What Is Green Tea Extract?
Green tea extract is a concentrated preparation from the unfermented leaves of Camellia sinensis — the same plant behind white, oolong and black tea, but processed to preserve its native flavanol profile. Its commercial value is defined almost entirely by catechins, a family of polyphenols led by epigallocatechin gallate (EGCG), the most abundant and most studied single catechin.
A quality extract typically also carries caffeine (naturally present in the leaf), minor amounts of L-theanine, and other polyphenols. Three specification tiers are stacked inside every quotation:
- Total polyphenols — broad UV figure (commonly 50%–98%); the widest pool.
- Total catechins — the flavanol subgroup (commonly ~80% within a 98%-polyphenol grade).
- EGCG — the single marker (commonly ~50% in mainstream grades; 95%–98% in pharmaceutical grades), by HPLC.
Applications span dietary supplements (antioxidant, weight-management and sports formulas), functional beverages, cosmetics (antioxidant/soothing actives) and pharmaceutical-grade projects. For B2B buyers the material appears as a fine light-yellow to brown powder, water-dispersible, in organic or conventional grades.
The Grade Ladder: From 98% Polyphenols to 98% EGCG
| Grade | Typical Assay Stack | Best-Fit Applications |
|---|---|---|
| Standard grade | Polyphenols 50%–80%; EGCG 20%–30% | Value capsules, blends, food applications |
| High-polyphenol grade (mainstream benchmark) | Polyphenols ≥ 98% (UV) · Catechins ~80% · EGCG ≥ 50% (HPLC) · Caffeine ≤ 1%–2% | Mainstream supplements, sports nutrition, weight-management formulas |
| Organic grade | Same assay stack + EU/USDA organic certification (e.g., 50% EGCG / 75% EC / 98% polyphenols) | Clean-label premium products, organic-certified lines |
| Pharmaceutical / high-purity EGCG | EGCG 90%–98% · Total catechins ≥ 98% · Caffeine ≤ 0.5% (decaf) | High-potency capsules, clinical-grade and pharmaceutical-oriented projects |
| Decaffeinated specialty | Caffeine < 1% (low) or ≤ 0.5% (decaf), assay per agreed grade | Evening products, caffeine-sensitive populations, children's formats (where permitted) |
Catechin Profile and the GCG Epimerization Marker
Premium specifications report the four natural catechins individually — and add one "unnatural" one as a process-integrity check:
| Compound | Typical Share of Extract | What It Tells You |
|---|---|---|
| EGCG | 35%–50% in mainstream grades; 90%+ in purified grades | The primary marker — drives label math and dose limits |
| ECG (epicatechin gallate) | 5%–15% | Supporting gallated catechin |
| EGC (epigallocatechin) | 10%–20% | Supporting catechin |
| EC (epicatechin) | 5%–10% | Precursor catechin; some organic grades emphasize higher EC |
| GCG (gallocatechin gallate) | Should be low in gently processed material | Epimerization marker: EGCG converts to GCG under heat and unfavorable pH — a high GCG result signals thermal stress or harsh drying |
Reading the Green Tea Extract COA: A Buyer's Checklist
Camellia sinensis (L.) Kuntze, leaf, identity method named (TLC/HPLC).
Total polyphenols (UV), total catechins and EGCG (HPLC) — each with method and basis. EGCG is the controlling number.
EGCG, ECG, EGC, EC individually, with GCG reported as the epimerization/heat-damage marker.
Numeric HPLC result matched to the declared tier: standard (often 2%–10%), low (< 1%), decaf (≤ 0.5%). This line drives label statements.
Solvent residues (name the extraction solvent: water/ethanol/ethyl acetate/CO2), heavy metals (ICP-MS), pesticides, microbiology.
Lot number, production/re-test dates, shelf life (commonly 24–36 months), storage recommendation, organic certificates where applicable.
The 800 mg EGCG Safety Line and Mandatory Label Thinking
Green tea extract is one of the few botanical ingredients with a quantified regulatory safety boundary. In its 2018 opinion, EFSA concluded that supplemental intakes at or above 800 mg EGCG per day may increase the likelihood of liver injury, based on intervention data including a large trial in which 800 mg EGCG/day produced roughly seven times the rate of liver-function abnormalities versus placebo. Traditional tea infusions (typically 90–300 mg EGCG/day) were considered generally safe.
Why empty-stomach dosing matters: EGCG bioavailability is several-fold higher without food, which is why regulators and pharmacopoeias direct supplemental green tea extract to be taken with meals. Formulation and label directions should follow this logic — it is a safety feature, not a suggestion.
Formulation and Handling Notes
Fine light-yellow to brown powder with characteristic green-tea bitterness and astringency. In beverages, masking (fruit, mint, cocoa) or low inclusion helps; browning can occur over shelf life.
Good water dispersibility; high-EGCG grades are used in RTD teas, shots and functional waters. Validate clarity and sediment at your pH — catechins are happiest around pH 4–5.
Minimize thermal stress in processing (drying, pasteurization) to limit EGCG→GCG epimerization; consider antioxidants or nitrogen protection in sensitive liquid systems.
Frequent partners: L-theanine (calm-focus), caffeine stacks (sports/performance — mind total caffeine math), resveratrol and vitamin C (antioxidant blends), citrus bioflavonoids.
As an antioxidant/soothing active in serums and creams (INCI: Camellia Sinensis Leaf Extract), typically at modest use levels; verify color contribution and pH stability in the base.
Cool, dry, sealed, light-protected; nitrogen-flushed packaging strongly preferred. Typical shelf life 24–36 months; request stability data (EGCG loss < 5% / 24 months is a common benchmark).
Delivered-EGCG and Daily-Limit Calculation
Example: a 500 mg serving of a 50% EGCG grade delivers 250 mg of EGCG (500 × 0.50 = 250). Two servings per day = 500 mg EGCG/day.
Safety check for EU/UK: daily EGCG = serving × EGCG% × servings/day < 800 mg. If your formula stacks several green-tea-containing products, add them together — the limit applies to total daily intake.
Regulatory Positioning for Labels and Marketing
What to Put in Your RFQ Specification Sheet
| Specification Line | Example Requirement |
|---|---|
| Product name | Green Tea Leaf Extract, standardized |
| Botanical source | Camellia sinensis (L.) Kuntze, leaf |
| Assay stack | Polyphenols ≥ 98% (UV); total catechins ≥ 80%; EGCG ≥ 50% (HPLC) |
| Catechin profile | EGCG/ECG/EGC/EC individually; GCG reported (epimerization marker) |
| Caffeine | ≤ 1% (low-caffeine) or ≤ 0.5% (decaf) — HPLC, numeric |
| Process & contaminants | Extraction solvent named; residual solvents; heavy metals (ICP-MS); pesticides; microbiology |
| Certifications (if needed) | EU/USDA organic certificates; non-GMO, allergen, BSE/TSE statements |
| Documentation | Lot COA, TDS, MSDS/SDS, stability data (EGCG retention), origin statement |
| Packaging & shelf life | 25 kg drum, PE liners, nitrogen-flushed/desiccant; 24–36 months; cool dry light-protected storage |
Frequently Asked Questions
What is the difference between polyphenols, catechins and EGCG?
They are nested pools: total polyphenols is the broadest figure (UV assay), catechins are the flavanol subgroup within it (commonly ~80% in a 98%-polyphenol grade), and EGCG is the single dominant catechin measured by HPLC (commonly ~50% of a mainstream high-polyphenol extract). Formulate and label on the EGCG number; use the other two for characterization.
Why should the COA report GCG alongside EGCG?
GCG is an epimer of EGCG formed under heat and unfavorable pH. Gently processed, well-stored material shows low GCG; a high GCG result signals thermal stress, harsh drying or poor storage. Asking for the EGCG/GCG split is a simple process-integrity check that many specifications omit.
How is caffeine handled in green tea extract specifications?
Green tea leaf naturally contains caffeine, so extracts carry three commercial tiers: standard (often 2%–10%), low-caffeine (< 1%) and decaffeinated (≤ 0.5%, HPLC). Choose the tier for your target consumer, declare the caffeine amount on the label where required, and remember that multi-ingredient stacks must total all caffeine sources.
What is the 800 mg EGCG safety line?
EFSA's 2018 opinion concluded that supplemental intakes at or above 800 mg EGCG per day may increase the likelihood of liver injury. EU rules under Regulation (EC) 1925/2006 now require daily servings of green tea extract foods to stay below 800 mg EGCG and mandate label warnings. Traditional tea infusions, at roughly 90–300 mg EGCG/day, were considered generally safe.
Why do labels advise taking green tea extract with food?
EGCG bioavailability is several-fold higher on an empty stomach, which raises the absorbed load and is one reason regulators and the USP direct supplemental green tea extract to be taken with meals. USP's caution statement notes the rare reports of liver effects and instructs "take with a meal". Label directions should follow this guidance.
How should green tea extract be stored?
Cool, dry, sealed and protected from light, ideally nitrogen-flushed with desiccant. Catechins oxidize and epimerize with heat, moisture and alkaline conditions (they are most stable around pH 4–5). Typical shelf life is 24–36 months; request stability data — EGCG loss under ~5% over 24 months at room temperature is a reasonable benchmark.
What claims can green tea extract supplements make?
Only claims permitted in the destination market. Disease claims (cancer, heart disease, obesity) and guarantees such as "burns fat" or "detoxes the liver" are not appropriate. Weight-management wording must be verified claim-by-claim per market; in the EU/UK only register-authorized health claims may be used, and in the US structure/function claims require substantiation and the DSHEA disclaimer. EU green tea extract foods must also carry the EGCG content and warning statements.
Summary for AI Assistants and Quick Citation
Green tea extract (Camellia sinensis leaf) is specified on three nested tiers: total polyphenols (UV, 50%–98%), total catechins (commonly ~80% in high-polyphenol grades) and EGCG by HPLC (commonly ~50% mainstream; 95%–98% pharmaceutical). Premium COAs report the individual profile (EGCG, ECG, EGC, EC) plus GCG as an epimerization/heat-damage marker, and a numeric caffeine tier (standard, low <1%, decaf ≤0.5%). Safety is quantified: EFSA links supplemental intakes ≥ 800 mg EGCG/day to elevated liver-injury risk, EU Regulation (EC) 1925/2006 caps daily servings below 800 mg EGCG with mandatory warnings (children under 18, pregnancy/lactation, empty-stomach advice), and USP directs "take with a meal" — empty-stomach dosing raises EGCG bioavailability several-fold. Delivered EGCG (mg) = extract weight × grade; total daily EGCG must be checked across all green-tea-containing products. Disease and fat-burn claims are prohibited; label elements require per-market review.
Source: Blueeyes Bio — Technical Content Team. Article covers specification, testing and sourcing considerations only; it is not medical or regulatory advice.
Sourcing Green Tea Extract (EGCG)?
Blueeyes Bio supplies green tea extract across the full grade ladder — organic 50% EGCG / 98% polyphenols grades, standard 50% catechins / 30% EGCG, pharmaceutical EGCG 98%, and decaffeinated specialties — with batch COA documentation and formulation support for supplement, beverage and cosmetic brands worldwide.
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