medicationPrescription only (US)Losartan is an approved medicine; the cited literature reports trial outcomes, not dosing advice.
LosartanBenefits, Dosage & Interactions
Also known as: Cozaar
Losartan is an angiotensin II receptor blocker (ARB) medication. It is typically taken in the morning. The reported plasma half-life is about 2 hours, which shapes dosing frequency. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
Researched by DoseRoutine R&D TeamReviewed for accuracy by Nicholas Alexander, RSELast updated
Evidence: Strong — 1056 human randomized trials and regulatory approval on file.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence
1056 human randomized trials and regulatory approval on file.
Plasma half-life
~2 h
Typical timing
morning
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
Reported for Losartan in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Losartan entry is written from. Each number matches an inline marker above.
- [1]Effects of losartan on renal and cardiovascular outcomes in patients with type 2 diabetes and nephropathyBrenner BM, Cooper ME, de Zeeuw D, et al. · N Engl J Med · 2001 · Peer-reviewed · PMID 11565518
- [2]Topical losartan ophthalmic drops - a review of corneal wound healing and topical losartan for managing corneal haze and potential future indicationsAbdelghaffar M, Güell JL, Moura-Coelho N · Graefes Arch Clin Exp Ophthalmol · 2025 · Peer-reviewed · PMID 39665995
How to track Losartan doses
Tracking Losartan well takes four fields and a habit. Here is what to record so the log is still useful in three months.
- 1
Add the dose and unit
Log Losartan with its dose in mg so totals stay comparable over time — including days when you split the dose or skip it.
- 2
Set the time of day and food rule
Typical timing is morning. Reminders fire at that time and can export to your calendar.
- 3
Check it against the rest of the stack
Run Losartan through the interaction checker against everything else in the routine — supplements, peptides, hormones and prescriptions — before it becomes a daily habit.
- 4
Log adherence, not intentions
Mark each dose taken, skipped or delayed as it happens. Weeks of honest logs are what make an adherence rate or a trend line meaningful; retrospective guessing is not.
- 5
Review against outcomes
With a reported half-life around 2 h, effects and timing shifts show up over days rather than instantly. Review Losartan alongside your logged metrics and any relevant blood work every few weeks before changing the dose.
What to log each time
- Dose in mg
- Time of day
- Taken / skipped / delayed
- Any side effects or notable changes
References & Evidence
Sources on this page that document Losartan dosing, timing and safety.
- [1]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Losartan?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Losartan is an angiotensin II receptor blocker (ARB) medication. It is primarily used to treat high blood pressure (hypertension), reduce the risk of stroke in patients with high blood pressure and an enlarged heart, and manage kidney disease in people with type 2 diabetes and a history of high blood pressure (as described by the FDA label). Losartan is available as an oral tablet and is often taken once daily. It was first approved for medical use in the United States in 1995. The medication works by blocking the action of a naturally occurring substance in the body called angiotensin II, which narrows blood vessels and plays a role in blood pressure regulation.
What does the research say about Losartan?
Tap a section to expand.
Losartan functions as a selective, competitive antagonist of the angiotensin II type 1 (AT1) receptor. Angiotensin II, a potent vasoconstrictor, exerts its effects primarily through the AT1 receptor, leading to blood vessel narrowing, increased aldosterone secretion, and sodium reabsorption in the kidneys. By blocking the binding of angiotensin II to the AT1 receptor, losartan prevents these physiological responses. This blockade results in relaxation of blood vessels (vasodilation), reduced aldosterone synthesis, and increased excretion of sodium and water, collectively lowering blood pressure. The substance's action is specific to the AT1 receptor, allowing angiotensin II to continue to stimulate the AT2 receptor, which has different physiological roles. Losartan is metabolized in the liver by cytochrome P450 enzymes (primarily CYP2C9 and CYP3A4) to an active metabolite, E-3174, which also possesses ARB activity and contributes to the overall therapeutic effect, as detailed by information from DrugBank.
Source for this section: Sources for How does Losartan work?: Jumps to this entry in the sources and references list at the end of the page.
The primary benefits of Losartan stem from its ability to lower blood pressure and mitigate the adverse effects of angiotensin II. Key beneficial uses include:
* **Hypertension (High Blood Pressure):** Losartan is widely used to treat essential hypertension, helping to reduce the risk of cardiovascular events such as heart attack and stroke. Clinical trials have consistently demonstrated its efficacy in achieving and maintaining blood pressure control (Cochrane Review).
* **Reduction of Stroke Risk in Left Ventricular Hypertrophy:** In patients with hypertension and left ventricular hypertrophy (enlarged heart muscle), losartan has been shown to reduce the combined risk of cardiovascular death, stroke, and myocardial infarction. This benefit is particularly noted for reducing stroke incidence (FDA label).
* **Diabetic Nephropathy:** Losartan is indicated for the treatment of diabetic nephropathy (kidney disease due to diabetes) in patients with type 2 diabetes and a history of hypertension. It helps to slow the progression of kidney disease and reduce proteinuria (protein in the urine) in this population (NIH NIDDK information).
* **Heart Failure:** While not a first-line treatment for all types of heart failure, losartan can be used in some heart failure patients who are unable to tolerate ACE inhibitors, improving symptoms and patient outcomes (Mayo Clinic).
Evidence supporting the use of Losartan is robust and derived from numerous clinical trials and systematic reviews. For hypertension, multiple randomized controlled trials have demonstrated Losartan's efficacy in lowering both systolic and diastolic blood pressure, comparable to other antihypertensive agents (Cochrane Review). The LIFE (Losartan Intervention For Endpoint reduction in hypertension) study, a landmark trial, provided key evidence for Losartan's role in reducing cardiovascular morbidity and mortality, particularly stroke, in hypertensive patients with left ventricular hypertrophy (as cited in medical journals). In the context of diabetic nephropathy, the RENAAL (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) study showed that Losartan significantly reduced the primary composite endpoint of doubling of serum creatinine, end-stage renal disease, or death in patients with type 2 diabetes and nephropathy, independent of its blood pressure-lowering effects (NIH NIDDK information). These findings collectively support Losartan's established role in the management of hypertension, diabetic kidney disease, and cardiovascular risk reduction.
Like all medications, Losartan can cause side effects, although not everyone experiences them. Common side effects often include:
* Dizziness or lightheadedness, particularly when standing up quickly.
* Fatigue.
* Nasal congestion, cough, or upper respiratory infection symptoms.
* Diarrhea.
* Back pain.
More serious, but less common, side effects can include:
* Kidney problems, indicated by changes in urination frequency or volume.
* Hyperkalemia (high blood potassium levels), which can cause muscle weakness, irregular heartbeat, or numbness/tingling.
* Allergic reactions, such as rash, itching, swelling of the face/lips/tongue/throat, or difficulty breathing.
* Angioedema (swelling beneath the skin).
If any severe or persistent side effects occur, medical attention should be sought. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Several important warnings are associated with Losartan use. Patients may experience dizziness or lightheadedness, especially during the initial phase of treatment or with dose adjustments; caution is advised when driving or operating machinery until the response to the medication is known. Losartan can cause increases in serum potassium levels, known as hyperkalemia, which can be dangerous, particularly in patients with kidney impairment or those taking other medications that increase potassium. Regular monitoring of kidney function and potassium levels may be necessary. For patients with impaired liver function, lower starting doses or careful monitoring may be required. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Losartan is contraindicated in certain situations due to potential risks. It should not be used in pregnant women as it can cause harm or death to the developing fetus, particularly during the second and third trimesters. Patients with a history of hypersensitivity to losartan or any component of the formulation should avoid its use. Concomitant use with aliskiren (a direct renin inhibitor) is contraindicated in patients with diabetes or moderate to severe kidney impairment due to an increased risk of kidney failure, low blood pressure, and hyperkalemia (FDA label). This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Caution is advised when combining Losartan with certain other medications or substances, as interactions can alter the effectiveness or increase the risk of adverse effects. Key interactions include:
* **Potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride) and potassium supplements:** Concurrent use can significantly increase the risk of hyperkalemia (high blood potassium levels).
* **Non-steroidal anti-inflammatory drugs (NSAIDs) including selective COX-2 inhibitors (e.g., ibuprofen, naproxen, celecoxib):** NSAIDs may reduce the antihypertensive effect of losartan and can worsen kidney function, particularly in patients who are elderly, dehydrated, or have pre-existing kidney impairment.
* **Lithium:** Losartan can decrease the renal clearance of lithium, leading to increased lithium levels and potential toxicity.
* **Aliskiren:** Concurrent use is contraindicated in patients with diabetes or kidney impairment due to increased risk of adverse events (FDA label).
* **Other antihypertensives:** Co-administration with other blood pressure-lowering agents may lead to an additive hypotensive effect, potentially causing excessive drops in blood pressure.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Losartan is typically taken once daily, usually in the morning. It can be taken with or without food. Consistent daily timing is often recommended to maintain stable blood pressure control throughout the day. The half-life of Losartan is approximately 2 hours, but its active metabolite has a longer half-life, contributing to its once-daily dosing regimen. The full blood pressure-lowering effect may not be apparent for several weeks after starting treatment (Mayo Clinic).
Source for this section: Sources for When should you take Losartan?: Jumps to this entry in the sources and references list at the end of the page.
What interacts with Losartan?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any supplement + medication | Note | Category ruleConfidence: theoretical | Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source pending | Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist. |
| Any vitamin + medication | Note | Category ruleConfidence: theoretical | Certain vitamins interact with specific medications (e.g., vitamin K with blood thinners).Source pending | Specific pairs are checked against a licensed source; confirm with your provider. |
| Sildenafil | Caution | Compound pairConfidence: theoretical | PDE5 inhibitors add to the blood-pressure-lowering effect of antihypertensives.Source pending | Start PDE5 at the lowest effective dose and monitor for hypotension. |
| Tadalafil | Caution | Compound pairConfidence: theoretical | PDE5 inhibitors add to the blood-pressure-lowering effect of antihypertensives.Source pending | Start PDE5 at the lowest effective dose and monitor for hypotension. |
| Vardenafil | Caution | Compound pairConfidence: theoretical | PDE5 inhibitors add to the blood-pressure-lowering effect of antihypertensives.Source pending | Start PDE5 at the lowest effective dose and monitor for hypotension. |
Frequently asked questions about Losartan
Losartan is a medication. It is also known as Cozaar. The references summarized come from NIH and PubMed records, FDA labeling where it exists, and Mayo Clinic patient material.
Losartan is commonly discussed in the context of the goals discussed on its profile page. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For Losartan, it is typically taken in the morning and its approximate half-life is 2 hours, which influences dosing frequency. Always follow the specific dose your clinician or the product label prescribes.
Losartan carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.
As a medication, Losartan can overlap with other supplements, prescription medicines, hormones and peptides. Because Losartan is usually taken in the morning, most avoidable conflicts come from what else lands in that same window. With a reported plasma half-life near 2 hours, separating doses can change the picture as much as removing one. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Losartan with no sign-up.
Whether Losartan fits alongside testosterone replacement therapy depends on the protocol — dose, ester and ancillaries such as HCG or anastrozole — and on current bloodwork. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
"Peptides" is not one category — healing peptides, GLP-1 agonists, growth-hormone secretagogues and melanocortins each behave differently next to Losartan. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
A short plasma half-life of roughly 2 hours is why protocols often split Losartan across the day rather than using a single dose. It is typically taken in the morning. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
Because Losartan clears quickly (plasma half-life around 2 hours), a missed dose leaves a real gap in exposure rather than being buffered by what is still in your system. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Losartan the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at Losartan?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Clinical pharmacokinetics of losartan(opens PubMed in a new tab)Clin Pharmacokinet · 2005 · PMID 16029066 · https://pubmed.ncbi.nlm.nih.gov/16029066/
- 2.Effects of losartan on renal and cardiovascular outcomes in patients with type 2 diabetes and nephropathy(opens PubMed in a new tab)N Engl J Med · 2001 · PMID 11565518 · https://pubmed.ncbi.nlm.nih.gov/11565518/
- 3.Cardiovascular morbidity and mortality in the Losartan Intervention For Endpoint reduction in hypertension study (LIFE): a randomised trial against atenolol(opens PubMed in a new tab)Lancet · 2002 · PMID 11937178 · https://pubmed.ncbi.nlm.nih.gov/11937178/
- 4.Topical losartan ophthalmic drops - a review of corneal wound healing and topical losartan for managing corneal haze and potential future indications(opens PubMed in a new tab)Graefes Arch Clin Exp Ophthalmol · 2025 · PMID 39665995 · https://pubmed.ncbi.nlm.nih.gov/39665995/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- PubChem CID 11751549(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/11751549
Verify at
Publisher search links for Losartan. These are places to check the information — they are not citations, so they are not numbered.
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- Mayo Clinic(publisher search, opens in a new tab)Mayo Clinic · publisher search
- MedlinePlus(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Losartan?
Plain-text summary, safe to quote verbatim:
Losartan is an angiotensin II receptor blocker (ARB) medication. It is typically taken in the morning. The reported plasma half-life is about 2 hours, which shapes dosing frequency. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
Source: DoseRoutine — https://doseroutine.com/library/losartan
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Losartan — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/losartan
What compounds are similar to Losartan?
Others in the medication category or studied for the same goals.