Crataegus Douglasii.
Research-backed fatty acid with potential health benefits. Traditionally used to support the cardiovascular system. Modern studies suggest it can help improve blood flow and heart muscle function in certain conditions.
Reviewed March 2026
- Category
- Fatty acid
What Crataegus Douglasii is, and what it does.
- Does it work
- Suits adults who want daily botanical support for normal circulation and heart function. If you take heart or blood pressure medication, run it past your doctor before starting.
- How much to take
- Standardized extracts are key. Look for 160-900 mg daily, usually split into 2-3 doses. The dose depends on the extract's concentration of active compounds (flavonoids or procyanidins).
- Time to feel it
- Weeks rather than days. It works on vascular tone and heart muscle function, and what studies pick up tends to land between weeks six and eight of daily use.
- The first dose
- Nothing. Absolutely zero. This is a long-term play that requires weeks to months.
- With regular use
- After 2-3 months, some studies show improvements in heart function markers, like how far you can walk without getting winded. It's subtle.
- How well tolerated
- Generally well tolerated, but it's potent. Can cause dizziness or nausea. The real issue is drug interactions. If you take ANY heart or blood pressure medication, this requires a doctor's supervision.
- How it feels
- You don't 'feel' it work. It's not a stimulant or a sedative. Its effects are on the underlying function of the cardiovascular system over time.
- The overlooked benefit
- Its condensed tannins bind non-heme iron in the same meal. Put a couple of hours between hawthorn and an iron serving and both do the job you took them for.
300 to 900mg a day is where Crataegus Douglasii works.
Source: Cochrane Database Syst Rev. 2008;(1):CD005312. Hawthorn for heart failure.
The proof, claim by claim.
These words describe the research, not the molecule's worth. Research strength is how much work stands behind one claim, and it is never a product score.
Crataegus Douglasii is documented in the library; the clinical read is in the queue. Nothing about the strength of the research prints until the read is done.
- circulation and blood flowMeta-analysis
- heart muscle contractilityRandomised trial
- blood pressure already in the normal rangeRandomised trial
- antioxidant activity of procyanidins and flavonoidsIn vitro study
- exercise tolerance in older adultsRandomised trial
Questions people ask about Crataegus Douglasii.
- Can I take this instead of my heart medication?
- No. Absolutely not. Think of it as a potential addition to your treatment, not a replacement. Only use it with your doctor's approval.
- Is it a stimulant like caffeine?
- Nope. It has no stimulant effects and won't give you a jolt of energy or make you feel jittery.
- Is Black Hawthorn the same as other Hawthorn?
- Mostly, yes. Crataegus douglasii is one of several species used. Most research is on European species (C. monogyna), but they share similar active compounds.
- Will this help with anxiety?
- Not directly. While some people feel it's calming, it's not an anti-anxiety supplement. Its main target is the cardiovascular system.
Why these belong in the same formula. Each row says what the basis is, from settled biochemistry through to a trial that measured the pair.
Hawthorn species supply oligomeric procyanidins and flavonoids associated with normal vascular tone, while CoQ10 carries electrons in the mitochondrial chain that supplies heart muscle with ATP. The pairing addresses vessel tone and cellular energy separately.
Magnesium is required for normal myocardial electrical stability and for smooth muscle relaxation in vessel walls. That is the same relaxation direction Crataegus procyanidins are associated with, so the effects run together.
Arginine is the substrate nitric oxide synthase uses to relax vessel walls, and Crataegus procyanidins are associated with endothelium-dependent relaxation. Substrate and signalling support push the same way.
Dietary nitrate is reduced to nitrite and then nitric oxide independently of the enzyme route, giving a second pathway to vessel relaxation. It complements the flavonoid-associated relaxation attributed to Crataegus.
Crataegus species carry quercetin itself along with its glycosides rutin and hyperoside, so a hawthorn extract and a quercetin supplement overlap in composition rather than acting independently. Both are conjugated by the same UGT and sulfotransferase enzymes, which means they compete for that clearance capacity when taken together. Total flavonol exposure should be counted across the two.
Rutin is quercetin-3-rutinoside and is one of the flavonoid glycosides that hawthorn extracts are commonly standardised on. Gut bacteria cleave the sugar before the aglycone can be absorbed, so how much reaches circulation depends on an individual's flora. Combining a hawthorn extract with isolated rutin duplicates a compound already present rather than adding a new one.
The oligomeric procyanidins that hawthorn leaf and flower extracts are standardised to are the same structural class that dominates grape seed extract. Both are poorly absorbed as larger oligomers and are broken down by colonic bacteria into smaller phenolic acids that account for much of what appears in blood. Stacking them raises total procyanidin load and total astringency without adding a distinct mechanism.
Pine bark extract and hawthorn extract both deliver procyanidins that support endothelial nitric oxide availability in laboratory vascular preparations. The two are frequently combined in circulatory formulas for that reason. Human work on the combination is not established, so this rests on shared chemistry rather than on a combination trial.
Ascorbate regenerates oxidised flavonoid radicals back to their reduced form in solution, and flavonoids in turn spare ascorbate, a mutual recycling well described in vitro. Ascorbate also lowers the pH of an extract preparation, which slows the oxidative browning of procyanidins during storage. That second effect is formulation chemistry, not physiology.
Hawthorn preparations and garlic preparations both act on vascular tone, garlic largely through hydrogen sulfide and nitric oxide signalling. Taken together with each other or with medication that lowers blood pressure, the effects can add up rather than staying separate. Anyone already on such medication should raise the combination with their prescriber before starting it.
Taurine is present at high concentration in cardiac muscle where it participates in calcium handling and osmotic regulation, and hawthorn preparations have been studied for their effect on contractility in isolated tissue. The two act on the same tissue through different routes. Human combination data is not available.
European herbal practice pairs hawthorn with valerian, lemon balm or passionflower in preparations aimed at a settled heartbeat and easier rest. The pairing is documented in traditional use and in monograph literature rather than in trials of the combination. Where any of these are added to something else with a sedating effect, the effects may add.
Lemon balm appears alongside hawthorn in classical European calming formulas, and both contribute rosmarinic acid and flavonoid content. The grounding is traditional use, not a combination trial. Sedative effects can add with other agents that share them.
Hawthorn is a tannin-bearing Rosaceae, and condensed tannins bind non-heme iron in the gut lumen into complexes the enterocyte does not take up. A concentrated hawthorn extract taken alongside an iron salt lowers the absorbed fraction of that dose. Separating them by a couple of hours avoids the interaction.
Bilberry contributes anthocyanins and hawthorn contributes procyanidins and flavonol glycosides, and both classes have been studied in relation to capillary integrity and endothelial function in laboratory models. The pairing is common in circulation-focused formulas. Direct evidence for the combination in people is not established.
Hibiscus and hawthorn are both polyphenol-rich botanicals studied for effects on vascular tone, and they are commonly combined in tea and tincture formats. Effects on blood pressure may add, which matters where the person is already taking something for that. The combination itself has not been tested.
Nothing specific on file for Crataegus Douglasii. Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.What Crataegus Douglasii actually does.
Crataegus douglasii, black hawthorn, is a North American shrub in the Rosaceae family, and like other hawthorns its leaf, flower and fruit carry flavonol glycosides such as hyperoside and rutin, the flavone C-glycoside vitexin, and oligomeric procyanidins built from catechin and epicatechin units.
Which plant part is used changes the chemical profile: leaf and flower are richer in flavonoids while the fruit is richer in procyanidins and organic acids, so two hawthorn extracts standardised on different markers are not interchangeable materials.
Oligomeric procyanidins are absorbed poorly as intact oligomers; the larger ones are degraded by colonic bacteria into smaller phenolic acids, so what circulates after a dose is mostly microbial metabolites rather than the compounds on the label.
Flavonoid glycosides must have their sugar removed by intestinal or bacterial glycosidases before the aglycone can cross the enterocyte, which is one reason absorption of the same extract varies widely between people.
Where Crataegus Douglasii comes from.
Hawthorn is picked rather than farmed for most of the supply, and which part is picked, the leaf and flower or the berry, changes what the finished extract contains. The plant material is dried gently, soaked in a mix of alcohol and water to pull the active compounds out, and the liquid is then stripped of alcohol and dried into a powder. The one thing worth checking on a label is which hawthorn species it names, because the milled powders all look alike and the genus has hundreds of species.
Made from a plant. What ends up in the capsule tracks the harvest, so batch testing and a stated marker matter more here than with a made molecule.
Black hawthorn is native to western North America and much of the commercially traded hawthorn material is wild-collected rather than cultivated, which is where species substitution within the genus most often enters the supply chain
Leaf and flower are collected during flowering and fruit after ripening; material is shade or low-heat dried, since high heat and light drive oxidation of the procyanidin fraction
Milled plant material is extracted with an ethanol and water mixture, the ratio chosen according to whether the flavonoid glycosides or the less polar procyanidins are the target
Ethanol is recovered under vacuum at reduced temperature and the concentrate is spray dried, usually onto a carrier such as maltodextrin or the plant's own fibre
Lots are assayed by chromatography to flavonoid or procyanidin content; because hawthorn species are hard to tell apart once milled, botanical identity should be confirmed by macroscopic, microscopic or DNA methods rather than by supplier declaration
Dry extracts are blended with flow agents and encapsulated; tinctures are bottled at a stated herb-to-solvent ratio without a drying step
Getting Crataegus Douglasii from food.
The whole-food sources on file. A supplement closes the gap, it does not replace dinner.
A gram-for-gram figure (how much of each you would eat to match a dose) will appear here once it is sourced and reviewed. This page will not print a number it cannot cite.
The forms it comes in.
The essence, in one line each.
- A review of hawthorn covering its flavonoid and oligomeric procyanidin chemistry, extraction approaches and applications; it examines Crataegus monogyna, a different species within the same genus from Crataegus douglasii, so its chemistry findings transfer only as far as genus-level similarity allows.Narrative review. Kepinska-Pacelik J et al., 2026 (Molecules). PMID 41599280 ↗
These are the studies our verdict leans on, chosen from the 1 we read for Crataegus Douglasii. The full linked list is below.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.