High-Dose Vitamin C Injection (Merit-C)Gangnam, Seoul
This is the vitamin C injection listed on our treatment menu as high-dose Merit-C. Merit-C Injection is a prescription-only ascorbic acid 500mg/mL medicine approved for Huons Co., Ltd. Its approved dose is 50–1,000mg per day, so high doses measured in grams exceed the approved dose. In people with G6PD deficiency, high doses can cause hemolysis, so QD Clinic always checks for this before giving it. At QD Clinic in Gangnam, Seoul, South Korea, consultation helps determine which options suit your concerns.
Who it’s for
- You want to know how high-dose vitamin C differs from a standard vitamin C injection
- You don’t know whether you have G6PD deficiency — this needs checking before it is given
- You have a history of kidney stones or gout and want to discuss it in advance
High-dose vitamin C has no Korean approval as a treatment for any specific disease. Please don’t use it in place of treatment you are receiving.
How it works
Merit-C Injection’s approved dose is 50–1,000mg per day. In the MFDS drug database (nedrug), Merit-C Injection (ascorbic acid) is a prescription-only medicine in brown vials containing 500mg of ascorbic acid per mL; the marketing authorization holder is Huons Co., Ltd., and it is contract-manufactured by Humedix Co., Ltd. Its indications are the same as those of standard ascorbic acid injections, and the dosage is 50–1,000mg per day. The label states that injecting too fast can cause temporary fainting, dizziness and vein pain, so it is to be injected as slowly as possible.
THE MECHANISM, STEP BY STEP
01Product
Merit-C Injection (ascorbic acid), Huons Co., Ltd. Brown vials containing 500mg of ascorbic acid per mL.
02Approved dose
50–1,000mg a day, given subcutaneously, intramuscularly or intravenously once to several times a day. High doses exceed this range.
03G6PD deficiency
It is contraindicated in patients with G6PD deficiency. The label states that high doses can cause hemolysis.
04Injection speed
Injecting fast can cause temporary fainting, dizziness and vein pain, so it is to be injected as slowly as possible.
Treatment areas
- Discuss at consultation
- We check for G6PD deficiency. The label states that high doses can cause hemolysis.
- Medical assessment
- We check for calcium oxalate kidney stones, gout, cystinuria, hyperoxaluria and thalassemia.
- Before treatment
- We explain that high doses go beyond the approved dose (50–1,000mg per day) and that we could not find any official Korean guideline on high-dose use.
What the procedure is like
- 1Medical history — G6PD, kidney stones, gout, medicines
- 2Explanation of the dose versus the approved dose
- 3Dilution, then slow intravenous administration
- 4Check for dizziness and any change in urine afterwards
Infusion time depends on the dose and dilution, and is explained at your consultation. The label says to inject as slowly as possible.
Recovery & aftercare
- If you feel dizzy after the infusion, lie down and rest for a while before getting up.
- Drink plenty of water on the day.
- If your urine turns as dark as cola, seek medical care immediately.
What to expect over time
A general guide to how the days and months after treatment usually unfold. Results vary by individual.
During infusion Speed-related reactions
Tell us at once if you feel dizzy or faint, or have vein pain.
On the day Digestive symptoms
Nausea, diarrhea or heartburn may occur. The label states that the risk of diarrhea may increase at 1g or more per day.
Within a few days Signs of hemolysis or stones
If your urine turns dark or you have flank pain, see a doctor straight away.
Sessions & results
Our treatment menu has a single session and 5 sessions. Because high doses go beyond the approved dose, we decide each time whether to repeat it and do not recommend a set number of sessions.
How it compares
Even with the same ascorbic acid, there is more to check as the dose goes up.
| Comparison | High-Dose Vitamin C Injection (Merit-C) | Vitamin C Injection |
|---|---|---|
| Product | Merit-C Injection (500mg/mL, Huons Co., Ltd.) | Ascorbic acid injection (product explained at consultation) |
| Relation to the approved dose | Doses in grams exceed the approved dose | Set within the approved dose (50–1,000mg per day) |
| Must check before infusion | G6PD deficiency, calcium oxalate kidney stones, gout | Kidney stones, gout; asthma if the product contains sulfites |
We could not find any official Korean guideline on high-dose administration.
Safety & considerations
Contraindications in the label
- Hypersensitivity to ascorbic acid
- G6PD deficiency (hemolysis at high doses)
- Calcium oxalate kidney stones (at 1g or more per day)
- Gout, cystinuria, hyperoxaluria, thalassemia
Adverse reactions and cautions in the label
- Nausea, vomiting, diarrhea, heartburn, flushing, headache, insomnia
- Higher risk of diarrhea and kidney stones at 1g or more per day
- Temporary fainting, dizziness or vein pain with fast injection
High-dose vitamin C injection is use beyond the approved dose. G6PD deficiency carries a risk of hemolysis, so it must be checked before the infusion. Individual responses vary.
Your care at QD Clinic
G6PD and kidney check
We check for contraindications such as G6PD deficiency, calcium oxalate kidney stones and gout. How this is checked is explained at your consultation.
Explaining the dose
We explain the difference between the approved dose and the actual dose, and the limits of the evidence for high doses.
Slow infusion
We give it slowly as the label directs and check for dizziness and vein pain.
Frequently asked questions
Its official name is Merit-C Injection (ascorbic acid). The approval holder is Huons Co., Ltd., and it is contract-manufactured by Humedix Co., Ltd. It was approved as a prescription-only medicine in July 2003 and contains 500mg of ascorbic acid per mL. It comes in a brown vial, and its indications are the same as those of other ascorbic acid injections.
No. Merit-C Injection’s approved dose is 50–1,000mg per day. High doses given in grams go beyond this range, and we could not find any official Korean guideline on them.
The label states that giving high doses to patients with G6PD deficiency can cause hemolysis, and it is contraindicated for them. If you don’t know whether you have the deficiency, it needs to be checked before a high dose. Other contraindications, such as calcium oxalate kidney stones and gout, are checked at the same time before the injection.
This may be a sign of hemolysis or a kidney problem. According to the label, high doses can cause hemolysis in people with G6PD deficiency, and the risk of kidney stones may rise at 1g or more per day. Seek medical care right away and tell them which injection and dose you received.
The Merit-C Injection label states that injecting too fast can cause temporary fainting or dizziness. Tell us straight away if you feel dizzy. We will slow down or stop.
For international patients
Consultation in English / 中文 / 日本語 · WhatsApp · WeChat · KakaoTalk · a 4-minute walk from Sinnonhyeon / Nonhyeon Station (hours in KST).
How many days should I stay?
Surgery and course-based treatments need a check-up. We tell you before you book whether that means staying longer or coming back another time.
For International Patients