Fat Dissolving Injections: Swelling and Results Timeline

How long swelling lasts and what shows up in the first days

This article is about fat dissolving injections, also called meso fat in Thailand (เมโสแฟต). [5] It does not cover injecting your own fat back into the body.

A clinic in India reviewed 14 years of records from 1,269 clients. Almost everyone felt stinging in the first few hours, and local swelling lasted about 24 to 48 hours. [1] Many people had red skin for 1 to 2 days, especially people with lighter skin. [1] The authors concluded that pain, swelling, redness and stinging are temporary and mostly clear within a few hours to 2 to 3 days. [1]

Other sources do not fully agree. A Thai health information site, quoting one clinic, says swelling and redness last about 1 to 2 days. [7] But in the trials of the US FDA-approved under-chin fat injection, 87% of people given the drug had swelling, and 20% were still swollen after 30 days. [2] So the honest answer is a wide range, not one number for everyone.

If swelling grows instead of shrinking, or other symptoms appear, see the section on when to see a doctor below.

Timeline after fat dissolving injections: how long each effect lasts

The table below collects the timings reported by the same clinic study. [1] Use it as an overview of what can happen, not a schedule everyone will follow.

Lumps under the skin appeared in more than half of the clients in that study. Some researchers suggest they come from acute inflammation that heals with tiny scars. [1] The US FDA label for the under-chin injection reports lumps in 13% of people and says some lumps may not go away on their own and need medical treatment. [2]

Bruising occurred in 72% of people given that drug. [2] The label advises caution in people with bleeding disorders, including those taking antiplatelet or blood-thinning medicines, because bleeding or heavy bruising may occur. [2]

How long to see results from fat dissolving injections: what studies say

The authors of the Indian study report that 80% of clients saw their clearest result by day 10, and the product keeps working for another 6 to 8 weeks. [1] The same authors say the result becomes clear at the end of the course of treatment, not partway through. [1]

A review of the US FDA-approved under-chin injection measured results 12 weeks after the last treatment. [3] A Thai health information site, quoting one clinic, says results start within the first 1 to 2 weeks and are clearest at 1 month. [7]

The three sources give different time frames. The first study's authors say that using this mixture off-label leaves the amount, technique and treatment plan unstandardized, and that the field has no shared agreement. [1] That is why there is no standard number of days to see results.

Ask your doctor when they will judge the result, and compare photos taken from the same angle each time instead of checking the mirror every day.

Double chin fat injections: results timing and what happens under the chin

Fat under the chin is the only area where the US FDA has approved a fat dissolving injection. The drug is deoxycholic acid, and the label says a health care professional must give it. [2][4] A review of that drug measured results 12 weeks after the last treatment. [3] That is a point where the study measured, not a promise of when you will see a result.

In the trials of that drug, 87% of people given it had swelling, 70% had pain and 66% had numbness. [2] In the placebo group, 43% had swelling, 32% had pain and 6% had numbness. [2] Numbness (42%) and swelling (20%) were still present after 30 days in some people. [2]

Two effects matter especially for injections under the chin. Trouble swallowing occurred in 2% and went away on its own in 1 to 81 days, with a median of 3 days. [2] Facial weakness or an uneven smile occurred in 4% and went away on its own in 1 to 298 days, with a median of 44 days. [2]

All of this is data for one drug, not for every meso fat product, and the label says it is not approved for fat outside the under-chin area. [2]

What to avoid after fat dissolving injections, and why advice differs

The US FDA patient information for the under-chin injection that we read has no list of activities to avoid after treatment, such as alcohol, exercise or massage. [2]

Clinics give different advice. The Indian clinic in the study recommends a compression garment and massage to reduce the chance of lumps. [1] A Thai health information site, quoting one clinic, advises avoiding heat such as saunas and hot baths, avoiding massage for about 1 week, and skipping alcohol and cigarettes. [7]

These two sources contradict each other on massage. [1][7] So do not copy an avoid list from the internet. Ask the person who injected you what applies to your mixture and area.

Before treatment, tell the provider about every medicine and supplement you take, especially antiplatelet or blood-thinning medicines. [2] Injection should not be done when the area has an infection. [2]

• Should I use a compress or massage the area, and when can I start?
• How long should I avoid alcohol, heat and exercise?
• What kind of swelling or lumps is normal for the mixture I was given?
• Which symptoms mean I should call the clinic right away, and on which number?
• When is my follow-up visit?

Symptoms after fat dissolving injections that need urgent care

The list below comes from the US FDA label for the under-chin injection [2] and a warning from Thailand's Food and Drug Administration (Thai FDA, อย.). [5]

In 2018 the Thai FDA warned that fat dissolving injections risk a severe allergic reaction that can be fatal, and possible bacterial or fungal infection. People with side effects should see a specialist doctor urgently. [5]

The label reports infections including cellulitis and abscess that needed intravenous antibiotics and drainage. [2] In a US database of adverse event reports (MAUDE), 2 people were hospitalized because of skin tissue death, and both had existing health conditions. [6]

The US FDA says consumers reported permanent scars, severe infections, skin deformities, cysts and deep, painful hard lumps after using fat dissolving injections that are not approved. [4] If you have side effects, tell your provider, and if you do not have a regular doctor, get medical care. [4]

• Facial weakness or an uneven smile [2]
• Trouble swallowing, or existing symptoms getting worse [2]
• Redness, pain, an open wound, or fluid leaking from the injection site [2]
• A lump that does not go down, because the label says some lumps may not go away on their own [2]
• A severe allergic reaction [5]