EGCG Safe Dosage for Dogs & Cats | Pet Food Guide
The 40 mg EGCG/kg body weight/day canine NOAEL, converted into per-kilogram inclusion rates for 50%
Green Tea Extract in Pet Food: EGCG Inclusion Rates Derived From Peer-Reviewed NOAEL Data
A formulator's conversion from the 40 mg EGCG/kg BW/day canine NOAEL to per-kg inclusion rates for 50%, 60% and 98% grades — and why cats have no established ceiling.
Quick answer
The conservative canine ceiling used in the peer-reviewed literature is 40 mg EGCG per kg body weight per day — the NOAEL from fasted Beagle dogs, adopted by EFSA (2018) and by Beynen (2020). For a 20 kg dog that is 800 mg EGCG/day, equal to 2,417 mg EGCG per kg of complete dry food, or 4.0 g of a 60% EGCG extract per kg of dry food.
The number is ten times lower than the fed-state NOAELs (300–500 mg/kg BW/day) because it came from fasted dogs dosed by capsule as a bolus. Products delivered as a bolus between meals — treats, chews, capsules, pastes — should be designed against the fasted figure. Complete foods eaten in divided meals are the fed scenario.
For cats, no safe ceiling has been established. Beynen (2020) states there is no available information on maximum safe intake or metabolic handling of EGCG in cats. The only published feline datum is 142 mg EGCG per kg diet over 45 days, which is 17 times lower than the canine dietary equivalent. A working cap of ≤140 mg EGCG per kg complete dry food is recommended pending better data.
On this page
- Why every "safe dose" you can find online disagrees with the next one
- What the four canine studies actually reported
- The tenfold gap is about delivery format, not about the ingredient
- Conversion tables: from NOAEL to inclusion rate
- Cats: the honest answer is that no safe ceiling exists
- Where caffeine actually matters — and where it does not
- What to put on the purchase order
- Frequently asked questions
- Limitations
- References
1. Why every "safe dose" you can find online disagrees with the next one
Pet food formulators researching green tea extract usually assemble three answers from three sources, and the three do not reconcile:
- "Around 0.4% of dry food is fine." This traces back to Beynen's conservative reading of the canine data — roughly 4 g of a 60% EGCG extract per kg of dry food.1
- "Up to 500 mg EGCG per kg body weight per day showed no effect." Also true, also published — but it is the fed-state NOAEL from a study in which that dose was the highest tested.2,3 It is 12.5 times the first number.
- "Green tea extract is toxic to dogs and should be kept out of pet food." Also traceable to the literature: in the fasted arm of one study, 200 mg of extract per kg body weight per day was toxic and the trial was halted early because of mortality.1,4
All three claims come from the same four subchronic oral toxicity studies in Beagle dogs. They disagree because each takes a different point of departure: a different NOAEL, from a different feeding state, with a different safety philosophy. The ingredient did not change. The experimental conditions did.
This article resolves the discrepancy by showing which figure applies to which product format, and then converts the applicable figure into inclusion rates you can put straight into a formula sheet.
2. What the four canine studies actually reported
Beynen's 2020 review of green tea extract in petfood collates four (sub)chronic oral toxicity studies in Beagle dogs receiving purified green tea preparations at levels corresponding to 0–650 mg EGCG per kg body weight per day.1 EFSA's 2018 opinion on the safety of green tea catechins reaches the same conclusions from the primary studies.4
| Feeding state | Test material | NOAEL (as reported) | NOAEL as EGCG | Source |
|---|---|---|---|---|
| Fed | Green tea extract | 300 mg/kg BW/day | 300 mg EGCG/kg BW/day | Johnson et al.2; via Beynen1, EFSA4 |
| Fed | Highly purified extract | 500 mg/kg BW/day (highest dose tested) | ≈459 mg EGCG/kg BW/day | Isbrucker et al.3; via EFSA4, Health Canada5 |
| Fasted | Green tea extract | No NOAEL achieved; 200 mg/kg BW/day toxic | — | Isbrucker et al.3; via Beynen1 |
| Fasted | Re-crystallised EGCG (80% purity) | 50 mg/kg BW/day | 40 mg EGCG/kg BW/day | Johnson et al.2; via Beynen1, EFSA4 |
Three details from these studies are more important than the headline numbers:
- The fasting protocol was extreme. Dosing occurred after a minimum of 15 hours of fasting and 3–4 hours before feeding. This is not a realistic model of a dog eating kibble, but it is a very good model of a dog eating a treat or a supplement capsule between meals.
- The group sizes were tiny and the variation was enormous. Each treatment had 8 dogs (four males, four females). Beynen notes "extreme variation in toxic response within the treatment groups," which is why he recommends accepting the lowest NOAEL of 40 mg/kg BW/day as the lower toxicity threshold.1
- The toxicity was serious, not marginal. Chronic toxicity involved lethal liver, gastrointestinal and renal abnormalities.1
The mechanism is not settled — and that matters for how you use the number. EFSA reports that systemic exposure at the fasted NOAEL was in fact lower than at the fed NOAEL: AUC values of 9.2 and 12.1 µg·h/mL in fasted female and male dogs, versus 39.9 and 88.3 µg·h/mL in fed dogs.4 In other words, higher plasma exposure does not explain the fasted toxicity. The alternative hypothesis — that fasting renders target organs more vulnerable — is unresolved, and both hypotheses are weakened by the high within-group variation. When the mechanism is unknown and the sample size is eight, you do not optimise against the highest NOAEL.
3. The tenfold gap is about delivery format, not about the ingredient
The practical consequence is that green tea extract has two different safety ceilings depending on how the product is eaten:
| Product format | Realistic exposure pattern | Design against |
|---|---|---|
| Complete dry or wet food | Dose divided across meals, always ingested with a food matrix | Fed-state scenario; conservative ceiling 40 mg/kg BW/day still recommended (see Table 5) |
| Treats, chews, dental sticks | Bolus, frequently given between meals on a relatively empty stomach | Fasted NOAEL: 40 mg EGCG/kg BW/day |
| Capsules, tablets, pastes, oral gels (supplements) | Single bolus, commonly dosed before or well away from a meal | Fasted NOAEL: 40 mg EGCG/kg BW/day |
| Topical / oral-care rinses | Low systemic exposure, but swallowing must be assumed | Model worst-case ingestion against the fasted ceiling |
Two further operating rules follow directly from this:
- Rule 1 — cap the daily total, not the individual product. If a dog eats both a green-tea-containing complete food and a green-tea-containing treat, the sum of EGCG from both must stay within the conservative ceiling
