Crocetin

Other Names

(2E,4E,6E,8E,10E,12E,14E)-2,6,11,15-Tetramethyl-2,4,6,8,10,12,14-hexadecaheptaenedioic acid(2E,4E,6E,8E,10E,12E,14E)-2,6,11,15-tetramethylhexadeca-2,4,6,8,10,12,14-heptaenedioic acid2,4,6,8,10,12,14-Hexadecaheptaenedioic acid, 2,6,11,15-tetramethyl-, (2E,4E,6E,8E,10E,12E,14E)-2,6,11,15-tetramethyl-2E,4E,6E,8E,10E,12E,14E-hexadecaheptaenedioic acid8,8'-Diapo-ψ,ψ-carotene-8,8'-dioic acid8,8'-Diapo-ψ,ψ-carotenedioic acid8,8'-diapocarotene-8,8'-dioic acid8,8'-Diapocarotenedioic acidalpha-CrocetinApocarotenic acidCrocetic acidCrocetin (6CI)NSC 407300NSC407300Saffron C.I.trans-CrocetinTranscrocetinα-Crocetin

Synopsis

Crocetin: A Comprehensive Encyclopedic Reference

1. Identity: Chemical and Botanical Profile

1.1 Nomenclature and Chemical Structure

Crocetin is a natural apocarotenoid dicarboxylic acid, a diterpenoid, and a branched-chain dicarboxylic acid. Its formal chemical name is 8,8′-diapo-8,8′-carotenedioic acid, also rendered as trans-crocetin or all-trans-crocetin when referring to its most stable geometric isomer. Crocetin is a carotenoid characterized by a diterpenic and symmetrical structure with seven double bonds and four methyl groups. Its elementary composition is C₂₀H₂₄O₄ and its molecular weight is 328.4. The chain is stabilized in its terminal parts by two carboxylic groups, giving it the designation of a dicarboxylic apocarotenoid. Unlike the great majority of carotenoids — which are 40-carbon compounds — crocetin's backbone is shortened to 20 carbons, placing it in the apocarotenoid subclass. Crocetin belongs to the large family of natural dyes known as carotenoids, but it does not have a pro-vitamin function.

Crocetin is slightly soluble in aqueous solution (approximately 20 μM at pH 8.0) and is soluble in organic bases such as pyridine. Crocetin exhibits poor solubility in water and most organic solvents, except for pyridine and dimethyl sulfoxide. Normally, the trans-form is more stable than the cis-form. This physicochemical property has significant implications for bioavailability and pharmaceutical formulation, as discussed below.

The sodium salt of crocetin — transcrocetinate sodium (INN, also known as trans sodium crocetinate or TSC) — is an experimental drug that increases the movement of oxygen from red blood cells into hypoxic (oxygen-starved) tissues. Transcrocetinate sodium belongs to a group of substances known as bipolar trans carotenoid salts, which constitute a subclass of oxygen diffusion-enhancing compounds, and it was one of the first such compounds discovered.

1.2 Relationship to Crocin

Crocetin is an aglycone of crocin, naturally occurring in saffron and produced in biological systems by hydrolysis of crocin as a bioactive metabolite. The crocins are a class of hydrophilic carotenoids that are either mono- or di-glycosyl polyene esters of crocetin, in which D-gentiobiose and/or D-glucose appear as carbohydrate residues. Six different forms of the crocin family's glycosyl esters have been found in saffron; trans-crocins 3 and 4 are the most prevalent of the crocin analogs, which include crocins 1–4 and are virtually glycosides of trans-crocetin in saffron. Because the glycoside moieties render crocin water-soluble while the aglycone crocetin is lipophilic, gut microbiota and intestinal enzymes are understood to hydrolyze crocin to yield crocetin after oral ingestion.

1.3 Natural Sources

The main sources of crocetin and its glycosidic precursors are the dried stigmas of Crocus sativus L. (commonly named saffron) and the fruits of Gardenia jasminoides E. Crocus sativus L., commonly known as saffron, is a small perennial plant belonging to the family Iridaceae, cultivated in many countries including Iran, Afghanistan, Turkey, and Spain. Crocetin isolated from saffron is one of the two principal chemicals responsible for the red color of saffron, and constitutes approximately 0.3% of the total weight of the saffron stigma. Gardenidin, a compound obtained from gardenias, is identical to crocetin.

Crocetin is an apocarotenoid formed from the oxidative cleavage of zeaxanthin, by the carotenoid cleavage enzymes CCD2 (in Crocus species) and specific CCD4 enzymes in Buddleja davidii and Gardenia jasminoides. Crocetin accumulates in the stigma of saffron in the form of glucosides and crocins, which contain one to five glucose molecules. In Gardenia jasminoides (Cape Jasmine, known as "Zhi Zi" in Traditional Chinese Medicine), gardenia yellow is a yellowish food colorant and member of the carotenoid family, whose principal pigments are crocin/crocetin derivatives, obtained by extraction with water or ethanol from the fruit of Gardenia.

Crocetin was the first plant carotenoid to be recognized as early as 1818, while the history of saffron cultivation reaches back more than 3,000 years. Beyond saffron and gardenia, minor quantities of crocetin-related compounds have been identified in other species, but these two plants remain by far the most commercially and pharmacologically significant sources.

1.4 Common Forms and Preparations

Crocetin is available or studied in several forms:

Free crocetin (aglycone): The lipophilic free-acid form, rarely found naturally in significant amounts but produced by hydrolysis of crocin. Used in experimental and some clinical studies.
Standardized saffron extracts: The major carotenoid derivatives found in saffron are crocetin, picrocrocin, and safranal; crocin is a mixture of glycosides — crocetin, a dicarboxylic terpene lipid, and alpha-crocin, a digentiobiose ester of crocetin.
Gardenia yellow extract: Gardenia yellow is listed in the list of existing food additives in Japan and has been used as a food colorant for Japanese traditional foods, such as yellow rice (ohagi) colored with gardenia fruit and yellow chestnuts soaked in syrup.
Trans-sodium crocetinate (TSC): Transcrocetinate sodium can be prepared by reacting saffron with sodium hydroxide and extracting the salt of the trans crocetin isomer from the solution. This is an investigational pharmaceutical form.
Cyclodextrin inclusion complexes: Pharmacokinetic and biodistribution studies showed that a CRT-γ-cyclodextrin inclusion complex significantly increased the bioavailability of crocetin and facilitated its crossing of the blood-brain barrier to enter the brain.
Soft oral capsules: Used in multiple human clinical trials at doses of 7.5 mg/day, a soft capsule taken orally once a day with a sufficient amount of water has been the standard delivery format in clinical myopia and sleep trials.

2. Traditional and Historical Use

2.1 Ancient Origins and Cross-Cultural Use

Saffron — the primary source of crocetin — has been known for more than 4,000 years and was used mostly in traditional medicine as a tonic agent and antidepressant drug. Its dried stigma was used as a drug, dye, perfume, and condiment in ancient Egypt, Greece, India, Persia, and Rome. Saffron has accompanied all civilizations, whether for its culinary role, for its quality as a dye, or for its ancestral virtues rooted in folk medicine.

2.2 Persian and Islamic Medicine (Avicenna / Ibn Sina)

A review of Avicenna's Book II of the Canon of Medicine (al-Qanun fi al-tib) and modern scientific studies reveals that the traditional uses of saffron and its pharmacological activities overlap extensively. Avicenna described various uses of saffron, including its use as an antidepressant, hypnotic, anti-inflammatory, hepatoprotective, bronchodilatory, aphrodisiac, inducer of labour, and emmenagogue, among others. A variety of properties of saffron including diuretic, analgesic, anti-inflammatory, hepatoprotective, appetite suppressant, hypnotic, antidepressant, and bronchodilator effects were mentioned in the Al-Hawi of al-Razi. Modern studies have confirmed most of these characteristics.

2.3 Traditional Indian and Asian Use

In countries like India and other Asian countries, saffron has been used in traditional medicine from pre-historic ages. Traditional practitioners used saffron for treating depression, inflammations, and gastrointestinal, liver, respiratory, urogenital, eye, and skin diseases. In Ayurvedic practice, saffron preparations — rich in crocetin precursors — were prepared as warm milk infusions, pastes, and decoctions, prescribed across a wide range of therapeutic conditions.

2.4 Traditional Chinese Medicine (Gardenia Source)

Gardenia jasminoides, commonly known as Cape Jasmine or "Zhi Zi" in Traditional Chinese Medicine (TCM), has a rich history of use spanning centuries. Revered in ancient China, Gardenia fruit was lauded for its cooling properties and was often used to clear heat and eliminate irritability, with applications including remedies for fever, jaundice, headaches, and urinary tract difficulties, as well as use in swelling, trauma, and inflammation. Medicinally, it was frequently employed as a natural remedy for liver and heart health. Gardenia has also been used in Japan and China as an herbal drug for antiphlogistic, diuretic, antipyretic, haemostatic, and cholagogic effects, and can be used to treat contusions. A paste of the herb with flour and wine was used as a poultice on twists, sprains, strains, bruises, and abscesses; it was considered very effective in injuries to tendons, ligaments, joints, and muscles. Furthermore, it is considered an important crude drug in traditional Asian medical prescriptions, with sedative, antipyretic, diuretic, choleretic, and anti-inflammatory effects.

2.5 Reproductive and Other Traditional Uses

Saffron, as well as other spices, enjoyed a reputation as an aphrodisiac in different Egyptian, Greek, Roman, and other civilizations. Traditionally, Muslims, Phoenicians, and Chinese use saffron as a sexual stimulant. Historically, and particularly in traditional Persian medicine, saffron has been regarded as an abortifacient agent. As an antispasmodic, saffron has been used for stomach pain by helping digestion and improving appetite, and it also reduces tension and alleviates symptoms of premenstrual syndrome and renal colic.

3. Key Constituents, Biosynthesis, and Mechanisms of Action

3.1 Phytochemical Context in Saffron

More than 150 compounds have been identified in saffron stigma, including colored carotenoids (e.g., crocetin and crocins as glycosidic derivatives), colorless monoterpene aldehydes, and volatile agents (e.g., safranal and picrocrocin, which are the bitter components). According to the literature, the main active ingredients of saffron are carotenoids (crocetins, crocins, α-carotene, β-carotene, lycopene, zeaxanthin, mangicrocin, xanthone-carotenoid), monoterpene aldehydes (picrocrocin, safranal and its isomers), monoterpenoids (crocusatins), and flavonoids (kaempferol derivatives).

3.2 Principal Mechanisms of Action

Crocetin can act via different mechanisms, such as enhancing the rate of oxygen transport and diffusivity, inhibiting pro-inflammatory mediators, protecting cells from reactive oxygen species (ROS) damage, and stimulating apoptosis in cancer cells. These four overarching mechanisms underpin most of crocetin's observed pharmacological activities.

3.2.1 Oxygen Diffusion Enhancement

Crocetin enhances oxygen diffusivity through liquids such as plasma. As a consequence of this property, it has been observed that crocetin increases alveolar oxygen transport and enhances pulmonary oxygenation, and it improves cerebral oxygenation in hemorrhaged rats. Trans sodium crocetinate (TSC), a synthetic derivative, is a small-molecule that has the ability to enhance oxygen diffusion to hypoxic tissue. An obvious mechanism by which TSC provides neuroprotection is by facilitating oxygen diffusion to ischemic brain tissues; it is a novel synthetic carotenoid compound that improves diffusion of small molecules including oxygen in solutions. This property is unique among naturally occurring carotenoids and distinguishes crocetin from typical antioxidant phytochemicals.

3.2.2 Antioxidant and ROS Scavenging

Crocetin significantly inhibited hydroxyl radical generation compared with control in electron spin resonance studies. Crocetin significantly reduced oxidative stress in the isolated brain by acting as a scavenger of reactive oxygen species, especially hydroxyl radical, as demonstrated by both in vitro and ex vivo electron spin resonance analysis. Crocetin down-regulated lipid peroxidation in the hippocampus, reduced hippocampal superoxide dismutase (SOD) activity, up-regulated nuclear factor erythroid 2-related factor 2 (Nrf2) signaling, and attenuated reactive oxygen species (ROS).

3.2.3 Anti-inflammatory Signaling

The beneficial effects of saffron's active constituents, including crocetin, on inhibition of serum levels of nuclear transcription factor κB (NF-κB) p65 unit, tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and some interleukins such as IL-1β, IL-6, IL-12, and IL-17A have been reported. These effects reflect crocetin's capacity to interfere with major pro-inflammatory signaling cascades.

3.2.4 Neuroprotective and Neurotrophic Signaling

Crocetin, an apocarotenoid derived from saffron and Gardenia jasminoides, exhibits promising neuroprotective effects by scavenging reactive oxygen species, attenuating neuroinflammatory signaling, enhancing mitochondrial bioenergetics, and improving insulin sensitivity. It further upregulates brain-derived neurotrophic factor (BDNF), modulates PI3K/Akt signaling, and restores gut microbiota balance, thereby reinforcing the gut-brain axis and maintaining blood-brain barrier integrity.

3.2.5 Anti-cancer Mechanisms

Crocetin retards the growth of cancer cells via inhibiting nucleic acid synthesis, enhancing the anti-oxidative system, and inducing apoptosis and differentiation pathways. Crocetin and crocin are two important carotenoids isolated from saffron (Crocus sativus L.), which have been used as natural biomedicines with beneficial effects for improving the suboptimal health status associated with abnormal angiogenesis.

3.2.6 Lipid Metabolism and Cardiovascular Pathways

Based on the theory of lipid metabolism disorder, hyperlipidemia is the main risk factor for atherosclerosis. Several experiments using different animal models have shown that oral administration of crocetin (5–50 mg/kg) reduced serum triacylglycerol (TG), total cholesterol (TC), LDL, and very-low-density lipoprotein levels via antioxidant and anti-inflammatory effects associated with the p38 MAPK pathway.

4. Pharmacokinetics and Bioavailability

Poor water solubility and bioavailability are the major obstacles in formulation development and pharmaceutical applications of crocetin. The metabolic stability of crocetin is further compromised by the fact that it has an extensive first-pass effect in the liver, where it is oxidized and glucuronidated rapidly. Its free tissue availability is also inhibited by conjugation with plasma proteins, which constrains its neuroprotective effects.

Pharmacokinetic studies indicate that crocin (the glycoside form) has poor bioavailability and needs to convert to crocetin in order to cross the blood-brain barrier. This conversion takes place largely through intestinal hydrolysis by gut microbiota. Crocetin therapy presents one of the greatest limitations due to ineffective capacity to pass the blood-brain barrier (BBB) in its unconjugated form, and various formulation strategies such as nano-encapsulation, liposomal carriers, or prodrug strategies have been suggested to overcome its low bioavailability and improve its pharmacokinetics.

Crocetin binds strongly to serum albumin; however, displacement of plasma-bound drugs by this interaction has not been formally evaluated. Attributes of crocetin based on rules of drug-likeness, lipophilicity, pKa, P-gp inhibitory activity, plasma stability, RBC partitioning, metabolic stability, CYP inhibitory action, blood-brain barrier (BBB) permeability, oral bioavailability, and pharmacokinetic interaction with marketed anti-Alzheimer's drugs (memantine, donepezil, galantamine, and rivastigmine) have been assessed. Aqueous solubility, chemical stability, plasma protein binding, and P-gp induction are concerns associated with this molecule that should be taken into consideration during its further development.

Pharmacokinetics and biodistribution studies showed that a CRT-γ-cyclodextrin inclusion complex significantly increased the bioavailability of crocetin and facilitated its crossing of the blood-brain barrier to enter the brain, demonstrating that a water-soluble γ-cyclodextrin inclusion complex helps deliver crocetin across the BBB.

5. Scientific Evidence by Health Area

5.1 Neurological and Cognitive Health

Crocetin has seen a large number of studies in preclinical cognitive impairment models, especially Western diet-induced neurodegeneration. Its potential to act as a neuroprotective agent is illustrated by animal experiments demonstrating its capability to reverse neuroinflammation, insulin resistance, oxidative stress, and synaptic dysfunction.

Clinical evidence: Despite strong preclinical evidence, limited human studies have evaluated crocetin's efficacy in cognitive health. Clinical trials have predominantly focused on its effects on oxidative stress, metabolic function, and vascular health, which indirectly influence cognitive outcomes. In a randomized, placebo-controlled trial involving elderly individuals with mild cognitive impairment (MCI), daily crocetin supplementation for 12 weeks significantly improved episodic memory, verbal fluency, and working memory performance compared to the placebo group. The number of such dedicated human cognitive trials remains small, and independent replication with larger populations is needed to establish firm conclusions.

Crocetin has shown various neuroprotective effects in preclinical models, such as antioxidant activities and the inhibition of amyloid-β fibril formation, and is thus considered a potential therapeutic candidate for Alzheimer's disease. In cell-based studies, crocetin showed stronger ability to downregulate the expression of C-terminus fragments and levels of amyloid-β compared to free drug controls, and was able to prevent neuronal cell death from H₂O₂-induced toxicity. These remain in vitro and preclinical findings; definitive human Alzheimer's disease trials have not yet been conducted.

Evidence strength: Preclinical evidence (animal and cell-based) is substantial. Human clinical evidence is preliminary and limited in scale.

5.2 Sleep Quality

Crocetin is a pharmacologically active carotenoid compound of Gardenia jasminoides Ellis used as a traditional herbal medicine and natural colorant. A pilot study investigated the effect of crocetin on sleep in a double-blind, placebo-controlled, crossover trial of 21 healthy adult men with a mild sleep complaint, including two intervention periods of 2 weeks each separated by a 2-week washout period. Objective sleep quality was measured using an actigraph, and subjective symptoms were assessed using the St Mary's Hospital Sleep Questionnaire. Actigraph data showed that after administration of crocetin, the number of wakening episodes was reduced compared to placebo (p = 0.025). Subjective data showed that crocetin tended to improve quality of sleep.

A larger follow-up trial extended these findings: a randomized, double-blind, placebo-controlled, crossover study with two intervention periods of 14 days each, separated by a 14-day wash-out period, enrolled 30 participants randomly assigned to one of two sequence groups. Each group was given crocetin at 7.5 mg/day or placebo. Objective sleep parameters were measured using single-channel electroencephalography and subjective parameters were assessed using a validated sleep inventory. Delta power was significantly increased with crocetin compared with placebo. There were no significant differences in sleep latency, sleep efficiency, total sleep time, and wake after sleep onset. Subjective scores for sleepiness on rising and feeling refreshed were significantly improved with crocetin compared with placebo. The findings suggest that crocetin supplementation contributes to sleep maintenance, leading to improved subjective sleep quality. A daily intake of 7.5 mg of crocetin increased delta power — a marker of deep, slow-wave sleep — in these EEG studies.

Evidence strength: Two small, well-controlled crossover RCTs in healthy adults with mild complaints demonstrated consistent improvements in objective sleep maintenance (fewer awakenings, increased delta power) and subjective sleep quality at 7.5 mg/day. These are pilot-level findings and require larger, longer-term replication.

5.3 Cardiovascular Health

Studies have shown that crocetin plays a potential role in prevention and treatment of cardiovascular diseases such as hypertension, myocardial hypertrophy, myocardial ischemia, and atherosclerosis.

Clinical evidence (CAD/atherosclerosis): In a clinical trial assessing the effect of crocetin for treating atherosclerosis, 50 patients diagnosed with coronary artery disease (CAD) were randomly divided into two groups to receive one capsule of crocetin (10 mg) or placebo once daily for 60 days. Compared with the placebo group, the crocetin group showed significantly reduced serum homocysteine (Hcy) and heart-type fatty acid-binding protein (h-FABP). In addition, the gene expression of sirtuin1 and AMP-activated protein kinase was increased, while the expression levels of oxidized LDL receptor 1 and NF-κB were decreased in isolated peripheral blood mononuclear cells in the crocetin group, suggesting that crocetin could alter the expression of endothelial cell adhesion molecules and atherogenic genes in patients with CAD. A separate analysis of the same trial reported: serum circulating homocysteine, heart-type fatty acid binding protein, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and monocyte chemoattractant protein 1 all decreased significantly after the trial in the crocetin group, while HDL significantly increased.

Evidence strength: A single small (n=50) pilot RCT in CAD patients showed favorable effects on multiple atherogenic biomarkers with 10 mg/day for 60 days. Results are promising but require replication in larger, adequately powered trials with clinical endpoints.

5.4 Ocular Health and Myopia

The natural carotenoid crocetin has been reported to suppress experimental myopia in mice. This finding was translated into a controlled human study: a multicenter randomized double-blind placebo-controlled clinical trial was performed with 69 participants aged 6 to 12 years, whose cycloplegic spherical equivalent refractions (SER) were between −1.5 and −4.5 diopters. Participants were randomized to receive either a placebo or crocetin and followed up for 24 weeks, with axial length elongation and changes in SER evaluated for 24 weeks. A dose of 7.5 mg/day of crocetin was administered in the clinical trial. The change in SER in the placebo group (−0.41 ± 0.05 D) was significantly more myopic compared to that in the crocetin group (−0.33 ± 0.05 D, p = 0.049). The axial length elongation in the placebo group (0.21 ± 0.02 mm) was significantly bigger than that in the crocetin group (0.18 ± 0.02 mm, p = 0.046). Dietary crocetin may have a suppressive effect on myopia progression in children, but large-scale studies are required in order to confirm this effect.

Evidence strength: One multicenter, double-blind, placebo-controlled RCT of 69 children (24 weeks, 7.5 mg/day) demonstrated a statistically significant but numerically modest slowing of myopia progression. The authors themselves call for large-scale confirmatory studies. This is a meaningful pilot finding in a condition with limited pharmacological options.

5.5 Physical Fatigue and Exercise Performance

Some early research shows that taking crocetin might decrease fatigue in men during exercise. Crocetin's proposed mechanism in this context relates to its oxygen diffusion-enhancing properties in blood plasma. In a clinical trial, the effect of daily oral administration of crocetin was evaluated in physical fatigue in human subjects. These studies remain limited in scale, and the evidence base for this application is considered preliminary.

Evidence strength: Very preliminary; based on small studies. Mechanistic plausibility exists through the oxygen diffusion enhancement property but has not been robustly established in larger controlled trials.

5.6 Cancer (Preclinical) and Oncological Applications of TSC

Crocetin, an important carotenoid constituent of saffron, has shown significant potential as an anti-tumor agent in animal models and cell culture systems. In in-vitro studies, crocetin has shown anti-cancer, cardio-protective, and antioxidant properties against oxidative stress, while in in-vivo studies, crocetin has demonstrated cardio-protective, neuroprotective, and anti-cancer effects. Crocetin retards the growth of cancer cells via inhibiting nucleic acid synthesis, enhancing the anti-oxidative system, and inducing apoptosis and differentiation pathways.

The pharmaceutical derivative TSC has received the most advanced clinical investigation in the cancer context. Owing to a long history dating back to the 1970s and its unique mode of O₂-diffusion enhancement action, TSC is at the centre stage of clinical development for various cancers, and is being investigated for improving the outcome of radiotherapy for inoperable cancers such as glioblastoma multiforme (GBM) and other difficult-to-treat cancers.

Evidence strength: Anti-tumor effects are well-characterized in vitro and in animal models. For crocetin itself as a dietary supplement in humans with cancer, there are no completed clinical trials of sufficient scale. The TSC derivative is in clinical investigation for oncological radiotherapy sensitization.

5.7 Antidiabetic and Metabolic Effects

Crocetin, the active constituent of saffron, was found to possess antidiabetic activity in fructose-fed rats, as it alleviated free fatty acid-induced insulin insensitivity and dysregulated mRNA expression of adiponectin, TNF-alpha, and leptin in primary cultured rat adipocytes, suggesting the possibility of crocetin treatment as a preventive strategy of insulin resistance and related diseases. These remain preclinical findings; dedicated human clinical trials specifically on crocetin for diabetes are not yet reported in the available literature.

Evidence strength: Preclinical only at the level of crocetin as an isolate. Some saffron-whole-extract trials in metabolic syndrome exist, but isolating crocetin's contribution is not confirmed in human studies.

5.8 Hepatoprotective Effects

Crocetin has high medicinal value and possesses cardioprotective, hepatoprotective, neuroprotective, antidepressant, antiviral, anticancer, antidiabetic, and memory-enhancing properties. Hepatoprotective effects have been characterized in preclinical models through antioxidant and anti-inflammatory mechanisms. In modern studies, saffron and its constituents have been used for treating liver fibrosis, fatty liver, and metabolic diseases.

Evidence strength: Primarily preclinical. Human clinical trials targeting hepatoprotection with isolated crocetin are not yet established.

5.9 Stroke and Cerebral Ischemia

Trans-sodium crocetinate (TSC) is a novel synthetic carotenoid compound that improves diffusion of small molecules including oxygen in solutions and has been shown to provide neuroprotection in healthy rats and rabbits. Results suggest that 0.14 mg/kg TSC given by a bolus-infusion-bolus regimen provides neuroprotection in obese mice, involving reduced oxidative stress, inflammation, and MMP-9 expression and activity in ischemic brain tissues. Because TSC is a promising drug candidate to treat acute ischemic stroke (AIS), it has been tested in a rabbit small clot embolic stroke model using clinical rating scores as the endpoint.

Evidence strength: The TSC derivative has advanced further than the natural compound form in ischemic stroke research, with preclinical evidence in multiple animal models. Human clinical translation for both natural crocetin and TSC in stroke is not fully established.

6. Body Systems and Health Areas Associated with Crocetin

Central nervous system: Neuroprotection, Alzheimer's disease preclinical modeling, cognitive function, antidepressant effects (via saffron-based evidence), sleep architecture.
Cardiovascular system: Atherosclerosis, hypertension, myocardial ischemia, lipid metabolism, platelet aggregation.
Ocular system: Myopia progression control, age-related macular degeneration (AMD preclinical), retinal protection, glaucoma (preclinical).
Metabolic system: Insulin resistance, antidiabetic mechanisms, adipokine modulation.
Hepatic system: Hepatoprotection, liver fibrosis, fatty liver (mainly preclinical).
Oncology: Anti-proliferative, pro-apoptotic, and anti-angiogenic effects in multiple cancer cell lines; TSC in radiotherapy sensitization.
Respiratory/systemic oxygenation: Oxygen diffusion enhancement in plasma, relevant to hypoxia, exercise physiology, and ischemia.
Immune system: Modulation of NF-κB, cytokine signaling, and immune cell function.

7. Dosage Forms and Dosages Reported in Studies

The following dosages are drawn exclusively from the primary studies referenced in this article:

Sleep quality (adults): Crocetin at 7.5 mg/day administered as a daily capsule in 14-day intervention periods in a double-blind, placebo-controlled crossover study of 30 adults.
Sleep quality (initial pilot): A double-blind, placebo-controlled, crossover trial of 21 healthy adult men with a mild sleep complaint, with two intervention periods of 2 weeks each separated by a 2-week washout.
Myopia control in children: 7.5 mg/day of crocetin was administered in a multicenter RCT of children aged 6–12 years over 24 weeks.
Coronary artery disease (CAD): 10 mg crocetin once daily for 60 days in 50 patients with CAD in a randomized, double-blind, placebo-controlled pilot trial.
Saffron supplementation (general clinical range): Clinical studies have evaluated doses ranging from 20 to 400 mg/day of pure saffron extract (noting that saffron extract is not equivalent to isolated crocetin by weight).
Animal/preclinical hypolipidemic studies: Oral administration of crocetin (5–50 mg/kg) was used in different animal models to assess lipid-lowering effects.
Animal/preclinical TSC (ischemia): TSC was administered by two boluses via tail vein at total doses of 0.14, 0.28, and 0.7 mg/kg, or by a bolus-infusion-bolus strategy with a total dose of 0.14 mg/kg, in mouse cerebral ischemia models.

Previous research on the safety of dietary crocetin indicated no adverse effects in adults who received oral doses ranging from 7.5 mg to 22.5 mg.

8. Safety Considerations and Known Interactions

8.1 General Safety Profile

Crocetin's safety profile is supported by centuries of consumption in saffron-based traditional medicine with no reports of serious adverse effects at culinary and therapeutic doses. It has been documented that crocetin could be tolerated without major toxicity at therapeutic dosage in experimental models. Limited clinical trials have been reported, highlighting the need for further large-scale human trials to confirm the safety and efficacy of the compound.

8.2 Dose-Dependent Toxicity (Saffron/Crocin Source)

Daily consumption of saffron up to 1.5 g/day has not been found to be associated with any adverse effect. However, doses higher than 5 g are toxic, and at 20 g are lethal. Saffron doses over 10 g have been used for abortion with high risk of maternal death. At this latter dose, saffron can induce vomiting, uterus bleeding, hematuria, gastrointestinal bleeding, and vertigo. The most frequent adverse effects of saffron mentioned in studied texts were headache, nausea, head fullness, dizziness, hypomania, and appetite suppression; yellowing of the sclera, skin, or mucosa is another side effect reported for saffron, due to accumulation of colored constituents.

8.3 Observed Adverse Effects in Human Trials

Saffron is possibly safe for most people when taken by mouth as a medicine for up to 6 weeks. Some possible side effects include dry mouth, anxiety, dizziness, drowsiness, nausea, change in appetite, and headache. In a safety evaluation of crocin tablets in healthy volunteers: no major adverse events were reported during the trial. However, three volunteers showed adverse effects in the crocin group: one reported a burning symptom localized to the kidney region (he had a history of kidney stones); another showed somnolence, urinary frequency, and occasional burning sensation; and one woman had heavy and prolonged menstrual bleeding with an early menstrual period. These symptoms resolved without need for discontinuation of treatment.

8.4 Pregnancy and Reproductive Safety

Saffron should be avoided in pregnancy. Amounts higher than those used in food (e.g., 5 g or more) have uterine stimulant and abortifacient effects. Historically, and particularly in traditional Persian medicine, saffron has been regarded as an abortifacient agent. Farmer women exposed to saffron had increased rates of miscarriage. This could be due to the fact that saffron stimulates uterine contractions.

8.5 Drug Interactions

Conflicting results regarding saffron's effect on human platelets in healthy volunteers have been reported, while an aqueous extract of saffron inhibited human platelet aggregation in vitro. Interactions with anti-aggregating drugs are therefore theoretically possible, and saffron is contraindicated in bleeding disorders. Crocetin binds strongly to serum albumin; however, displacement of plasma-bound drugs has not been evaluated. Saffron may enhance the anticoagulant effect of rivaroxaban. Aqueous solubility, chemical stability, plasma protein binding, and P-gp induction are concerns associated with crocetin that should be taken into consideration during its further development, particularly for co-administration with drugs that are P-glycoprotein substrates.

8.6 Special Populations

Saffron seems to be able to affect mood and may trigger excitability and impulsive behavior in people with bipolar disorder. People who are allergic to plants of the Lolium, Olea (including olive), and Salsola species may also be allergic to saffron, indicating cross-reactive allergic potential.

8.7 Bioavailability Limitations as a Safety Factor

Although poor bioavailability hinders therapeutic applications, derivatization and formulation preparation technologies have broadened the application prospects for crocetin. The low and variable oral bioavailability of crocetin means that pharmacological effects from dietary or supplemental intake may differ substantially from those seen in in-vitro studies using high concentrations, and comparisons across studies must account for this variability.

9. Research Gaps and Overall Evidence Assessment

Limited clinical trials have been reported for crocetin specifically, highlighting the need for further large-scale human trials to confirm its pharmacological actions. A critical assessment of the mechanistic links is warranted, distinguishing well-supported findings from speculative associations and emphasizing discrepancies between preclinical and human evidence. At the time of writing, the most robustly characterized human clinical effects of isolated crocetin are: (1) modest improvement in sleep maintenance and quality at 7.5 mg/day; (2) slowing of myopia progression in myopic children at 7.5 mg/day over 24 weeks; and (3) improvements in multiple atherogenic biomarkers in CAD patients at 10 mg/day over 60 days. All three areas require replication in larger trials before clinical recommendations can be made.

References

Health Conditions

Health conditions that Crocetin may help support.

Healthy Lens & Vision with AgeScientific
Crocetin is one of the principal bioactive carotenoid compounds of saffron (Crocus sativus) with demonstrated clinical evidence for improving visual function and retinal health in age-related macular degeneration. Clinical studies using 5–15 mg/day for 3–12 months showed significant improvements in visual acuity, contrast sensitivity, and retinal function measured by electroretinography. Mechanisms include antioxidant, neuroprotective, and anti-angiogenic effects in retinal tissue.

Body Systems

Body systems that Crocetin may help support.

No body systems available.