Buffalo Hump: Causes, Cushing's Signs, and Whether Weight Loss Shrinks It

Most buffalo humps are a weight problem, not a hormone problem: the bulge at the back of the neck is a fat deposit, and it usually grows alongside general weight gain. In one clinic series of 354 people with ordinary obesity, 72% had one; two of the 354 turned out to have a cortisol-making adrenal tumor.^[3] No trial has measured whether losing weight, by diet, surgery or a GLP‑1 drug such as Wegovy or Zepbound, shrinks the hump. It is a reasonable inference, since the hump tracks body fat and these drugs remove fat throughout the body, but it is an inference. The one cause that must not be missed is Cushing’s syndrome, which the hump alone does not signal. Easy bruising, a flushed face, weak thigh and shoulder muscles and wide purple stretch marks do.^[1]

What a buffalo hump is

The medical name is a dorsocervical fat pad: dorso for the back, cervical for the neck. The deposit lies under the skin where the neck meets the shoulders, over the seventh cervical vertebra and the first few thoracic ones. Surgeons who operate on it find fat. In a Chinese series of 383 people who had a hump removed, MRI and pathology sorted 77.6% as a discrete fat pad, 11.2% as a broader spread of fat, and 10.2% as a lipoma, a benign fatty lump.^[8] Only one of the 383 had HIV.

That makes it different from a rounded upper back caused by the spine itself, sometimes called a dowager’s hump, which is a forward curve of the vertebrae rather than a fat pad. The two can coexist. Posture exercises such as chin tucks are widely recommended online for a buffalo hump, but no published trial has tested whether they reduce the fat pad. They may change how a person holds the neck, which can change how the hump looks.

What causes it

Excess weight

The Turkish obesity study screened 354 consecutive patients with an average BMI of 40. Besides the 72% with dorsocervical fat, 28.8% had stretch marks on the abdomen. Seven failed the overnight dexamethasone suppression test, a standard screening test for Cushing’s, and further testing found an adrenal tumor making cortisol in two. The authors concluded that routine screening of everyone with obesity was not needed.^[3] A Korean surgical series of 12 people without HIV who had a hump removed found an average BMI of 30, high blood pressure and diabetes in two-thirds each, high cholesterol in three-quarters, and three people whose metabolic disease was diagnosed only when they came in about the hump.^[9] The authors suggested the hump can be an outward sign of metabolic disease. Twelve patients is a small base for that.

Cushing's syndrome and steroid medicines

Cortisol excess moves fat to the face, the trunk and the back of the neck, and the hump is one of the textbook signs. The NIH’s kidney and endocrine institute lists “a fatty hump between the shoulders” among the clear signs of long, high cortisol exposure.^[2] The commonest cause by far is medicine: long-term, high-dose glucocorticoids such as prednisone, taken for asthma, arthritis, lupus or after a transplant, or injected into joints.^[2] The Endocrine Society tells clinicians to take a full drug history before ordering any cortisol test, covering steroids taken by mouth, inhaled, rubbed on the skin, injected or used rectally, and warns that skin-lightening creams, herbal “tonics” and joint injections are easy to miss.^[1]

People with HIV face a specific trap. Ritonavir and cobicistat, used to boost some HIV drugs, slow the breakdown of several steroids, so an ordinary inhaled or injected dose can build up to Cushing’s levels.^[10][11] One reported case joins this to weight loss: a man on a cobicistat-boosted regimen had a sleeve gastrectomy at a BMI of 50.9, was later started on an inhaled steroid for asthma, and a year after surgery had stalled weight loss, weak muscles, high blood pressure and a new buffalo hump. The cause was the drug interaction.^[10]

HIV-associated lipodystrophy

The hump became widely known in the late 1990s among people taking early antiretroviral therapy. In the first careful study, eight men with HIV and a new hump all had normal cortisol suppression testing, only four were on a protease inhibitor, and the authors concluded the hump could not be blamed on high cortisol.^[6] In two HIV populations the hump was reported by 2% of a general Australian clinic sample and 19% of people who already had lipodystrophy. Those with a hump had higher insulin levels, higher BMI and higher blood pressure, and longer exposure to ritonavir or zidovudine.^[7] The link to insulin, a feature shared by obesity and Cushing’s, is one reason the authors advised checking for diabetes. The wider condition, and the semaglutide trial in it, is covered in GLP-1 drugs and HIV-associated lipohypertrophy.

Does the hump mean Cushing's?

On its own, usually not. The Endocrine Society’s diagnostic guideline sorts the signs of Cushing’s into two groups. The hump sits in the group that is common in the general population and does little to separate Cushing’s from ordinary weight gain, alongside obesity, high blood pressure, type 2 diabetes, facial fullness and fatigue.^[1] The features that best discriminate it are different:

Easy bruising. Facial plethora. Proximal myopathy (or proximal muscle weakness). Striae (especially if reddish purple and > 1 cm wide).

— Endocrine Society guideline on the diagnosis of Cushing's syndrome, Table 1

Plethora means a red, flushed face. Proximal weakness means trouble rising from a chair or lifting the arms overhead. The guideline recommends testing people with several features that are getting worse, especially the discriminating ones, and people with features unusual for their age, such as osteoporosis or high blood pressure when young.^[1]

The hump is not worthless as a clue. In a Spanish study of 353 people referred to endocrine clinics for suspected Cushing’s, a scoring system built from three examination findings (muscle wasting, osteoporosis and the neck fat pad) plus a cortisol level measured in saliva at bedtime identified the 26 true cases well.^[4] That was a population already suspected of the disease, and the score has not been validated elsewhere. Going the other way, Italian endocrinologists set 61 patients with partial lipodystrophy, a rare disorder of fat distribution, against 56 with Cushing’s in 2026. People with lipodystrophy had the neck fat pad more often than the Cushing’s patients did; muscle wasting and osteoporosis pointed to Cushing’s.^[5] A hump plus muscle weakness and bruising means something different from a hump plus weight gain.

Does weight loss or a GLP-1 drug shrink a buffalo hump?

No study has measured it for any method of weight loss, including calorie restriction, exercise, bariatric surgery and all the GLP‑1 drugs. Most of the nearest drug studies measured fat elsewhere in the body.

The semaglutide trial in people with HIV is the closest test of a GLP‑1 in a population where the hump is common, and it measured fat by abdominal compartment and in the whole body.^[12] The tirzepatide body-scan study reported whole-body fat and lean mass.^[13] Neither reported the neck or upper back. How these drugs move fat region by region is covered in what Ozempic does to the buttocks, which runs into the same gap.

The case for expecting some shrinkage is indirect. The hump goes with higher BMI, higher insulin and more trunk fat,^[6][7] and GLP‑1 drugs reduce fat in every compartment that has been measured. The case for caution is also indirect. Fat pads that have been present for years often contain fibrous tissue, which is why surgeons describe them as fibro-fatty and need special cannulas to remove them.^[17][18] It is a reasonable inference, though untested, that fibrous tissue will not shrink the way fat cells do, so a person who loses a large amount of weight may find the hump smaller but still present.

When the weight comes off but the hump does not

One case report shows why a stubborn hump on a GLP‑1 deserves a second look. A 21-year-old woman with a dorsocervical fat pad, a round face and stretch marks lost 42 pounds on Ozempic and then plateaued. Testing found mild cortisol excess with no tumor on imaging. With a cortisol-blocking drug added, she lost another 47 pounds and her cortisol normalized.^[22] It is one case. The broader point is that a GLP‑1 does not treat high cortisol: in 20 people with Cushing’s syndrome given these drugs, weight fell by about 10 kg while cortisol stayed where it was.^[23] That study is covered in GLP-1 drugs in Cushing’s syndrome.

Tesamorelin and growth hormone

Tesamorelin (Egrifta) is the only drug approved for a fat-redistribution problem in HIV. Its label limits it to belly fat in adults with HIV who have lipodystrophy, and states that it is not indicated for weight loss because it does not change body weight.^[15] It is not approved for the hump. In a manufacturer-supported reanalysis of its phase 3 trials, 130 of 337 participants (39%) had dorsocervical fat at the start, and the drug lowered belly fat just as often in them as in people without it, 68% against 70%. The hump was recorded only as present or absent at baseline; whether it changed was not reported.^[14] Sellers marketing tesamorelin for general fat loss are covered in tesamorelin for weight loss.

The only drug study that measured the hump directly used growth hormone itself. Eight men with HIV-related fat gain took 3 mg a day, open-label, and five completed six months. Hump size and abdominal fat fell, and total fat dropped from 17.9 to 13.5 kg. The dose pushed IGF‑1 to as much as three times the upper limit of normal, insulin sensitivity worsened in the first month, and one man developed symptomatic high blood sugar.^[16] Growth hormone is not a treatment for a buffalo hump outside a trial.

Liposuction and surgery

Surgery is the one treatment with outcome data, all from case series. A 2026 systematic review pooled 22 studies covering 218 patients, most with HIV. After liposuction the hump came back in 10.6% and 15.3% needed a second procedure; after excluding outlier studies those figures fell to 1.4% and 1.3%. Open excision, by itself or paired with suction, produced zero recurrences in the pooled data at the price of more complications, including fluid collections, bleeding and wound breakdown. The reviewers rated the evidence low quality.^[17]

• The 383-patient series. No recurrences were reported. Complications were numbness of the skin in 14.4%, a fluid collection (seroma) in 6.3%, a thickened scar in 2.1% and a blood collection in 0.8%.^[8]
• Dissector-assisted liposuction, 57 patients. The fat pads averaged 329 mL. The surgeons reported no complications and better patient ratings at six months.^[18]
• People continuing HIV therapy. An Italian follow-up found surgery had a lasting benefit in most patients, even though the drugs linked to the hump were continued.^[19]

Surgery removes fat that is there. It does not treat the cause, so anyone whose hump came from steroids or Cushing’s needs that dealt with first. Timing after large weight loss is covered in when it is safe to have the skin removed.

Fat-dissolving injections

Deoxycholic acid (Kybella) is approved only for fat under the chin. Its label is explicit:

KYBELLA is not approved for the treatment of subcutaneous fat outside the submental region, and such use is not recommended.

— Kybella (deoxycholic acid) prescribing information, section 1

A single 2026 case report describes a 71-year-old man with an HIV-related hump that had survived two liposuctions and an excision. Three off-label injection sessions three months apart cleared it, with no recurrence three years later.^[20][21] One case cannot say how often that works or what can go wrong.

When to see a doctor

A hump that has grown slowly alongside weight gain is not an emergency, but it is worth mentioning at a routine visit, with a check of blood sugar and blood pressure.^[9][7] Ask for a prompt appointment if any of these come with it:^[1][2]

• Bruising without an obvious knock, or thin skin that tears easily.
• Wide purple or red stretch marks on the belly, hips, breasts or under the arms.
• Weakness in the thighs or shoulders: trouble climbing stairs, standing from a chair or lifting the arms.
• A red, round face, or new fullness above the collarbones.
• Thin arms and legs while the trunk grows, or weight gain that keeps going despite a GLP-1 or surgery.
• A fracture from a minor fall, or high blood pressure or diabetes at a young age.
• Any steroid use in the past months, including inhalers, nasal sprays, joint injections and skin creams, especially alongside HIV medicines boosted with ritonavir or cobicistat.

What to ask

1. Could any of my medicines be doing this? Bring every steroid, cream, inhaler and injection, and any HIV medicines.
2. Do I have any of the features that point to Cushing’s? Ask specifically about bruising, muscle weakness and purple stretch marks.
3. Should my blood sugar, blood pressure and cholesterol be checked? The hump travels with all three.
4. If I lose weight on a GLP-1, what should I expect? Expect the hump to be reassessed after the weight has settled, not judged early.
5. If I want it removed, what is the recurrence and complication rate in your own patients?