Lactate

What it is

Lactate as a medicine means the lactate anion given as its sodium salt, sodium lactate. It is almost never given alone: in practice it arrives as one component of lactated Ringer's Injection (Hartmann's solution, compound sodium lactate), a sterile crystalloid that per litre supplies sodium 130 mEq, potassium 4 mEq, calcium 2.7 mEq, chloride 109 mEq and lactate 28 mEq, with an osmolarity of 273 mOsmol/L and a pH around 6.5. A much more concentrated form, half-molar or hypertonic sodium lactate at 500 mmol/L or more, is used in research and in some intensive care units as an osmotic and metabolic therapy. We scoped this entry to those two drug products and excluded lactate as a laboratory measurement, as a food additive, and lactylate or lactic-acid cosmetics.

What the research says

The lactate in these fluids does two separate jobs: it is an alkalinising agent, because the body converts it to bicarbonate, and it is a way of giving a balanced salt solution whose chloride load is closer to plasma than saline's. For the big question, whether balanced fluid beats saline in critically ill adults, the trials disagree. The 15,802-patient SMART trial found a small advantage, SALT-ED found none on its primary outcome, and BaSICS and PLUS found no mortality difference; an individual-patient meta-analysis of 34,685 people put the absolute mortality difference at 0.4 percentage points, and found the opposite in traumatic brain injury, where balanced fluid was associated with 3.2 percentage points more in-hospital deaths. In acute pancreatitis a small meta-analysis favoured lactated Ringer's over saline on low-quality evidence. Hypertonic sodium lactate lowers intracranial pressure about as well as mannitol or hypertonic saline, but whether it improves recovery is unknown. The documented harms are electrolyte and acid-base: hyperkalaemia, hyponatraemia, hypercalcaemia, metabolic alkalosis, worsening acidosis in severe liver failure, and a lethal incompatibility with ceftriaxone in newborns.

Evidence grade: Disputed.

How it works

Drug class: Alkalinising agent and electrolyte-replenishing crystalloid; the lactate anion is a bicarbonate precursor and an oxidisable metabolic fuel

Infused lactate is not acid. The lactate ion is taken up and converted via pyruvate, and the hydrogen ion consumed in the process leaves behind bicarbonate, which is why a lactate-containing fluid raises rather than lowers blood pH. The sodium that comes with it stays in the extracellular fluid and holds water there, which is the volume-expanding part. Brain and heart can also burn lactate as fuel instead of glucose, which is the rationale behind the concentrated (hypertonic) sodium lactate infusions being studied in brain injury and heart failure. (Source 1)

What it is used for

• This is the licensed indication and it rests on physiology rather than outcome trials: the lactate is converted to bicarbonate, which raises blood pH, and the sodium holds the infused water in the extracellular space. No outcome trial tests the indication as written. Evidence: established. (Source 2)
• Four large trials disagree. SMART found about one percentage point fewer major adverse kidney events, SALT-ED found no difference in hospital-free days, and BaSICS and PLUS found no mortality difference. Pooling individual patient data from six trials gave an absolute mortality difference of 0.4 percentage points with moderate certainty, which is small enough that reasonable clinicians differ. Evidence: disputed. (Source 3)
• Fluid therapy is standard in acute pancreatitis and lactated Ringer's is one of the licensed options. A 2025 meta-analysis of five small trials, 299 patients in total, found fewer intensive care admissions and less disease progression than with saline, but no difference in death or length of stay, and the authors describe the evidence as mostly low quality. Evidence: limited. (Source 4)
• Small physiological studies show concentrated sodium lactate lowers intracranial pressure at least as well as mannitol or hypertonic saline and is better tolerated haemodynamically, and that the injured brain does take up and burn lactate. Whether any of this improves survival or recovery is untested; no outcome trial exists. Evidence: limited. (Source 5)
• Short human infusion studies report increases in cardiac output, stroke volume and ejection fraction. This is physiology measured over hours in small samples, not a trial of symptoms, admissions or survival, and the review that collected them calls for large-scale trials. Evidence: limited. (Source 6)
• This is the one setting where the pooled evidence points the other way. In the prespecified traumatic brain injury subgroup of a 34,685-patient individual-patient meta-analysis, balanced solutions were associated with 3.2 percentage points more in-hospital deaths than saline, with a 0.975 posterior probability of harm. Evidence: not-supported. (Source 7)

Interactions

• Ceftriaxone (label): The calcium in lactated Ringer's can form a precipitate with ceftriaxone. In newborns this has been fatal, and the two must never be given at the same time; in older patients they may be given one after the other with the line flushed in between. (Source 2)
• Potassium supplements and any medicine that raises potassium (potassium-sparing diuretics, ACE inhibitors, angiotensin II receptor blockers, calcineurin inhibitors) (label): The fluid itself supplies potassium, so adding anything else that raises potassium stacks the risk of a dangerously high level. (Source 8)
• Vitamin D (and thiazide diuretics) (label): Lactated Ringer's contains calcium salts. Vitamin D raises calcium absorption, and thiazides reduce calcium excretion, so either can push calcium too high when the fluid is being given. (Source 9)
• Digoxin (label): Calcium-containing solutions raise the risk of digoxin toxicity, so the volume or rate may need reducing. (Source 8)
• Lithium (label): The sodium load changes how the kidney handles lithium, so lithium levels can shift; the label says to avoid the combination or monitor levels more often. (Source 8)
• Medicines cleared by the kidney in a pH-dependent way (label): Because the lactate makes the urine more alkaline, acidic drugs are cleared faster and alkaline drugs more slowly. (Source 10)
• Alcohol (case reports): Heavy alcohol use raises blood lactate in its own right and can cause severe lactic acidosis, and alcohol-related liver disease impairs the liver's ability to convert infused lactate to bicarbonate. The evidence for this is case reports plus the label's own warning about severe liver impairment, not a controlled interaction study. (Source 11)
• Diuretics and medicines that cause SIADH (label): Lactated Ringer's is slightly hypotonic relative to plasma, so combining it with drugs that lower sodium raises the risk of hyponatraemia. (Source 8)

Stopping it

• These are intravenous fluids given for a defined clinical purpose, not treatments a person takes long term, and we found no literature on dependence, withdrawal or tapering. What the label asks for instead is monitoring during prolonged infusion, because the risks accumulate with volume and duration. (Source 2)
• The volume given also has to stop before it causes harm: the label records that fluid overload and pulmonary oedema depend on how much is given and how fast. (Source 9)

What goes wrong

In patients with traumatic brain injury the same pooled analysis found balanced solutions were associated with more in-hospital deaths, an absolute increase of 3.2 percentage points. (Source 7)

• Meta-analysis, Moderate certainty.
• Size: 1,961 patients with traumatic brain injury within the 34,685-patient dataset.
• Who: Adults in intensive care with traumatic brain injury.
• How long: To hospital discharge.
• Result: Death 191/999 (19.1%) with balanced solutions vs 141/962 (14.7%) with saline; odds ratio 1.424 (1.100 to 1.818), absolute difference 3.2 percentage points (0.7 to 8.7); posterior probability of harm 0.975.
• Funding: HCor (Brazil) and The George Institute for Global Health (Australia); prespecified subgroup.

In patients with traumatic brain injury, 191 (19·1%) of 999 assigned balanced and 141 (14·7%) of 962 assigned saline died (OR 1·424 [1·100 to 1·818], absolute difference 3·2 percentage points [0·7 to 8·7]).

Newborn deaths have occurred when calcium-containing solutions such as lactated Ringer's were given with ceftriaxone, and the two must not be co-administered in neonates. (Source 12)

• Official position, Certainty not rated.
• Size: Not applicable - regulatory position drawing on post-marketing reports.
• Who: Neonates 28 days of age or younger.
• How long: Position current as of SPL version 16, published 27 July 2026.
• Result: No rate given; the label records deaths and an absolute instruction not to co-administer in neonates.
• Funding: Label held by Baxter Healthcare Corporation.

Deaths have occurred in neonates (28 days of age or younger) who received concomitant intravenous calcium-containing solutions with ceftriaxone.

Because the lactate is converted to bicarbonate, lactated Ringer's can cause or worsen metabolic alkalosis. (Source 9)

• Official position, Certainty not rated.
• Size: Not applicable - regulatory position.
• Who: Patients with or at risk of alkalosis.
• How long: Position current as of 27 July 2026.
• Result: No rate given.
• Funding: Label held by Baxter Healthcare Corporation.

Because lactate is metabolized to bicarbonate, administration of Lactated Ringer’s Injection may result in, or worsen, metabolic alkalosis.

In severe liver failure the lactate load may not be cleared, so the fluid can worsen rather than correct acidosis, and the label says to avoid it. (Source 9)

• Official position, Certainty not rated.
• Size: Not applicable - regulatory position.
• Who: Patients with severe hepatic impairment.
• How long: Position current as of 27 July 2026.
• Result: No rate given; the label advises avoiding the fluid and monitoring bicarbonate if it cannot be avoided.
• Funding: Label held by Baxter Healthcare Corporation.

In patients with severe hepatic impairment, decreased lactate metabolism may result in worsening anion gap metabolic acidosis.

Giving lactated Ringer's can distort the blood lactate measurement that clinicians use to judge how sick someone is. (Source 10)

• Official position, Certainty not rated.
• Size: Not applicable - regulatory position.
• Who: Patients with severe metabolic acidosis, including lactic acidosis.
• How long: Position current as of 27 July 2026.
• Result: No rate given; the label instructs that clinical assessment should not rest on the lactate measurement alone.
• Funding: Label held by Baxter Healthcare Corporation.

Because administration of Lactated Ringer’s Injection may interfere with the interpretation of serum lactate levels in patients with severe metabolic acidosis, including lactic acidosis, assessment of the patient’s clinical status should not solely rely on the measurement of serum lactate.

Lactated Ringer's contains potassium and calcium, so it can raise either, and the label advises avoiding it in people at risk of hyperkalaemia or hypercalcaemia. (Source 13)

• Official position, Certainty not rated.
• Size: Not applicable - regulatory position.
• Who: Patients with severe renal impairment, acute dehydration, extensive tissue injury or burns, heart failure, hypercalcaemia or calcium-containing renal stones.
• How long: Position current as of 27 July 2026.
• Result: The solution supplies potassium 4 mEq/L and calcium 2.7 mEq/L; no event rates are given.
• Funding: Label held by Baxter Healthcare Corporation.

Potassium-containing solutions, including Lactated Ringer’s Injection, may increase the risk of hyperkalemia. This risk is increased in patients predisposed to hyperkalemia including those with severe renal impairment, acute dehydration, extensive tissue injury or burns, heart failure, or in those using concomitant drugs that are associated with hyperkalemia.

Heavy alcohol use can itself produce severe lactic acidosis, which matters both for interpreting a lactate result and for giving a lactate-containing fluid to someone whose liver is handling alcohol. (Source 11)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: A 42-year-old man after a week of heavy alcohol consumption.
• How long: Four-day admission; lactate normalised by 16 hours.
• Result: pH 6.86, bicarbonate 5.9 mmol/L, anion gap 40 mmol/L, lactate greater than 20 mmol/L, serum ethanol 297 mg/dL, ketones 6.5 mmol/L; lactate fell to 4.6 mmol/L by 10 hours.
• Funding: not stated in the record we read; a single case report, which cannot establish frequency.

Alcohol-associated lactic acidosis (AALA) is a rare but potentially life-threatening complication of acute or chronic alcohol exposure.

The same review reports that hypertonic sodium lactate infusions are generally well tolerated, with minor electrolyte changes the most common side effect; it gives no event rates. (Source 6)

• Systematic review, Very low certainty.
• Size: Human studies of hypertonic sodium lactate identified by a PubMed and Medline search; number not given in the record we read.
• Who: Adults; case reports, paediatric, preclinical and psychiatric studies excluded.
• How long: Short infusions.
• Result: No rates given; minor electrolyte changes described as the most common side effect.
• Funding: not stated in the record we read; the review itself calls for large-scale trials.

Hypertonic lactate infusions are generally well tolerated, with minor electrolyte changes as the most common side effect.

What the evidence supports

In the largest trial of balanced crystalloid versus saline in critically ill adults, balanced fluid (lactated Ringer's or Plasma-Lyte A) reduced a composite kidney-and-death outcome by about one percentage point. (Source 3)

• Randomized trial, Moderate certainty.
• Size: 15,802 adults (7,942 balanced, 7,860 saline)
• Who: Adults admitted to five intensive care units at one US academic centre.
• How long: 30 days, censored at hospital discharge.
• Result: Major adverse kidney event within 30 days 14.3% vs 15.4% (absolute difference about 1.1 percentage points); marginal odds ratio 0.91 (95% CI 0.84 to 0.99), P=0.04. In-hospital mortality at 30 days 10.3% vs 11.1% (P=0.06), new renal-replacement therapy 2.5% vs 2.9% (P=0.08)
• Funding: Vanderbilt Institute for Clinical and Translational Research and others; pragmatic cluster-randomised, unblinded, single centre.

Among the 7942 patients in the balanced-crystalloids group, 1139 (14.3%) had a major adverse kidney event, as compared with 1211 of 7860 patients (15.4%) in the saline group (marginal odds ratio, 0.91; 95% confidence interval [CI], 0.84 to 0.99; conditional odds ratio, 0.90; 95% CI, 0.82 to 0.99; P=0.04).

The same trial did find fewer major adverse kidney events with balanced crystalloid, a secondary outcome. (Source 14)

• Randomized trial, Low certainty.
• Size: 13,347 patients.
• Who: Adults given intravenous crystalloid in the emergency department and hospitalised outside intensive care.
• How long: 30 days.
• Result: Major adverse kidney events within 30 days 4.7% vs 5.6% (absolute difference about 0.9 percentage points); adjusted odds ratio 0.82 (95% CI 0.70 to 0.95), P=0.01.
• Funding: Vanderbilt Institute for Clinical and Translational Research and others; this was a secondary outcome.

Balanced crystalloids resulted in a lower incidence of major adverse kidney events within 30 days than saline (4.7% vs. 5.6%; adjusted odds ratio, 0.82; 95% CI, 0.70 to 0.95; P=0.01).

Pooling individual patient data from six trials, the absolute in-hospital mortality advantage of balanced solutions over saline was 0.4 percentage points, with moderate certainty. (Source 7)

• Meta-analysis, Moderate certainty.
• Size: 34,685 participants from six randomised trials (17,407 balanced, 17,278 saline)
• Who: Adults in intensive care units; mean age 58.8 years.
• How long: To hospital discharge.
• Result: In-hospital death 2,907/17,313 (16.8%) with balanced solutions vs 2,975/17,166 (17.3%) with saline; odds ratio 0.962 (95% CrI 0.909 to 1.019), absolute difference -0.4 percentage points (-1.5 to 0.2); posterior probability of benefit 0.895.
• Funding: HCor (Brazil) and The George Institute for Global Health (Australia); two of six trials were judged low risk of bias and four high risk.

Among patients who provided consent to report in-hospital mortality, 2907 (16·8%) of 17 313 assigned balanced solutions and 2975 (17·3%) of 17 166 assigned saline died in hospital (odds ratio [OR] 0·962 [95% CrI 0·909 to 1·019], absolute difference -0·4 percentage points [-1·5 to 0·2]).

In acute pancreatitis, pooled randomised data favoured lactated Ringer's over saline for intensive care admission and disease progression, on evidence the authors call mostly low quality. (Source 4)

• Meta-analysis, Low certainty.
• Size: 5 trials, 299 patients.
• Who: Adults with acute pancreatitis receiving initial fluid therapy.
• How long: Up to 72 hours of reported outcomes.
• Result: Intensive care admission RR 0.39 (95% CI 0.18-0.85), p = 0.02; progression of pancreatitis RR 0.63 (95% CI 0.40-0.98), p = 0.04; C-reactive protein at 48 h SMD -3.91 (95% CI -4.66 to -3.17), p < 0.00001, but not at 72 h.
• Funding: not stated in the record we read; trials assessed with the Jadad scale and judged mostly low quality.

Five trials with 299 patients showed that, in patients with AP, Lactated Ringer significantly reduced ICU admission (RR: 0.39; 95% CI: 0.18-0.85; p = 0.02) and the progression of pancreatitis (RR: 0.63; 95% CI: 0.40-0.98; p = 0.04).

A systematic review of lactate-based osmotherapy in acute brain injury found sodium lactate lowered intracranial pressure at least as well as mannitol or hypertonic saline. (Source 5)

• Systematic review, Low certainty.
• Size: 12 preclinical and 12 clinical studies.
• Who: Traumatic brain injury, ischaemic stroke and cardiac arrest.
• How long: Varied; mostly short physiological studies.
• Result: No pooled estimate; the review reports effective intracranial pressure reduction and better systemic haemodynamic tolerance than conventional osmotherapy in several studies.
• Funding: not stated in the record we read; small physiological studies, no outcome trial.

Across most models, sodium lactate was effective in reducing ICP and at least as effective and safe as mannitol or hypertonic saline in clinical settings.

A review restricted to human studies of hypertonic sodium lactate at 500 mmol/L or more reports that lactate infusion increases cardiac output, stroke volume and ejection fraction. (Source 6)

• Systematic review, Very low certainty.
• Size: Human studies of hypertonic sodium lactate identified by a PubMed and Medline search; number not given in the record we read.
• Who: Adults; case reports, paediatric, preclinical and psychiatric studies excluded.
• How long: Short infusions.
• Result: No pooled estimate; the review reports lactate supports up to 20% of cerebral energy metabolism, and in traumatic brain injury increases cerebral glucose availability, reduces intracranial pressure and enhances cognitive recovery.
• Funding: not stated in the record we read; the review itself calls for large-scale trials.

In the heart, lactate infusion increases cardiac output, stroke volume, and ejection fraction, potentially benefiting heart failure patients.

What the evidence does not support

In non-critically ill emergency-department patients, balanced crystalloid made no difference to the primary outcome of hospital-free days. (Source 14)

• Randomized trial, Moderate certainty.
• Size: 13,347 patients.
• Who: Adults given intravenous crystalloid in the emergency department and then hospitalised outside intensive care.
• How long: 28 days.
• Result: Median 25 hospital-free days in each group; adjusted odds ratio 0.98 (95% CI 0.92 to 1.04), P=0.41. Median crystalloid volume given in the emergency department was 1,079 mL.
• Funding: Vanderbilt Institute for Clinical and Translational Research and others; single centre, multiple-crossover by calendar month.

The number of hospital-free days did not differ between the balanced-crystalloids and saline groups (median, 25 days in each group; adjusted odds ratio with balanced crystalloids, 0.98; 95% confidence interval [CI], 0.92 to 1.04; P=0.41).

In an 11,052-patient double-blind Brazilian trial, a balanced solution did not improve 90-day survival over saline. (Source 15)

• Randomized trial, High certainty.
• Size: 11,052 randomised, 10,520 analysed.
• Who: Adults admitted to 75 Brazilian intensive care units with at least one risk factor for worse outcomes.
• How long: 90 days.
• Result: Death by day 90 in 1,381 of 5,230 (26.4%) with balanced solution vs 1,439 of 5,290 (27.2%) with saline; adjusted hazard ratio 0.97 (95% CI 0.90 to 1.05), P=.47. Median 1.5 L of fluid in the first day in both arms.
• Funding: not stated in the record we read; investigator-initiated multicentre trial.

By day 90, 1381 of 5230 patients (26.4%) assigned to a balanced solution died vs 1439 of 5290 patients (27.2%) assigned to saline solution (adjusted hazard ratio, 0.97 [95% CI, 0.90-1.05]; P = .47).

A 5,037-patient double-blind Australian and New Zealand trial of a balanced multielectrolyte solution found no reduction in death or acute kidney injury. (Source 16)

• Randomized trial, High certainty.
• Size: 5,037 patients from 53 intensive care units.
• Who: Critically ill adults in Australia and New Zealand.
• How long: 90 days.
• Result: Death within 90 days in 530 of 2,433 (21.8%) vs 530 of 2,413 (22.0%), difference -0.15 percentage points (95% CI -3.60 to 3.30), P = 0.90; new renal-replacement therapy 12.7% vs 12.9%.
• Funding: National Health and Medical Research Council of Australia and the Health Research Council of New Zealand.

Death within 90 days after randomization occurred in 530 of 2433 patients (21.8%) in the BMES group and in 530 of 2413 patients (22.0%) in the saline group, for a difference of -0.15 percentage points (95% confidence interval [CI], -3.60 to 3.30; P = 0.90).

The same overview reports that the methodological quality of the existing reviews is poor, which is a reason to treat the pooled estimates cautiously. (Source 17)

• Review of reviews, Low certainty.
• Size: 14 systematic reviews.
• Who: Critically ill patients.
• How long: Not applicable.
• Result: One review had no critical domain weaknesses; 13 had limitations in critical domains on AMSTAR-2.
• Funding: not stated in the record we read.

The methodological quality assessment of reviews using AMSTAR-2 revealed that most reviews had critical weaknesses in one or more domains.

In the same pancreatitis analysis lactated Ringer's made no difference to death or length of hospital stay. (Source 4)

• Meta-analysis, Low certainty.
• Size: 5 trials, 299 patients.
• Who: Adults with acute pancreatitis.
• How long: Hospital admission.
• Result: No significant difference in mortality or hospital stay (SMD -0.89; 95% CI -2.26 to 0.48; p = 0.23); no clear effect on SIRS at 24, 48 or 72 hours.
• Funding: not stated in the record we read; evidence described as mostly low quality.

There was no significant difference in mortality or hospital stay (SMD: -0.89; 95% CI: -2.26 to 0.48; p = 0.23).

The same review found no reliable evidence that lactate-based therapy improves recovery, and that its metabolic benefit depends on the brain still being able to use oxygen. (Source 5)

• Systematic review, Low certainty.
• Size: 12 preclinical and 12 clinical studies.
• Who: Acute brain injury.
• How long: Varied.
• Result: Metabolic benefits were inconsistent and dependent on preserved oxidative metabolism, baseline metabolic status, timing and dose; functional outcome data were limited.
• Funding: not stated in the record we read.

The impact of lactate-based treatments on meaningful functional outcomes remains uncertain and warrants further investigation in targeted clinical trials.

Where the evidence is mixed

An overview of fourteen systematic reviews concluded there is a small advantage for balanced crystalloids, but that almost all of the reviews had critical methodological weaknesses. (Source 17)

• Review of reviews, Low certainty.
• Size: 14 systematic reviews with meta-analyses published 2018 to 2024.
• Who: Critically ill patients, including sepsis, trauma, hypovolaemia, traumatic brain injury, postoperative and elderly subgroups.
• How long: Varied.
• Result: No single pooled estimate; the overview reports a small benefit overall and in sepsis, and 13 of 14 reviews had AMSTAR-2 critical-domain weaknesses.
• Funding: not stated in the record we read.

Evidence synthesis indicated a small benefit of balanced crystalloids compared to normal saline, especially among patients with sepsis and those without traumatic brain injury.

The review's own conclusion is that hypertonic sodium lactate may have therapeutic potential in neurology and cardiology, but that large-scale trials are still needed to show whether it works, what dose to use, and whether it is safe in the long term. (Source 6)

• Systematic review, Very low certainty.
• Size: Human studies of hypertonic sodium lactate identified by a PubMed and Medline search; number not given in the record we read.
• Who: Adults; case reports, paediatric, preclinical and psychiatric studies excluded.
• How long: Short infusions.
• Result: No pooled estimate; conclusion of the review.
• Funding: not stated in the record we read; the review itself calls for large-scale trials.

Hypertonic sodium lactate infusions have potential therapeutic benefits within neurology and cardiology, but large-scale trials are required to evaluate efficacy, optimize dosing, and assess long-term safety.

Where the research disagrees

Whether a lactate-containing balanced fluid is better than 0.9% saline for critically ill adults

• The SMART investigators, A 15,802-patient pragmatic cluster-randomised multiple-crossover trial at one centre: Among critically ill adults, the use of balanced crystalloids for intravenous fluid administration resulted in a lower rate of the composite outcome of death from any cause, new renal-replacement therapy, or persistent renal dysfunction than the use of saline. (Source 3)
• The BaSICS investigators, An 11,052-patient double-blind randomised trial across 75 intensive care units: Among critically ill patients requiring fluid challenges, use of a balanced solution compared with 0.9% saline solution did not significantly reduce 90-day mortality. The findings do not support the use of this balanced solution. (Source 15)
• The PLUS investigators, A 5,037-patient double-blind randomised trial across 53 intensive care units: We found no evidence that the risk of death or acute kidney injury among critically ill adults in the ICU was lower with the use of BMES than with saline. (Source 16)
• The BEST-Living individual patient data meta-analysis, Bayesian individual patient data meta-analysis of six trials, 34,685 participants: The probability that using balanced solutions in the ICU reduces in-hospital mortality is high, although the certainty of the evidence was moderate and the absolute risk reduction was small. (Source 7)

How much

• Reference intake: There is no reference intake for an intravenous fluid. As a position, the US prescribing information for Lactated Ringer's Injection (SPL version 16, 27 July 2026) states that the dose and duration are set by the prescriber from the patient's age, weight, clinical condition and other treatment. Each litre supplies 28 mEq of lactate alongside sodium 130 mEq, potassium 4 mEq, calcium 2.7 mEq and chloride 109 mEq. (Source 2)
• Upper limit: No upper limit or maximum dose is stated in the label we read; it gives no numeric ceiling and instead makes the amount a clinical judgement with monitoring, and warns that volume and rate determine the risk of fluid overload. (Source 9)
• Studied: SMART assigned 15,802 intensive care patients to receive either saline or balanced crystalloid (lactated Ringer's solution or Plasma-Lyte A) for all intravenous fluid, by unit randomisation. (Source 3)
• Studied: In SALT-ED the median crystalloid volume given in the emergency department was 1,079 mL, and 88.3% of patients received only the assigned fluid. (Source 14)
• Studied: In BaSICS patients in both arms received a median of 1.5 L of fluid during the first day after enrolment. (Source 15)
• Studied: The hypertonic lactate literature is restricted to sodium lactate solutions with a lactate concentration of 500 mmol/L or more, given as short infusions in adults. (Source 6)

A common belief, and what the research shows

The belief: Giving lactate must worsen lactic acidosis, because lactate is the acid you measure when someone is in shock.

What the research shows: Infused lactate behaves as a base, not an acid: the label states that "Because lactate is metabolized to bicarbonate, administration of Lactated Ringer's Injection may result in, or worsen, metabolic alkalosis." The real problems are the opposite ones. It can distort the measurement clinicians rely on, since "Administration of Lactated Ringer's Injection may result in interference with the interpretation of serum lactate levels in patients with severe metabolic acidosis, including lactic acidosis"; and if the liver cannot process it, "In patients with severe hepatic impairment, decreased lactate metabolism may result in worsening anion gap metabolic acidosis."

Questions and answers

What is it?

Lactate as a medicine is the lactate ion given as sodium lactate, almost always inside lactated Ringer's Injection (Hartmann's solution). It is a clear sterile salt solution that per litre supplies 28 mEq of lactate with sodium, potassium, calcium and chloride, at an osmolarity of 273 mOsmol/L. A much stronger version, hypertonic or half-molar sodium lactate at 500 mmol/L or more, is used in research and some intensive care units. (Source 18)

What does it do in the body?

The lactate ion is converted via pyruvate, and because a hydrogen ion is consumed on the way, the net result is bicarbonate: the fluid raises blood pH rather than lowering it. The sodium that comes with it keeps the infused water in the extracellular space, which is the volume effect. Brain and heart tissue can also oxidise lactate as fuel, which is the basis for the concentrated infusions being studied in brain injury and heart failure. (Source 1)

Is it good or bad for you?

It depends almost entirely on who is receiving it. In general critical care the balance of large trials is a small advantage or none at all, with an absolute mortality difference of 0.4 percentage points in the pooled individual-patient data. In traumatic brain injury the same pooled analysis found the opposite: 3.2 percentage points more in-hospital deaths than with saline. And in severe liver failure, high potassium or high calcium, the label says to avoid it. (Source 7)

How do you get more of it?

Not something anyone obtains deliberately. Sodium lactate is a prescription sterile injectable given by a clinician into a vein, and the amount is a clinical decision rather than an intake. Your own body also makes lactate continuously from glucose, particularly in exercising muscle, and that endogenous supply is what feeds the brain and heart. (Source 2)

If it is harmful, what reduces it?

A high lactate is usually a sign of something else, so the treatment is the underlying cause rather than the lactate. Healthy liver and kidney clear lactate quickly, which is why in the alcohol-related case report the level fell from above 20 mmol/L to 4.6 mmol/L within ten hours on supportive treatment alone. When the fluid itself is the problem, the responses in the label are to stop or avoid it and monitor bicarbonate, potassium and calcium. (Source 19)

Why might someone be low in it or missing it?

There is no recognised lactate deficiency. Lactate is produced constantly by the body's own metabolism and is now understood as a fuel and signalling molecule rather than a waste product, so being "low" in it is not a clinical state anyone tests for or treats. The relevant shortfall is the reverse: being unable to clear lactate, which happens in severe liver disease and in shock. (Source 6)

Which whole foods contain it or feed it?

The sources we read do not address dietary lactate at all. Lactate does occur in fermented foods and is produced by muscle during exercise, but none of the trials, reviews or prescribing information we fetched discusses food as a source, and the medicine itself is given only intravenously. We are not willing to assert food figures without a source in front of us. (Source 6)

We searched: Europe PMC searches for sodium lactate with dietary, food and oral terms, and the full description, clinical pharmacology and pharmacokinetics sections of the Lactated Ringer's prescribing information; none addressed dietary lactate as a source.

What happens if you do not have it?

Not having the medicine means dehydration, electrolyte loss or acidosis goes uncorrected, which is exactly what it is licensed for. There is no deficiency syndrome from lacking sodium lactate, and in several settings its absence is preferable: saline was associated with lower in-hospital mortality than balanced fluid in traumatic brain injury, and the label tells prescribers to avoid lactated Ringer's altogether in severe liver impairment. (Source 2)

How can you test for it?

Blood lactate is measured routinely on a blood gas or venous sample and is one of the standard markers of how sick someone is; in the case report we read it was above 20 mmol/L at presentation. The important caveat is that giving a lactate-containing fluid can corrupt that very test, and the label states that clinical assessment should not rest on the lactate measurement alone in people with severe metabolic acidosis. (Source 20)

References

1. DailyMed / US FDA Structured Product Label, Baxter Healthcare Corporation. LACTATED RINGER'S INJECTION, USP - full prescribing information (SPL version 16, published 27 July 2026) - section 12.1 Mechanism of Action. 2026. Read the source
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