Most weight gain pills are not safe to take while breastfeeding. The most popular appetite-stimulant pills contain ingredients that can interfere with your milk supply, pass into breast milk, and cause side effects in your baby. Gaining weight safely during this period comes down to eating more calorie-dense foods rather than relying on supplements that haven’t been tested in nursing mothers.
Why Most Weight Gain Pills Are Risky
The biggest concern is a drug called cyproheptadine, the active ingredient in many weight gain and appetite-stimulant products. Cyproheptadine is an antihistamine that blocks serotonin activity in the brain, which increases appetite as a side effect. The problem for breastfeeding mothers is that this same serotonin-blocking action lowers prolactin, the hormone your body needs to produce milk. At doses of 16 to 24 mg daily, cyproheptadine measurably suppresses prolactin. Whether lower doses have the same effect simply hasn’t been studied.
The National Institute of Child Health and Human Development states that cyproheptadine should be avoided during lactation because it may interfere with milk production, especially before breastfeeding is well established. In broader studies of antihistamines and breastfeeding, about 10% of exposed infants showed irritability and colic-like symptoms, and 1.6% showed drowsiness. None of those cases required medical attention, but the research on cyproheptadine specifically is so thin that its full risks to infants remain unknown.
Apetamin and Similar Products
Apetamin is one of the most widely searched weight gain products, and it deserves special attention. The FDA has issued a direct warning: Apetamin is not approved, is manufactured overseas, and is illegally imported into the United States. It contains cyproheptadine, which requires a prescription in the U.S., meaning you’re essentially taking an unregulated prescription drug without medical oversight.
The FDA reviewed adverse event reports from people taking Apetamin and found cases of nervous system problems (dizziness, sleepiness, tremor), irregular heartbeat, and liver injury. Antihistamine overdose can cause hallucinations, convulsions, slowed breathing and heart rate, coma, and death within six hours. The agency believes the true number of people harmed is higher than what’s been reported. For a breastfeeding mother, taking an unregulated product with unknown dosing precision adds another layer of risk on top of the milk supply concerns.
Protein Powders and Mass Gainers
Not all weight gain supplements are appetite stimulants. Protein powders and mass gainer shakes take a different approach: they simply pack a lot of calories and protein into a convenient form. Common ingredients include whey protein, pea protein, maltodextrin (a carbohydrate powder), and medium-chain triglycerides from coconut oil. These are generally food-based ingredients rather than drugs.
The catch is that dietary supplements in the U.S. aren’t tested for safety or purity before they hit store shelves. A protein powder could contain contaminants, undisclosed ingredients, or inaccurate labeling. If you want to use a protein powder while breastfeeding, look for products that have been third-party tested by organizations like NSF International or Informed Sport. These certifications verify that what’s on the label matches what’s in the container.
Testosterone boosters, pre-workout formulas, and herbal appetite stimulants are a different story. These often contain ingredients like DHEA, ashwagandha, tribulus terrestris, high-dose caffeine, or beta-alanine, none of which have been adequately studied in breastfeeding women. They’re best avoided.
Fenugreek: A Complicated Case
Fenugreek is interesting because it sits at the intersection of weight gain and breastfeeding. It’s one of the most popular galactagogues (herbs taken to boost milk supply), but in a survey of 421 nursing mothers in Australia who were taking fenugreek, 17% reported side effects. The most common ones were weight gain, stomach cramps, nausea, dry mouth, body odor, and headache.
So fenugreek can cause weight gain, and some women take it hoping to increase milk supply at the same time. But even for milk production, the evidence is mixed. As one breastfeeding physician at Cleveland Clinic put it, in some women certain supplements could increase supply, while in others, the same supplement could decrease it. There’s not enough evidence to predict which outcome you’ll get. Fenugreek is not a reliable weight gain strategy, and its effects on your milk supply are unpredictable.
How Many Extra Calories You Actually Need
Breastfeeding burns a significant amount of energy. The CDC recommends that well-nourished breastfeeding mothers eat an additional 330 to 400 calories per day compared to what they consumed before pregnancy. If you’re trying to gain weight while nursing, you need to cover that breastfeeding calorie cost first, then eat beyond it. For many women who are underweight or losing weight while breastfeeding, simply meeting that baseline is the issue.
The exact number varies based on your age, body mass index, activity level, and whether you’re exclusively breastfeeding or supplementing with formula. A woman who is exclusively nursing a large, hungry baby will burn more calories than someone who is combo-feeding.
Foods That Support Weight Gain While Nursing
The most effective and safest approach to gaining weight while breastfeeding is increasing your calorie intake through nutrient-dense foods. This matters because your baby depends on the quality of your diet for key nutrients delivered through breast milk. Empty calories from processed snacks add weight but shortchange both of you.
Focus on foods that pack a lot of calories into small portions:
- Nut butters: A tablespoon of peanut butter on whole-grain bread adds roughly 200 calories with protein and healthy fat
- Full-fat dairy: Yogurt, cheese, and whole milk provide calcium alongside calories
- Eggs: Easy to prepare in large quantities and rich in protein and choline
- Avocado: Half an avocado adds about 160 calories and healthy fats
- Beans and lentils: High in both calories and fiber, and inexpensive
- Lean meats and low-mercury seafood: Protein-rich options that support both your recovery and your baby’s development
- Dried fruit and trail mix: Calorie-dense snacks you can eat one-handed while nursing
Eating more frequently often works better than trying to eat larger meals. Adding a fourth or fifth smaller meal to your day, or keeping calorie-dense snacks within arm’s reach during nursing sessions, can make a real difference over weeks. If you’re struggling to gain weight despite eating more, or if you’re losing weight rapidly while breastfeeding, that’s worth bringing up with your healthcare provider. Underlying issues like thyroid dysfunction or inadequate calorie absorption could be at play, and those have straightforward solutions once identified.