How UFC Fighters Rehydrate—and Why IVs Were Restricted

A fighter makes weight one day, then enters the cage noticeably heavier the next. The apparent transformation is possible because UFC official weigh-ins generally happen the day before the fight, leaving time to drink, eat, and replace some of what was lost during the weight cut.

But the number on the scale tells only part of the story. Regaining weight is not the same as fully recovering. And during the years when the United States Anti-Doping Agency, or USADA, administered the UFC’s anti-doping program, fighters could not simply use large intravenous infusions as a routine shortcut.

To understand why, you need to separate two questions: How does the body recover after a cut? And why would an anti-doping program restrict an IV bag containing ordinary saline?

What Fighters Are Replacing After Weigh-Ins

The rapid weight loss immediately before a weigh-in is not primarily a loss of body fat. Much of it can come from losing body water, reducing food in the digestive tract, and depleting stored carbohydrate.

After making weight, fighters therefore have several things to restore—not just a missing number of pounds.

Water and electrolytes

Electrolytes are minerals, including sodium and potassium, that carry an electrical charge when dissolved in body fluids. They help regulate fluid balance and support nerve and muscle function.

When fighters lose water through sweating, they also lose electrolytes. Recovery is therefore not simply a matter of drinking as much plain water as possible.

Sodium is particularly important because it helps the body retain the fluid being consumed. That is why post-weigh-in recovery commonly involves electrolyte-containing drinks and salty foods rather than water alone.

Stored carbohydrate

Fighters also eat carbohydrates to replenish glycogen, the form in which the body stores carbohydrate in the muscles and liver.

Think of glycogen as a readily available fuel reserve. It can be depleted during the preparation for a weigh-in, especially when carbohydrate intake has been restricted. Glycogen is also stored alongside water, so replenishing it contributes to the rebound in body weight.

A fighter’s post-weigh-in meals typically combine carbohydrates, salt, and some protein. The goal is both to restore fluid balance and to make energy available for the fight.

The scale measures total weight. It does not tell you whether fluid balance, fuel stores, and physical function have all returned to normal.

How Rehydration Usually Works

For most athletes who do not need medical treatment, rehydration happens by mouth: drinking appropriate fluids and eating.

In broad terms, the recovery process involves:

• Replacing fluids with drinks that contain sodium and other electrolytes.
• Eating carbohydrate-rich foods to rebuild glycogen stores.
• Including salt and some protein in meals.
• Spreading intake over the available hours, rather than trying to replace everything at once.

That last point matters. The stomach and intestines need time to tolerate and absorb what is consumed. Trying to force down an entire recovery plan immediately can cause discomfort or nausea rather than useful recovery.

The day-before weigh-in creates a window for this process. It does not create a guarantee that the process will be complete.

Why gaining the weight back is not proof of recovery

Suppose a fighter loses a substantial amount of weight and then regains it before the bout. It is tempting to conclude that the cut has been “undone.”

But weight is only one measurement. It cannot show whether fluid has returned to the appropriate places in the body, whether electrolyte balance has normalized, or whether the effects of a severe cut have resolved.

Some regained weight may also be food and fluid still moving through the digestive tract.

That is why a dramatic rebound on the scale should not be confused with a clean bill of health. A severe cut can leave a fighter incompletely recovered even after much of the lost weight has returned.

Why Use an IV at All?

An intravenous infusion, usually shortened to IV, delivers fluid directly into a vein. It bypasses the digestive tract and can be medically important when someone cannot drink adequately or needs treatment for a serious condition.

That direct route can make an IV sound like an obvious shortcut after a weight cut. But it is not a complete recovery system.

An IV containing saline—a solution of salt in water—does not replace a fighter’s need to eat, replenish carbohydrate stores, or recover from the broader strain of a severe cut. Delivering fluid directly into the bloodstream also does not establish that every consequence of dehydration has been reversed.

USADA’s explanation of its IV rules emphasized that oral rehydration is generally appropriate when an athlete can drink and does not have a medical need for an infusion.

Why the USADA-Era UFC Rules Restricted IVs

The central reason was anti-doping, not that saline itself was a prohibited drug.

An anti-doping policy can prohibit both particular substances and particular methods. A method may be restricted because it can help conceal doping or interfere with the interpretation of test results—even when the fluid being administered is otherwise ordinary.

Large IV infusions can rapidly expand blood-plasma volume. Plasma is the liquid portion of blood. Changing its volume can dilute the concentration of substances in a sample and alter measurements used in anti-doping monitoring.

In other words, regulators were concerned not just about what was in the bag, but also about what a large infusion could do to the evidence they were trying to measure.

A permitted substance can still be administered through a prohibited method.

The restriction also discouraged routine IV use when drinking would have been sufficient.

What was the historical limit?

The date matters because anti-doping rules change.

For example, the limit applicable under the UFC program in 2017 prohibited IV infusions or injections totaling more than 50 milliliters within six hours, unless an applicable medical exception or exemption covered the treatment.

That is a small volume compared with what people usually imagine when they picture a rehydration drip. A large saline infusion could therefore breach the rule even though saline was not itself banned.

USADA discussed the historical rule in its 2017 explanation of an Ian McCall case.

Medical Treatment Was Not Simply Banned

Calling the policy an “IV ban” can obscure an important qualification: it was not a ban on emergency medical care.

The rules provided routes for qualifying treatment through medical exceptions or a therapeutic use exemption, commonly called a TUE. A TUE is authorization to receive an otherwise prohibited substance or method for a legitimate medical reason, subject to the relevant requirements.

Those provisions were not a blanket permission to book a routine post-weigh-in drip. Whether treatment qualified depended on the circumstances and the policy in force.

The practical distinction was between medical care that was genuinely needed and elective IV use as a standard recovery habit.

Keep the Historical Rules Separate From Today’s Rules

USADA’s administration of the UFC anti-doping program ended at the close of 2023, with a different program taking over in 2024.

That means the phrase “USADA-era rules” is essential. A threshold quoted from 2017 should not be treated as a statement of the UFC’s current policy.

The lasting lesson is broader than a particular volume limit: fighters usually recover after weigh-ins through carefully paced drinking and eating, while IV rules address a separate concern about medical necessity and the integrity of drug testing.

Neither a heavier scale reading nor an IV bag is proof that a severe weight cut has been safely reversed.