Ornithine alpha-ketoglutarate
A salt of 2 ornithine molecules with 1 α-ketoglutarate, originally developed as a clinical-nutrition compound for hospitalized catabolic patients (burns, trauma, sepsis, elderly malnutrition). Provides building blocks for arginine, glutamine, proline, and polyamines that drive wound healing and protein anabolism. Strongest evidence is from burn-unit RCTs (De Bandt 1998, Coudray-Lucas 2000) showing faster wound closure and improved nitrogen balance. Consumer 'sports performance' claims rest on mechanism, not direct outcomes.
Quick decision guide
May help most
Hospitalized patients with severe burns or trauma (under clinical supervision); elderly patients with malnutrition or pressure ulcers. Not a typical consumer supplement.
Common dosing range
Clinical: 10–30 g/day enteral. Consumer (off-label): 2–5 g/day pre-workout for purported anabolic effect (low-quality evidence).
When to expect effects
Weeks for wound-healing effects in clinical settings; rapid (hours) for amino-acid availability.
Watch out for
Primarily a clinical-nutrition compound. GI upset (cramping, diarrhea) common above 10 g/day. Avoid in renal or hepatic impairment without clinical supervision.
Evidence snapshot
What is it
Ornithine alpha-ketoglutarate (OKG, ornithine oxoglutarate) is a salt formed from two molecules of the non-proteinogenic amino acid L-ornithine and one molecule of alpha-ketoglutarate (a Krebs-cycle intermediate). After ingestion it dissociates into its component parts, which feed converging biochemical pathways: ornithine enters the urea cycle and can be converted to glutamate, polyamines, proline, and arginine, while alpha-ketoglutarate serves as a substrate for the tricarboxylic acid cycle, amino acid transamination, and collagen-related prolyl hydroxylase reactions. Together, these substrates are thought to support anti-catabolic, anabolic, and ammonia-buffering effects, the rationale for OKG's historical use in clinical nutrition for burn injury, surgical recovery, and undernourished elderly patients.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
Severe burn injury — wound healing & nitrogen balance Good Evidence | Wound healing time 60 vs 90 days (Coudray-Lucas); improved nitrogen balance and reduced muscle catabolism markers | Hospitalized severe burn patients receiving enteral nutrition | Weeks (significant wound-healing differences emerge by 3–4 weeks) |
Elderly malnutrition / pressure ulcer healing Good Evidence | Significantly accelerated pressure ulcer surface area reduction in elderly at 10 g/day for 6 weeks | Elderly hospitalized or institutionalized patients with malnutrition, pressure ulcers, or post-acute recovery | 4–6 weeks |
Hepatic encephalopathy / ammonia metabolism Limited Evidence | Reduces blood ammonia mechanistically (closely related to LOLA, which has HE trial data) | None established for OKG specifically in HE (LOLA is the studied form) | Not established for OKG in HE |
Athletic performance / muscle gain Mixed Evidence | No reliable improvement in performance or lean mass in well-controlled trials in healthy adults | None established for healthy athletes | Not established |
Severe burn injury — wound healing & nitrogen balance
- Effect
- Wound healing time 60 vs 90 days (Coudray-Lucas); improved nitrogen balance and reduced muscle catabolism markers
- Best fit
- Hospitalized severe burn patients receiving enteral nutrition
- Time
- Weeks (significant wound-healing differences emerge by 3–4 weeks)
Elderly malnutrition / pressure ulcer healing
- Effect
- Significantly accelerated pressure ulcer surface area reduction in elderly at 10 g/day for 6 weeks
- Best fit
- Elderly hospitalized or institutionalized patients with malnutrition, pressure ulcers, or post-acute recovery
- Time
- 4–6 weeks
Hepatic encephalopathy / ammonia metabolism
- Effect
- Reduces blood ammonia mechanistically (closely related to LOLA, which has HE trial data)
- Best fit
- None established for OKG specifically in HE (LOLA is the studied form)
- Time
- Not established for OKG in HE
Athletic performance / muscle gain
- Effect
- No reliable improvement in performance or lean mass in well-controlled trials in healthy adults
- Best fit
- None established for healthy athletes
- Time
- Not established
Evidence for 4 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Severe burn injury — wound healing & nitrogen balance
Disease adjunctOKG has direct RCT evidence in burn-unit settings. De Bandt 1998 in 54 patients with 20–50% total burn surface area showed OKG (10–30 g/day enteral) improved nitrogen balance and reduced 3-methylhistidine and hydroxyproline urinary elimination (markers of protein catabolism). Bolus administration significantly accelerated wound healing (last graft at day 23.7 vs 39.9 in controls). Coudray-Lucas 2000 reported wound healing time of 60 ± 7 days with OKG vs 90 ± 12 days with isonitrogenous control. Mechanism: ornithine is a direct precursor of arginine, proline, and polyamines (all required for collagen deposition and cell proliferation); α-ketoglutarate is a glutamine precursor and nitrogen scavenger.
Bottom line: Direct RCT evidence in hospital burn units. Not a consumer indication — used under clinical supervision.
Elderly malnutrition / pressure ulcer healing
Disease adjunctThe Meaume 2009 RCT (n=200) in elderly patients with heel pressure ulcers compared OKG 10 g/day for 6 weeks against placebo, and reported significantly faster wound surface area reduction with good tolerability. Earlier Brocker 1994 work in 194 convalescent elderly showed OKG-supplemented patients had improved functional status and appetite vs controls. Ornithine precursor of arginine and proline is biologically logical for collagen-dependent wound healing.
Bottom line: Reasonable adjunct in clinical-nutrition protocols for malnourished or wound-healing elderly patients.
Hepatic encephalopathy / ammonia metabolism
Mechanism onlyL-ornithine L-aspartate (LOLA, a different ornithine salt) has clinical use in hepatic encephalopathy, lowering ammonia via stimulation of urea-cycle enzymes and glutamine synthesis. OKG shares some mechanism but is not the form used in hepatic encephalopathy trials. Mechanism is plausible; direct OKG outcome evidence in HE is limited.
Bottom line: Related compound (LOLA) is studied in HE; OKG itself isn't the standard. Use evidence-based therapy.
Athletic performance / muscle gain
Mechanism onlyMarketed for sports performance based on the theory that OKG enhances growth-hormone release and anabolism. Early small studies suggested OKG might raise insulin and growth hormone, but larger and better-controlled trials in healthy athletes have not consistently shown improvements in strength, lean mass, or power output beyond what creatine, protein adequacy, and resistance training already deliver. Mechanism-based, not outcome-validated, for performance use.
Bottom line: Mostly mechanism-only marketing. Healthy adults should prioritize creatine and protein adequacy first.
How to take it
What to track
Bottom line: Use under clinical supervision for the supported indications (burns, malnutrition, pressure ulcers). Not a high-value consumer supplement.
4 commercial forms
Compare the main delivery options and what they’re best suited for.
Ornithine alpha-ketoglutarate (OKG)
Clinical compoundSalt of 2 ornithine molecules with 1 α-ketoglutarate. The form used in burn-unit RCTs (De Bandt, Coudray-Lucas) and elderly malnutrition trials (Meaume). Available as Cetornan in some clinical-nutrition markets.
Standard clinical-nutrition compound; orally bioavailable as separate amino acids after absorption.
L-ornithine HCl
Plain ornithineJust the ornithine portion. Marketed for 'GH release' and sleep aid. Less direct clinical evidence than OKG; modest effect on plasma ornithine and arginine.
Well-absorbed; doesn't provide the α-KG nitrogen-scavenging effect.
L-ornithine L-aspartate (LOLA)
Used in liver diseaseDifferent ornithine salt with α-amino acid aspartate instead of α-KG. Has clinical use for hepatic encephalopathy under medical care. Different mechanism focus than OKG.
Available as prescription in some countries; oral/IV.
Alpha-ketoglutaric acid (AKG)
Just α-KGJust the α-ketoglutarate side. Used for purported longevity/aging research (e.g., calcium-AKG products). Different from OKG.
Calcium salt commonly used; rapid absorption.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
Renal impairment patients — accumulation of ornithine and ammonia metabolites possible; clinical oversight required.
Hepatic insufficiency — urea cycle load may worsen encephalopathy in advanced liver disease.
Who should avoid it
- People with chronic kidney disease (urea cycle load).
- People with advanced liver disease unless using related compound LOLA under specialist care.
- Pregnant or breastfeeding women — safety data inadequate for clinical-nutrition compounds.
- Children — not studied for routine supplementation.
Pregnancy & breastfeeding
OKG safety in pregnancy is not established. As a clinical-nutrition compound it would only be used in pregnancy under specialist supervision (e.g., a severely burned pregnant patient in ICU). Routine consumer use in pregnancy is not appropriate.
Bottom line: Primarily a clinical-nutrition compound. GI side effects are dose-dependent. Renal or hepatic impairment requires clinical oversight.
Interactions
OKG metabolism loads the urea cycle and may affect renal handling of other compounds. No specific established drug interactions but caution in renal impairment.
Both lower ammonia by different mechanisms. Use of OKG alongside without specialist guidance is not standard.
OKG marketed (off-label) for GH-promoting effect; theoretical additive effects if combined with prescribed GH or insulin. No reliable clinical interactions documented.
Food sources
| Food | Amount | %DV |
|---|---|---|
| Ornithine alpha-ketoglutarate | Pharmaceutical/supplement only | — |
Ornithine alpha-ketoglutarate
- Amount
- Pharmaceutical/supplement only
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
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References by claim
Severe burn injury — wound healing & nitrogen balance
Elderly malnutrition / pressure ulcer healing
Meaume et al., 2009 — J Nutr Health Aging — OKG in heel pressure ulcers in elderly (2009) link
Athletic performance / muscle gain
Cynober, 1991 — Nutrition — OKG in nutritional support review (1991) link
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Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.