Protein supplies the amino acids your body uses to build new tissue, and wound repair depends on that building work, including the production of collagen [2][3][4]. Healthy adults need at least 0.8 g of protein per kilogram of body weight a day, and clinical nutrition guidance suggests more, often 1.2 to 1.5 g/kg, for older adults who are ill, with targets set by the care team [1][2]. Trials of extra protein and specific nutrients for healing are smaller and less certain than many articles suggest.
Key Takeaways
- Protein provides the amino acids for new tissue; vitamin C is also needed to make collagen, a key part of healing tissue [3][4].
- The RDA for healthy adults is 0.8 g of protein per kg of body weight per day [1].
- ESPEN guidance for older adults: at least 1.0 g/kg, 1.2 to 1.5 g/kg with illness, and up to 2.0 g/kg with severe illness, injury or malnutrition [2].
- A 2024 Cochrane review rated the evidence for nutrition supplements and healing as low to very low certainty [6].
- Food first: an ounce of meat or fish, one egg, a quarter cup of tofu or half a cup of beans each provide about 7 g of protein [3].
- For surgical wounds or pressure injuries, follow your care team, and ask before raising protein if you have kidney problems [10].
Evidence grade: Moderate. Protein's role in tissue building and the adult RDA are well established, and guideline panels recommend nutrition support for malnourished patients with wounds; but trials of extra protein, arginine, zinc or vitamin C are few and small, and a 2024 Cochrane review rated most results low to very low certainty.
How Protein Supports Tissue Repair
When you eat protein, digestion breaks it into amino acids. Your body uses them to build and repair its own proteins, including those in skin and connective tissue. Some amino acids become "conditionally essential" during illness and stress, meaning the body may not make enough of them on its own [3].
Collagen is the main structural protein in connective tissue, and NIH describes it as playing a vital role in wound healing [4]. Making collagen takes both amino acids from protein and vitamin C, which is required for collagen synthesis [4]. Zinc is involved in protein and DNA synthesis, immune function and wound healing [5].
Healing also raises demand. The European Society for Clinical Nutrition and Metabolism (ESPEN) notes that protein requirements may increase with inflammation, infections and wounds, although by how much is hard to measure [2]. When intake falls short, as it often does in frail or sick older adults, the body has fewer resources for repair [2].
How Much Protein? Intake Ranges Used in Guidance
There is no single protein number for every wound. The ranges below come from the U.S. RDA and ESPEN's 2022 guideline for older adults. Clinicians adjust them for body weight, kidney function, appetite and the size of the wound [1][2].
| Situation | Protein per kg body weight per day | Example for a 70 kg (154 lb) adult |
|---|---|---|
| Healthy adult (RDA) [1] | 0.8 g | About 56 g |
| Healthy older adult (expert groups cited by ESPEN) [2] | 1.0 to 1.2 g; at least 1.0 g | About 70 to 84 g |
| Older adult with acute or chronic illness [2] | 1.2 to 1.5 g | About 84 to 105 g |
| Severe illness, injury or malnutrition [2] | Up to 2.0 g | Up to about 140 g |
The older version of this article gave 0.8 g/kg as the target for wound healing. That figure is the minimum for healthy adults, not a healing target [1]. Higher clinical ranges apply to people under medical care, and the right number for you should come from your doctor or a registered dietitian.
What Trials Show About Nutrition and Healing
Most controlled research on nutrition and healing has been done in people with pressure injuries (bedsores), often older adults in hospitals or care homes. The results are more cautious than many online articles suggest.
- Cochrane review, 2024. Thirty-three randomized trials with 7,920 participants were reviewed. Supplements providing energy, protein and micronutrients may slightly increase the number of wounds that heal (about 366 per 1,000 people versus 253 per 1,000 with a standard diet), but this was rated low-certainty evidence. For protein alone, vitamin C, zinc and different doses of arginine, the evidence was very uncertain. One trial of collagen supplements in 74 people probably improved wound size, rated moderate certainty [6].
- ESPEN guideline. ESPEN recommends offering nutrition support to older adults who are malnourished and have pressure injuries, noting that benefits may depend on nutritional status [2].
The takeaway is that getting enough protein and energy matters most for people who are not eating enough. There is little evidence that piling on extra protein speeds healing in people who are already well nourished.
Arginine, Zinc and Vitamin C: An Honest Look
Arginine
Arginine is an amino acid often added to specialized nutrition drinks. In a 2015 trial, 200 malnourished adults with pressure injuries drank 400 mL a day of a high-protein formula enriched with arginine, zinc and antioxidants, or a formula with the same calories and protein but without the extras, for 8 weeks. Wound area shrank by 60.9% with the enriched formula versus 45.2% with the control, but complete healing did not differ [7]. A 2021 meta-analysis of five human arginine studies found higher levels of hydroxyproline, a marker of collagen formation [8]. These are promising signals, but the Cochrane review still rated arginine dosing evidence as very uncertain [6]. Arginine formulas are used under clinical supervision, not as a self-care step.
Zinc
Zinc is needed for normal wound healing, and NIH notes that zinc deficiency in older adults can delay it [5]. That does not mean extra zinc helps people who already get enough; Cochrane rated zinc supplement evidence for healing as very uncertain [6]. Zinc has an upper limit of 40 mg a day for adults [5].
Vitamin C
Vitamin C is required for collagen, and severe deficiency (scurvy) causes poor wound healing [4]. In a 1995 trial of 88 patients with pressure injuries, 500 mg of vitamin C twice a day did not speed healing compared with 10 mg twice a day [9]. Meeting the RDA, 90 mg for men and 75 mg for women, is possible from food; fruits and vegetables are the best sources [4]. See our article on vitamins and minerals essential for post-surgical recovery for more on micronutrients.
Food-First Protein Sources
Animal and plant foods both supply protein. MedlinePlus lists these as roughly equal 7 g portions [3]:
| Food | Amount for about 7 g protein | Notes |
|---|---|---|
| Meat, fish or poultry | 1 oz (30 g) | Skinless poultry, lean cuts, fish or shellfish |
| Egg | 1 large | Easy to prepare when appetite is low |
| Tofu | 1/4 cup (60 mL) | Plant protein |
| Beans or lentils, cooked | 1/2 cup (65 g) | Also provide fiber |
Dairy foods such as milk, yogurt and cheese also provide protein, and whole grains contain more protein than refined grains [3]. By the same measure, a 3 oz portion of fish or chicken provides about 21 g. Spreading protein foods across meals and snacks can make higher targets easier to reach when appetite is poor.
If you are preparing for a planned procedure, our guide to optimizing nutrient intake before surgery covers what to discuss with your team ahead of time.
Follow Your Care Team
Surgical wounds, pressure injuries and slow-healing wounds need medical care. Nutrition supports that care but does not replace it. ESPEN recommends that older adults be screened routinely for malnutrition so problems are caught early [2]. Practical steps:
- Tell your care team if you are eating less than usual or losing weight.
- Ask whether you should see a registered dietitian and what protein target fits you.
- Use nutrition drinks or supplements only when your care team recommends them.
- Keep up fluids; our article on hydration and its role in recovery explains why.
Safety and Interactions
- Kidney problems. People with chronic kidney disease may need to limit protein, so do not raise protein intake without your provider's guidance [10].
- High protein intakes. The Food and Nutrition Board has not set an upper limit for protein, because the risk from food is very low, but it advises caution for people getting high intakes from foods plus supplements [1].
- Zinc. The upper limit is 40 mg a day for adults. Taking 50 mg or more for weeks can reduce copper absorption and immune function; high doses can cause nausea, vomiting and headaches. Zinc can interact with quinolone and tetracycline antibiotics and penicillamine, and thiazide diuretics increase zinc loss. Talk to your doctor or pharmacist if you take these [5].
- Vitamin C. The upper limit is 2,000 mg a day; higher doses can cause diarrhea, nausea and cramps. If you are having chemotherapy or radiation, talk to your oncologist before taking vitamin C or other antioxidant supplements [4].
- Specialized formulas. Arginine-enriched and other medical nutrition drinks were studied under clinical supervision. Use them only if your care team recommends them [6][7].
Frequently Asked Questions
How much protein should I eat for wound healing?
Healthy adults need at least 0.8 g/kg a day [1]. For older adults, ESPEN suggests at least 1.0 g/kg, 1.2 to 1.5 g/kg with illness, and up to 2.0 g/kg with severe illness, injury or malnutrition [2]. Your care team should set your target, especially if you have kidney problems.
What are the best protein sources for wound recovery?
Meat, fish, poultry, eggs, dairy, tofu, beans and lentils all work. One ounce of meat or fish, one egg, a quarter cup of tofu or half a cup of cooked beans each provide about 7 g of protein [3].
When should I eat protein for wound healing?
No good research shows that a particular time of day helps wounds heal faster. Including a protein food at each meal and snack makes it easier to reach your daily target.
Do vitamin C or zinc supplements speed healing?
Both nutrients are needed for normal healing, and deficiency slows it [4][5]. But a trial of high-dose vitamin C found no faster healing, and evidence for zinc supplements is very uncertain [6][9]. Focus on meeting normal needs unless your care team finds a deficiency.
Do I need a protein supplement?
Usually not if you eat well. Supplements and nutrition drinks help most when people cannot eat enough, which is why guidelines target malnourished patients [2][6]. Ask your care team before starting one.
What happens if I do not get enough protein while healing?
Low protein and energy intake is part of malnutrition, which guideline panels treat as a reason to provide nutrition support to people with wounds, especially older adults [2][6].
Sources
- NIH Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Health Professionals. National Institutes of Health.
- Volkert D, Beck AM, Cederholm T, et al. ESPEN practical guideline: Clinical nutrition and hydration in geriatrics. Clinical Nutrition. 2022.
- MedlinePlus Medical Encyclopedia. Protein in diet. U.S. National Library of Medicine.
- NIH Office of Dietary Supplements. Vitamin C: Fact Sheet for Health Professionals. National Institutes of Health.
- NIH Office of Dietary Supplements. Zinc: Fact Sheet for Health Professionals. National Institutes of Health.
- Langer G, Wan CS, Fink A, Schwingshackl L, Schoberer D. Nutritional interventions for preventing and treating pressure ulcers. Cochrane Database Syst Rev. 2024.
- Cereda E, Klersy C, Serioli M, Crespi A, D'Andrea F; OligoElement Sore Trial Study Group. A nutritional formula enriched with arginine, zinc, and antioxidants for the healing of pressure ulcers: a randomized trial. Ann Intern Med. 2015.
- Arribas-López E, Zand N, Ojo O, Snowden MJ, Kochhar T. The Effect of Amino Acids on Wound Healing: A Systematic Review and Meta-Analysis on Arginine and Glutamine. Nutrients. 2021.
- ter Riet G, Kessels AG, Knipschild PG. Randomized clinical trial of ascorbic acid in the treatment of pressure ulcers. J Clin Epidemiol. 1995.
- MedlinePlus Medical Encyclopedia. Diet - chronic kidney disease. U.S. National Library of Medicine.
Disclosure: OPA Nutrition sells supplements, including products mentioned in this article. This content is for education only and is not medical advice. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your healthcare provider before using any supplement, especially if you take medication or have a medical condition.
Written and reviewed by Michael Gonzales, Founder, OPA Nutrition · Last reviewed: · How OPA researches and writes
