The goal of this clinical trial is to assess whether Amino Acid (15) Peritoneal Dialysis Solution can improve the nutritional status of adults with end-stage kidney disease who have received peritoneal dialysis for 6 months or longer. It will also observe the solution's effects on dialysis adequacy and peritoneal transport function, as well as monitor its short-term safety. The main questions it aims to answer are:

1. Can Amino Acid (15) Peritoneal Dialysis Solution raise the level of serum albumin (a key indicator of nutritional status) in participants?
2. How does this solution affect participants' dialysis adequacy and peritoneal transport function?
3. What adverse reactions might participants experience when using this solution? This is a single-arm study with a self-controlled design. Researchers will compare participants' health indicators before and after the intervention to evaluate the solution's effectiveness and safety.

Participants will:

1. Continue their original peritoneal dialysis routine, replacing one bag of dialysis solution with Amino Acid (15) Peritoneal Dialysis Solution (2L per bag) after lunch every day for 6 months.
2. Undergo comprehensive health checks (including blood tests, nutritional status assessments, and peritoneal function evaluations) on the enrollment day (baseline), as well as at 3 and 6 months after the intervention.
3. Attend follow-up visits every 2 weeks to record dialysis-related data (such as ultrafiltration volume) and any uncomfortable symptoms or adverse reactions.
4. Maintain stable doses of medications affecting protein metabolism and nutritional supplements throughout the study; report to researchers immediately if any dose

Inclusion Criteria:

1. Aged 18 years or older.
2. Have received peritoneal dialysis for 6 months or longer.
3. Serum albumin level < 38 g/L.
4. No history of peritonitis in the past 3 months and no hospitalization in the past 1 month.
5. No severe heart, liver, kidney diseases, or malignant tumors.
6. Expected survival time > 1 year.
7. Good compliance and willingness to sign the informed consent form.
8. Diagnosed with end-stage renal disease (ESRD) with an estimated glomerular filtration rate (eGFR) < 15 mL/(min·1.73 m²).

Exclusion Criteria:

1. Hypersensitivity or allergy to Amino Acid (15) Peritoneal Dialysis Solution or any of its components.
2. Hepatic dysfunction (ALT/AST ≥ 2 times the upper limit of normal).
3. Taking medications that affect protein metabolism and unable to maintain a stable dose during the study period.
4. Need for adjustment of nutritional supplement doses during the study.
5. Uncorrectable severe gastrointestinal reactions.
6. Pregnant, lactating, or planning to undergo kidney transplantation.