Saline-Based HPL Injections: Mechanism, Sessions and Side Effects

At a glance: Three things define HPL: the mechanism, the session rhythm and the side effects. A hypotonic (low-salt) saline-based solution draws water into fat cells by osmotic pressure, so they swell, become fragile and are cleared by the body. Sessions take around 30 to 40 minutes, repeat every 7 to 10 days over a short course, and the usual after-effects are temporary swelling, fluid drainage and more frequent urination.

HPL sits in the same broad family as other fat-dissolving injections, but it works on a different principle from deoxycholic acid. Understanding that difference helps you choose sensibly, especially if you are planning treatment around a limited stay in Seoul.

What is HPL and how does it work?

HPL is built around a hypotonic solution. "Hypotonic" means the solution has a lower salt concentration than the fluid inside your cells. When a hypotonic solution surrounds fat cells, water naturally flows into them to balance the concentration, a process called osmosis.

As water enters, the fat cells swell. Swollen cells are more fragile and easier for the body to break down and clear through its normal processes. In practice, HPL is often described as a gentler, more gradual approach that works with fluid movement rather than a chemical that directly disrupts cell membranes.

The formula used at 365mc

At 365mc, the HPL solution is a steroid-free formula. Some fat-dissolving cocktails elsewhere have included steroids, which can carry their own side effects, so it is reasonable to ask any clinic what its HPL mixture contains.

What does an HPL course involve?

1. Consultation: a doctor confirms the area is mainly fat, checks skin quality, and asks about your health, particularly anything affecting fluid balance, and current medicines.
2. Session: the solution is injected into the target fat layer. A session typically takes around 30 to 40 minutes.
3. Repeat sessions: treatments are usually spaced about 7 to 10 days apart so your body can clear the treated fat and fluid between visits.
4. Review: progress is assessed as the course goes on, and the plan adjusted if needed.

Because the intervals are relatively short, HPL can be easier to fit into a longer trip than treatments that need several weeks between sessions.

Who may suit HPL, and who may not?

HPL may suit you if

• You have mild to moderate localised fat, such as on the abdomen, flanks, upper arms or thighs.
• You prefer an injection-based option without anaesthesia.
• You are near your stable weight and are looking for gradual refinement.
• You can stay in Seoul for a couple of weeks or return for further sessions.

HPL may not suit you if

• You want a substantial, one-off change in a larger area; LAMS or liposuction usually achieves more in a single visit.
• Your concern is mainly loose skin or visceral fat (fat around the organs), which injections do not address.
• You have kidney, heart or other conditions affecting fluid balance; the doctor will decide whether HPL is appropriate.
• You are pregnant or breastfeeding.

Side effects and what to expect afterwards

Because HPL works with fluid, its typical side effects relate to fluid shifts. Common, usually temporary effects include:

• Swelling in the treated area, often for around 24 hours.
• Some fluid drainage from injection points.
• Increased urination as your body processes the extra fluid.
• Mild dizziness in some people.
• Tenderness, redness or small bruises at injection sites.

Plan to rest for the remainder of the day, drink water as advised, and wear loose, comfortable clothing to your session. If you have unusual pain, spreading redness, fever or persistent dizziness, contact the clinic promptly. For a broader picture of how clinics manage complications, read the safety and risks guide.

HPL compared with DCA and LAMS

• Mechanism: HPL uses osmotic pressure; DCA (deoxycholic acid, used in the O-Slim Shot) breaks down fat-cell membranes directly; LAMS draws fat out mechanically through a fine tube.
• Session length: HPL around 30 to 40 minutes; DCA around 10 to 20 minutes; LAMS is a procedure under local anaesthesia that takes longer.
• Session spacing: HPL about every 7 to 10 days; DCA sessions are generally spaced further apart; LAMS is often a single procedure per area.
• Typical side effects: HPL often brings short-term swelling, drainage and increased urination; DCA can bring more pronounced local swelling and burning; LAMS involves swelling and bruising during recovery.
• Scale of change: injections give gradual, modest change; LAMS usually gives a more noticeable change in one session.

For a direct comparison of removal and dissolving approaches, see LAMS vs fat-dissolving injections.

What affects the cost of HPL?

Expect a personalised figure rather than a public tariff, as Korean rules restrict advertising of uninsured treatment prices. HPL quotes generally reflect:

• The number and size of areas treated.
• The amount of solution required per session.
• How many sessions are recommended.
• Whether HPL is part of a combined plan with other treatments.

Ask for the total course estimate rather than a per-session figure, and check whether the fees are eligible for the visitor tax refund.

Planning HPL around a stay in Korea

• Length of stay: with sessions around 7 to 10 days apart, a two- to three-week stay could fit two or three sessions. Discuss a realistic schedule before booking flights.
• Day of treatment: keep the evening free; increased urination and mild dizziness are easier to manage near your accommodation.
• Hydration and alcohol: follow the clinic's advice on fluids, and avoid heavy drinking during the course.
• Combining treatments: if you also plan LAMS or liposuction, the doctor will advise how to sequence treatments and how long to wait between them.
• After you return: your coordinator can keep in touch by message if you have questions between trips. The international patient journey page explains how visits are usually organised.

One last point: HPL refines contour in small areas and will not bring your weight down. Untreated fat cells nearby can still grow if you gain weight, so steady habits help protect the change.

Still wondering?

How many HPL sessions will I need?

It varies with the area and amount of fat. A course of several sessions is common, and your doctor will suggest a plan after assessing you.

Is HPL the same as other fat-dissolving injections?

No. HPL relies on a hypotonic solution and osmotic pressure, whereas DCA injections break down fat-cell membranes directly. They differ in session length, spacing and side effects.

Why do I need to urinate more after HPL?

The solution adds fluid to the treated area, and your body processes and excretes some of it. This is generally temporary.

Can I exercise after an HPL session?

Light activity is usually fine, but many doctors suggest avoiding strenuous exercise for the rest of the day. Follow the specific advice you are given.

Does HPL contain steroids?

The HPL formula used at 365mc is steroid-free. If you are treated elsewhere, ask what the solution contains.

If you would like to know whether HPL sessions could fit the length of your stay, you can ask a coordinator to map out a session schedule with you. A doctor can review your target area by online or video consultation before you book flights.

The details above describe HPL in general and are not personal medical advice. Your suitability, the number of sessions and how you respond are determined individually, after an in-person assessment by a doctor.