Product FAQs
What are the active ingredients in King Dong, and what are their dosages per capsule?
The main active ingredients are L-Citrulline, Transresveratrol, and Piperine at doses of 400mg, 150mg, and 5mg respectively, per capsule. The advised dosage is 2 capsules per day.
How and when should I take King Dong for best results?
Because our formula is based on clinical data - we also advise following the same consumption pattern as the study subjects. They took their dosage daily (time not specified), every day.
This is expected to lead to more consistent delivery of vasodilation and vascular relaxation effects - allowing you to be more spontaneous in regards to sexual activity ie no need to pre-plan when to take the supplement ahead of intercourse.
It is noted though, that, after an oral dose, plasma citrulline levels peak roughly one to two hours post-dose, and its elimination half-life in healthy adults is approximately 60 to 75 minutes.
Trans-resveratrol has a similar half-life/uptake, though when taken repeatedly (daily dosing), the apparent half-life can extend to about two to five hours, owing to accumulation of metabolites - further strengthening the approach to dose daily.
It is possible, on days where intercourse can be pre-empted, to take a further 2 capsule dose within 60 minutes of starting sexual activity (in addition to your regular daily dose), to ensure plasma levels are peaked when required - though it's advisable to seek medical advice prior to undertaking this approach, and it must be noted that this was not the approach taken in the published studies.
Why does King Dong contain L-citrulline instead of L-arginine?
Both citrulline and arginine can serve as precursors to nitric oxide (NO), which dilates blood vessels and improves blood flow. King Dong uses L-citrulline rather than arginine because citrulline bypasses first-pass metabolism in the gut and liver; it is converted into arginine in the kidneys, producing a more sustained rise in blood arginine levels.
So, rather ironically - supplementing with citrulline leads to greater arginine blood levels, than supplementing with arginine itself.
A clinical comparison by Kharitonova and colleagues (2020) found that oral citrulline produced a significantly larger and longer-lasting increase in blood arginine than the same dose of arginine itself. In practical terms, citrulline delivers a steadier and more reliable boost in nitric oxide production, which is essential for maintaining erection firmness and duration.
Choosing citrulline ensures King Dong provides consistent support for NO production and better overall erectile function.
Are there any known side effects or contraindications with King Dong?
Most people tolerate King Dong well when taken as directed, but a few considerations apply. Because L-citrulline can lower blood pressure by increasing nitric oxide, you may notice mild flushing, headache, or lightheadedness—especially if you already take antihypertensives. Trans-resveratrol is generally safe at 150 mg per dose, but in sensitive individuals it can occasionally cause stomach discomfort, diarrhea, or a mild headache. Piperine (black-pepper extract) may increase absorption of other medications, so consult a doctor if you’re on blood thinners, antihypertensives, or any prescription that notes “avoid grapefruit” (many of the same liver enzymes are involved). If you have a bleeding disorder, are scheduled for surgery, or are pregnant or nursing, you should avoid King Dong or get medical approval first. Finally, because King Dong is designed to be taken alongside PDE5 inhibitors, check with your physician before combining it with any heart or blood-pressure medications.
Can I take King Dong if I’m already using prescription ED medication?
Yes. In fact, the clinical trials on which King Dong is based were conducted in men who were already taking a PDE-5 inhibitor but still experiencing only partial benefit. Adding 800 mg of citrulline and 300 mg of trans-resveratrol daily helped those men achieve firmer, longer-lasting erections and higher satisfaction scores than with medication alone. Citrulline boosts nitric-oxide precursors, and resveratrol supports endothelial health, so together they fill in the gaps where pharmaceutical solutions sometimes fall short.
That said, because both citrulline and resveratrol can lower blood pressure by enhancing vasodilation, you should check with your doctor before combining King Dong with any heart or blood-pressure medications (including PDE-5 inhibitors). Your physician can confirm that your current dosage of medication is safe to continue and help you decide whether adding King Dong makes sense in your individual case.
Is King Dong suitable for vegans or anyone with common food allergies?
King Dong is formulated to be vegan‐friendly and free of common allergens. The active ingredients—L-citrulline, trans-resveratrol, and piperine—are all plant-derived. We use a vegetable-based (HPMC) capsule shell rather than gelatin, and there are no dairy, soy, gluten, nuts, or shellfish components.
What role does trans-resveratrol play, and why is piperine included?
Trans-resveratrol acts as a powerful antioxidant and supports healthy blood-vessel function by helping to preserve endothelial cells that line the arteries. In the context of erectile function, it enhances nitric-oxide signaling, which promotes vessel dilation and improves blood flow to penile tissue. Because trans-resveratrol is rapidly metabolized and has relatively low bioavailability on its own, King Dong includes piperine—a natural extract from black pepper—to help more of each dose enter the bloodstream. Clinical research shows that adding piperine can increase resveratrol absorption by over 200 percent, ensuring you receive the full benefit of its vascular support.
Study FAQs
Which clinical studies support the efficacy of citrulline + resveratrol for erectile function?
The primary evidence comes from two randomized, placebo‐controlled human trials conducted in men already using prescription PDE-5 inhibitors but still experiencing incomplete results. The first, published in Sexual Medicine Open Access in 2018, enrolled men with erectile dysfunction who continued their usual PDE-5 inhibitor yet had suboptimal outcomes. Over one month on a daily combination of 800 mg L-citrulline plus 300 mg trans-resveratrol, these men saw a roughly 32 percent rise in overall erectile function scores, a 45 percent gain in erection confidence, a 35 percent boost in erection firmness, and about a 17 percent improvement in erection hardness compared with placebo. Intercourse satisfaction also jumped by about 40 percent. A follow-up trial published in the World Journal of Men’s Health in 2021 used a similar daily dose of citrulline and resveratrol (800 mg and 300 mg, respectively) as part of a multi-ingredient drink taken for two weeks alongside continued PDE-5 inhibitor therapy. The results echoed the earlier findings: men reported firmer, more reliable erections, higher sexual desire and confidence, and a 35–40 percent increase in intercourse satisfaction versus placebo. These studies together demonstrate that adding citrulline and resveratrol to standard ED medication significantly enhances erection quality and sexual satisfaction.
What improvements did participants see in SHIM scores and Erection Hardness Score (EHS)?
Participants taking 800 mg of L-citrulline plus 300 mg of trans-resveratrol each day experienced a notable rise in their Sexual Health Inventory for Men (SHIM) total score (SHIM-T) from about 8.3 on placebo to roughly 11.0 when on the supplement—an increase of approximately 32 percent. When broken down into SHIM subscores, erection confidence (SHIM-1) went from around 1.43 to 2.08 (about a 45 percent gain), erection firmness (SHIM-2) rose from 1.80 to 2.43 (a 35 percent boost), and intercourse satisfaction (SHIM-5) climbed from 1.60 to 2.24 (roughly 40 percent higher). Meanwhile, the Erection Hardness Score (EHS) improved from about 2.18 on placebo to 2.56 with the supplement—a roughly 17 percent increase—indicating that men achieved firmer, more durable erections when citrulline and resveratrol were added to their standard ED therapy.
How long did the referenced trials run, and how soon did users notice benefits?
The 2018 trial in Sexual Medicine Open Access ran for one month (four weeks) on citrulline + resveratrol versus placebo, with erectile‐function scores measured at the end of that period. Participants generally reported small but noticeable improvements in firmness and confidence by the second or third week, with the most pronounced gains—about a 32 percent increase in total SHIM score and a 17 percent rise in EHS—evident after four weeks of daily dosing.
The 2021 study in World Journal of Men’s Health used a two‐week supplementation period (followed by a one‐week washout and crossover). In that trial, men began to feel firmer erections and greater confidence within the first week of taking 800 mg citrulline plus 300 mg resveratrol, and by the end of two weeks they experienced about a 35–40 percent boost in firmness and satisfaction compared to placebo.
Were the clinical trials placebo-controlled, and did they include men already on PDE5 inhibitors?
Yes. Both of the key trials were randomized, double‐blind, placebo‐controlled crossover studies. In each trial, every participant continued their usual PDE5 inhibitor throughout the study. They first received a placebo drink or capsules for the designated period and then crossed over to the citrulline + resveratrol intervention (or vice versa), ensuring that all participants served as their own controls while still being on PDE5i therapy.
How does King Dong’s ingredient profile match the dosages used in published studies?
King Dong delivers exactly the same dosing that was used in the published trials: two capsules per day provide 800 mg of L-citrulline and 300 mg of trans-resveratrol, matching the amounts shown to improve erectile function in men already taking PDE5 inhibitors.
Is there evidence that piperine significantly improves resveratrol absorption?
Yes. A human pharmacokinetic study demonstrated that co-administering piperine with resveratrol dramatically increases resveratrol’s absorption. In that trial, volunteers took a single 25 mg dose of resveratrol alone, then after a washout period they took 25 mg of resveratrol combined with 20 mg of piperine. Blood measurements showed that adding piperine raised resveratrol’s peak concentration by about 154 percent and overall exposure (AUC) by roughly 229 percent compared to resveratrol on its own. In practical terms, piperine blocks certain enzymes in the gut and liver that normally break down resveratrol too quickly, allowing a much larger fraction of each dose to reach circulation. This is why King Dong includes piperine—to ensure more of the trans-resveratrol actually enters the bloodstream and can exert its vascular benefits.
How does a citrulline supplement compare to arginine in boosting nitric oxide?
Oral L-citrulline is more effective than L-arginine at raising blood arginine levels—and therefore nitric oxide—because citrulline bypasses first‐pass breakdown in the gut and liver. When you take arginine by mouth, much of it is converted to other compounds before it ever reaches the bloodstream. In contrast, citrulline is absorbed intact, then converted into arginine by the kidneys. A clinical study comparing equal doses found that citrulline increased plasma arginine by roughly 200 percent, whereas the same amount of arginine produced only about a 66 percent rise. In other words, taking citrulline delivers a steadier, longer-lasting boost in nitric oxide precursors, which is why King Dong uses citrulline rather than arginine.
Delivery/Service FAQs
What payment methods do you accept at checkout?
We accept all major credit and debit cards (Visa, MasterCard, American Express), as well as PayPal. This is all conducted via PayPal checkout.
How long does domestic shipping take, and do you offer expedited options?
Domestic shipping typically takes between two and four business days after your order is processed. Orders are usually processed within 24 hours during weekdays (orders placed on weekends or holidays will begin processing the next business day). If you need your order sooner, we offer an expedited option at checkout—this upgrade reduces delivery time to one to two business days, depending on your location. Expedited shipping charges vary based on your address and will be displayed before you complete your purchase.
Do you ship internationally, and are there additional customs or VAT charges?
We offer shipping Worldwide (charges differ based on your specific location, so please follow the checkout process to receive a quote for shipping). All International shipments are sent from the UK, and on DAP terms - meaning, depending on the Country you live, there may be additional customs duties/VAT to pay to the carrier in order to receive your parcel. You will be contacted by your carrier if this is the case, to make payment. You should check your Country's import value thresholds and duty rates before placing your order.
What is your return policy if I’m not satisfied with King Dong?
If you’re not satisfied with King Dong, you can return any unopened bottles for a full refund within 30 days of delivery. Simply contact our customer-support team at info@king-dong.com to request a return authorization, and we’ll send you a prepaid shipping label. Once we receive the unopened product, we’ll issue a full refund to your original payment method within three to five business days.
Will my package arrive in discreet, unbranded packaging?
Yes - we use unbranded packaging on all orders (either Jiffy style envelopes or plain cardboard boxes, depending on order size). Shipping label may reference the company name Reign Strong Ltd - but no reference to the 'King Dong' brand name or the nature of the product will be made on the exterior of the packaging.
Can I track my order once it’s been shipped?
Yes. Once your order ships, we’ll send you a confirmation email containing the carrier name and tracking number. You can click the tracking link or enter the number on the carrier’s website to see the current delivery status. If you created a customer account, you can also log in and view tracking information under “Order History.”