Inclusion Criteria:

1. Provision of signed and dated informed consent form. 2. Stated willingness to comply with all study procedures and availability for the duration of the study. 3. Male or female, aged 40-85 years old. 4. Participant has IPF satisfying the 2022 ATS diagnostic criteria, confirmed by enrolling investigator at Visit 1. 5. Participant must have been on a stable dose of nintedanib twice daily or pirfenidone three times daily dose for at least 12 weeks prior to baseline (Visit 2). 6. Participant has a FVC ≥ 50% predicted using the global lung function initiative (GLI). 7. Participant has a DLCO corrected for hemoglobin ≥ 35% predicted using the GLI. 8. Women of child bearing potential (WCBP), defined as a sexually mature woman not surgically sterilized or not post-menopausal for at least 24 consecutive months if < 55 years or 12 months if > 55 years, must have a negative serum pregnancy test within 1 week prior to the first dose of study drug and must agree to use adequate methods of birth control throughout the study. Adequate methods of contraception include use of oral contraceptives or Depo-Provera, with an additional barrier method (diaphragm with spermicidal gel or condoms with spermicide), double-barrier methods (diaphragm with spermicidal gel and condoms with spermicide), partner vasectomy, and total abstinence. 9. Participant has a life expectancy of at least 9 months at Visit 1. 10. Ability to take oral medication and be willing to adhere to EGCG regimen. 11. Agreement to refrain from drinking green tea in excess of a cup a day or eating green tea extract for 4 weeks before baseline and during the trial.

Exclusion Criteria:

1. AST, ALT, or direct bilirubin above upper limit normal from any cause at the Screening Visit. 2. Any history of HCV or HBV infection, NASH/NAFLD, or cirrhosis. 3. Alcohol consumption greater than 7 drinks per week. 4. Participant has emphysema ≥ 50% or the extent of emphysema is greater than the extent of fibrosis as per interpretation of Site Investigator or radiologist. 5. Participant has received investigational therapy for IPF within 4 weeks before baseline (Visit 2). 6. Participant is receiving systemic corticosteroids equivalent to prednisone > 10 mg/day or equivalent within 2 weeks of baseline visit (Visit 2). 7. Participant has any concurrent condition other than IPF that, in the Investigator's opinion, is unstable and/or would impact the likelihood of survival for the study duration or the participant's ability to complete the study as designed, or may influence any of the safety or efficacy assessments included in the study. 8. Participant has baseline resting oxygen saturation of < 89% on room air or need for continuous oxygen use at baseline visit (Visit 2). 9. Consumption of GTE products in excess of a cup of green tea a day within one month of the baseline visit (Visit 2). 10. Participant is receiving digoxin at the time of screening (Visit 1) and for the duration of the study. 11. Active respiratory infection requiring treatment with antibiotics within 4 weeks of the baseline visit (Visit 2).

This is a multi-center, double-blind, placebo-controlled, dose-ranging Phase I study of once daily EGCG administered for 12 weeks. The study will assess safety, pharmacokinetics, and biomarker measurements of drug effect in IPF patients already receiving background therapy for IPF with either nintedanib or pirfenidone. Two different doses of EGCG will be studied. The rationale for this study is 1) extensive pre-clinical data in mice that EGCG is efficacious in attenuating pulmonary fibrosis by blocking collagen cross-linking and the pro-fibrotic pathway mediated by TGFβ1 signaling and 2) recently published data demonstrating that in humans EGCG is safe and capable of blocking lung tissue pro-fibrotic signaling when given two weeks prior to diagnostic surgical biopsy of pulmonary fibrosis patients, many of whom were subsequently diagnosed with IPF.

Arms

Active Comparator: EGCG 300 mg with Nintedanib

Patients enrolled in this group will be given oral capsule EGCG 300 mg daily with doctor provided Nintedanib for 12 weeks.

Active Comparator: EGCG 300 mg with Pirfenidone

Patients enrolled in this group will be given oral capsule EGCG 300 mg daily with doctor provided Pirfenidone for 12 weeks.

Placebo Comparator: Placebo for EGCG 300 mg

Patients enrolled in this group will be given oral capsule Placebo daily for 12 weeks with doctor provided Nintedanib or Pirfenidone. The number of placebo capsules will be equal to that of 300 mg EGCG.

Active Comparator: EGCG 600 mg with Nintedanib

Patients enrolled in this group will be given oral capsule EGCG 600 mg daily with doctor provided Nintedanib for 12 weeks.

Active Comparator: EGCG 600 mg with Pirfenidone

Patients enrolled in this group will be given oral capsule EGCG 300 mg daily with doctor provided Pirfenidone for 12 weeks.

Placebo Comparator: Placebo for EGCG 600 mg

Patients enrolled in this group will be given oral capsule Placebo daily for 12 weeks with doctor provided Nintedanib or Pirfenidone. The number of placebo capsules will be equal to that of 600 mg EGCG.

Interventions

Combination Product: - EGCG 300 mg + Nintedanib

Dietary Supplement: EGCG Capsules with Teavigo EGCG (at least 94% purity). 300 mg EGCG (2 capsules) taken orally daily for 12 weeks. Drug: Nintedanib

Combination Product: - EGCG 300 mg + Pirfenidone

Dietary Supplement: EGCG Capsules with Teavigo EGCG (at least 94% purity). 300 mg EGCG (2 capsules) taken orally daily for 12 weeks. Drug: Pirfenidone

Combination Product: - Placebo 2 capsules + Nintedanib or Pirfenidone

Dietary Supplement: Placebo Placebo (2 capsules) taken orally daily for 12 weeks. Drug: Nintedanib Drug: Pirfenidone

Combination Product: - EGCG 600 mg + Nintedanib

Dietary Supplement: EGCG Capsules with Teavigo EGCG (at least 94% purity). 600 mg EGCG (2 capsules) taken orally daily for 12 weeks. Drug: Nintedanib

Combination Product: - EGCG 600 mg + Pirfenidone

Dietary Supplement: EGCG Capsules with Teavigo EGCG (at least 94% purity). 600 mg EGCG (2 capsules) taken orally daily for 12 weeks. Drug: Pirfenidone

Combination Product: - Placebo 4 capsules + Nintedanib or Pirfenidone

Dietary Supplement: Placebo Placebo (4 capsules) taken orally daily for 12 weeks. Drug: Nintedanib Drug: Pirfenidone