Thylakoids (spinach extract)
Summary
Thylakoids are spinach-leaf membranes that slow fat digestion. In a 12-week trial of 38 overweight women, 5 g/day led to 5.0 kg weight loss versus 3.5 kg on placebo, and a PCOS trial reported more weight and fat loss with dieting. A 2025 meta-analysis of 5 studies found modestly less hunger and more fullness. Most early trials came from the Swedish group that developed the extract.
Key facts
- 38 women aged 40–65: 5 g/day before breakfast for 12 weeks gave 5.0 kg versus 3.5 kg weight loss on placebo[2]
- 48 women with obesity and PCOS on a calorie-restricted diet: 5 g/day for 12 weeks gave 6.97 kg versus 3.19 kg weight loss[3]
- 5 studies: thylakoids with meals reduced hunger by about 2.4 mm and raised fullness by about 4.6 mm on a 100 mm scale[1]
- A single 5 g dose reduced hunger over 2 hours but did not lower food eaten at dinner in 60 adults[6]
- The Swedish trials come from the group of the extract's co-inventor, and the US satiety trial was funded by Appethyl maker Greenleaf Medical[2][6]
- 4 graded human outcomes on this page
- October 13, 2026
How it works
ProposedThylakoids bind to fat droplets and slow fat digestion by lipase, which delays fat absorption and raises satiety hormones such as CCK and GLP-1. Trials measured higher GLP-1 and CCK after thylakoid meals.[6][2][5]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Appetite | Grade D | Mixed | Crossover RCT · n = 60 · 2015 | 2 rows |
| Weight | Grade D | Improved | RCT · n = 48 · 2020 | 2 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Hunger, cravings and dinner intake after a single dose | Mixed | Grade D | Crossover RCT · n = 60 · 2015 Adults with overweight or obesity (USA) Form: Concentrated spinach thylakoid extract · Dose: 5 g single dose with lunch · Duration: Single day Hunger and longing for food over 2 hours fell versus placebo, and post-meal glucose rose; energy intake at an ad libitum dinner and blood lipids did not differ. | 26029978 (opens PubMed)Source [6] |
| Weight, waist, fat mass and insulin in women with obesity and PCOS | Improved | Grade D | RCT · n = 48 · 2020 Women with obesity and polycystic ovary syndrome on calorie-restricted diets (Iran) Form: Spinach-derived thylakoids · Dose: 5 g/day · Duration: 12 weeks Versus placebo, weight (−6.97 vs −3.19 kg), waist (−7.78 vs −3.73 cm), fat mass and insulin fell more; insulin resistance and testosterone also fell. | 32782010 (opens PubMed)Source [3] |
| Body weight, cholesterol and cravings in overweight women | Improved | Grade D | RCT · n = 38 · 2014 Women aged 40–65 with BMI 25–33 (Sweden) Form: Spinach thylakoid extract (green-plant membranes) · Dose: 5 g/day before breakfast · Duration: 12 weeks Weight loss was 5.0 kg versus 3.5 kg on placebo (p < 0.01); total and LDL cholesterol fell more, and GLP-1 rose and urges for sweets fell after test meals. Waist, body fat and leptin did not differ between groups. | 24993695 (opens PubMed)Source [2] |
| Hunger, CCK and post-meal glucose after a high-carbohydrate breakfast | Improved | Grade D | Crossover RCT · n = 20 · 2013 Moderately overweight women (Sweden) Form: Thylakoids added to breakfast · Dose: Added to test meals (amount not stated in the abstract) · Duration: Single meals Hunger motivation fell, CCK rose from 180 minutes and post-meal hypoglycaemia was prevented from 90 minutes. | 23632035 (opens PubMed)Source [4] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Spinach thylakoid extract powder (e.g. Appethyl) | Varies[6][5] | Acts in the gut by slowing fat digestion; it is not designed to be absorbed.[6][5] | Given daily for 12 weeks in two trials without reported safety problems in the abstracts.[2][3] | Weight and appetite trials (5 g per dose) |
Studied doses
Doses studied in human trials ranged from 5 g/day before breakfast or with meals (12 weeks) to 7.4 g/day in trials pooled by a 2025 appetite meta-analysis.[2][3][1]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines
- Fat-soluble medicines and vitamins (theoretical)RCTThylakoids work by retarding fat digestion, so they could in theory delay absorption of fat-soluble compounds taken at the same meal. This has not been studied.[6]
- Diabetes medicinesRCTThylakoids changed post-meal glucose in short trials (raising it in one and preventing a late dip in another) and lowered insulin over 12 weeks in PCOS; effects alongside diabetes drugs are unstudied.[6][4][3]
Who should be careful
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
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Cost per studied dose
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Frequently asked questions
What are thylakoids?
The membranes inside plant chloroplasts where photosynthesis happens; supplements extract them from spinach.[5][6]
Do thylakoids help weight loss?
Two 12-week trials found more weight loss than placebo (1.5 kg extra in one, about 3.8 kg extra with dieting in women with PCOS). Larger independent trials are lacking.[2][3]
Sources
- [1]Thylakoid supplementation and hunger and fullness perception: a systematic review and dose-response meta-analysis of randomized controlled trials.. Nutr Rev, 2025. meta-analysis
- [2]Body weight loss, reduced urge for palatable food and increased release of GLP-1 through daily supplementation with green-plant membranes for three months in overweight women.. Appetite, 2014. RCT
- [3]The effects of spinach-derived thylakoid supplementation in combination with calorie restriction on anthropometric parameters and metabolic profiles in obese women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled clinical trial.. Nutr J, 2020. RCT
- [4]Supplementation by thylakoids to a high carbohydrate meal decreases feelings of hunger, elevates CCK levels and prevents postprandial hypoglycaemia in overweight women.. Appetite, 2013. crossover-RCT
- [5]Consumption of thylakoid-rich spinach extract reduces hunger, increases satiety and reduces cravings for palatable food in overweight women.. Appetite, 2015. RCT
- [6]Acute Effects of a Spinach Extract Rich in Thylakoids on Satiety: A Randomized Controlled Crossover Trial.. J Am Coll Nutr, 2015. crossover-RCT
What changed
- Independent adversarial review: maker funding disclosed: the 60-person satiety trial was funded by Greenleaf Medical (Appethyl) with a Greenleaf employee and the patent co-inventor as co-authors; Swedish weight trial now notes the senior author's patent and adviser role.
- Second-pass self-review: every PMID re-checked against NCBI esummary (title, year, no retraction or expression-of-concern flag), every dose, n and duration re-read against the PubMed abstract or PMC full text, grades held conservative, and interactions limited to what a cited source supports.
- First draft. Source titles and years taken from NCBI E-utilities esummary; abstracts read for every evidence row.