects.
8.3 Antihypertensive Drug Interactions
Although moderate consumption is unlikely to cause significant adverse effects, individuals on anticoagulant or antihypertensive therapy should consult their healthcare providers before increasing their intake.
8.4 Special Populations
Pregnant and lactating women should be cautious due to limited safety data in these populations.
Given the increasing incorporation of hempseed-derived ingredients into functional foods, continued risk assessment is essential to ensure consumer safety, particularly in individuals with existing seed or nut allergies.
8.5 Trace THC Content and Drug Testing
Despite the widespread use of hemp seeds or oils in the food and medical sectors, many countries also negatively evaluate hemp product use due to the ambiguity of the Δ9-THC content analysis methods and corresponding standards. Consumption of hempseed oil containing trace Δ9-THC at levels permitted under EU and US regulations has been reported to occasionally result in detectable (though generally low) THC metabolite levels in urine, which can be relevant in drug-testing contexts.
8.6 Oxidative Stability
Due to its high PUFA content, hempseed oil is susceptible to lipid peroxidation upon exposure to heat, light, and oxygen. Cold pressing has low extraction efficiency and leads to oil with high chlorophyll levels; high amounts of chlorophyll negatively influence oil quality and shelf life, since it can lead to oil photooxidation due to chlorophyll's role as a sensitizer. Unrefined cold-pressed hempseed oil should be stored in sealed, dark containers away from heat to minimize oxidative degradation.
References
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