Spirulina Extract
Research reviewed: Up until 03/2026
Spirulina Extract is a dietary supplement with 10 published peer-reviewed studies involving 376 participants, researched for Blood sugar, Exercise Performance, Weight management and 2 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Blood sugar
StrongExercise Performance
ModerateWeight management
ModerateBlood pressure
ModerateCholesterol
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Blood sugar
To assess the efficacy, safety, and anti-atherogenic (plaque-fighting) effect of Spirulina platensis as an add-on supplement alongside existing medication in patients with inadequately controlled type 2 diabetes (patients whose HbA1c remained above target despite medical treatment).
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To assess the efficacy, safety, and anti-atherogenic (plaque-fighting) effect of Spirulina platensis as an add-on supplement alongside existing medication in patients with inadequately controlled type 2 diabetes (patients whose HbA1c remained above target despite medical treatment).
Dose
2 g/day Spirulina platensis tablets or matching placebo, added to existing diabetes medication
Participants
60 patients with inadequately controlled type 2 diabetes
Duration
3 months
Results
Researchers observed that compared with the placebo group, people taking spirulina had several significant health improvements. HbA1c (the 3-month average blood sugar) significantly dropped by 1.43 percentage points. Fasting blood sugar also significantly decreased by 24.94 mg/dL. In addition, LDL (“bad”) cholesterol was significantly reduced, and the anti-atherogenic index (a measure of protection against plaque buildup in arteries) significantly improved. The treatment was well tolerated, with no serious adverse events reported.
To evaluate the hypoglycaemic (blood-sugar-lowering) and hypolipidaemic (blood-fat-lowering) role of spirulina supplementation in patients with type 2 diabetes mellitus.
Study Type
Randomised controlled trial
Purpose
To evaluate the hypoglycaemic (blood-sugar-lowering) and hypolipidaemic (blood-fat-lowering) role of spirulina supplementation in patients with type 2 diabetes mellitus.
Dose
2 g/day Spirulina or no supplementation (control group)
Participants
25 subjects with type 2 diabetes mellitus, randomly assigned to spirulina (study) or control group.
Duration
2 months
Results
Researchers observed that after 2 months of spirulina supplementation, participants had several significant improvements in blood sugar control compared with the control group. Fasting blood glucose (FBG)—blood sugar measured after about 12 hours without eating—decreased by 19.3 mg/dL. Postprandial blood glucose (PPBG)—blood sugar measured 2 hours after a meal—dropped by 16.1 mg/dL. In addition, HbA1c, which reflects the average blood sugar level over the past 2–3 months, decreased by 1.0 percentage point. This is considered a clinically meaningful improvement, since even a 1% reduction in HbA1c can lower the risk of diabetes-related complications by about 20%.
To investigate the effect of spirulina delivered via a functional food (spirulina sauce) on glycaemic indices (blood sugar control markers), lipid profile, oxidative stress, and insulin sensitivity in type 2 diabetic patients
Study Type
Randomised, double-blind clinical trial
Purpose
To investigate the effect of spirulina delivered via a functional food (spirulina sauce) on glycaemic indices (blood sugar control markers), lipid profile, oxidative stress, and insulin sensitivity in type 2 diabetic patients
Dose
20 g/day spirulina sauce (containing 2 g Spirulina platensis) or placebo sauce
Participants
40 patients with type 2 diabetes randomized (20 per group)
Duration
2 months
Results
Researchers observed that compared with the placebo group, people taking spirulina had several significant improvements in metabolic health. Insulin sensitivity improved, shown by an increase in the QUICKI score (a measure calculated from fasting blood sugar and insulin that indicates how well the body responds to insulin) by 0.025, meaning cells became more responsive to insulin and could absorb sugar more effectively. Blood fats also improved: triglycerides dropped by about 68.6 mg/dL, which is a large reduction, total cholesterol decreased by 29.55 mg/dL, and LDL (“bad”) cholesterol decreased by 17.7 mg/dL, showing significant improvements in cholesterol levels.
Exercise Performance
To investigate whether spirulina supplementation improves submaximal oxygen uptake (VO2 — how efficiently the body uses oxygen during exercise; a key measure of aerobic fitness and exercise economy) during arm cycling exercise
Study Type
Randomised, double-blind, placebo-controlled crossover trial
Purpose
To investigate whether spirulina supplementation improves submaximal oxygen uptake (VO2 — how efficiently the body uses oxygen during exercise; a key measure of aerobic fitness and exercise economy) during arm cycling exercise
Dose
3 g/day Spirulina platensis powder mixed into water or matching placebo
Participants
13 healthy untrained male and female adults
Duration
7 days
Results
Researchers observed that spirulina significantly increased hemoglobin (Hb)—the protein in red blood cells that carries oxygen in the body—from 144.1 g/L to 154.5 g/L compared with placebo. During the 30-minute exercise sessions, participants taking spirulina used less oxygen (2170 ml/min vs. 2311 ml/min) and had a slightly lower heart rate (149 beats per minute vs. 154 bpm), suggesting their bodies were working more efficiently during exercise. The respiratory exchange ratio (RER)—a measure that shows whether the body is burning more fat or carbohydrates for energy—did not change significantly. However, oxygen uptake at the point of fatigue (a measure of aerobic capacity) significantly increased from 34.10 to 37.37 ml/kg/min with spirulina. Despite these improvements, the total time participants could exercise before reaching fatigue did not significantly change.
To assess the effects of 21 days of spirulina supplementation on submaximal exercise heart rate, power output during repeated sprint cycling, and cycling performance in trained cyclists
Study Type
Randomised, double-blind, placebo-controlled crossover trial
Purpose
To assess the effects of 21 days of spirulina supplementation on submaximal exercise heart rate, power output during repeated sprint cycling, and cycling performance in trained cyclists
Dose
3 g/day Spirulina platensis powder or matched placebo
Participants
15 trained males with an average age of 40 years
Duration
21 days per arm
Results
Researchers observed that after taking spirulina, participants showed several significant improvements during exercise. During moderate-intensity endurance tests, blood lactate—a substance that builds up in muscles during hard exercise and contributes to fatigue—was significantly lower (2.05 mmol/L vs 2.39 mmol/L), and heart rate was also lower (139 bpm vs 144 bpm) compared with placebo, suggesting the body was handling exercise stress better. Hemoglobin—the oxygen-carrying protein in red blood cells—was significantly higher (152.6 g/L vs 143.2 g/L). During repeated sprint performance tests (RSPTs), both peak power (968 W vs 929 W) and average power (770 W vs 738 W) were significantly higher with spirulina. However, there were no significant differences between spirulina and placebo for oxygen consumption, 16.1-km cycling time trial performance, or lactate threshold tests. Overall, the results suggest that spirulina may help reduce physical strain during moderate exercise and improved power output during short, intense sprint efforts.
Weight management
To evaluate the effects of Spirulina platensis on body weight, BMI, serum lipids, and appetite in obese individuals
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To evaluate the effects of Spirulina platensis on body weight, BMI, serum lipids, and appetite in obese individuals
Dose
1 g/day total Spirulina platensis tablets (2 x 500 mg) or placebo
Participants
64 obese adults (29 spirulina, 27 placebo), aged 20–50 years.
Duration
12 weeks
Results
Researchers observed that both the spirulina group and the placebo group lost some body weight and had lower body mass index (BMI), but the reduction was significantly greater in the Spirulina platensis group. Total cholesterol in the blood also decreased significantly in the spirulina group. In addition, people taking spirulina reported a significant reduction in appetite. However, VEGF (a protein involved in blood vessel growth), LDL (“bad”) cholesterol, and triglycerides did not change significantly after the intervention. HDL (“good”) cholesterol increased significantly in both groups, but the size of the increase was similar, meaning spirulina did not produce a greater change than placebo for HDL.
Blood pressure
To assess the effects of Spirulina maxima on body weight, systolic and diastolic blood pressure, and endothelial function (how well blood vessel walls relax and dilate — a key marker of cardiovascular health) in overweight adults with hypertension who had no existing cardiovascular disease.
Study Type
Randomised, double-blind, placebo-controlled parallel trial
Purpose
To assess the effects of Spirulina maxima on body weight, systolic and diastolic blood pressure, and endothelial function (how well blood vessel walls relax and dilate — a key marker of cardiovascular health) in overweight adults with hypertension who had no existing cardiovascular disease.
Dose
2 g/day Hawaiian Spirulina maxima (capsules) or matching placebo
Participants
40 adults with hypertension but without existing cardiovascular disease.
Duration
12 weeks
Results
Patients taking spirulina showed significant improvements compared with the placebo group. Their BMI significantly dropped from 26.9 to 25.0 kg/m², and their weight decreased from 75.5 to 70.5. Systolic blood pressure significantly fell from 149 to 143 mmHg, and arterial stiffness significantly improved from 7.2 to 6.9 m/s. In contrast, the placebo group showed no changes in any of these measures.
Cholesterol
To determine the lipid-lowering effects of Greek-produced Spirulina (Arthrospira platensis) in adults with recently diagnosed dyslipidaemia (abnormally elevated blood fats)
Study Type
Prospective clinical study
Purpose
To determine the lipid-lowering effects of Greek-produced Spirulina (Arthrospira platensis) in adults with recently diagnosed dyslipidaemia (abnormally elevated blood fats)
Dose
1 g/day Spirulina platensis
Participants
52 adult Cretan outpatients (32 men, 20 women),aged 37–61 years, with recently diagnosed dyslipidaemia.
Duration
3 months
Results
Researchers observed that at the end of the 3-month intervention, participants experienced significant improvements in their cholesterol and blood fat levels: triglycerides dropped by 16.3%, LDL (“bad”) cholesterol fell by 10.1%, total cholesterol decreased by 8.9%, non-HDL cholesterol went down by 10.8%, and the ratio of total cholesterol to HDL (“good”) cholesterol improved by 11.5%. On the other hand, HDL cholesterol showed a small, non-significant increase of 3.5%.
To examine the effects of spirulina supplementation on blood glucose, lipids, oxidative stress, and adiponectin (a hormone secreted by fat cells that increases insulin sensitivity and protects against inflammation and atherosclerosis) in Korean patients with type 2 diabetes.
Study Type
Randomised controlled trial
Purpose
To examine the effects of spirulina supplementation on blood glucose, lipids, oxidative stress, and adiponectin (a hormone secreted by fat cells that increases insulin sensitivity and protects against inflammation and atherosclerosis) in Korean patients with type 2 diabetes.
Dose
8 g/day Spirulina platensis or control (no supplementation)
Participants
37 Korean type 2 diabetic patients
Duration
12 weeks
Results
Researchers observed that in the spirulina group, several significant improvements occurred over the 12-week trial: triglycerides (blood fats) dropped from 125.8 to 98.5 mg/dL, a 21.7% reduction; diastolic blood pressure also decreased significantly; plasma malondialdehyde (MDA), a marker of oxidative damage to blood fats, was significantly reduced, while plasma adiponectin, a protective hormone that improves insulin sensitivity and lowers cardiovascular risk, increased significantly. However, there were no significant changes in fasting blood glucose, HbA1c, total cholesterol, LDL, or HDL during this higher-dose spirulina trial.
To investigate the effects of Spirulina maxima on insulin sensitivity (how effectively the body responds to insulin to regulate blood sugar), along with lipid profile (levels of fats in the blood, such as cholesterol and triglycerides) and antioxidant status (the body’s ability to counteract harmful molecules called free radicals), in obese patients with hypertension
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To investigate the effects of Spirulina maxima on insulin sensitivity (how effectively the body responds to insulin to regulate blood sugar), along with lipid profile (levels of fats in the blood, such as cholesterol and triglycerides) and antioxidant status (the body’s ability to counteract harmful molecules called free radicals), in obese patients with hypertension
Dose
2 g/day Spirulina maxima capsules or matching placebo
Participants
50 obese adults with well-treated hypertension (25 spirulina, 25 placebo) on stable antihypertensive medication.
Duration
3 months
Results
Researchers observed a significant improvement in insulin sensitivity, with the M-value (a measure of how effectively the body uses insulin to process glucose) increasing from 3.2 to 4.3 mg/kg/min, representing a 34% improvement. For context, healthy individuals typically have M-values above 6 mg/kg/min, while values below 4 indicate insulin resistance—so this change reflects a meaningful improvement in insulin function. Additional significant findings compared to placebo (all p < 0.001) included: • LDL cholesterol (often called “bad” cholesterol): decreased from 3.5 ± 0.9 to 3.0 ± 0.6 mmol/L (−14%) • Total cholesterol: significantly reduced • Total antioxidant status (the body’s ability to neutralize harmful molecules called free radicals): significantly increased, suggesting that antioxidant effects may help improve insulin sensitivity • BMI, waist circumference, and body weight: all significantly reduced, indicating broader metabolic improvements
Frequently Asked Questions
Common questions about Spirulina Extract research
There are currently 10 peer-reviewed studies on Spirulina Extract (Spirulina Extract), involving 376 total participants. Research covers Blood sugar, Exercise Performance, Weight management and 2 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (10 human studies), and reported outcomes.
Spirulina Extract has been researched for: Blood sugar, Exercise Performance, Weight management, Blood pressure, Cholesterol. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 10 out of 10 studies are human trials. Human trials carry more weight in our evidence scoring system.
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