Facial carboxytherapy: mechanism, indications and limits
Quick facts
- What it is
- Subcutaneous or intradermal injection of medical-grade carbon dioxide, in small amounts, to stimulate microcirculation and tissue oxygenation.
- Proposed mechanism
- CO2 causes local vasodilation and stimulates circulation, with a possible effect on skin quality and on the color of vascular under-eye circles.
- Evidence
- Limited and heterogeneous for the face, with small samples and subjective outcomes.
- Limits
- It does not replace filler, a biostimulator or surgical treatment, and response varies.
Carboxytherapy is a procedure that uses medical-grade carbon dioxide injected in small amounts under or into the skin. It started on the body and was adapted for the face, mainly for under-eye circles and skin quality. It is a method with a plausible mechanism but limited evidence in the facial region. This page explains, at a review level, what it is proposed to do, where it is usually used, what the risks are and what the limits are. Indication, equipment and protocol follow the training and the decision of the qualified professional, in line with the rules of their professional board in Brazil.
What is carboxytherapy and how does it act?
Carbon dioxide, delivered in a controlled way, diffuses through the tissue. One proposed explanation is that CO2 causes local vasodilation and stimulates circulation, favoring tissue oxygenation. This response, called the Bohr effect by some, is the theoretical basis for uses on cellulite, scars and stretch marks on the body, and it was extended to the face. On the face, the most common goal is to improve the look of under-eye circles with a vascular component and skin quality.
Important: the physiological hypothesis is reasonable, but translating it into a measurable aesthetic result on the face does not have the same level of support as other uses. Whoever presents the method to the patient should distinguish a proposed mechanism from a proven result.
What is facial carboxytherapy usually indicated for?
| Indication | Reading |
|---|---|
| Under-eye circles with a vascular component (purplish or bluish tone) | May be considered as part of the plan; variable response |
| Thin, dull skin in the periorbital region | Complementary option, without replacing hydration and sun protection |
| Skin quality in general | Limited evidence; other approaches may have more data |
| Skin preparation before other procedures | Described use, no consensus |
| Under-eye circles from volume loss or a bag | Generally not the best option; see under-eye circles: types and assessment |
The distinction between types of under-eye circles is decisive. Pigmentary, vascular, structural (shadow from volume loss) and mixed circles respond in very different ways, and treating the wrong type is the most common cause of frustration. For direct treatment of the area with filler, see under-eye filler.
What is known about the evidence?
The literature on facial carboxytherapy consists largely of case series, small studies and reports with subjective assessment. There are descriptions of improvement in the color of under-eye circles and in skin quality, but with poorly standardized outcomes, short follow-up and few comparative studies. This allows the method to be considered in selected patients, but not to state an effect size or compare it with other treatments. For critical-reading reasoning, see how to read a clinical trial of injectables and levels of evidence in HOF.
What are the risks and expected effects?
- Pain and discomfort during the infusion, with a sensation of pressure, burning or tingling.
- Ecchymosis and hematoma, especially in the periorbital region, where the skin is thin and vascular.
- Local swelling, generally temporary.
- Passing erythema.
- Subcutaneous emphysema, with crepitus, which usually resolves on its own but frightens the patient.
- Infection, rare, related to antisepsis.
- Post-inflammatory hyperpigmentation in predisposed patients, after repeated ecchymoses.
- Unsatisfactory result from an inappropriate indication.
The periorbital region deserves extra attention: the skin is the thinnest on the face, the vessels are numerous and the patient easily notices any purple mark. See periorbital anatomy for injectables and infraorbital hyperpigmentation after a procedure.
Contraindications and selection care
In general, carboxytherapy is avoided in pregnancy, with active infection in the area, severe coagulation disorders, decompensated cardiopulmonary disease and situations in which the gas could be a problem. Patients on anticoagulants need special care because of the risk of hematoma. The exact list depends on the equipment and the protocol, and should be checked in specific training. See general contraindications in HOF and anticoagulants and injectable procedures.
How does it compare with other methods?
Carboxytherapy, microneedling, skinbooster and biostimulators have different mechanisms. None replaces another, and the choice starts from the patient's concern. If the problem is under-eye color from vessels, carboxytherapy enters the discussion. If it is volume loss, the answer lies elsewhere. If it is skin quality in general, there are approaches with more data. Planning without mixing everything into the same session helps identify what worked and what caused a complication.
Expectations, number of sessions and maintenance
Whoever offers facial carboxytherapy usually proposes a cycle of sessions, not a single session. The number, the interval and the maintenance vary between protocols and have no universal standard backed by robust evidence. That is why the professional should explain that the schedule is a working proposal, that it will be reassessed over time, and that the patient can stop if they see no benefit. Promising "results in so many sessions" is a kind of promise the literature does not support.
It is also important to talk frankly about cost-benefit. When there are alternatives with more evidence for the same concern, the patient has the right to know. The final decision is theirs, informed, and the consent form should record the nature of the method, the risks and the absence of any guarantee. See informed consent and consent form by procedure.
How do you talk to the patient?
Where does Harmy fit in?
Frequently asked questions
Does carboxytherapy work for under-eye circles?
It may help under-eye circles with a vascular component, in some patients, but the evidence is limited and response varies. Circles caused by pigmentation, a fat-pad shadow or volume loss have other causes and other options.
Does facial carboxytherapy hurt?
It usually causes discomfort, burning or pressure while the gas is infused, and this varies between patients. Some people tolerate it well, others need comfort measures.
Does facial carboxytherapy have risks?
Yes. Ecchymosis, swelling, pain, a burning sensation, erythema and, rarely, subcutaneous emphysema. Patient selection and suitable equipment lower the risk.
Does carboxytherapy replace a skinbooster or a biostimulator?
No. The mechanisms and outcomes are different. Each method has its own indication and evidence, and they can be considered together at the professional's discretion.
Harmy images are illustrative simulations generated by AI from the patient's photo to support the conversation between practitioner and patient. They are not a promise of results. Indication, technique, product and volume are solely the decision of the licensed practitioner. This content is for information only and does not replace a clinical assessment.